The mineralogical characterization of tellurium in copper anodes

Science.gov (United States)

Chen, T. T.; Dutrizac, J. E.

1993-12-01

A mineralogical study of a «normal» commercial copper anode and six tellurium-rich copper anodes from the CCR Refinery of the Noranda Copper Smelting and Refining Company was carried out to identify the tellurium carriers and their relative abundances. In all the anodes, the major tellurium carrier is the Cu2Se-Cu2Te phase which occurs as a constituent of complex inclusions at the copper grain boundaries. In tellurium-rich anodes, the molar tellurium content of the Cu2Se-Cu2Te phase can exceed that of selenium. Although >85 pct of the tellurium occurs as the Cu2Se-Cu2Te phase, minor amounts are present in Cu-Pb-As-Bi-Sb oxide, Cu-Bi-As oxide, and Cu-Te-As oxide phases which form part of the grain-boundary inclusions. About 1 pct of the tellurium content of silver-rich anodes occurs in various silver alloys, but gold tellurides were never detected. Surprising is the fact that 2 to 8 pct of the total tellurium content of the anodes occurs in solid solution in the copper-metal matrix, and presumably, this form of tellurium dissolves at the anode interface during electrorefining.

Tellurium in active volcanic environments: Preliminary results

Science.gov (United States)

Milazzo, Silvia; Calabrese, Sergio; D'Alessandro, Walter; Brusca, Lorenzo; Bellomo, Sergio; Parello, Francesco

2014-05-01

Tellurium is a toxic metalloid and, according to the Goldschmidt classification, a chalcophile element. In the last years its commercial importance has considerably increased because of its wide use in solar cells, thermoelectric and electronic devices of the last generation. Despite such large use, scientific knowledge about volcanogenic tellurium is very poor. Few previous authors report result of tellurium concentrations in volcanic plume, among with other trace metals. They recognize this element as volatile, concluding that volcanic gases and sulfur deposits are usually enriched with tellurium. Here, we present some results on tellurium concentrations in volcanic emissions (plume, fumaroles, ash leachates) and in environmental matrices (soils and plants) affected by volcanic emissions and/or deposition. Samples were collected at Etna and Vulcano (Italy), Turrialba (Costa Rica), Miyakejima, Aso, Asama (Japan), Mutnovsky (Kamchatka) at the crater rims by using common filtration techniques for aerosols (polytetrafluoroethylene filters). Filters were both eluted with Millipore water and acid microwave digested, and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Volcanic ashes emitted during explosive events on Etna and Copahue (Argentina) were analyzed for tellurium bulk composition and after leaching experiments to evaluate the soluble fraction of tellurium. Soils and leaves of vegetation were also sampled close to active volcanic vents (Etna, Vulcano, Nisyros, Nyiragongo, Turrialba, Gorely and Masaya) and investigated for tellurium contents. Preliminary results showed very high enrichments of tellurium in volcanic emissions comparing with other volatile elements like mercury, arsenic, thallium and bismuth. This suggests a primary transport in the volatile phase, probably in gaseous form (as also suggested by recent studies) and/or as soluble salts (halides and/or sulfates) adsorbed on the surface of particulate particles and ashes. First

Tellurium: providing a bright future for solar energy

Science.gov (United States)

Goldfarb, Richard J.

2015-01-01

Tellurium is one of the least common elements on Earth. Most rocks contain an average of about 3 parts per billion tellurium, making it rarer than the rare earth elements and eight times less abundant than gold. Grains of native tellurium appear in rocks as a brittle, silvery-white material, but tellurium more commonly occurs in telluride minerals that include varied quantities of gold, silver, or platinum. Tellurium is a metalloid, meaning it possesses the properties of both metals and nonmetals.

Synthesis and structure of aromatic and heterocyclic compounds of tellurium

International Nuclear Information System (INIS)

Sadekov, I.D.; Maksimenko, A.A.; Rivkin, B.B.

1983-01-01

A new universal method of preparing assymmetric and symmetric diaryl-tellurium chlorides and-dibromides, based on the interaction of diarylditellurides with cations of aryl-diazonium in the presence of copper (2) halogenides is developed. High yields of diaryltellium dihalogenices (60-90 de %), the possibility of the a wide variation of the nature of substituents in both components make this reaction one of the most general methods of preparing assymmetric diaryltellurium dihalogenides. It is advisable to use aryldiazonium boron fluorides instead of halogenides in this reaction

Extractive separation of tellurium(4)

International Nuclear Information System (INIS)

Gawali, S.B.; Shinde, V.M.

1977-01-01

A method is described for the extraction of tellurium (4) from hydrobromic acid media using 4-methyl-2-pentanol as an extractant. The method affords the determination of tellurium after its separation from Se, Au, Cu, Pb, Fe, Os, V and Al. (author)

A new tellurium-containing amphiphilic molecule induces apoptosis in HCT116 colon cancer cells.

Science.gov (United States)

Du, Peng; Saidu, Nathaniel Edward Bennett; Intemann, Johanna; Jacob, Claus; Montenarh, Mathias

2014-06-01

Chalcogen-based redox modulators over the years have attracted considerable attention as anti-cancer agents. New selenium- and tellurium-containing compounds with a polar head group and aryl-groups of various lengths have recently been reported as biologically active in several organisms. In the present study, we used the most active of the tellurium compound DP41, and its selenium counterpart DP31 to investigate their effects on the human cancer cell line HCT116. Cells were treated with DP41 or DP31 and the formation of superoxide radicals was determined using dihydroethidium. Cell cycle analysis and apoptosis was determined by cytofluorimetry. Proteins involved in ER signaling and apoptosis were determined by Western blot analysis and fluorescence microscopy. With 50μM of DP41, we observed an increase in O2(-) formation. There was, however, no such increase in O2(-) after treatment with the corresponding selenium compound under the same conditions. In the case of DP41, the production of O2(-) radicals was followed by an up-regulation of Nrf2, HO-1, phospho-eIF2α and ATF4. CHOP was also induced and cells entered apoptosis. Unlike the cancer cells, normal retinal epithelial ARPE-19 cells did not produce elevated levels of O2(-) radicals nor did they induce the ER signaling pathway or apoptosis. The tellurium-containing compound DP41, in contrast to the corresponding selenium compound, induces O2(-) radical formation and oxidative and ER stress responses, including CHOP activation and finally apoptosis. These results indicate that DP41 is a redox modulating agent with promising anti-cancer potentials. Copyright © 2014 Elsevier B.V. All rights reserved.

Tellurium self-diffusion and point defects in lead telluride

International Nuclear Information System (INIS)

Simirskij, Yu.N.; Firsova, L.P.

1982-01-01

Method of radioactive indicators was used to determine factors of tellurium self-diffusion in lead telluride with different deviation of the composition from stoichiometric in the range of enrichment by tellurium. It was found that at 973 K factors of tellurium self-diffusion in lead telluride depend slightly on the vapor pressure of tellurium equilibrium with solid phase

Tellurium release and deposition during the TMI-2 accident

International Nuclear Information System (INIS)

Vinjamuri, K.; Osetek, D.J.; Hobbins, R.R.; Jessup, J.S.

1984-09-01

The estimated behavior of tellurium during and after the accident at the Three Mile Island Unit-2 is presented. The behavior is based on all available measurement data for /sup 129m/Te, 132 Te, stable tellurium ( 126 Te, 128 Te and 130 Te), and best estimate calculations of tellurium release and transport. The predicted release was calculated using current techniques that relate release rate to fuel temperature and holdup of tellurium in zircaloy until significant oxidation occurs. The calculated release fraction was low, approx. 7%, but the total measured release for samples analyzed to date is about 5.8%. Of the measured tellurium about 2.4, 1.8, 0.88, 0.42, 0.17 and 0.086% of core inventory were in the containment sump water, upper plenum assembly surfaces, containment solids in the sump water, makeup and purification demineralizer, containment inside surface, and the reactor primary coolant, respectively. A significant fraction (54%) of the tellurium calculated to be retained on the upper plenum surfaces (4.61% of the core inventory) was deposited during the high pressure injection of coolant at about 200 min after the reactor scram. Comparison of tellurium behavior with in-pile and out-of-pile tests strongly suggests that zircaloy holds tellurium until significant cladding oxidation occurs

Tellurium behavior during and after the TMI-2 accident

International Nuclear Information System (INIS)

Vinjamuri, K.; Osetek, D.J.; Hobbins, R.R.

1984-01-01

The estimated behavior of tellurium during and after the accident at the Three Mile Island Unit-2 is presented. The behavior is based on all available measurement data for /sup 129m/Te, 132 Te and stable tellurium ( 126 Te, 128 Te and 130 Te), and best estimate calculations of tellurium release and transport. The predicted release was calculated using current techniques that relate release rate to fuel temperature and holdup of tellurium in zircaloy until significant oxidation occurs. The calculated release fraction was low, approximately 7%, but the total measured release for samples analyzed to date is about 4.0%. Of the measured tellurium about 2.4, 0.88, 0.42, 0.17 and 0.086% of core inventory were in the containment sump water, containment solids in water, makeup and purification demineralizer, containment inside surface, and the reactor primary coolant, respectively. A significant fraction (54%) of the calculated tellurium retained on the upper plenum surfaces (4.61% of the core inventory) was deposited during the high pressure injection of coolant at about 200 minutes after the reactor scram. Comparison of tellurium behavior with inpile and out-of-pile tests strongly suggests that zircaloy holds tellurium until significant cladding oxidation occurs

Fission product tellurium chemistry from fuel to containment

International Nuclear Information System (INIS)

McFarlane, J.

1996-01-01

Chemical equilibrium calculations were performed on the speciation of tellurium in-core and inside the primary heat transport system (PHTS) under loss-of-coolant accident conditions. Data from recent Knudsen-cell experiments on the volatilization of Cs 2 Te were incorporated into the calculation. These data were used to recalculate thermodynamic quantities for Cs 2 Te(g), including Δ f G o (298 K)= -118±9 kJ.mol -1 . The description of the condensed high-temperature cesium-tellurium phase was expanded to include Cs 2 Te 3 (c) in addition to Cs 2 Te(c). These modifications were incorporated into the database used in the equilibrium calculations; the net effect was to stabilize the condensed cesium-tellurium phase and reduce the vapour pressure of Cs 2 Te(g) between 1200 and 1600 K. The impact of tellurium speciation in containment, after release from the PHTS, is discussed along with the possible effect of tellurium on iodine chemistry. (author) 10 figs., 5 tabs., 21 refs

Fission product tellurium chemistry from fuel to containment

Energy Technology Data Exchange (ETDEWEB)

McFarlane, J [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

1996-12-01

Chemical equilibrium calculations were performed on the speciation of tellurium in-core and inside the primary heat transport system (PHTS) under loss-of-coolant accident conditions. Data from recent Knudsen-cell experiments on the volatilization of Cs{sub 2}Te were incorporated into the calculation. These data were used to recalculate thermodynamic quantities for Cs{sub 2}Te(g), including {Delta}{sub f}G{sup o}(298 K)= -118{+-}9 kJ.mol{sup -1}. The description of the condensed high-temperature cesium-tellurium phase was expanded to include Cs{sub 2}Te{sub 3}(c) in addition to Cs{sub 2}Te(c). These modifications were incorporated into the database used in the equilibrium calculations; the net effect was to stabilize the condensed cesium-tellurium phase and reduce the vapour pressure of Cs{sub 2}Te(g) between 1200 and 1600 K. The impact of tellurium speciation in containment, after release from the PHTS, is discussed along with the possible effect of tellurium on iodine chemistry. (author) 10 figs., 5 tabs., 21 refs.

Intergranular tellurium cracking of nickel-based alloys in molten Li, Be, Th, U/F salt mixture

Science.gov (United States)

Ignatiev, Victor; Surenkov, Alexander; Gnidoy, Ivan; Kulakov, Alexander; Uglov, Vadim; Vasiliev, Alexander; Presniakov, Mikhail

2013-09-01

In Russia, R&D on Molten Salt Reactor (MSR) are concentrated now on fast/intermediate spectrum concepts which were recognized as long term alternative to solid fueled fast reactors due to their attractive features: strong negative feedback coefficients, easy in-service inspection, and simplified fuel cycle. For high-temperature MSR corrosion of the metallic container alloy in primary circuit is the primary concern. Key problem receiving current attention include surface fissures in Ni-based alloys probably arising from fission product tellurium attack. This paper summarizes results of corrosion tests conducted recently to study effect of oxidation state in selected fuel salt on tellurium attack and to develop means of controlling tellurium cracking in the special Ni-based alloys recently developed for molten salt actinide recycler and tranforming (MOSART) system. Tellurium corrosion of Ni-based alloys was tested at temperatures up to 750 °C in stressed and unloaded conditions in molten LiF-BeF2 salt mixture fueled by about 20 mol% of ThF4 and 2 mol% of UF4 at different [U(IV)]/[U(III)] ratios: 0.7, 4, 20, 100 and 500. Following Ni-based alloys (in mass%): HN80М-VI (Mo—12, Cr—7.6, Nb—1.5), HN80МТY (Mo—13, Cr—6.8, Al—1.1, Ti—0.9), HN80МТW (Mo—9.4, Cr—7.0, Ti—1.7, W—5.5) and ЕМ-721 (W—25.2, Cr—5.7, Ti—0.17) were used for the study in the corrosion facility. If the redox state the fuel salt is characterized by uranium ratio [U(IV)]/[U(III)] uranium intermetallic compounds and alloys with nickel and molybdenum. This leads to spontaneous behavior of alloy formation processes on the specimens' surface and further diffusion of uranium deep into the metallic phase. As consequence of this films of intermetallic compounds and alloys of nickel, molybdenum, tungsten with uranium are formed on the alloys specimens' surface, and intergranular corrosion does not take place. In the fuel salt with [U(IV)]/[U(III)] = 4-20 the potentials of uranium

Quantitative analysis of tellurium in simple substance sulfur

International Nuclear Information System (INIS)

Arikawa, Yoshiko

1976-01-01

The MIBK extraction-bismuthiol-2 absorptiometric method for the quantitative analysis of tellurium was studied. The method and its limitation were compared with the atomic absorption method. The period of time required to boil the solution in order to decompose excess hydrogen peroxide and to reduce tellurium from 6 valance to 4 valance was examined. As a result of experiment, the decomposition was fast in the alkaline solution. It takes 30 minutes with alkaline solution and 40 minutes with acid solution to indicate constant absorption. A method of analyzing the sample containing tellurium less than 5 ppm was studied. The experiment revealed that the sample containing a very small amount of tellurium can be analyzed when concentration by extraction is carried out for the sample solutions which are divided into one gram each because it is difficult to treat several grams of the sample at one time. This method also is suitable for the quantitative analysis of selenium. This method showed good addition effect and reproducibility within the relative error of 5%. The comparison between the calibration curve of the standard solution of tellurium 4 subjected to the reaction with bismuthiol-2 and the calibration curve obtained from the extraction of tellurium 4 with MIBK indicated that the extraction is perfect. The result by bismuthiol-2 method and that by atom absorption method coincided quite well on the same sample. (Iwakiri, K.)

Facile electrochemical synthesis of tellurium nanorods and their photoconductive properties

Energy Technology Data Exchange (ETDEWEB)

Li, H.H. [Center for Photon Manufacturing Science and Technology, School of Materials Science and Engineering, Jiangsu University, Zhenjiang - 212013 (China); Zhang, P. [Dongguan University of Technology, Dongguan-523808 (China); School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou - 510275 (China); Liang, C.L. [Instrumental Analysis and Research Center, SunYat-sen University, Guangzhou - 510275 (China); Yang, J. [School of Materials Science and Engineering, Jiangsu University, Zhenjiang - 212013 (China); Zhou, M. [Center for Photon Manufacturing Science and Technology, School of Materials Science and Engineering, Jiangsu University, Zhenjiang - 212013 (China); The State Key Laboratory of Tribology, Tsinghua University, Beijing - 10084 (China); Lu, X.H. [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou - 510275 (China); Hope, G.A. [School of Biomolecular and Physical Sciences, Griffith University, Nathan - Qld 4111 (Australia)

2012-10-15

Tellurium nanorods have been successfully fabricated by template and surfactant-free electrochemical technique from an aqueous solution at room temperature. The as-prepared tellurium nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectrometry, UV-vis spectroscopy and photoluminescence spectroscopy. Films based on tellurium nanorods were constructed to study the photoresponse and I-V curves. These photoresponse measurements demonstrate that tellurium nanorods exhibited enhanced conductivity under illumination compared to in the dark measurement. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Analysis of tellurium thin films electrodeposition from acidic citric bath

Energy Technology Data Exchange (ETDEWEB)

Kowalik, Remigiusz; Kutyła, Dawid [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, al. A. Mickiewicza 30, 30-059 Krakow (Poland); Mech, Krzysztof [AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, al. A. Mickiewicza 30, Krakow (Poland); Żabiński, Piotr, E-mail: rkowalik@agh.edu.pl [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, al. A. Mickiewicza 30, 30-059 Krakow (Poland)

2016-12-01

This work presents the description of the electrochemical process of formation thin tellurium layers from citrate acidic solution. The suggested methodology consists in the preparation of stable acidic baths with high content of tellurium, and with the addition of citrate acid. In order to analyse the mechanism of the process of tellurium deposition, the electroanalytical tests were conducted. The tests of cyclic voltammetry and hydrodynamic ones were performed with the use of polycrystalline gold disk electrode. The range of potentials in which deposition of tellurium in direct four-electron process is possible was determined as well as the reduction of deposited Te° to Te{sup 2−} and its re-deposition as a result of the comproportionation reaction. On the basis of the obtained results, the deposition of tellurium was conducted by the potentiostatic method. The influence of a deposition potential and a concentration of TeO{sub 2} in the solution on the rate of tellurium coatings deposition was examined. The presence of tellurium was confirmed by X-ray spectrofluorometry and electron probe microanalysis. In order to determine the phase composition and the morphology, the obtained coatings were analysed with the use of x-ray diffraction and scanning electron microscopy.

Properties of low-alloy steel with tellurium

International Nuclear Information System (INIS)

Popova, L.V.; Lebedev, D.V.; Litvinenko, D.A.; Nasibov, A.G.

1983-01-01

The results of investigations into 09G2 and 09G2F steels alloyed with tellurium after controlled rolling are presented. 0.002-0.011% tellurium additions did not change strength and plastic properties of the steels after controlled rolling. Tellurium additions results in 40-50% increase of the steel impact strength on samples With circular and sharp cuts in brittle-viscous region. 0.002-0.003% of tellurium is considered to be the optimum content from the view point of increa=. sing steel strength. Increase of impact strength takes place at the expense of growth of both work function of crack formation and work function of crack propagation but in different temperature ranges: at the expense of firstone at 80-40 deg C, at the expense of second one at 20-40 deg C. 0.002-0.011% teilurium additions mainly at the expense of sulphide globularization bring about decrease of anisotropy of steet properties by impact strength reducing anisotropy factor from 2 to 1.5

Analysis of tellurium-silicon alloys. Part 1. Determination of tellurium by the reduction from perchloric acid solution

International Nuclear Information System (INIS)

Teperek, J.

1977-01-01

When 100-150 mg of tellurium is dissolved in the solution containing 20 cm 3 72 wt.% of perchloric acid, the reduction of tellurium to elementary form is possible only after adding 60-100 milimoles of HCl. The reduction is performed by adding 1 cm 3 of saturated sodium pyrosulphite solution (Na 2 S 2 O 5 ) and 10 cm 3 of 10 wt.% hydrazine hydrochloride solution (N 2 H 4 .2HCl) to 80-90 cm 3 of cold solution of Te in HClO 4 -HCl mixture. The reduction is completed after 3-5 min. of boiling. When 150-200 mg sample of Te-Si alloy is dissolved in 20 cm 3 of hot 72% per chloric acid, the separation of components is reached. Tellurium can be determinated in filtrate by proposed procedure with high accuracy and precision. (author)

Polarographic determination of selenium and tellurium in silver-gold alloys

International Nuclear Information System (INIS)

Gornostaeva, T.D.; Shmargun, S.V.

1986-01-01

The determination of selenium and tellurium is of importance in monitoring the composition of silver-gold alloys (SGA) since these elements are harmful impurities in the pure metals. Tellurium is determined in silver alloys by atomic absorption and atomic emmission methods; selenium determination is made by atomic absorption methods. This paper examines the polarographic determination of silver and tellurium in SGA containing platinum metals and copper. Copper and the bulk of the platinum and palladium were removed by precipitating selenium and tellurium with potassium hypophosphite in the elementary state from 6 M HC1. The results of an analysis of samples of SGA according to the proposed method were compared with the results obtained by the atomic absorption method. the relative deviation in the determination of 0.02-1.0% by weight selenium and tellurium does not exceed 0.12 (n = 5)

Modelling the chemical behaviour of tellurium species in the reactor pressure vessel and the reactor cooling system under severe accident conditions

International Nuclear Information System (INIS)

Alonso, A.; Gonzalez, C.

1991-07-01

This state of the art report contains information on the behaviour of tellurium and its compounds in the reactor pressure vessel and the reactor coolant system under light water reactor severe accident conditions. To characterise tellurium behaviour, it is necessary the previous knowledge of the species of tellurium released from the core, and simultaneity of its release with that of other materials which can alter the transport, for instance, control rod and structural materials. Release and transport experiments have been reviewed along with the models implemented in the codes which are used in the international community: TRAPMELT, RAFT, VICTORIA and SOPHIE. From the experiments, it can be concluded that other species different to Te 2 , such as tin telluride and cesium telluride, may be released from the fuel. That is why they must be considered in the transport phenomena. There is also experimental evidence of the strong interaction of Te 2 with Inconel 600 and stainless steel of the pipe walls and structures, however this strong interaction is in competition with the interaction of tellurium with aerosols, which under severe accident conditions may represent an area greater than that of the primary system. It is for the absence of significant tellurium species in the transport models, and also for the interaction of tellurium with aerosols, for which some codes show the greatest deficiencies

Biosynthesis and recovery of rod-shaped tellurium nanoparticles and their bactericidal activities

Energy Technology Data Exchange (ETDEWEB)

Zare, Bijan; Faramarzi, Mohammad Ali; Sepehrizadeh, Zargham [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451 Tehran (Iran, Islamic Republic of); Shakibaie, Mojtaba [Department of Pharmacognosy and Biotechnology, School of Pharmacy, Pharmaceutics Research Center, Kerman University of Medical Sciences, P.O. Box 76175-493 Kerman (Iran, Islamic Republic of); Rezaie, Sassan [Department of Medical Biotechnology, School of Advanced Medical Technologies, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza, E-mail: shahverd@sina.tums.ac.ir [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451 Tehran (Iran, Islamic Republic of)

2012-11-15

Highlights: ► Biosynthesis of rod shape tellurium nanoparticles with a hexagonal crystal structure. ► Extraction procedure for isolation of tellurium nanoparticles from Bacillus sp. BZ. ► Extracted tellurium nanoparticles have good bactericidal activity against some bacteria. -- Abstract: In this study, a tellurium-transforming Bacillus sp. BZ was isolated from the Caspian Sea in northern Iran. The isolate was identified by various tests and 16S rDNA analysis, and then used to prepare elemental tellurium nanoparticles. The isolate was subsequently used for the intracellular biosynthesis of elemental tellurium nanoparticles. The biogenic nanoparticles were released by liquid nitrogen and purified by an n-octyl alcohol water extraction system. The shape, size, and composition of the extracted nanoparticles were characterized. The transmission electron micrograph showed rod-shaped nanoparticles with dimensions of about 20 nm × 180 nm. The energy dispersive X-ray and X-ray diffraction spectra respectively demonstrated that the extracted nanoparticles consisted of only tellurium and have a hexagonal crystal structure. This is the first study to demonstrate a biological method for synthesizing rod-shaped elemental tellurium by a Bacillus sp., its extraction and its antibacterial activity against different clinical isolates.

Biosynthesis and recovery of rod-shaped tellurium nanoparticles and their bactericidal activities

International Nuclear Information System (INIS)

Zare, Bijan; Faramarzi, Mohammad Ali; Sepehrizadeh, Zargham; Shakibaie, Mojtaba; Rezaie, Sassan; Shahverdi, Ahmad Reza

2012-01-01

Highlights: ► Biosynthesis of rod shape tellurium nanoparticles with a hexagonal crystal structure. ► Extraction procedure for isolation of tellurium nanoparticles from Bacillus sp. BZ. ► Extracted tellurium nanoparticles have good bactericidal activity against some bacteria. -- Abstract: In this study, a tellurium-transforming Bacillus sp. BZ was isolated from the Caspian Sea in northern Iran. The isolate was identified by various tests and 16S rDNA analysis, and then used to prepare elemental tellurium nanoparticles. The isolate was subsequently used for the intracellular biosynthesis of elemental tellurium nanoparticles. The biogenic nanoparticles were released by liquid nitrogen and purified by an n-octyl alcohol water extraction system. The shape, size, and composition of the extracted nanoparticles were characterized. The transmission electron micrograph showed rod-shaped nanoparticles with dimensions of about 20 nm × 180 nm. The energy dispersive X-ray and X-ray diffraction spectra respectively demonstrated that the extracted nanoparticles consisted of only tellurium and have a hexagonal crystal structure. This is the first study to demonstrate a biological method for synthesizing rod-shaped elemental tellurium by a Bacillus sp., its extraction and its antibacterial activity against different clinical isolates.

Structure and activity of tellurium-cerium oxide acrylonitrile catalysts

International Nuclear Information System (INIS)

Bart, J.C.J.; Giordano, N.

1982-01-01

Ammoxidation of propylene to acrylonitrile (ACN) was investigated over various silica-supported (Te,Ce)O catalysts at 360 and 440 0 C. The binary oxide system used consists of a single nonstoichiometric fluorite-type phase α-(Ce,Te)O 2 up to about 80 mole% TeO 2 and a tellurium-saturated solid solution β-(Ce,Te)O 2 at higher tellurium concentrations. The ACN yield varies almost linearly with the tellurium content of (Ce,Te)O 2 . The β-(Ce,Te)O 2 phase is the most active component of the system (propylene conversion and ACN selectivity at 440 C of 76.7 and 74%, respectively) and is slightly more selective to ACN than α-Te0 2 . Tellurium reduces the overoxidation properties of cerium and selective oxidation occurs through Te(IV)-bonded oxygen

A recycling model of the biokinetics of systemic tellurium.

Science.gov (United States)

Giussani, Augusto

2014-11-01

To develop a compartmental model of the systemic biokinetics of tellurium required for calculating the internal dose and interpreting bioassay measurements after incorporation of radioactive tellurium. The compartmental model for tellurium was developed with the software SAAM II v. 2.0 (©The Epsilon Group, Charlottesville, Virginia, USA). Model parameters were determined on the basis of published retention and excretion data in humans and animals. The model consists of two blood compartments, one compartment each for liver, kidneys, thyroid, four compartments for bone tissues and a generic compartment for the soft tissues. The model predicts a rapid urinary excretion of systemic tellurium: 45% in the first 24 h and 84% after 50 d. Faecal excretion amounts to 0.4% after 3 d and 9% after 50 d. Whole body retention is 55% after one day, and 2.8% after 100 d. These values as well as the retained fractions in the single organs are reasonably consistent with the available human and animal data (studies with swine and guinea pigs). The proposed model gives a realistic description of the available biokinetic data for tellurium and will be adopted by the International Commission on Radiological Protection for applications in internal dosimetry.

Atomic absorption determination of ultratrace tellurium in rocks utilizing high sensitivity sampling systems

International Nuclear Information System (INIS)

Beaty, R.D.

1973-01-01

The sampling boat and the graphite furnace were shown to possess the required sensitivity to detect tellurium at ultratrace levels, in a variety of sample types, by atomic absorption. In the sampling boat approach, tellurium in sample solutions is chemically separated and concentrated by extraction into methyl isobutyl ketone before measurement. For samples exhibiting extraction interferences or excessively high background absorption, a preliminary separation of tellurium by coprecipitation with selenium is described. Using this technique, tellurium can be quantitatively detected down to 5 nanograms and linear response is observed to 100 nanograms. Relative standard deviations of better than 7 percent are achieved for 50 nanograms of tellurium. For samples that have a tellurium content below the detection limits of the sampling boat, the graphite furnace is used for atomization. By this method, as little as 0.07 nanograms of tellurium can be detected, and a precision of 1 percent relative standard deviation is achievable at the 5 nanogram level. A routinely applicable procedure was developed for determining tellurium in rocks, using the graphite furnace, after a hydrofluoric acid decomposition of the sample. Using this procedure, tellurium data were obtained on 20 different rocks, and the significance of this new information is discussed. (Diss. Abstr. Int., B)

METHODS OF SYNTHESIS EIGHT-TELLURIUM-CONTAINING HETEROCYCLES WITH MORE HETEROATOMS

Directory of Open Access Journals (Sweden)

G. M. Abakarov

2013-01-01

Full Text Available In this article systematized and summarized data on the synthesis of neweight-embered tellurium-containing heterocycles and new preparative methods described above produce heterocyclic tellurium.

Inclusion free cadmium zinc tellurium and cadmium tellurium crystals and associated growth method

Science.gov (United States)

Bolotnikov, Aleskey E [South Setauket, NY; James, Ralph B [Ridge, NY

2010-07-20

The present disclosure provides systems and methods for crystal growth of cadmium zinc tellurium (CZT) and cadmium tellurium (CdTe) crystals with an inverted growth reactor chamber. The inverted growth reactor chamber enables growth of single, large, high purity CZT and CdTe crystals that can be used, for example, in X-ray and gamma detection, substrates for infrared detectors, or the like. The inverted growth reactor chamber enables reductions in the presence of Te inclusions, which are recognized as an important limiting factor in using CZT or CdTe as radiation detectors. The inverted growth reactor chamber can be utilized with existing crystal growth techniques such as the Bridgman crystal growth mechanism and the like. In an exemplary embodiment, the inverted growth reactor chamber is a U-shaped ampoule.

Rapid radiochemical ion-exchange separation of iodine from tellurium: a novel radioiodine-132 generator

Energy Technology Data Exchange (ETDEWEB)

Abrao, A

1975-01-01

Tellurium ions form a soluble cationic complex with thiourea in acid medium. The cationic tellurium-thiourea species is strongly absorbed on a cationic ion exchanger. The retention of tellurium on the resin enables many interesting separation schemes for tellurium from various ions. With special interest, the separation of iodine from tellurium was studied. An efficient and convenient iodine-132 generator is described, in which the radio-iodine is eluted with water or 9 g/1 NaCl, when desired.

Electrophilic addition of selenium and tellurium halides to methyldiethynylsilane

International Nuclear Information System (INIS)

Amosova, S.V.; Penzik, M.V.; Martynov, A.V.; Zhilitskaya, L.V.; Voronkov, M.G.

2009-01-01

Reaction of TeCl 4 with methyldiethynylsilane (MDES) proceeds with the predominant formation of E-isomer 1,1,3,6-tetrachlorine-1-methyl-1-(methyldiethynylsiloxy)-1,4-tellurium(IV) silafulvic due to the interaction of intermediate E-isomer 4-methyl-1,1,3,6-tetrachlorine-1,4-tellurium(IV)silafulvic with MDES. TeCl 4 Reacts with MDES without reduction of Te(IV) in Te(II). Tetracoordination of tellurium atom in heterocycle was established by NMR 125 Te. Mass spectrum of heterocycle shows the presence of fragmentary ions [M-Cl 2 ] + . According elemental analysis Te:Cl=1:4 ratio proves composition of heterocycle

Purification and in vitro antioxidant activities of tellurium-containing phycobiliproteins from tellurium-enriched Spirulina platensis

Directory of Open Access Journals (Sweden)

Yang F

2014-10-01

Full Text Available Fang Yang,1 Ka-Hing Wong,2 Yufeng Yang,3 Xiaoling Li,1 Jie Jiang,1 Wenjie Zheng,1 Hualian Wu,1 Tianfeng Chen1 1Department of Chemistry, Jinan University, Guangzhou, People’s Republic of China; 2Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, People’s Republic of China; 3Institute of Hydrobiology, College of Life Science and Technology, Jinan University, Guangzhou, People’s Republic of China Abstract: Tellurium-containing phycocyanin (Te-PC and allophycocyanin (Te-APC, two organic tellurium (Te species, were purified from tellurium-enriched Spirulina platensis by a fast protein liquid chromatographic method. It was found that the incorporation of Te into the peptides enhanced the antioxidant activities of both phycobiliproteins. With fractionation by ammonium sulfate precipitation and hydroxylapatite chromatography, Te-PC and Te-APC could be effectively separated with high purity, and Te concentrations were 611.1 and 625.3 µg g-1 protein in Te-PC and Te-APC, respectively. The subunits in the proteins were identified by using MALDI-TOF-TOF mass spectrometry. Te incorporation enhanced the antioxidant activities of both phycobiliproteins, as examined by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid assay. Moreover, Te-PC and Te-APC showed dose-dependent protection on erythrocytes against the water-soluble free radical initiator 2,2'-azo(2-asmidinopropanedihydrochloride-induced hemolysis. In the hepatoprotective model, apoptotic cell death and nuclear condensation induced by tert-butyl hydroperoxide in HepG2 cells was significantly attenuated by Te-PC and Te-APC. Taken together, these results suggest that Te-PC and Te-APC are promising Te-containing proteins with application potential for treatment of diseases related to oxidative stress. Keywords: tellurium, phycocyanin, allophycocyanin, purification, antioxidant activity

Synthesis of Novel E-2-Chlorovinyltellurium Compounds Based on the Stereospecific Anti-addition of Tellurium Tetrachloride to Acetylene

Directory of Open Access Journals (Sweden)

Svetlana V. Amosova

2012-05-01

Full Text Available The reaction of tellurium tetrachloride with acetylene proceeds in a stereospecific anti-addition manner to afford the novel products E-2-chlorovinyltellurium trichloride and E,E-bis(2-chlorovinyltellurium dichloride. Reaction conditions for the selective preparation of each of these products were found. The latter was obtained in 90% yield in CHCl₃ under a pressure of acetylene of 10–15 atm, whereas the former product was formed in up to 72% yield in CCl₄ under a pressure of acetylene of 1–3 atm. Synthesis of the previously unknown E,E-bis(2-chlorovinyl telluride, E,E-bis(2-chlorovinyl ditelluride, E-2-chlorovinyl 1,2,2-trichloroethyl telluride and E,E-bis(2-chlorovinyl-tellurium dibromide is described.

Purification and in vitro antioxidant activities of tellurium-containing phycobiliproteins from tellurium-enriched Spirulina platensis.

Science.gov (United States)

Yang, Fang; Wong, Ka-Hing; Yang, Yufeng; Li, Xiaoling; Jiang, Jie; Zheng, Wenjie; Wu, Hualian; Chen, Tianfeng

2014-01-01

Tellurium-containing phycocyanin (Te-PC) and allophycocyanin (Te-APC), two organic tellurium (Te) species, were purified from tellurium-enriched Spirulina platensis by a fast protein liquid chromatographic method. It was found that the incorporation of Te into the peptides enhanced the antioxidant activities of both phycobiliproteins. With fractionation by ammonium sulfate precipitation and hydroxylapatite chromatography, Te-PC and Te-APC could be effectively separated with high purity, and Te concentrations were 611.1 and 625.3 μg g(-1) protein in Te-PC and Te-APC, respectively. The subunits in the proteins were identified by using MALDI-TOF-TOF mass spectrometry. Te incorporation enhanced the antioxidant activities of both phycobiliproteins, as examined by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid assay. Moreover, Te-PC and Te-APC showed dose-dependent protection on erythrocytes against the water-soluble free radical initiator 2,2'-azo(2-asmidinopropane)dihydrochloride-induced hemolysis. In the hepatoprotective model, apoptotic cell death and nuclear condensation induced by tert-butyl hydroperoxide in HepG2 cells was significantly attenuated by Te-PC and Te-APC. Taken together, these results suggest that Te-PC and Te-APC are promising Te-containing proteins with application potential for treatment of diseases related to oxidative stress.

Flame and flameless atomic-absorption determination of tellurium in geological materials

Science.gov (United States)

Chao, T.T.; Sanzolone, R.F.; Hubert, A.E.

1978-01-01

The sample is digested with a solution of hydrobromic acid and bromine and the excess of bromine is expelled. After dilution of the solution to approximately 3 M in hydrobromic acid, ascorbic acid is added to reduce iron(III) before extraction of tellurium into methyl isobutyl ketone (MIBK). An oxidizing air-acetylene flame is used to determine tellurium in the 0.1-20 ppm range. For samples containing 4-200 ppb of tellurium, a carbon-rod atomizer is used after the MIBK extract has been washed with 0.5 M hydrobromic acid to remove the residual iron. The flame procedure is useful for rapid preliminary monitoring, and the flameless procedure can determine tellurium at very low concentrations. ?? 1978.

A rapid radiochemical ion-exchange separation of iodine from tellurium: a novel radioiodine-132 generator

International Nuclear Information System (INIS)

Abrao, A.

1975-01-01

Tellurium ions form a soluble cationic complex with thiourea in acid medium. The cationic tellurium-thiourea species is strongly absorbed on a cationic ion exchanger. The retention of tellurium on the resin enables many interesting separation schemes for tellurium from various ions. With special interest, the separation of iodine from tellurium was studied. An efficient and convenient iodine-132 generator is described, in which the radio-iodine is eluted with water or 9 g/1 NaCL, when desired

Study of distribution coefficients of admixtures in tellurium

International Nuclear Information System (INIS)

Kuchar, L.; Drapala, J.; Kuchar, L. jr.

1986-01-01

Limit areas of tellurium-admixture binary systems were studied and the values determined of steady-state distribution coefficients of admixtures. A second order polynomial was used to express equations of solidus and liquidus curves for Te-Se, Te-S, Te-Hg systems; the curves are graphically represented. The most effective method for preparing high-purity tellurium is zonal melting with material removal. (M.D.). 4 figs., 4 tabs., 16 refs

Effects of tellurium concentration on the structure of melt-grown ZnSe crystals

International Nuclear Information System (INIS)

Atroshchenko, Lyubov V.; Galkin, Sergey N.; Rybalka, Irina A.; Voronkin, Evgeniy F.; Lalayants, Alexandr I.; Ryzhikov, Vladimir D.; Fedorov, Alexandr G.

2005-01-01

It has been shown that isovalent doping by tellurium positively affects the structural perfection of ZnSe crystals related to the completeness of the wurtzite-sphalerite phase transition. The optimum concentration range of tellurium in ZnSe crystals is 0.3-0.6 mass %. X-ray diffraction studies have shown that in ZnSe 1-x Te x crystals at tellurium concentrations below 0.3 mass % twinning and packing defects occur, while tellurium concentrations above 0.6 mass % lead to formation of tetragonal crystal lattice

Thermal neutron capture cross sections of tellurium isotopes

International Nuclear Information System (INIS)

Tomandl, I.; Honzatko, J.; Egidy, T. von; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.

2003-01-01

New values for thermal neutron capture cross sections of the tellurium isotopes 122 Te, 124 Te, 125 Te, 126 Te, 128 Te, and 130 Te are reported. These values are based on a combination of newly determined partial γ-ray cross sections obtained from experiments on targets contained natural Te and γ intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given

Thermal neutron capture cross sections of tellurium isotopes

International Nuclear Information System (INIS)

Tomandl, I.; Honzatko, J.; Egidy, T. von; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.

2004-01-01

New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given

Thermal neutron capture cross sections of tellurium isotopes

Energy Technology Data Exchange (ETDEWEB)

Tomandl, I.; Honzatko, J.; von Egidy, T.; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.

2004-03-01

New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given.

Van der Waals epitaxy and photoresponse of hexagonal tellurium nanoplates on flexible mica sheets.

Science.gov (United States)

Wang, Qisheng; Safdar, Muhammad; Xu, Kai; Mirza, Misbah; Wang, Zhenxing; He, Jun

2014-07-22

Van der Waals epitaxy (vdWE) is of great interest due to its extensive applications in the synthesis of ultrathin two-dimensional (2D) layered materials. However, vdWE of nonlayered functional materials is still not very well documented. Here, although tellurium has a strong tendency to grow into one-dimensional nanoarchitecture due to its chain-like structure, we successfully realize 2D hexagonal tellurium nanoplates on flexible mica sheets via vdWE. Chemically inert mica surface is found to be crucial for the lateral growth of hexagonal tellurium nanoplates since it (1) facilitates the migration of tellurium adatoms along mica surface and (2) allows a large lattice mismatch. Furthermore, 2D tellurium hexagonal nanoplates-based photodetectors are in situ fabricated on flexible mica sheets. Efficient photoresponse is obtained even after bending the device for 100 times, indicating 2D tellurium hexagonal nanoplates-based photodetectors on mica sheets have a great application potential in flexible and wearable optoelectronic devices. We believe the fundamental understanding of vdWE effect on the growth of 2D tellurium hexagonal nanoplate can pave the way toward leveraging vdWE as a useful channel to realize the 2D geometry of other nonlayered materials.

Investigation of γ-irradiation influence on the DLTS spectra in silicon diluted by tellurium

International Nuclear Information System (INIS)

Sultanov, N.A.; Tadzhibaev, M.; Mirzabadalov, Zh

1997-01-01

The influence of gamma-radiation on deep level transient spectroscopy(DLTS) spectra for silicon crystals doped with tellurium was studied. The DLTS spectra have shown that tellurium in silicon formed two deep levels with fixed ionization energy. It was shown that the presence of tellurium prevents the formation of radiation defects

Selenium and tellurium nanomaterials

Science.gov (United States)

Piacenza, Elena; Presentato, Alessandro; Zonaro, Emanuele; Lampis, Silvia; Vallini, Giovanni; Turner, Raymond J.

2018-04-01

Over the last 40 years, the rapid and exponential growth of nanotechnology led to the development of various synthesis methodologies to generate nanomaterials different in size, shape and composition to be applied in various fields. In particular, nanostructures composed of Selenium (Se) or Tellurium (Te) have attracted increasing interest, due to their intermediate nature between metallic and non-metallic elements, being defined as metalloids. Indeed, this key shared feature of Se and Te allows us the use of their compounds in a variety of applications fields, such as for manufacturing photocells, photographic exposure meters, piezoelectric devices, and thermoelectric materials, to name a few. Considering also that the chemical-physical properties of elements result to be much more emphasized when they are assembled at the nanoscale range, huge efforts have been made to develop highly effective synthesis methods to generate Se- or Te-nanomaterials. In this context, the present book chapter will explore the most used chemical and/or physical methods exploited to generate different morphologies of metalloid-nanostructures, focusing also the attention on the major advantages, drawbacks as well as the safety related to these synthetic procedures.

Status of tellurium--hastelloy N studies in molten fluoride salts

International Nuclear Information System (INIS)

Keiser, J.R.

1977-10-01

Tellurium, which is a fission product in nuclear reactor fuels, can embrittle the surface grain boundaries of nickel-base structural materials. This report summarizes results of an experimental investigation conducted to understand the mechanism and to develop a means of controlling this embrittlement in the alloy Hastelloy N. The addition of a chromium telluride to salt can be used to provide small partial pressures of tellurium simulating a reactor environment where tellurium appears as a fission product. The intergranular embrittlement produced in Hastelloy N when exposed to this chromium telluride-salt mixture can be reduced by adding niobium to the Hastelloy N or by controlling the oxidation potential of the salt in the reducing range

Comparison between selenium and tellurium clusters

International Nuclear Information System (INIS)

Benamar, A.; Rayane, D.; Tribollet, B.; Broyer, M.; Melinon, P.

1991-01-01

Selenium and tellurium clusters are produced by the inert gas condensation technique. The mass spectra of both species are completely different and reveal different properties. In selenium, a periodicity of 6-7 is observed and may be interpreted by the binding energy between small cyclic molecules. Moreover, it was very difficult to obtained large clusters probably because the binding energy between these molecules is very small. In tellurium, these periodic structures do not exist and large clusters are easily obtained in nucleation conditions where only small selenium clusters are present. These results are discussed and a simple nucleation model is used to illustrate this different behavior. Finally these clusters properties are correlated to the bulk structure of both materials. (orig.)

Electrodeposition of antimony, tellurium and their alloys from molten acetamide mixtures

NARCIS (Netherlands)

Nguyen, H.P.; Peng, X.; Murugan, G.; Vullers, R.J.M.; Vereecken, P.M.; Fransaer, J.

2013-01-01

We examine the electrodeposition of antimony (Sb), tellurium (Te) and their alloys from molten mixtures of acetamide - antimony chloride and tellurium chloride. The binary mixtures of acetamide with SbCl3 and TeCl 4 exhibit eutectic formation with large depressions of freezing points to below room

Neutron activation analysis of high purity tellurium

International Nuclear Information System (INIS)

Gil'bert, Eh.N.; Verevkin, G.V.; Obrazovskij, E.G.; Shatskaya, S.S.

1980-01-01

A scheme of neutron activation analysis of high purity tellurium is developed. Weighed amount of Te (0.5 g) is irradiated for 20-40 hr in the flux of 2x10 13 neutron/(cm 2 xs). After decomposition of the sample impurities of gold and palladium are determined by the extraction with organic sulphides. Tellurium separation from the remaining impurities is carried out by the extraction with monothiobenzoic acid from weakly acidic HCl solutions in the presence of iodide-ions, suppressing silver extraction. Remaining impurity elements in the refined product are determined γ-spectrometrically. The method allows to determine 34 impurities with determination limits 10 -6 -10 -11 g

The defects produced by electron irradiation in tellurium-doped germanium

International Nuclear Information System (INIS)

Fukuoka, Noboru; Saito, Haruo

1989-01-01

The nature of the irradiation induced defects in a germanium single crystal doped with tellurium was studied by DLTS and electrical measurements. The E c -0.21 eV level produced by irradiation with 1.5 MeV electrons was studied using the DLTS technique. It was found that the defect associated with this level is a divacancy. The E-center like defect (group V impurity-vacancy pair) introduces the E c -0.20 eV level in samples doped with a group V impurity. The level introduced by a tellurium (group VI impurity)-vacancy pair is deeper. The E c -0.16 eV level was generated by annealing at 430 K. A tellurium-vacancies complex is proposed as the defect associated with this level. (author)

DETECTION OF THE SECOND r-PROCESS PEAK ELEMENT TELLURIUM IN METAL-POOR STARS ,

International Nuclear Information System (INIS)

Roederer, Ian U.; Lawler, James E.; Cowan, John J.; Beers, Timothy C.; Frebel, Anna; Ivans, Inese I.; Schatz, Hendrik; Sobeck, Jennifer S.; Sneden, Christopher

2012-01-01

Using near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, we detect neutral tellurium in three metal-poor stars enriched by products of r-process nucleosynthesis, BD +17 3248, HD 108317, and HD 128279. Tellurium (Te, Z = 52) is found at the second r-process peak (A ≈ 130) associated with the N = 82 neutron shell closure, and it has not been detected previously in Galactic halo stars. The derived tellurium abundances match the scaled solar system r-process distribution within the uncertainties, confirming the predicted second peak r-process residuals. These results suggest that tellurium is predominantly produced in the main component of the r-process, along with the rare earth elements.

Review of tellurium release rates from LWR fuel elements under accident conditions

International Nuclear Information System (INIS)

Lorenz, R.A.; Beahm, E.C.; Wichner, R.P.

1983-01-01

Although fission product tellurium presents a potentially significant radiohazard, its release and transport in source-term experiments is frequently overlooked because it does not possess a readily measurable, gamma emission; moreover, a recent study emphasized noble gas, iodine and cesium release from LWR fuel elements because of the large data base that exists for these materials. Some new tests show that in some cases tellurium may be held up in core material to a greater degree than previously assumed - an observation that prompts a careful reappraisal of the existing tellurium-release data and its chemical foundation

Methods of selenium and tellurium determination in geological and enviromental materials

International Nuclear Information System (INIS)

Nazarenko, I.I.; Kislova, I.V.

1988-01-01

Atomic-absorption and atomic-emission methods of tellurium determination in ores and products of their processing are described. Flame variant with extractional concentration permits to determine tellurium with the concentration up to 6x10 -6 %, the use of graphite cuvette after preliminary concentration-up to 1x10 -6 %. Atomic-emissional method permits to determine 3x10 -4 % Te from sample of 0.5 g

Selenium and tellurium as carbon substitutes

International Nuclear Information System (INIS)

Knapp, F.F. Jr.

1980-01-01

This review has summarized structure-activity studies with 75 Se- and /sup 123m/Te-labeled radiopharmaceuticals in which the selenium or tellurium heteroatom has been inserted between carbon-carbon bonds. The agents that have been investigated in most detail include steroids for adrenal imaging and long-chain fatty acids, and a variety of other unique agents have also been studied. Because of the great versatility of the organic chemistry of selenium and tellurium, there is continuing interest in the preparation of radiopharmaceuticals labeled with 75 Se, 73 Se, and /sup 123m/Te. There are two important factors which will determine the extent of future interest in such agents. These include the necessity of a decrease in the cost of highly enriched 122 Te to make the reactor production of /sup 123m/Te cost effective. In addition, the potential preparation of large amounts of 73 Se should stimulate the development of 73 Se-labeled radiopharmaceuticals

Investigation of biomethylation of arsenic and tellurium during composting

International Nuclear Information System (INIS)

Diaz-Bone, Roland A.; Raabe, Maren; Awissus, Simone; Keuter, Bianca; Menzel, Bernd; Kueppers, Klaus; Widmann, Renatus; Hirner, Alfred V.

2011-01-01

Though the process of composting features a high microbiological activity, its potential to methylate metals and metalloids has been little investigated so far in spite of the high impact of this process on metal(loid) toxicity and mobility. Here, we studied the biotransformation of arsenic, tellurium, antimony, tin and germanium during composting. Time resolved investigation revealed a highly dynamic process during self-heated composting with markedly differing time patterns for arsenic and tellurium species. Extraordinary high concentrations of up to 150 mg kg -1 methylated arsenic species as well as conversion rates up to 50% for arsenic and 5% for tellurium were observed. In contrast, little to no conversion was observed for antimony, tin and germanium. In addition to experiments with metal(loid) salts, composting of arsenic hyperaccumulating ferns Pteris vittata and P. cretica grown on As-amended soils was studied. Arsenic accumulated in the fronds was efficiently methylated resulting in up to 8 mg kg -1 methylated arsenic species. Overall, these studies indicate that metal(loid)s can undergo intensive biomethylation during composting. Due to the high mobility of methylated species this process needs to be considered in organic waste treatment of metal(loid) contaminated waste materials.

Continuous reduction of tellurite to recoverable tellurium nanoparticles using an upflow anaerobic sludge bed (UASB) reactor.

Science.gov (United States)

Ramos-Ruiz, Adriana; Sesma-Martin, Juan; Sierra-Alvarez, Reyes; Field, Jim A

2017-01-01

According to the U.S. Department of Energy and the European Union, tellurium is a critical element needed for energy and defense technology. Thus methods are needed to recover tellurium from waste streams. The objectives of this study was to determine the feasibility of utilizing upflow anaerobic sludge bed (UASB) reactors to convert toxic tellurite (Te IV ) oxyanions to non-toxic insoluble elemental tellurium (Te 0 ) nanoparticles (NP) that are amendable to separation from aqueous effluents. The reactors were supplied with ethanol as the electron donating substrate to promote the biological reduction of Te IV . One reactor was additionally amended with the redox mediating flavonoid compound, riboflavin (RF), with the goal of enhancing the bioreduction of Te IV . Its performance was compared to a control reactor lacking RF. The continuous formation of Te 0 NPs using the UASB reactors was found to be feasible and remarkably improved by the addition of RF. The presence of this flavonoid was previously shown to enhance the conversion rate of Te IV by approximately 11-fold. In this study, we demonstrated that this was associated with the added benefit of reducing the toxic impact of Te IV towards the methanogenic consortium in the UASB and thus enabled a 4.7-fold higher conversion rate of the chemical oxygen demand. Taken as a whole, this work demonstrates the potential of a methanogenic granular sludge to be applied as a bioreactor technology producing recoverable Te 0 NPs in a continuous fashion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determining arsenic in elemental antimony containing selenium and tellurium

International Nuclear Information System (INIS)

Mogileva, M.G.; Kozlova, E.L.

1986-01-01

The authors have developed a method of determining arsenic in metallic antimony containing selenium, tellurium, and mercury, in which they isolated it in elementary form for separation from the antimony and the associated elements (silicon and phosphorus), followed by colorimetric determination of the arsenic from arsenic-molbdenum blue. The reducing agents to reduce the arsenic were sodium hypophosphite and tin(II) chloride, which do not reduce antimony and which do not interfere with the determination. This method of determining arsenic in metallic antimony without preliminary separation of the selenium and tellurium is in no way inferior in accuracy to the method given in All-Union State Standard (GOST) 1367.4-83

Release of tellurium and cesium from UO2 in LWR fuel rods during irradiation

International Nuclear Information System (INIS)

Malen, K.A.

1983-01-01

In this paper the release of tellurium (Te-132) and cesium (Cs-134 and Cs-137) from UO 2 -fuel is analyzed. The basis for the analysis is the experimental results from the S176 series of experiments performed at Studsvik. It seems that the model developed earlier for release of iodine applies also to tellurium and cesium. This model assumes sweeping up of the species in question by moving grain boundaries and subsequent release through grain boundary porosity. An interesting extra feature is deposition of tellurium at temperatures in the range 1500-2000 K believed to be due to condensation. (author)

METALCOMPLEXES OF TELLURIUM-CONTAINING AMINES AND AZOMETINES

Directory of Open Access Journals (Sweden)

G. M. Abakarov

2014-01-01

Full Text Available In this article methods of synthesis and reactionary ability of metalcomplexes of tellurium-containing amines, azometines, of a problem of competitive coordination with use of the principle of "soft" and "rigid" acids and the bases (R. Pearson.

The characterisation of vapour-phase alkali metal-tellurium-oxygen species

International Nuclear Information System (INIS)

Gomme, R.A.; Ogden, J.S.; Bowsher, B.R.

1986-10-01

Detailed assessments of hypothetical severe accidents in light water reactors require the identification of the chemical forms of the radionuclides in order to determine their transport characteristics. Caesium and tellurium are important volatile fission products in accident scenarios. This report describes detailed studies to characterise the chemical species that vaporise from heated mixtures of various alkali metal-tellurium-oxygen systems. The molecular species were characterised by a combination of quadrupole mass spectrometry and matrix isolation-infrared spectroscopy undertaken in conjunction with experiments involving oxygen-18 substitution. The resulting spectra were interpreted in terms of a vapour-phase molecule with the stoichiometry M 2 TeO 3 (M = K,Rb,Cs) for M/Te molecular ratios of ∼ 2, and polymeric species for ratios < 2. This work has demonstrated the stability of caesium tellurite. The formation of this relatively low-volatility, water-soluble species could significantly modify the transport and release of caesium and tellurium. The data presented in this report should allow more comprehensive thermodynamic calculations to be undertaken that assist in the quantification of fission product behaviour during severe reactor accidents. (author)

Double beta decay of tellurium-130

International Nuclear Information System (INIS)

Richardson, J.F.; Manuel, O.K.; Sinha, B.; Thorpe, R.I.

1986-01-01

The isotopic composition of xenon is reported in four, neutron-irradiated tellurium minerals - tellurobismuthite from Boliden, Sweden, native tellurium from the Good Hope Mine of Gunnison County, Colorado, altaite from the Kirkland Lake area, Ontario, and altaite from the Mattagami Lake area, Quebec. From the amount of radiogenic 130 Xe and pile-produced 131 Xe in these samples, it is concluded that the half-life of 130 Te for ββ-decay is 21 y based on measured values of (1.0+-0.3) . 10 21 y and higher. Our results demonstrate that there has been no significant partial leakage of radiogenic 130 Xe from these minerals over geologic time. Larger values of Tsub(1/2), as indicated from some of the analysis reported here and in other studies, are attributed to recrystallization of the soft telluride minerals and complete resetting of the Te-Xe system after mineralization. The value obtained here for the half-life of 130 Te is substantiated by recent measurements on xenon in tellurides from Kalgoorlie, Western Australia. (orig.)

RILIS-ionized mercury and tellurium beams at ISOLDE CERN

Energy Technology Data Exchange (ETDEWEB)

Day Goodacre, T., E-mail: thomas.day.goodacre@cern.ch [CERN (Switzerland); Billowes, J. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Chrysalidis, K. [CERN (Switzerland); Fedorov, D. V. [Petersburg Nuclear Physics Institute (Russian Federation); Fedosseev, V. N.; Marsh, B. A. [CERN (Switzerland); Molkanov, P. L. [Petersburg Nuclear Physics Institute (Russian Federation); Rossel, R. E.; Rothe, S.; Seiffert, C. [CERN (Switzerland); Wendt, K. D. A. [Johannes Gutenberg Universität, Institut für Physik (Germany)

2017-11-15

This paper presents the results of ionization scheme development for application at the ISOLDE Resonance Ionization Laser Ion Source (RILIS). Two new ionization schemes for mercury are presented: a three-step three-resonance ionization scheme, ionizing via an excitation to a Rydberg level and a three-step two-resonance ionization scheme, with a non-resonant final step to the ionization continuum that corresponded to a factor of four higher ionization efficiency. The efficiency of the optimal mercury ionization scheme was measured, together with the efficiency of a new three-step three resonance ionization scheme for tellurium. The efficiencies of the mercury and tellurium ionization schemes were determined to be 6 % and >18 % respectively.

Nano-Structured Crystalline Te Films by Laser Gas-Phase Pyrolysis of Dimethyl Tellurium

Czech Academy of Sciences Publication Activity Database

Pola, Josef; Pokorná, Veronika; Boháček, Jaroslav; Bastl, Zdeněk; Ouchi, A.

2004-01-01

Roč. 71, č. 2 (2004), s. 739-746 ISSN 0165-2370 R&D Projects: GA AV ČR IAA4072107; GA MŠk OC 523.60 Institutional research plan: CEZ:AV0Z4072921; CEZ:AV0Z4032918; CEZ:AV0Z4040901 Keywords : dimethyl tellurium * tellurium films * laser Subject RIV: CA - Inorganic Chemistry Impact factor: 1.352, year: 2004

Thermoelectric properties of electrodeposited tellurium films and the sodium lignosulfonate effect

International Nuclear Information System (INIS)

Abad, Begoña; Rull-Bravo, Marta; Hodson, Stephen L.; Xu, Xianfan; Martin-Gonzalez, Marisol

2015-01-01

The effect of the addition of a surfactant, sodium lignosulfonate (SLS), on the thermoelectric properties of tellurium films prepared by electrochemical deposition is studied. The growth mechanism is found to have an important role in the thermoelectric properties since the grain size of the films is sharply reduced when the surfactant is added to the solution. For this reason, the electrical resistivity of the tellurium films when the surfactant is not added is 229 μΩ·m, which is lower than 798 μΩ·m with SLS. The Seebeck coefficient values are not influenced, with values in the vicinity of 285 μV/K for both solutions. The power factor resulted higher values than previous works, reaching values of 280 μW/m·K 2 (without SLS) and 82 μW/m·K 2 (with SLS) at room temperature. Finally, the thermal conductivity was measured by means of the Photoacoustic technique, which showed values of the order of 1 W/m·K for both solutions, which is a factor of 3 less than the bulk value of tellurium. A notable observation is that the power factor and the thermal conductivity of electrodeposited tellurium films have the same order of magnitude of bismuth telluride films grown by electrodeposition. The figure of merit is estimated to be approximately one order of magnitude higher than the bulk value, 0.09 without SLS and 0.03 with SLS, both at room temperature

Influence of ion beam irradiation induced defects on the structural, optical and electrical properties of tellurium nanowires

Energy Technology Data Exchange (ETDEWEB)

Kumar, Narinder [Department of Physics, Chaudhary Devi Lal University, Sirsa, 125055 (India); Department of Physics, Haryana College of Technology & Management, Kaithal, 136027 (India); Kumar, Rajesh [Department of Physics, RN College of Engineering & Technology, Madlauda, 132104 (India); Kumar, Sushil, E-mail: sushil_phys@rediffmail.com [Department of Physics, Chaudhary Devi Lal University, Sirsa, 125055 (India); Chakarvarti, S.K. [Research and Development, Manav Rachana International University, Faridabad, 121001 (India)

2016-11-01

In this study, tellurium nanowires were electrodeposited into the polymer membranes from aqueous acidic bath containing HTeO{sub 2}{sup +} ions. The field emission scanning electron microscopy (FESEM) images confirmed the formation of uniform and straight nanowires. The influence of 110 MeV Ni{sup 8+} ion irradiation induced defects on the structural, optical and electrical properties of as–deposited tellurium nanowires were examined using X-ray diffraction (XRD), UV–visible absorption spectroscopy and current–voltage (I–V) measurements. The XRD data depicted the hexagonal phase of tellurium nanowires and further revealed a variation in the intensity of diffraction peaks of ion irradiated nanowires. Williamson–Hall (WH) analysis is used for convoluting the size and microstrain contributions to the width of diffraction peaks. Tellurium nanowires exhibited a distinct absorbance band in the visible region at 686 nm, while this was absent in bulk tellurium. Electrical properties of nanowires are explored on the basis of I–V curves, which revealed a significant increase in the electrical conductivity of irradiated nanowires. A possible mechanism for the enhanced electrical conductivity is the increase in carrier concentration due to thermally excited defects. The defects produced by ion irradiation play a vital role in modifying the properties of semiconducting nanowires. - Highlights: • 110 MeV Ni{sup 8+} ion beam induced changes in tellurium nanowires have been examined. • Nanowires were prepared using template electrodeposition method. • Irradiation improved the electrical conductivity of tellurium nanowires. • Mechanism for enhanced electrical conductivity of irradiated nanowires was discussed.

Kinetics and mechanism of oxidation of tellurium (IV) by periodate in alkaline medium

International Nuclear Information System (INIS)

Srinivas, K.; Vani, P.; Dikshitulu, L.S.A.

1995-01-01

Detailed kinetic study of the oxidation of tellurium (IV) by periodate in alkaline medium has been carried out to compare the mechanisms of oxidation in the acid and alkaline media. It is interesting to note that the rate step involves a two-electron transfer from tellurium (IV) to periodate in alkaline medium although the kinetic pattern is somewhat different from that in the acid medium. 7 refs., 1 tab

Chemical Process for Treatment of Tellurium and Chromium Liquid Waste from I-131 Radioisotope Production

International Nuclear Information System (INIS)

Zainus-Salimin; Gunandjar; Dedy-Harsono; Hendro; Sugeng-Purnomo; Mohammad-Faruq; Zulfakhri

2000-01-01

The I-131 radioisotope is used in nuclear medicine for diagnosis and therapy. The I-131 radioisotope is produced by wet distillation at Bandung Nuclear Research Center and generated about 4,875 Itr of liquid waste containing 2,532.8 ppm of tellurium and 1,451.8 ppm chromium at pH 1. Considering its negative impact to the environment caused by toxic behaviour of tellurium and chromium, it is necessary to treat chemically that's liquid waste. The research of chemical treatment of tellurium and chromium liquid waste from I-131 radioisotope production has been done. The steps of process are involved of neutralisation with NaOH, coagulation-flocculation process for step I using Ca(OH) 2 coagulant for precipitation of sulphate, sulphite, oxalic, chrome Cr 3+ , and coagulation-flocculation process for step II using BaCI 2 coagulant for precipitation of chrome Cr 6+ and tellurium from the supernatant of coagulation in step I. The best result of experiment was achieved at 0.0161 ppm of chromium concentration on the supernatant from coagulation-flocculation of step I using 3.5 g Ca(OH) 2 for 100 ml of liquid waste, and 0.95 ppm of tellurium concentration on the final supernatant from coagulation-flocculation by of step II using 0.7 g BaCI 2 for supernatant from coagulation of step I. (author)

Enhancement of Au-Ag-Te contents in tellurium-bearing ore minerals via bioleaching

Science.gov (United States)

Choi, Nag-Choul; Cho, Kang Hee; Kim, Bong Ju; Lee, Soonjae; Park, Cheon Young

2018-03-01

The purpose of this study was to enhance the content of valuable metals, such as Au, Ag, and Te, in tellurium-bearing minerals via bioleaching. The ore samples composed of invisible Au and Au paragenesis minerals (such as pyrite, chalcopyrite, sphalerite and galena) in combination with tellurium-bearing minerals (hessite, sylvanite and Tellurobismuthite) were studied. Indigenous microbes from mine drainage were isolated and identified as Acidithiobacillus ferrooxidans, which were used in bioleaching after adaption to copper. The effect of the microbial adaption on the bioleaching performance was then compared with the results produced by the non-adaptive process. The microbial adaption enhanced the Au-Ag-Te contents in biological leaching of tellurium-bearing ore minerals. This suggests that bioleaching with adapted microbes can be used both as a pretreatment and in the main recovery processes of valuable metals.

Peroxide coordination of tellurium in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Mikhaylov, Alexey A.; Medvedev, Alexander G. [Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); The Casali Center of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem (Israel); Churakov, Andrei V.; Grishanov, Dmitry A.; Prikhodchenko, Petr V. [Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Lev, Ovadia [The Casali Center of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem (Israel)

2016-02-15

Tellurium-peroxo complexes in aqueous solutions have never been reported. In this work, ammonium peroxotellurates (NH{sub 4}){sub 4}Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 4}(OH){sub 2} (1) and (NH{sub 4}){sub 5}Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 5}(OH).1.28 H{sub 2}O.0.72 H{sub 2}O{sub 2} (2) were isolated from 5 % hydrogen peroxide aqueous solutions of ammonium tellurate and characterized by single-crystal and powder X-ray diffraction analysis, by Raman spectroscopy and thermal analysis. The crystal structure of 1 comprises ammonium cations and a symmetric binuclear peroxotellurate anion [Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 4}(OH){sub 2}]{sup 4-}. The structure of 2 consists of an unsymmetrical [Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 5}(OH)]{sup 5-} anion, ammonium cations, hydrogen peroxide, and water. Peroxotellurate anions in both 1 and 2 contain a binuclear Te{sub 2}(μ-OO){sub 2}(μ-O) fragment with one μ-oxo- and two μ-peroxo bridging groups. {sup 125}Te NMR spectroscopic analysis shows that the peroxo bridged bitellurate anions are the dominant species in solution, with 3-40 %wt H{sub 2}O{sub 2} and for pH values above 9. DFT calculations of the peroxotellurate anion confirm its higher thermodynamic stability compared with those of the oxotellurate analogues. This is the first direct evidence for tellurium-peroxide coordination in any aqueous system and the first report of inorganic tellurium-peroxo complexes. General features common to all reported p-block element peroxides could be discerned by the characterization of aqueous and crystalline peroxotellurates. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Rutherford backscatter measurements on tellurium and cadmium implanted gallium arsenide

International Nuclear Information System (INIS)

Bell, E.C.

1979-10-01

The primary aim of the work described in this thesis was to examine implanted layers of the dopant impurities cadmium and tellurium in gallium arsenide and to experimentally assess their potential for producing electrically active layers. 1.5 MeV Rutherford backscattering measurements of lattice disorder and atom site location have been used to assess post implantation thermal annealing and elevated temperature implantations to site the dopant impurities on either gallium or arsenic lattice positions in an otherwise undisordered lattice. Pyrolitically deposited silicon dioxide was used as an encapsulant to prevent thermal dissociation of the gallium arsenide during annealing. It has been shown that high doses of cadmium and tellurium can be implanted without forming amorphous lattice disorder by heating the gallium arsenide during implantation to relatively low temperatures. Atom site location measurements have shown that a large fraction of a tellurium dose implanted at 180 0 C is located on or near lattice sites. Channeled backscatter measurements have shown that there is residual disorder or lattice strain in gallium arsenide implanted at elevated temperatures. The extent of this disorder has been shown to depend on the implanted dose and implantation temperature. The channeling effect has been used to measure annealing of the disorder. (author)

Study On Analytical Methods Of Tellurium Content In Natriiodide (Na131I) Radiopharmaceutical Solution Produced In The Dalat Nuclear Reactor

International Nuclear Information System (INIS)

Vo Thi Cam Hoa; Duong Van Dong; Nguyen Thi Thu; Chu Van Khoa

2007-01-01

This report describes the practical methods for analyzing of Tellurium content in Na 131 I solution produced at the Dalat Nuclear Research Institute. We studied analytical methods to control Tellurium content in final Na 131 I solution product used in medical purposes by three methods such as: spot test, gamma spectrometric and spectrophotometric methods. These investigation results are shown that the spot test method is suitable for controlling Tellurium trace in the final product. This spot test can be determinate Tellurium trace less than 10 ppm and are used to quality control of Na 131 I solution using in medical application. (author)

Reaction of 1-bromo-3-chloropropane with tellurium and dimethyl telluride in the system of hydrazine hydrate-alkali

International Nuclear Information System (INIS)

Russavskaya, N.V.; Levanova, E.P.; Sukhomazova, Eh.N.; Grabel'nykh, V.A.; Elaev, A.V.; Klyba, L.V.; Zhanchipova, E.R.; Albanov, A.I.; Korotaeva, I.M.; Toryashinova, D.S.D.; Korchevin, N.A.

2006-01-01

A synthesis of oligomeric substance of thiocol type, the poly(trimethyleneditelluride), from 1-bromo-3-chloropropane and elemental tellurium is performed using a hydrazine hydrate-alkali system. Reductive splitting of the tellurocol followed by alkylation with methyl iodide give rise to preparation of bis(methyltelluro)propane, which was synthesized also from dimethyl telluride and 1,3-dihalopropanes using the N 2 H 4 ·H 2 O/KOH system. The reaction products were characterized by elementary analysis, NMR, and IR spectra. Mass spectra of the synthesized low molecular weight organotellurium compounds are considered [ru

Simple and effective method for nuclear tellurium isomers separation from antimony cyclotron targets

International Nuclear Information System (INIS)

Bondarevskij, S.I.; Eremin, V.V.

1999-01-01

Simple and effective method of generation of tellurium nuclear isomers from irradiated on cyclotron metallic antimony is suggested. Basically this method consists in consideration of the big difference in volatilities of metallic forms of antimony, tin and tellurium. Heating of the tin-antimony alloy at 1200 K permits to separate about 90 % of produced quantity of 121m Te and 123m Te (in this case impurity of antimony radionuclides is not more than 1 % on activity) [ru

Simultaneous determination of selenium and tellurium in native sulfur by atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Arikawa, Yoshiko; Hirai, Shoji; Ozawa, Takejiro.

1979-01-01

A method for the determination of selenium and tellurium in native sulfur has been investigated by means of atomic absorption spectrophotometry. Native sulfur collected from around fumarole or volcanic crater is ground down into powder, a portion of which weighing 1 g is subjected to analysis. A 2.6% (w/v) sodium hydroxide solution is added by 10 ml to the sample in a teflon beaker, and the mixture is then heated on a hot plate. Sulfur is decomposed and dissolved in the form of disulfide and thiosulfate. A 30% hydrogenperoxide solution is added by 10 ml to oxidize them to sulfate. At the same time selenium and tellurium contained in the sulfur sample are also thought to be oxidized to Se(VI) and Te(VI) states. The solution is neutralized with hydrochloric acid and diluted with distilled water to 100 ml. The sample solution thus prepared is sprayed into the air-acetylene flame of the atomic absorption spectrophotometer. The absorbance is measured at 195.9 nm for selenium and 214.2 nm for tellurium. Calibration curve is prepared by measuring the absorbances of the solutions prepared as follows. One gram portions of pure sulfur (99.9999%) are decomposed as for the samples. After neutralization, standard solutions containing each same amount of selenium and tellurium (0 -- 1000 μg) are added to the sulfur solution and then diluted with water to 100 ml. The standard deviations were estimated to be 50.4 ppm for selenium at 756 ppm and 16.6 ppm for tellurium at 587 ppm. For the check of the reliability of the method, results were compared with those obtained by neutron activation analysis. Results obtained by both methods showed good agreement. (author)

Electrochemical characterization of the underpotential deposition of tellurium on Au electrode

International Nuclear Information System (INIS)

Zhu, W.; Yang, J.Y.; Zhou, D.X.; Bao, S.Q.; Fan, X.A.; Duan, X.K.

2007-01-01

Electrochemical characterization of the underpotential deposition (UPD) of tellurium on Au substrate has been performed in this paper. The mechanism of Te deposition and its voltammetry dependence on the Te ion concentration were studied, and it suggests that variations in the metal ion concentration may affect the UPD process kinetics. The effect of tellurium adsorbates on UPD behavior of Te has also been investigated. The results show that the tellurium adsorbates could be irreversibly adsorbed upon the Au substrate surface under the open-circuit conditions. Subsequent removal of the Te adsorbates was also proved to be very difficult within the Au double-layer region, and a standard electrochemical cleaning procedure is necessary to remove the Te adsorbates completely. When the potential was cycled into the Au oxidation region, a substantial loss of Te adsobates was observed, which occurs simultaneously with the Au oxidation features. Scan rate dependent cyclic voltammetry experiments reveal that the peak current in the Te UPD peak is not a linear function of the scan rate, ν, but of a 2/3 power of the scan rate, ν 2/3 . It is in good consistent with a two-dimension nucleation and growth mechanism

Speciation analysis of tellurium by solid-phase extraction in the presence of ammonium pyrrolidine dithiocarbamate and inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Yu, Chunhai; Cai, Qiantao; Guo, Zhong-Xian; Yang, Zhaoguang [Centre for Advanced Water Technology, Innovation Centre (NTU), Singapore (Singapore); Khoo, Soo Beng [Department of Chemistry, National University of Singapore (Singapore)

2003-05-01

Under acidic conditions tellurium(IV) formed a complex with ammonium pyrrolidine dithiocarbamate (APDC). The tellurium(IV) complex was completely retained on a non-polar Isolute silica-based octadecyl (C{sub 18}) sorbent-containing solid-phase extraction (SPE) cartridge, while the uncomplexed Te(VI) passed through the cartridge and remained as a free species in the solution. Only partial Te(IV) was retained on the SPE cartridge for samples without addition of APDC. On the basis of different retention behaviours of the complexed Te(IV) and uncomplexed Te(VI), a simple and highly sensitive method is proposed for the determination of total tellurium and Te(VI) by SPE separation and inductively coupled plasma mass spectrometry (ICP-MS) detection. The Te(IV) concentration was calculated as the difference between total tellurium and Te(VI) concentrations. The detection limit (3{sigma}) is 3 ng L{sup -1} tellurium. Factors affecting the separation and detection of tellurium species were investigated. Coexisting ions did not show significant interferences with the Te(IV)-APDC complex retention and the subsequent ICP-MS detection of Te. The method has been successfully applied to the tellurium speciation analysis in waters with spiked recoveries for Te(IV) and Te(VI) of 86.0-108% and 87.1-97.4%, respectively. (orig.)

Determination of tellurium in coal samples by means of graphite furnace atomic absorption spectrometry after coprecipitation with iron(III) hydroxide

Energy Technology Data Exchange (ETDEWEB)

Oda, S.; Arikawa, Y. [Japan Womens University, Tokyo (Japan)

2005-11-01

A simple and accurate method for the determination of tellurium in coal samples was investigated by the combustion of samples under a high pressure of oxygen and coprecipitation with Fe(OH){sub 3}, followed by a measurement by graphite furnace atomic absorption spectrometry (GF-AAS). About 0.5 g of an accurately weighed ground coal sample and 0.5 g of starch were combusted in an oxygen combustion bomb filled with oxygen to 3 MPa and added with 3 ml of water as an absorbing solution. The formed tellurium trioxide TeOs dissolved in water as TeO{sub 4}{sup 2-}, which was in turn reduced to TeO{sub 3}{sup 2-} by heating. After diluting the above-mentioned solution up to about 50 ml with water, Fe(OH){sub 3} is formed upon adding Fe(NO{sub 3}){sub 3} and sodium hydroxide solutions at pH 8-9 and left standing overnight. After dissolving the precipitate by HCl, the solution was diluted to 10 ml with water and the concentration of tellurium was measured by GF-AAS at a wavelength of 214.3 nm. The standard addition method was employed for the determination of tellurium in real coal samples, because those processes for the formation of tellurium(VI) oxide and coprecipitation with Fe(OH)3 were interfered by matrices. For NIST SRM 1632c, the standard coal sample tellurium content of 0.057 {+-} 0.004 mg kg{sup -1} was in good agreement with the information value of 0.05 mg kg{sup -1} with 7% of RSD in five replicate analyses. The tellurium contents in 20 real coal samples given by Center for Coal Utilization, Japan were also determined. The tellurium contents in these samples were scattered over the narrow range between 0.032 and 0.100 mg kg{sup -1}.

Site-specific nucleation and controlled growth of a vertical tellurium nanowire array for high performance field emitters

International Nuclear Information System (INIS)

Safdar, Muhammad; Zhan Xueying; Mirza, Misbah; Wang Zhenxing; Sun Lianfeng; He Jun; Niu Mutong; Zhang Jinping; Zhao Qing

2013-01-01

We report the controlled growth of highly ordered and well aligned one-dimensional tellurium nanostructure arrays via a one-step catalyst-free physical vapor deposition method. The density, size and fine structures of tellurium nanowires are systematically studied and optimized. Field emission measurement was performed to display notable dependence on nanostructure morphologies. The ordered nanowire array based field emitter has a turn-on field as low as 3.27 V μm −1 and a higher field enhancement factor of 3270. Our finding offers the possibility of controlling the growth of tellurium nanowire arrays and opens up new means for their potential applications in electronic devices and displays. (paper)

Exploring molecular and spin interactions of Tellurium adatom in reduced graphene oxide

Energy Technology Data Exchange (ETDEWEB)

Alegaonkar, Ashwini [Department of Chemistry, Savitribai Phule Pune University (Formerly University of Pune), Ganeshkhind, Pune, 411 007, MS (India); Alegaonkar, Prashant [Department of Applied Physics, Defence Institute of Advance Technology, Girinagar, Pune, 411 025, MS (India); Pardeshi, Satish, E-mail: skpar@chem.unipune.ac.in [Department of Chemistry, Savitribai Phule Pune University (Formerly University of Pune), Ganeshkhind, Pune, 411 007, MS (India)

2017-07-01

The transport of spin information fundamentally requires favourable molecular architecture and tunable spin moments to make the medium pertinent for spintronic. We report on achieving coherent molecular-spin parameters for rGO due to Tellurium (Te) adatom. Initially, GO prepared using graphite, was modified into rGO by in situ incorporation of 1 (w/w)% of Te. Both the systems were subjected to ESCA, FTIR, Raman dispersion, ESR spectroscopy, and electron microscopy. Analysis revealed that, Te substantially reacted with epoxides, carbonyl, and carboxylate groups that improved C-to-O ratio by twice. However, the spin splitting character, between Te and C, seems to be quenched. Moreover, Te altered the dynamical force constant between C-C and C=C that generated the mechanical stress within rGO network. The layer conjugation, nature of folding, symmetry, and electronic states of the edges were also affected by precipitation and entrapment of Te. The calculated dynamic molecular Raman and ESR spin parameters indicated that, Te acted as a bridging element for long range spin transport. This is particularly due to, the p-orbital moments of Te contributing, vectorially, to spin relaxation process operative at broken inversion symmetry sites. Our study suggests that, facile addition of Te in rGO is useful to achieve favourable spintronic properties. - Highlights: • Spin interactions and molecular dynamics modification due to Tellurium adatom in rGO. • Molecular level manipulation of Tellurium adatom for favourable spintronic properties. • Bychocov-Rashaba coupling are the operative channels in rGO. • Extrinsic coupling component get added vectorially by Tellurium. • Te-rGO is a viable medium for molecular spintronics.

Structural Modeling of Djenkolic Acid with Sulfur Replaced by Selenium and Tellurium

Directory of Open Access Journals (Sweden)

Petr Melnikov

2014-04-01

Full Text Available The comparative structural modeling of djenkolic acid and its derivatives containing selenium and tellurium in chalcogen sites (Ch = Se, Te has provided detailed information about the bond lengths and bond angles, filling the gap in what we know about the structural characteristics of these aminoacids. The investigation using the molecular mechanics technique with good approximation confirmed the available information on X-ray refinements for the related compounds methionine and selenomethionine, as well as for an estimate made earlier for telluromethionine. It was shown that the Ch-C(3 and Ch-C(4 bond lengths grow in parallel with the increasing anionic radii. Although the distances C-C, C-O, and C-N are very similar, the geometry of conformers is quite different owing to the possibility of rotation about four carbon atoms, hence the remarkable variability observed in dihedral angles. It was shown that the compounds contain a rigid block with two Ch atoms connected through a methylene group. The standard program Gaussian 03 with graphical interface Gaussview 4.1.2 has proved to be satisfactory tool for the structural description of less-common bioactive compositions when direct X-ray results are absent.

Dismantling and chemical characterization of spent Peltier thermoelectric devices for antimony, bismuth and tellurium recovery.

Science.gov (United States)

Balva, Maxime; Legeai, Sophie; Garoux, Laetitia; Leclerc, Nathalie; Meux, Eric

2017-04-01

Major uses of thermoelectricity concern refrigeration purposes, using Peltier devices, mainly composed of antimony, bismuth and tellurium. Antimony was identified as a critical raw material by EU and resources of bismuth and tellurium are not inexhaustible, so it is necessary to imagine the recycling of thermoelectric devices. That for, a complete characterization is needed, which is the aim of this work. Peltier devices were manually dismantled in three parts: the thermoelectric legs, the alumina plates on which remain the electrical contacts and the silicone paste used to connect the plates. The characterization was performed using five Peltier devices. It includes mass balances of the components, X-ray diffraction analysis of the thermoelectric legs and elemental analysis of each part of the device. It appears that alumina represents 45% of a Peltier device in weight. The electrical contacts are mainly composed of copper and tin, and the thermoelectric legs of bismuth, tellurium and antimony. Thermoelectric legs appear to be Se-doped Bi 2 Te 3 and (Bi 0,5 Sb 1,5 )Te 3 for n type and p type semiconductors, respectively. This work shows that Peltier devices can be considered as a copper ore and that thermoelectric legs contain high amounts of bismuth, tellurium and antimony compared to their traditional resources.

Selenium Se and tellurium Te

International Nuclear Information System (INIS)

Busev, A.I.; Tiptsova, V.G.; Ivanov, V.M.

1978-01-01

The basic methods for determining selenium and tellurium in various objects are presented. The bichromatometric determination of Te in cadmium, zinc and mercury tellurides is based on oxidation of Te(4) to (6) in H 2 SO 4 with potassium bichromate. In steels, Te is determined photometrically with the aid of KI. The determination is hindered by Fe(3), Cu(2), Bi(3) and Se(4) ions, which must be separated. The extraction-photometric determination of Te in native sulfur is carried out with the aid of 5-mercapto-3-(naphthyl-2)-1,3,4-thiadiazolthione-2 (pH=4.8-5.0). The dyed complex is readily extracted with chloroform and benzene. The spectrophotometric determination of Te in selenium is performed with the aid of 3,5-diphenylpyrazoline-1-dithiocarbamate of sodium. Te is determined in commercial indium, arsenic and their semiconductor compounds photometrically with the aid of copper diethyldithiocarbamate. The method permits determining 5x10 -5 % Te in a weighed amount of 0.5 g. The chloride complex of Te(4) with diantipyriodolpropylmethane is quantitatively extracted with dichloroethane from hydrochloric acid solutions. Thus, any amounts of Te can be separated from Se and determined photometrically. The extraction-photometric determination of Te in commercial lead and bismuth is carried out with the aid of pyrazolone derivatives, in commercial copper with the aid of diantipyridolpropylmethane, and in ores (more than 0.01% Te) with the aid of bismuthol 2. Also described is the extraction-polarographic determination of Te in sulfide ores

Comparison of analytical possibilities of inversion voltammetry of tellurium with cathodic and anodic potential scanning taking layer-by-layer analysis of GaAs-Te films as example

International Nuclear Information System (INIS)

Kaplin, A.A.; Portnyagina, Eh.O.; Gridaev, V.F.

1979-01-01

Possibility of application in analytical purposes of the process of tellurium precipitation electrosolution from the surfaces of graphite and mercury-graphite electrodes at the cathode scanning of the potential is shown. As a result of comparison of direct and inversion scanning with cathodic and anodic scanning of the potential, variants of voltammetric method of tellurium determination in artificial solutions and, taking the developed method of layer-by-layer analysis of the GaAsTe films as an example, advantage of mercury-graphite electrode with cathodic scanning as compared to graphite electrode with cathode scanning of the potential is shown. Reproducibility of the GaAs film analysis results according to anodic and cathodic tellurium peaks is satisfactory. Maximum deviation from the results of analysis of oxidation peaks and tellurium peduction does not exceed 15 rel. %. Thus, for tellurium concentrations, exceeding 5x10 -6 g-ion/l, both anodic and cathodic scanning of the potential can be used, though error in tellurium determination according to cathodic peaks is 1.5-2.0 times higher. At tellurium amounts lower 5x10 -6 g-ion/l the determination should be carried out according to the peaks of tellurium anodic oxidation from the surface of graphite electrode or according to the peaks of tellurium cathodic reduction from the surface of mercury-graphite electrode

The enhancing of Au-Ag-Te content in tellurium-bearing ore mineral by bio-oxidation-leaching

Science.gov (United States)

Kim, PyeongMan; Kim, HyunSoo; Myung, EunJi; Kim, YoonJung; Lee, YongBum; Park*, CheonYoung

2015-04-01

The purpose of this study is to enhance the content of valuable metals such as Au-Ag-Te in tellurium-bearing minerals by bio-oxidation-leaching. It was confirmed that pyrite, chalcopyrite, sphalerite and galena were produced together with tellurium-bearing minerals including hessite, sylvanite and tellurobismuthite from ore minerals and concentrates through microscopic observation and SEM/EDS analysis. In a bio-oxidation-leaching experiment, with regard to Au, Ag, Te, Cu and Fe, the changes in the amount of leaching and the content of leaching residues were compared and analyzed with each other depending on the adaptation of an indigenous microbe identified as Acidithiobacillus ferrooxidans. As a result of the experiment, the Au-Ag-Te content in tellurium-bearing ore mineral was enhanced in the order of physical oxidation leaching, physical/non-adaptive bio-oxidation-leaching and physical/adaptive biological leaching. It suggests that the bio-oxidation-leaching using microbes adapted in tellurium-bearing ore mineral can be used as a pre-treatment and a main process in a recovery process of valuable metals. "This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2013R1A1A2004898)"

ELECTROCHEMICAL STUDY OF RHENIUM-TELLURIUM-COPPER SYSTEM

OpenAIRE

E.A.Salakhova*1, D.B.Tagiyev2, P.E.Kalantarova3 and A.M.Askerova4

2017-01-01

The formation of the triple alloys Re-Te-Cu on the platinum electrode at volt amperemetric cycling has been studied. The investigation was carried out from chloride acidic solution containing tellurium acid, potassium perrhenate, chloride copper. The kinetics of the processes was controlled using the measurements by the method of cyclic volt-amperometry on the device İVİUMSTAT. For the analysis of composition and structure the methods of XRD (X-ray diffraction analysis) were used, and the inv...

Acousto-optic measurements of ultrasound attenuation in tellurium dioxide crystal

International Nuclear Information System (INIS)

Voloshinov, V. B.; Lemyaskina, E. A.

1996-01-01

The paper is devoted to experimental investigation of ultrasound propagation in tellurium dioxide monocrystal. In particular, attenuation of slow shear acoustic modes in the crystal was measured. The measurements were performed by acousto-optic methods using probing of acoustic column by a laser beam. The paper describes measurements of acoustic attenuation coefficient for slow shear ultrasonic waves propagating at an angle =4.5 O with respect to the (110) direction in the (110) plane. The investigation was made at acoustic frequency f = 100 MHz with pulsed acoustic waves and with an optical beam of a He-Ne laser. It is found that the attenuation coefficient is α = 0.57 cm -1 ± 15 %. The attenuation at acoustic frequencies f ≥ 100 MHz influences performance characteristics of acousto-optical devices based on tellurium dioxide. As proved, spectral resolution of a quasicollinear acoustooptic filter decreases by a factor of 2 compared to a case of the attenuation absence. (authors)

Solvent Extraction of Tellurium from Chloride Solutions Using Tri-n-butyl Phosphate: Conditions and Thermodynamic Data

Directory of Open Access Journals (Sweden)

Dongchan Li

2014-01-01

Full Text Available The extractive separation of tellurium (IV from hydrochloric acid media with tri-n-butyl phosphate (TBP in kerosene was investigated. The dependence on the extraction of tellurium species, concentrations of tellurium and TBP, extraction time and stage, organic/aqueous ratio, and interferences from coexist metallic ions were examined and are discussed. Besides, the stripping agent and stripping time were also studied. It was found that the extraction reaction corresponds to the neutral complex formation mechanism and the extracted species is TeCl4·3TBP and that the extraction process is exothermic. The thermodynamic parameters of enthalpy ΔH, entropy ΔS, and free energy ΔG of the extraction process were evaluated at −26.2 kJ·mol−1, −65.6 J·mol−1·K−1, and −7.0 kJ·mol−1, respectively at 293 K.

Copper Tellurium Oxides - A Playground for Magnetism.

Energy Technology Data Exchange (ETDEWEB)

Norman, M. R.

2018-04-15

A variety of copper tellurium oxide minerals are known, and many of them exhibit either unusual forms of magnetism, or potentially novel spin liquid behavior. Here, I review a number of the more interesting materials with a focus on their crystalline symmetry and, if known, the nature of their magnetism. Many of these exist (so far) in mineral form only, and most have yet to have their magnetic properties studied. This means a largely unexplored space of materials awaits our exploration.

Liquid-liquid extraction of arsenic, antimony, selenium and tellurium by zinc diethyldithiocarbamate

International Nuclear Information System (INIS)

Bajo, S.; Wyttenbach, A.

1978-03-01

The authors report the solvent extraction, oxidation, reduction, extraction in the presence of iron, and reextraction of arsenic, antimony, selenium and tellurium. These processes were studied using radioactive tracers. (G.T.H.)

First example of a high-level correlated calculation of the indirect spin-spin coupling constants involving tellurium

DEFF Research Database (Denmark)

Rusakov, Yury Yu; Krivdin, Leonid B.; Østerstrøm, Freja From

2013-01-01

This paper documents a very first example of a high-level correlated calculation of spin-spin coupling constants involving tellurium taking into account relativistic effects, vibrational corrections and solvent effects for the medium sized organotellurium molecules. The 125Te-1H spin-spin coupling...... constants of tellurophene and divinyl telluride were calculated at the SOPPA and DFT levels in a good agreement with experiment. A new full-electron basis set av3z-J for tellurium derived from the "relativistic" Dyall's basis set, dyall.av3z, and specifically optimized for the correlated calculations...... of spin-spin coupling constants involving tellurium, was developed. The SOPPA methods show much better performance as compared to 15 those of DFT, if relativistic effects calculated within the ZORA scheme are taken into account. Vibrational and solvent corrections are next to negligible, while...

A Magnetic Resonance Force Microscopy Quantum Computer with Tellurium Donors in Silicon

OpenAIRE

Berman, G. P.; Doolen, G. D.; Tsifrinovich, V. I.

2000-01-01

We propose a magnetic resonance force microscopy (MRFM)-based nuclear spin quantum computer using tellurium impurities in silicon. This approach to quantum computing combines the well-developed silicon technology with expected advances in MRFM.

Subnanosecond pulse measurements of 10.6 μm radiation with tellurium

NARCIS (Netherlands)

Haselhoff, E.H.; Bonnie, R.J.M.; Ernst, G.J.; Witteman, W.J.

1988-01-01

Subnanosecond infrared pulses have been measured by noncollinear secondharmonic generation in tellurium. The method is very practical because due to the high refractive index the fine tuning of the phase matching is easily obtained by rotating the crystal around the optic axis.

Agglomeration during wet milling of LAST (lead-antimony-silver-tellurium) powders

International Nuclear Information System (INIS)

Hall, B.D.; Case, E.D.; Ren, F.; Johnson, J.R.; Timm, E.J.

2009-01-01

LAST (lead-antimony-silver-tellurium) compounds comprise a family of semiconducting materials with good thermoelectric properties. However, the as-cast form of LAST exhibits large grain size and hence low mechanical strength. Powder processing can produce a fine powder particle size that enhances fracture strength, however the powders tend to agglomerate if the individual powder diameters are less than a few microns across. Dry milling or wet milling (hexane additions of 0 cm 3 and 10 cm 3 ) produced hard agglomerates roughly 40 μm in diameter while wet milling with hexane additions of 25 cm 3 , 30 cm 3 or 50 cm 3 resulted in small, porous agglomerates roughly 20 μm in diameter. Thus, by adjusting the amount of milling liquid used while milling LAST powders, one can shift from hard to soft agglomerates, where the literature shows that soft agglomerates are less harmful to the final, sintered product. Also, in agreement with the results from the literature on other materials, wet milling of LAST powders produced smaller particle sizes but required longer times to reach the grindability limit

Flotation concentration for tellurium determination in industrial sewage

International Nuclear Information System (INIS)

Skripchuk, V.G.; Bormotova, L.V.; Lukoyanova, L.P.; Tret'yakova, M.I.

1983-01-01

Combination of the flotation of tellurium (4) precipitate with papaverine toluene and extraction-photometric determination of Te with butylrhodamine C allows one to determine 0.002-0.1 mg Te/l without its preliminary precipitation. Accompanying elements found in non-ferrous metallurgy sewage have no effect upon it. The duration of analysis of 10 samples is 1 to 1.5 h. Relative error is 12%. The method is introduced at the ''Uralelektromed'' plant

Magnetic resonance force microscopy quantum computer with tellurium donors in silicon.

Science.gov (United States)

Berman, G P; Doolen, G D; Hammel, P C; Tsifrinovich, V I

2001-03-26

We propose a magnetic resonance force microscopy (MRFM)-based nuclear spin quantum computer using tellurium impurities in silicon. This approach to quantum computing combines well-developed silicon technology and expected advances in MRFM. Our proposal does not use electrostatic gates to realize quantum logic operations.

Magnetic Resonance Force Microscopy Quantum Computer with Tellurium Donors in Silicon

International Nuclear Information System (INIS)

Berman, G. P.; Doolen, G. D.; Hammel, P. C.; Tsifrinovich, V. I.

2001-01-01

We propose a magnetic resonance force microscopy (MRFM)-based nuclear spin quantum computer using tellurium impurities in silicon. This approach to quantum computing combines well-developed silicon technology and expected advances in MRFM. Our proposal does not use electrostatic gates to realize quantum logic operations

Organoselenium compounds prevent hyperphosphorylation of cytoskeletal proteins induced by the neurotoxic agent diphenyl ditelluride in cerebral cortex of young rats

International Nuclear Information System (INIS)

Moretto, M.B.; Funchal, C.; Zeni, G.; Rocha, J.B.T.; Pessoa-Pureur, R.

2005-01-01

In this work we investigated the protective ability of the selenium compounds ebselen and diphenyl diselenide against the effect of diphenyl ditelluride on the in vitro incorporation of 32 P into intermediate filament (IF) proteins from slices of cerebral cortex of 17-day-old rats. We observed that ditelluride in the concentrations of 1, 15 and 50 μM induced hyperphosphorylation of the high-salt Triton insoluble neurofilament subunits (NF-M and NF-L), glial fibrillary acidic protein (GFAP) and vimentin, without altering the immunocontent of these proteins. Concerning the selenium compounds, diselenide (1, 15 and 50 μM) did not induce alteration of the in vitro phosphorylation of the IF proteins. Otherwise, ebselen induced an altered in vitro phosphorylation of the cytoskeletal proteins in a dose-dependent manner. At intermediate concentrations (15 and 30 μM) it increased the in vitro phosphorylation even though, at low (5 μM) or high (50 and 100 μM) concentrations this compound was ineffective in altering the activity of the cytoskeletal-associated phosphorylating system. In addition, 15 μM diselenide and 5 μM ebselen, presented a protective effect against the action of ditelluride, on the phosphorylation of the proteins studied. Considering that hyperphosphorylation of cytoskeletal proteins is associated with neuronal dysfunction and neurodegeneration, it is probable that the effects of ditelluride could be related to the remarkable neurotoxicity of this organic form of tellurium. Furthermore the neuroprotective action of selenium compounds against tellurium effects could be a promising route to be exploited for a possible treatment of organic tellurium poisoning

Determination of half life of tellurium isotopes: a proposal for the teaching of nuclear physics

International Nuclear Information System (INIS)

Ruivo, Julio C.; Zamboni, Cibele B.; Batista, Wagner F.

2013-01-01

This work aimed at the development of courseware for teaching nuclear physics, using experimental data of half-life measurement (T1/2) of Tellurium isotopes (A=127 and 131). The choice of Tellurium was established for providing nuclear data, which are fundamental in related investigations of nuclear structure and its use in various areas such as geochemistry, chemical and pharmaceutical industries, astrophysics etc. For evaluation of the proposal performance, the material was made available, bringing a lot of information about nuclear safety, production and storage of radioactive material and concepts of radioactive decay, subatomic particles, emission of gamma radiation, half-life, etc.

Determination of half life of tellurium isotopes: a proposal for the teaching of nuclear physics

Energy Technology Data Exchange (ETDEWEB)

Ruivo, Julio C.; Zamboni, Cibele B.; Batista, Wagner F., E-mail: julio.ruivo.costa@usp.br, E-mail: czamboni@ipen.br, E-mail: fisicawagner@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

This work aimed at the development of courseware for teaching nuclear physics, using experimental data of half-life measurement (T1/2) of Tellurium isotopes (A=127 and 131). The choice of Tellurium was established for providing nuclear data, which are fundamental in related investigations of nuclear structure and its use in various areas such as geochemistry, chemical and pharmaceutical industries, astrophysics etc. For evaluation of the proposal performance, the material was made available, bringing a lot of information about nuclear safety, production and storage of radioactive material and concepts of radioactive decay, subatomic particles, emission of gamma radiation, half-life, etc.

The dependence of the texture of tellurium thin films on vacuum deposition angle

International Nuclear Information System (INIS)

Cocks, F.H.; Peterson, M.J.; Jones, P.L.

1980-01-01

Vacuum-deposited tellurium thin films can show substantially different surface morphologies depending on the angle with which the vapor stream impinges on the substrate surface. These tellurium thin films have a tendency to grow as acicular crystallites but as the deposition angle is increased so that the vapor stream becomes tangential to the substrate surface the spacing between crystallites increases and approaches, at stream angles of approximately 80 0 from the normal, dimensions roughly once or twice the average wavelength of visible light. Such films may have application in solar energy collector systems because of the high absorptivity of sunlight shown by such films. Mechanisms which describe the tendency for crystallite spacing to increase with increasing angle are discussed. (Auth.)

Large-scale synthesis of Tellurium nanostructures via galvanic displacement of metals

Science.gov (United States)

Kok, Kuan-Ying; Choo, Thye-Foo; Ubaidah Saidin, Nur; Rahman, Che Zuraini Che Ab

2018-01-01

Tellurium (Te) is an attractive semiconductor material for a wide range of applications in various functional devices including, radiation dosimeters, optical storage materials, thermoelectric or piezoelectric generators. In this work, large scale synthesis of tellurium (Te) nanostructures have been successfully carried out in different concentrations of aqueous solutions containing TeO2 and NaOH, by galvanic displacements of Zn and Al which served as the sacrificial materials. Galvanic displacement process is cost-effective and it requires no template or surfactant for the synthesis of nanostructures. By varying the concentrations of TeO2 and NaOH, etching temperatures and etching times, Te nanostructures of various forms of nanostructures were successfully obtained, ranging from one-dimensional needles and rod-like structures to more complex hierarchical structures. Microscopy examinations on the nanostructures obtained have shown that both the diameters and lengths of the Te nanostructures increased with increasing etching temperature and etching time.

Iodine-129 in thyroids and tellurium isotopes in meteorites by neutron activation analysis

International Nuclear Information System (INIS)

Ballad, R.V.

1978-06-01

A combination of neutron activation and mass spectrometry has been used to determine the concentration of fissiogenic 129 I and the value of the 129 I/ 127 I ratio in thyroids of man, cow, and deer from Missouri. Deer thyroids show an average value of 129 I/ 127 I = 1.8 x 10 -8 and an average concentration of 3 x 10 -3 pCi 129 I per gram of thyroid (wet weight). Thyroids of cows and humans show successively lower values for the 129 I/ 127 I ratio and the 129 I content because their diets dilute fission-produced 129 I in the natural iodine cycle with mineral iodine. The results of analyses on a few thyroids from other geographic areas are also reported. The isotopic compositions of tellurium, krypton, and xenon were determined in acid-resistant residues of the Allende meteorite. Neutron activation and γ-counting were used to determine the relative abundances of six tellurium isotopes, and mass spectrometry was used to determine the isotopic compositions of krypton and xenon in aliquots of the same residues. Nucleogenetic anomalies were observed in the isotopic compositions of these three elements. The presence of isotopically distinct components of tellurium, krypton, and xenon in these residues provides strong support for the suggestion that our solar system formed directly from the debris of a supernova

Thermoelectric properties of bismuth antimony tellurium thin films through bilayer annealing prepared by ion beam sputtering deposition

Energy Technology Data Exchange (ETDEWEB)

Zheng, Zhuang-hao [College of Physics Science and Technology, Shenzhen University, 518060 (China); Shenzhen Key Laboratory of Sensor Technology, Shenzhen 518060 (China); Fan, Ping, E-mail: fanping308@126.com [College of Physics Science and Technology, Shenzhen University, 518060 (China); Shenzhen Key Laboratory of Sensor Technology, Shenzhen 518060 (China); Luo, Jing-ting [College of Physics Science and Technology, Shenzhen University, 518060 (China); Shenzhen Key Laboratory of Sensor Technology, Shenzhen 518060 (China); Cai, Xing-min; Liang, Guang-xing; Zhang, Dong-ping [College of Physics Science and Technology, Shenzhen University, 518060 (China); Ye, Fan [Shenzhen Key Laboratory of Sensor Technology, Shenzhen 518060 (China)

2014-07-01

Bismuth antimony tellurium is one of the most important tellurium-based materials for high-efficient thermoelectric application. In this paper, ion beam sputtering was used to deposit Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} bilayer thin films on borosilicate substrates at room-temperature. Then the bismuth antimony tellurium thin films were synthesized via post thermal treatment of the Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} bilayer thin films. The effect of annealing temperature and compositions on the thermoelectric properties of the thin films was investigated. After the thin films were annealed from 150 °C to 350 °C for 1 h in the high vacuum condition, the Seebeck coefficient changed from a negative sign to a positive sign. The X-ray diffraction results showed that the synthesized tellurium-based thermoelectric thin film exhibited various alloys phases, which contributed different thermoelectricity conductivity to the synthesized thin film. The overall Seebeck coefficient of the synthesized thin film changed from negative sign to positive sign, which was due to the change of the primary phase of the tellurium-based materials at different annealing conditions. Similarly, the thermoelectric properties of the films were also associated with the grown phase. High-quality thin film with the Seebeck coefficient of 240 μV K{sup −1} and the power factor of 2.67 × 10{sup −3} Wm{sup −1} K{sup −2} showed a single Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} phase when the Sb/Te thin film sputtering time was 40 min. - Highlights: • Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} thermoelectric thin films synthesized via bilayer annealing • The film has single Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} phase with best thermoelectric performance. • The film has high thermoelectric properties comparable with other best results.

Equilibrium state of delta-phase with tellurium in the Sb-Bi-Te system

International Nuclear Information System (INIS)

Gajgukova, V.S.; Dudkin, L.D.; Erofeev, R.S.; Musaelyan, V.V.; Nadzhip, A.Eh.; Sokolov, O.B.

1978-01-01

A research has been carried out with a view to establish the equilibrium state of delta-phase of the composition (Sbsub(1-x)Bisub(x)) 2 Te 3 with tellurium, depending on x and temperature. The Hall effect, the thermoelectromotive force, and the electric conductivity of the samples of Sb-Bi-Te alloys have been measured, the samples being annealed at various temperatures (550 to 250 deg C). The measurement results have shown that as the Bi 2 Te 3 content in the solid solutions increases and temperature decreases, the delta-phase-Te boundary monotonously approaches the stoichiometric composition. Using the research carrid out as the basis, the general character of the equilibrium delta-phase with tellurium boundary has been rendered more precise in Sb-Bi-Te system, depending on the temperature and Bi content (up to 25 at.%)

Antiparasitic activity of 1,3-dioxolanes containing tellurium in Trichomonas vaginalis.

Science.gov (United States)

Sena-Lopes, Ângela; das Neves, Raquel Nascimento; Bezerra, Francisco Silvestre Brilhante; de Oliveira Silva, Mara Thais; Nobre, Patrick C; Perin, Gelson; Alves, Diego; Savegnago, Lucielli; Begnini, Karine Rech; Seixas, Fabiana Kommling; Collares, Tiago; Borsuk, Sibele

2017-05-01

The increased prevalence of metronidazole-resistant infections has resulted in a search for alternative drugs for the treatment of trichomoniasis. In the present study, we report the preparation and in vitro activity of three 1,3-dioxolanes that contain tellurium (PTeDOX 01, PTeDOX 02, and PTeDOX 03) against Trichomonas vaginalis. Six concentrations of these compounds were analyzed for in vitro activity against ATCC 30236 isolate of T. vaginalis. PTeDOX 01 reported a cytotoxic effect against 100% of T. vaginalis trophozoites at a final concentration of 90μM with an IC 50 of 60μM. The kinetic growth curve of trophozoites indicated that PTeDOX 01 reduced the growth by 22% at a concentration of 90μM after an exposure of 12h, and induced complete parasite death at 24h. It induced cytotoxicity of 44% at 90μM concentration but and had no effect in lower concentrations in a culture of CHO-K1 cells. These results confirmed that PTeDOX 01 is an important drug for the treatment of T. vaginalis, and should be evaluated in other infectious agents as well. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

GALVANIC MAGNETIC PROPERTIES OF BISMUTH THIN FILMS DOPED WITH TELLURIUM MADE BY THERMAL VACUUM EVAPORATION

Directory of Open Access Journals (Sweden)

V. A. Komarov

2013-01-01

Full Text Available The influence of n-type impurity of tellurium (concentration range from 0.005 atomic % Te to 0.15 atomic % Te on galvanic magnetic properties (resistivity, magnetic resistance and Hall constant of Bi thin films with various thicknesses was studied. The properties were measured in temperature range from 77 to 300 K. It was established that the classical size effect in the films is significant and decreases with higher concentration of Te impurity. The analysis of experimental results was carried out in approximation of the law of Jones-Schoenberg dispersion for Bi films doped with tellurium. Calculation of concentration and mobility of charge carriers in the studied films was made.

Hydrogen-assisted post-growth substitution of tellurium into molybdenum disulfide monolayers with tunable compositions

Science.gov (United States)

Yin, Guoli; Zhu, Dancheng; Lv, Danhui; Hashemi, Arsalan; Fei, Zhen; Lin, Fang; Krasheninnikov, Arkady V.; Zhang, Ze; Komsa, Hannu-Pekka; Jin, Chuanhong

2018-04-01

Herein we report the successful doping of tellurium (Te) into molybdenum disulfide (MoS2) monolayers to form MoS2x Te2(1-x) alloy with variable compositions via a hydrogen-assisted post-growth chemical vapor deposition process. It is confirmed that H2 plays an indispensable role in the Te substitution into as-grown MoS2 monolayers. Atomic-resolution transmission electron microscopy allows us to determine the lattice sites and the concentration of introduced Te atoms. At a relatively low concentration, tellurium is only substituted in the sulfur sublattice to form monolayer MoS2(1-x)Te2x alloy, while with increasing Te concentration (up to ˜27.6% achieved in this study), local regions with enriched tellurium, large structural distortions, and obvious sulfur deficiency are observed. Statistical analysis of the Te distribution indicates the random substitution. Density functional theory calculations are used to investigate the stability of the alloy structures and their electronic properties. Comparison with experimental results indicate that the samples are unstrained and the Te atoms are predominantly substituted in the top S sublattice. Importantly, such ultimately thin Janus structure of MoS2(1-x)Te2x exhibits properties that are distinct from their constituents. We believe our results will inspire further exploration of the versatile properties of asymmetric 2D TMD alloys.

Electric field fluctuations in liquid tellurium alloys a hint to bond character

NARCIS (Netherlands)

Paulick, C.A.; Brinkmann, R.; Elwenspoek, Michael Curt; von Hartrott, M.; Kiehl, M.; Maxim, P.; Quitmann, D.

1985-01-01

Atomic scale electric field fluctuations in liquid tellurium alloys are detected as they induce nuclear spin relaxation rate RQ in noble gas impurity atoms, via quadrupolar interaction. Results for Xe in liquid Ag, Ga, In, Tl, Ge, Sn---Te alloys are discussed, assuming that bonding in these alloys

Vaporization studies on elemental tellurium and selenium by Knudsen effusion mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Viswanathan, R., E-mail: rvis1953@gmail.com; Balasubramanian, R., E-mail: rbs@igcar.gov.in; Darwin Albert Raj, D., E-mail: darwinalbertraj1953@gmail.com; Sai Baba, M., E-mail: msb@igcar.gov.in; Lakshmi Narasimhan, T.S., E-mail: tslak@igcar.gov.in

2014-08-01

Highlights: • A detailed KEMS study of vaporization of elemental tellurium and selenium systems. • Clusters Te{sub i}(g) (i = 2 to 7) and Se{sub i}(g) (i = 2 to 9) identified over Te(s) and Se(s). • p–T relations for Te{sub i}(g) (590 to 690 K) and Se{sub i}(g) (380 to 480 K). • Vapor phase of Te dominated by Te{sub 2}(g) (∼95%) while that of Se by Se{sub 6}(g) (∼50%) and Se{sub 5}(g) (∼25%). • Sublimation and atomization enthalpies deduced for Te{sub i}(g) and Se{sub i}(g). - Abstract: Vaporization studies on elemental tellurium and selenium were conducted by Knudsen effusion mass spectrometry in the temperature range of 590–690 K and 380–480 K, respectively. The ionic species Te{sub i}{sup +} (i = 1–7) and Se{sub i}{sup +}(g) (i = 1–9) were detected in the mass spectra over these two condensed phases. Measurement of ion intensities were performed as a function of electron impact energy and as a function of temperature (at different electron impact energies) for identifying the gaseous precursor species as well as for determining the partial pressure–temperature relations and sublimation enthalpies for these species. While the major species over elemental tellurium was confirmed to be Te{sub 2}(g) (with all other gaseous species Te{sub 3}–Te{sub 7} put together constituting less than 5%), the major species over elemental selenium was found to be Se{sub 6}(g), closely followed by Se{sub 5}(g) (with other gaseous species Se{sub 2}–Se{sub 4} and Se{sub 7}–Se{sub 9} put together also moderately constituting ∼25%). From the partial pressures, the thermodynamic data for the sublimation reactions i Te(s) = Te{sub i}(g) and i Se(s) = Se{sub i}(g) were deduced by second- and third-law methods. The atomization enthalpies of tellurium and selenium clusters were also deduced by using the recommended enthalpies of formation of monomeric species. Comparison of the findings obtained in the present study with those in previous studies revealed

Synthesis of ultra-thin tellurium nanoflakes on textiles for high-performance flexible and wearable nanogenerators

Energy Technology Data Exchange (ETDEWEB)

He, Wen; Van Ngoc, Huynh; Qian, Yong Teng; Hwang, Jae Seok; Yan, Ya Ping [Department of Physics and Interdisciplinary Course of Physics and Chemistry, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 16419, Gyeoggi-do (Korea, Republic of); Choi, Hongsoo [Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-873, Daegu (Korea, Republic of); Kang, Dae Joon, E-mail: djkang@skku.edu [Department of Physics and Interdisciplinary Course of Physics and Chemistry, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 16419, Gyeoggi-do (Korea, Republic of)

2017-01-15

Highlights: • Ultra-thin tellurium (Te) nanoflakes were successfully grown on textile and used as an active piezoelectric material. • Te nanoflake nanogenerator device was systematically studied by bending and compressing test. • The ultra-high output power during compressing test can light up 10 LEDs without any external power source. • The device can offer a breakthrough in applying tellurium nanoflakes into high-performance flexible and wearable piezoelectric nanogenerator. - Abstract: We report that ultra-thin tellurium (Te) nanoflakes were successfully grown on a sample of a gold-coated textile, which then was used as an active piezoelectric material. An output voltage of 4 V and a current of 300 nA were obtained from the bending test under a driving frequency of 10 Hz. To test the practical applications, Te nanoflake nanogenerator (TFNG) device was attached to the subject’s arm, and mechanical energy was converted to electrical energy by means of periodic arm-bending motions. The optimized open-circuit voltage and short-circuit current density of approximately 125 V and 17 μA/cm{sup 2}, respectively, were observed when a TFNG device underwent a compression test with a compressive force of 8 N and driving frequency of 10 Hz. This high-power generation enabled the instantaneous powering of 10 green light-emitting diodes that shone without any assistance from an external power source.

Catalytic activity of oxide cerium-molybdenum-tellurium catalysts in oxidation ammonolysis

International Nuclear Information System (INIS)

Dzhordano, N.; Bart, D.; Madzhori, R.

1984-01-01

A commercial catalyst containing a mixture of Ce-, Mo-, Te oxides deposited on SiO 2 is shown to manifest a high efficiency in oxidative ammonolysis of propylene (C 3 - ) to acrylonitrile (AN). The dependence of the catalytic properties on the catalyst composition and reaction conditions is studied. It is established that three-component mixtures are more active and selective than the systems with a lesser number of components. Using the catalyst with the optimum ratio of constituent oxides in a microreactor at 440 deg enabled one to achieve initial selectivity in terms of AN equal to 82.5% at 97% conversion of C 3 - . Acrolein, acetonitrile, HCN and nitrogen oxides are the reaction by-products. A supposition is made that the reaction proceeds via the formation of π-compleXes on the centres of Te(4). Setective oxidation occurs on oxygen atoms bonded with the Mo(6) ions. Tellurium enhances the molybdenum reducibleness due to delocalization of electrons, whereas the cerium addition to the mixture of tellurium- and molybdenum oxides increases the rate of molybdenum reoxidation and thus enhances the catalytic system stability

Determination of spins and radioactive widths of tellurium nuclear levels with capturre gamma rays

International Nuclear Information System (INIS)

Bianchini, F.G.

1973-01-01

Spins and levels widths of the tellurium, mainly 128 Te and 130 Te, were determinated by gamma spectroscopy. Measurements of inelastic and elastic scattering, angular distribution and scattering temperature dependence, were still made. Energy levels of this isotopes, were also determinated [pt

Deposition of tellurium films by decomposition of electrochemically-generated H{sub 2}Te: application to radiative cooling devices

Energy Technology Data Exchange (ETDEWEB)

Engelhard, T.; Jones, E.D.; Viney, I. [Coventry Univ. (United Kingdom). Centre for Data Storage Mater.; Mastai, Y.; Hodes, G. [Department of Materials and Interfaces, Weizmann Institute of Science, 76100, Rehovot (Israel)

2000-07-17

The preparation of homogenous, large area thin layers of tellurium on thin polyethylene foils is described. The tellurium was formed by room temperature decomposition of electrochemically generated H{sub 2}Te. Pre-treatment of the polyethylene substrates with KMnO{sub 4} to give a Mn-oxide layer was found to improve the Te adhesion and homogeneity. Optical characterization of the layers was performed using UV/VIS/NIR spectroscopy. Such coatings have favorable characteristics for use as solar radiation shields in radiative cooling devices. The simplicity of generation of the very unstable H{sub 2}Te was also exploited to demonstrate formation of size-quantized CdTe nanocrystals. (orig.)

Continuous removal and recovery of tellurium in an upflow anaerobic granular sludge bed reactor

International Nuclear Information System (INIS)

Mal, Joyabrata; Nancharaiah, Yarlagadda V.; Maheshwari, Neeraj; Hullebusch, Eric D. van; Lens, Piet N.L.

2017-01-01

Highlights: • Tellurite bioreduction coupled to recovery of biogenic Te(0) nanocrystals. • First report on continuous tellurite removal in a UASB reactor. • Biogenic Te(0) was mainly associated with loosely-bound EPS of granular sludge. • Repeated exposure to tellurite caused compositional changes in the EPS matrix. - Abstract: Continuous removal of tellurite (TeO 3 2− ) from synthetic wastewater and subsequent recovery in the form of elemental tellurium was studied in an upflow anaerobic granular sludge bed (UASB) reactor operated at 30 °C. The UASB reactor was inoculated with anaerobic granular sludge and fed with lactate as carbon source and electron donor at an organic loading rate of 0.6 g COD L −1 d −1 . After establishing efficient and stable COD removal, the reactor was fed with 10 mg TeO 3 2− L −1 for 42 d before increasing the influent concentration to 20 mg TeO 3 2− L −1 . Tellurite removal (98 and 92%, respectively, from 10 and 20 mg Te L −1 ) was primarily mediated through bioreduction and most of the removed Te was retained in the bioreactor. Characterization using XRD, Raman spectroscopy, SEM-EDX and TEM confirmed association of tellurium with the granular sludge, typically in the form of elemental Te(0) deposits. Furthermore, application of an extracellular polymeric substances (EPS) extraction method to the tellurite reducing sludge recovered up to 78% of the tellurium retained in the granular sludge. This study demonstrates for the first time the application of a UASB reactor for continuous tellurite removal from tellurite-containing wastewater coupled to elemental Te(0) recovery.

β-Telluroacroleins and β-tellurovinyl ketones: synthesis, reactions and structure

International Nuclear Information System (INIS)

Sadekov, I.D.

2002-01-01

Data on synthesis, reactivity, spectral characteristics and structure of new telluroorganic synthons, i.e. β-tellurovinylcarbonyl compounds, were generalized and systematized. Synthesis and reactions of β-telluroacroleins and similar cations were considered individually for each type of β-tellurovinylcarbonyl compounds. Special attention was paid to the use of the compounds for preparing tellurium-containing heterocycles. Reactions characteristics of carbonyl groups and tellurium-containing substituents, as well as transformation, as a result of which β-tellurovinylcarbonyl compounds and products of their reactions form tellurium-containing heterocycles, were discussed [ru

Characterization of tellurium-based films for NO2 detection

International Nuclear Information System (INIS)

Tsiulyanu, D.; Tsiulyanu, A.; Liess, H.-D.; Eisele, I.

2005-01-01

Sensing characteristics of tellurium-based thin films for NO 2 monitoring was studied systematically. The influence of contact materials, thermal treatment, temperature and thickness of the samples on the electrical conductivity and sensitivity to NO 2 with respect to scanning electron microscopy analyses is given. The possibility is shown to optimize the properties of the films for the development of a simple and stable NO 2 sensor device with rapid response/recovery time and low operating temperature. The sensing mechanism is discussed for the direct interaction of gaseous species with lone-pair electrons of chalcogen atoms

Tellurium adsorption on tungsten and molybdenum field emitters

International Nuclear Information System (INIS)

Collins, R.A.; Kiwanga, C.A.

1977-01-01

Studies of the adsorption of tellurium onto tungsten and molybdenum field emitters are described and the results obtained are compared with those obtained in previous work on the adsorption of silicon and selenium. The adsorption of Te onto W was found to be much more uniform than in the case of Se. Although Te is metallic in many of its properties its adsorptive behavior on field emitters is found to be similar to that of selenium and these adsorptive properties are basically common to all semiconductors. The most evident property of these adsorbates is that the work function and emission current decrease simultaneously at coverages of less than half a monolayer and the work function subsequently increases. (B.D.)

Dibromidochlorido{2-[(dimethylaminomethyl]phenyl-κ2N,C1}tellurium(IV

Directory of Open Access Journals (Sweden)

Prakul Rakesh

2012-01-01

Full Text Available The title compound, C9H13Br2ClNTe, was synthesized by reacting [2-(dimethylaminomethylphenyl]tellurium(II chloride with Br2. As a consequence, the Cl and Br atoms are not well ordered but distributed over the three possible positions such that the overall stiochiometry is two Br atoms and one Cl atom. The scrambling of the Br and Cl atoms indicates a small energy barrier for the exchange process between the apical and equatorial positions. Overall, the Te atom geometry is slightly distorted square pyramidal (τ = 0.052 for the major component. However, there is a weak secondary interaction between the Te atoms and the disordered Br/Cl atoms of a nearby molecule. The Te—Br and Te—Cl distances in both disorder components fall into two groups; a longer distance for the Br/Cl involved in this secondary interaction [2.6945 (17 Å for Br and 2.601 (9Å for Cl] and shorter bond distances to the remaining halogen atoms, indicating that this interaction has slightly weakened the Te—X bond, as is the case in the previously reported tribromido structure [Singh et al. (1990. J. Chem. Soc. Dalton Trans. pp. 907–913]. Otherwise, the metrical parameters in the two structures are not significantly different. An intermolecular C—H...Br interaction occurs.

Microbial-assisted synthesis and evaluation the cytotoxic effect of tellurium nanorods

Energy Technology Data Exchange (ETDEWEB)

Forootanfar, Hamid [Herbal and Traditional Medicines Research Center, Kerman University of Medical Sciences, Kerman (Iran, Islamic Republic of); Amirpour-Rostami, Sahar; Jafari, Mandana [Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman (Iran, Islamic Republic of); Forootanfar, Amir [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Yousefizadeh, Zahra [The Student Research Committee, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman (Iran, Islamic Republic of); Shakibaie, Mojtaba, E-mail: shakiba@kmu.ac.ir [Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman (Iran, Islamic Republic of)

2015-04-01

The present study was designed to isolate bacterial strain capable of tellurium nanorods' (Te NRs) production followed by purification and evaluation of the cytotoxic effect of Te NRs. Among 25 environmental samples collected for screening of Te NR-producer bacterial strains one bacterial colony (isolated from hot spring and identified as Pseudomonas pseudoalcaligenes strain Te) was selected and applied for biosynthesis of Te NRs. Thereafter, an organic–aqueous partitioning system was applied for the purification of the biogenic Te NRs and the purified Te NRs were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction spectroscopy (XRD), UV–visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR) techniques. The cytotoxic effect of biologically synthesized Te NRs and potassium tellurite on four cell lines of MCF-7, HT1080, HepG2 and A549 was then determined using the MTT assay method. The obtained results revealed lower toxicity for the rod-shaped biogenic tellurium nanostructures (~ 22 nm diameter by 185 nm length) compared to K{sub 2}TeO{sub 3}. - Highlights: • Te NR producing bacterial strain were isolated from hot springs. • Organic–aqueous partitioning system was applied for purification of Te nanorods. • The rod-shaped biogenic Te NPs showed lower cytotoxicity compared to K{sub 2}TeO{sub 3}.

Microbial-assisted synthesis and evaluation the cytotoxic effect of tellurium nanorods

International Nuclear Information System (INIS)

Forootanfar, Hamid; Amirpour-Rostami, Sahar; Jafari, Mandana; Forootanfar, Amir; Yousefizadeh, Zahra; Shakibaie, Mojtaba

2015-01-01

The present study was designed to isolate bacterial strain capable of tellurium nanorods' (Te NRs) production followed by purification and evaluation of the cytotoxic effect of Te NRs. Among 25 environmental samples collected for screening of Te NR-producer bacterial strains one bacterial colony (isolated from hot spring and identified as Pseudomonas pseudoalcaligenes strain Te) was selected and applied for biosynthesis of Te NRs. Thereafter, an organic–aqueous partitioning system was applied for the purification of the biogenic Te NRs and the purified Te NRs were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction spectroscopy (XRD), UV–visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR) techniques. The cytotoxic effect of biologically synthesized Te NRs and potassium tellurite on four cell lines of MCF-7, HT1080, HepG2 and A549 was then determined using the MTT assay method. The obtained results revealed lower toxicity for the rod-shaped biogenic tellurium nanostructures (~ 22 nm diameter by 185 nm length) compared to K 2 TeO 3 . - Highlights: • Te NR producing bacterial strain were isolated from hot springs. • Organic–aqueous partitioning system was applied for purification of Te nanorods. • The rod-shaped biogenic Te NPs showed lower cytotoxicity compared to K 2 TeO 3

Continuous removal and recovery of tellurium in an upflow anaerobic granular sludge bed reactor

Energy Technology Data Exchange (ETDEWEB)

Mal, Joyabrata, E-mail: joyabrata2006@gmail.com [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Nancharaiah, Yarlagadda V. [Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, 603102, Tamil Nadu (India); Homi Bhabha National Institute, Anushakti Nagar Complex, Mumbai 400094 (India); Maheshwari, Neeraj [CNRS UMR 7338, BMBI University de Technologie Compiegne, 60200 Compiegne (France); Hullebusch, Eric D. van [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Université Paris-Est, Laboratoire Géomatériaux et Environnement (LGE), EA 4508, UPEM, 77454, Marne-la-Vallée (France); Lens, Piet N.L. [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Department of Chemistry and Bioengineering, Tampere University of Technology, P.O-Box 541, Tampere (Finland)

2017-04-05

Highlights: • Tellurite bioreduction coupled to recovery of biogenic Te(0) nanocrystals. • First report on continuous tellurite removal in a UASB reactor. • Biogenic Te(0) was mainly associated with loosely-bound EPS of granular sludge. • Repeated exposure to tellurite caused compositional changes in the EPS matrix. - Abstract: Continuous removal of tellurite (TeO{sub 3}{sup 2−}) from synthetic wastewater and subsequent recovery in the form of elemental tellurium was studied in an upflow anaerobic granular sludge bed (UASB) reactor operated at 30 °C. The UASB reactor was inoculated with anaerobic granular sludge and fed with lactate as carbon source and electron donor at an organic loading rate of 0.6 g COD L{sup −1} d{sup −1}. After establishing efficient and stable COD removal, the reactor was fed with 10 mg TeO{sub 3}{sup 2−} L{sup −1} for 42 d before increasing the influent concentration to 20 mg TeO{sub 3}{sup 2−} L{sup −1}. Tellurite removal (98 and 92%, respectively, from 10 and 20 mg Te L{sup −1}) was primarily mediated through bioreduction and most of the removed Te was retained in the bioreactor. Characterization using XRD, Raman spectroscopy, SEM-EDX and TEM confirmed association of tellurium with the granular sludge, typically in the form of elemental Te(0) deposits. Furthermore, application of an extracellular polymeric substances (EPS) extraction method to the tellurite reducing sludge recovered up to 78% of the tellurium retained in the granular sludge. This study demonstrates for the first time the application of a UASB reactor for continuous tellurite removal from tellurite-containing wastewater coupled to elemental Te(0) recovery.

Surface studies on graphite furnace platforms covered with Pd, Rh and Ir as modifiers in graphite furnace atomic absorption spectrometry of tellurium

Energy Technology Data Exchange (ETDEWEB)

Pedro, Juana [Area de Química Analítica, Departamento de Química, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829 (S3000GL.N), Santa Fe (Argentina); Stripekis, Jorge [Laboratorio de Análisis de Trazas, Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (1428), Buenos Aires (Argentina); Departamento de Ingeniería Química, Instituto Tecnológico de Buenos Aires, Av. Eduardo Madero 399 (1106), Buenos Aires (Argentina); Bonivardi, Adrian [Area de Química Analítica, Departamento de Química, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829 (S3000GL.N), Santa Fe (Argentina); Tudino, Mabel, E-mail: tudino@qi.fcen.uba.ar [Laboratorio de Análisis de Trazas, Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (1428), Buenos Aires (Argentina)

2015-05-01

The main objective of this work is the study of correlations between the efficiency of the distribution of the permanent platinum group modifiers Pd, Rh and Ir over the graphite surface with the aim of improving analytical signal of tellurium. Modifier solution was deposited onto the platform and pyrolysed after drying. In the case of Pd, the physical vaporization/deposition technique was also tested. In order to analyze the differences amongst coverings (morphology, topology and distribution), the graphite surfaces were studied with scanning electron microscopy and energy dispersive X-ray microscopy. Micrographs for physical vaporization and pyrolytic deposition of Pd were also analyzed in order to explain the lack of signal obtained for tellurium with the first alternative. Similar micrographs were obtained for pyrolytic deposition of Ir and Rh and then, compared to those of Pd. Ir showed the most homogeneous distribution on the graphite surface and the tallest and sharpest transient. With the aim of improving the analytical signal of tellurium, the correlation between the surface studies and the tellurium transient signal (height, area and shape) is discussed. - Highlights: • Distribution of Rh, Pd and Ir onto graphite furnaces is evaluated by SEM and EDX • Micrographs and spectra showed that surface distribution could influence Te signal. • Ir showed the best signal together with the most homogeneous surface distribution. • Pd-PVD micrographs revealed the absence of graphite and no signal for Te.

Tellurium labeled analogues of the fatty acid hexadecenoic acid for imaging of myocardial tissue

International Nuclear Information System (INIS)

Mills, S.L.

1980-01-01

Non-invasive nuclear diagnostic procedures for the evaluation of acute myocardial infarction and ischemia are currently limited by problems associated with the availablity of radiopharmaceuticals, development of imaging equipment, and inherent characteristics of radionuclides. Myocardial tissue requires high levels of substrates which provide energy for the continuous functioning of this vital organ. Of the major sources of energy, the most utilized source is fatty acids. Tellurium-123m, with excellent gamma imaging characteristics was chosen as the radionuclide. A 16 carbon fatty acid, hexadecenoic acid, was chosen as the carrier molecule. The tellurium-123m fatty acid radiopharmaceuticals were formulated either in a solution of 20 percent ethanol, two percent polysorbate 80, and brought to volume with normal saline or in 12.5 percent human serum ablumin and brought to volume with normal saline. Biodistribution was performed in three animal species: Sprague-Dawley rats (three rats per time frame), Australian white rabbits (three rabbits per time frame), and mongrel dogs (one dog per time frame). Dosimetry calculations were performed to assess the radiation dose

Tellurium quantum dots: Preparation and optical properties

Science.gov (United States)

Lu, Chaoyu; Li, Xueming; Tang, Libin; Lai, Sin Ki; Rogée, Lukas; Teng, Kar Seng; Qian, Fuli; Zhou, Liangliang; Lau, Shu Ping

2017-08-01

Herein, we report an effective and simple method for producing Tellurium Quantum dots (TeQDs), zero-dimensional nanomaterials with great prospects for biomedical applications. Their preparation is based on the ultrasonic exfoliation of Te powder dispersed in 1-methyl-2-pyrrolidone. Sonication causes the van der Waals forces between the structural hexagons of Te to break so that the relatively coarse powder breaks down into nanoscale particles. The TeQDs have an average size of about 4 nm. UV-Vis absorption spectra of the TeQDs showed an absorption peak at 288 nm. Photoluminescence excitation (PLE) and photoluminescence (PL) are used to study the optical properties of TeQDs. Both the PLE and PL peaks revealed a linear relationship against the emission and excitation energies, respectively. TeQDs have important potential applications in biological imaging and catalysis as well as optoelectronics.

Radiochemical studies on the separation of iodine-131 and radioiodination of some organic compounds

International Nuclear Information System (INIS)

Mohamed, M.A.I.

2010-01-01

This thesis is constituted of three chapters:Chapter I: It deals with the theoretical consideration of the subject. The chapter deals with the importance of radioisotopes in medical applications, and the physical and biological properties of these isotopes. Also, this part deals with the chemical and physical properties of both tellurium and iodine and the methods of the production of radioiodine from tellurium targets especially dry distillation method and ion exchange method. It deals with general methods of labeling, chemistry of iodine especially the most frequently used in nuclear medicine, their methods of production and applications. It includes also the techniques used for the preparation of the radioiodinated compounds, especially the electrophilic technique or the oxidative radioiodination technique. In this technique, oxidizing agents are used to oxidize iodide ions to iodonium ions capable of electrophilic attack on the aryl group of the organic compound. This chapter deals also with the receptor tracers, their types and the effects that can occur due to the binding of these receptors to the cell membrane. Since these radiopharmaceuticals are used for diagnosis and therapeutic treatment of human diseases, quality control tests such as chemical purity, radionuclidic purity, radiochemical purity, sterility, apyrogenicity and biodistribution are performed to ensure the purity, the safety and efficiency of these products for the intended nuclear medicine application.Chapter II:It contains detailed information concerning the chemicals, reagents, the radionuclides, the equipment and the counting systems used in the study. It describes production technique of iodine-131 using dry distillation method. It describes also the electrophilic radioiodination for each of Y-indole and epidepride. Analysis of the labeled products was performed using two chromatographic techniques. The first technique is thin layer chromatography in which the compound was identified by

Characterization of tellurium-based films for NO{sub 2} detection

Energy Technology Data Exchange (ETDEWEB)

Tsiulyanu, D. [Technical University, Department of Physics, bul. Dacia 41, MD-2060 Kishinau (Moldova, Republic of)]. E-mail: tsiu@cni.md; Tsiulyanu, A. [Technical University, Department of Physics, bul. Dacia 41, MD-2060 Kishinau (Moldova, Republic of); Liess, H.-D. [University of the Bundeswehr Munich, Faculty of Electrical Engineering and Information Technology, Institute of Physics, D-85577 Neubiberg (Germany); Eisele, I. [University of the Bundeswehr Munich, Faculty of Electrical Engineering and Information Technology, Institute of Physics, D-85577 Neubiberg (Germany)

2005-08-01

Sensing characteristics of tellurium-based thin films for NO{sub 2} monitoring was studied systematically. The influence of contact materials, thermal treatment, temperature and thickness of the samples on the electrical conductivity and sensitivity to NO{sub 2} with respect to scanning electron microscopy analyses is given. The possibility is shown to optimize the properties of the films for the development of a simple and stable NO{sub 2} sensor device with rapid response/recovery time and low operating temperature. The sensing mechanism is discussed for the direct interaction of gaseous species with lone-pair electrons of chalcogen atoms.

Strong nonlinear photonic responses from microbiologically synthesized tellurium nanocomposites

Science.gov (United States)

Liao, K.-S.; Wang, Jingyuan; Dias, S.; Dewald, J.; Alley, N.J.; Baesman, S.M.; Oremland, R.S.; Blau, W.J.; Curran, S.A.

2010-01-01

A new class of nanomaterials, namely microbiologically-formed nanorods composed of elemental tellurium [Te(0)] that forms unusual nanocomposites when combined with poly(m-phenylenevinylene-co-2,5-dioctoxy-phenylenevinylene) (PmPV) is described. These bio-nanocomposites exhibit excellent broadband optical limiting at 532 and 1064 nm. Nonlinear scattering, originating from the laser induced solvent bubbles and microplasmas, is responsible for this nonlinear behavior. The use of bacterially-formed Te(0) when combined with an organic chemical host (e.g., PmPV) is a new green method of nanoparticle syntheses. This opens the possibilities of using unique, biologically synthesized materials to advance future nanoelectronic and nanophotonic applications. ?? 2009 Elsevier B.V. All rights reserved.

Extraction-spectrophotometric method for silicon determination in high-purity substances. 1. Silicon determination in tellurium

Energy Technology Data Exchange (ETDEWEB)

Shaburova, V P; Yudelevich, I G [AN SSSR, Novosibirsk (USSR). Inst. Neorganicheskoj Khimii

1989-01-01

The extraction-spectrophotometric method for silicon determination in tellurium based on extraction isolation of the base by tributyl phosphate from hydrochloride solutions and with addition of HNO/sub 3/ and spectrophotometric silicon determination using malachite green is developed. The method permits to determine 2x10/sup -1/-3x10/sup -4/ % Si.

The use of masking agents in the determination, by hydride generation and atomic-absorption spectrophotometry, of arsenic, antimony, selenium, tellurium, and bismuth in the presence of noble metals

International Nuclear Information System (INIS)

Kellerman, S.P.

1982-01-01

The effectiveness of thiosemicarbazide, tellurium, and potassium iodide as masking agents to eliminate interferences was assessed. Thiosemicarbazide was found to be effective in eliminating or reducing the interferences on arsenic, antimony, and bismuth, and tellurium reduced the interferences on selenium. The interferences on tellurium could not be eliminated. Arsenic, antimony, selenium, and bismuth were determined in metal sulphide concentrates that were spiked with the noble metals (defined here as gold plus all the platinum-group metals except osmium). The relative standard deviations for arsenic, antimony, bismuth, and selenium were 0,061, 0,017, 0,029, and 0,145 respectively. The values obtained for all the analytes agreed favourably with the preferred values for two in-house reference samples. The laboratory method is detailed in an appendix

Reaction of 1-bromo-3-chloropropane with tellurium and dimethyl telluride in the system of hydrazine hydrate-alkali; Reaktsiya 1-brom-3-khlorpropana s tellurom i dimetilditelluridom v sisteme gidrazin-gidrat-shcheloch'

Energy Technology Data Exchange (ETDEWEB)

Russavskaya, N V; Levanova, E P; Sukhomazova, Eh N; Grabel' nykh, V A; Elaev, A V; Klyba, L V; Zhanchipova, E R; Albanov, A I; Korotaeva, I M; Toryashinova, D S.D.; Korchevin, N A [SO RAN, Irkutskij Inst. Khimii imeni A.E. Favorskogo, Irkutsk (Russian Federation)

2006-05-15

A synthesis of oligomeric substance of thiocol type, the poly(trimethyleneditelluride), from 1-bromo-3-chloropropane and elemental tellurium is performed using a hydrazine hydrate-alkali system. Reductive splitting of the tellurocol followed by alkylation with methyl iodide give rise to preparation of bis(methyltelluro)propane, which was synthesized also from dimethyl telluride and 1,3-dihalopropanes using the N{sub 2}H{sub 4}{center_dot}H{sub 2}O/KOH system. The reaction products were characterized by elementary analysis, NMR, and IR spectra. Mass spectra of the synthesized low molecular weight organotellurium compounds are considered.

Improvement of physical properties of ZnO thin films by tellurium doping

Energy Technology Data Exchange (ETDEWEB)

Sönmezoğlu, Savaş, E-mail: svssonmezoglu@kmu.edu.tr; Akman, Erdi

2014-11-01

Highlights: • We report the synthesis of tellurium-doped zinc oxide (Te–ZnO) thin films using sol–gel method. • Highly c-axis oriented Te-doped ZnO thin films were grown on FTO glasses as substrate. • 1.5% Te-doping ratio could improve the physical properties of ZnO thin films. - Abstract: This investigation addressed the structural, optical and morphological properties of tellurium incorporated zinc oxide (Te–ZnO) thin films. The obtained results indicated that Te-doped ZnO thin films exhibit an enhancement of band gap energy and crystallinity compared with non-doped films. The optical transmission spectra revealed a shift in the absorption edge toward lower wavelengths. X-ray diffraction measurement demonstrated that the film was crystallized in the hexagonal (wurtzite) phase and presented a preferential orientation along the c-axis. The XRD obtained patterns indicate that the crystallite size of the thin films, ranging from 23.9 to 49.1 nm, changed with the Te doping level. The scanning electron microscopy and atomic force microscopy results demonstrated that the grain size and surface roughness of the thin films increased as the Te concentration increased. Most significantly, we demonstrate that it is possible to control the structural, optical and morphological properties of ZnO thin films with the isoelectronic Te-incorporation level.

High performance supercapacitor and non-enzymatic hydrogen peroxide sensor based on tellurium nanoparticles

Directory of Open Access Journals (Sweden)

M. Manikandan

2017-04-01

Full Text Available Tellurium nanoparticles (Te Nps were synthesized by wet chemical method and characterized by XRD, Raman, FESEM, TEM, XPS, UV–Vis and FL. The Nps were coated on graphite foil and Glassy carbon electrode to prepare the electrodes for supercapacitor and biosensor applications. The supercapacitor performance is evaluated in 2 M KOH electrolyte by both Cyclic Voltammetry (CV and galvanostatic charge-discharge method. From charge-discharge method, Te Nps show a specific capacitance of 586 F/g at 2 mA/cm2 and 100 F/g at 30 mA/cm2 as well as an excellent cycle life (100% after 1000 cycles. In addition, the H2O2 sensor performance of Te Nps modified glassy carbon electrode is checked by CV and Chronoamperometry (CA in phosphate buffer solution (PBS. In the linear range of 0.67 to 8.04 μM of hydrogen peroxide (H2O2, Te NPs show a high sensitivity of 0.83 mA mM−1 cm−2 with a correlation coefficient of 0.995. The detection limit is 0.3 μM with a response time less than 5 s. Keywords: Tellurium nanoparticles, Supercapacitor, Biosensor, Hydrogen peroxide

The crystal chemistry of novel thorium and uranium compounds with oxo-anions from group VI of periodic table (S, Se, Te, Cr, Mo and W)

Energy Technology Data Exchange (ETDEWEB)

Xiao, Bin

2016-01-26

This dissertation focus on the synthesis, phase studies and physicochemical properties of novel thorium and uranium compounds with the Group VI (S, Se, Te, Cr, Mo, W) of the Periodic Table. All the studied compounds are listed in Table 2.2 from the page 15. I subdivided all the newly synthesized compounds into several chapters according to their structural and topological differences. First, for thorium molybdates and tungstates, almost all of these compounds are based on corner-sharing of ThO{sub x} (x = 6, 8 and 9) and MoO{sub 4} or WO{sub x} (x = 4, 5, 6) polyhedra. Interestingly, all these compounds can be seen as derived from a pure thorium molybdate compound (ThMo{sub 2}O{sub 8}) which was isolated from high-temperature solid-state synthesis method. Therefore, the polymorphs of this most basic ThMo{sub 2}O{sub 8} compound is firstly introduced (see Chapter 3.1 from page 18). The thermodynamic, electronic and vibrational properties of all investigated ThMo{sub 2}O{sub 8} polymorphs were studied using ab initio calculations. Then, two subfamilies of thorium molybdates, that is, rubidium thorium molybdate and cesium thorium molybdate and their thermal and vibrational behaviors were discussed in details in Chapter 4.1 from page 37 and Chapter 4.2 from page 50, respectively. Moreover, some new insights about the complexity of thorium tungstates were also discussed (Chapter 4.3 from page 59). Some novel thorium molybdate and chromate compounds synthesized from aqueous condition are discussed in Chapter 5 from page 71. In the Chapter 8.2.4, the stereochemistry for thorium and uranium compounds are introduced, especially thorium selinites and uranyl tellurites (see Chapter 6.1 from page 82), thorium tellurites (Chapter 6.2 from page 93), and uranyl tellurites (Chapter 6.3 from page 99 for sodium uranyl tellurium and Chapter 6.4 from page 110 for potassium uranyl tellurium, respectively). In the actinide tellurium systems, additional MoO{sub 3}/WO{sub 3} were also

Intrinsic two-dimensional states on the pristine surface of tellurium

Science.gov (United States)

Li, Pengke; Appelbaum, Ian

2018-05-01

Atomic chains configured in a helical geometry have fascinating properties, including phases hosting localized bound states in their electronic structure. We show how the zero-dimensional state—bound to the edge of a single one-dimensional helical chain of tellurium atoms—evolves into two-dimensional bands on the c -axis surface of the three-dimensional trigonal bulk. We give an effective Hamiltonian description of its dispersion in k space by exploiting confinement to a virtual bilayer, and elaborate on the diminished role of spin-orbit coupling. These intrinsic gap-penetrating surface bands were neglected in the interpretation of seminal experiments, where two-dimensional transport was otherwise attributed to extrinsic accumulation layers.

Improved selectivity for Pb(II) by sulfur, selenium and tellurium analogues of 1,8-anthraquinone-18-crown-5: synthesis, spectroscopy, X-ray crystallography and computational studies.

Science.gov (United States)

Mariappan, Kadarkaraisamy; Alaparthi, Madhubabu; Hoffman, Mariah; Rama, Myriam Alcantar; Balasubramanian, Vinothini; John, Danielle M; Sykes, Andrew G

2015-07-14

We report here a series of heteroatom-substituted macrocycles containing an anthraquinone moiety as a fluorescent signaling unit and a cyclic polyheteroether chain as the receptor. Sulfur, selenium, and tellurium derivatives of 1,8-anthraquinone-18-crown-5 (1) were synthesized by reacting sodium sulfide (Na2S), sodium selenide (Na2Se) and sodium telluride (Na2Te) with 1,8-bis(2-bromoethylethyleneoxy)anthracene-9,10-dione in a 1 : 1 ratio. The optical properties of the new compounds are examined and the sulfur and selenium analogues produce an intense green emission enhancement upon association with Pb(II) in acetonitrile. Selectivity for Pb(II) is markedly improved as compared to the oxygen analogue 1 which was also competitive for Ca(II) ion. UV-Visible and luminescence titrations reveal that 2 and 3 form 1 : 1 complexes with Pb(II), confirmed by single-crystal X-ray studies where Pb(II) is complexed within the macrocycle through coordinate covalent bonds to neighboring carbonyl, ether and heteroether donor atoms. Cyclic voltammetry of 2-8 showed classical, irreversible oxidation potentials for sulfur, selenium and tellurium heteroethers in addition to two one-electron reductions for the anthraquinone carbonyl groups. DFT calculations were also conducted on 1, 2, 3, 6, 6 + Pb(II) and 6 + Mg(II) to determine the trend in energies of the HOMO and the LUMO levels along the series.

Tellurium Enrichment in Jurassic Coal, Brora, Scotland

Directory of Open Access Journals (Sweden)

Liam Bullock

2017-11-01

Full Text Available Mid-Jurassic pyritic coals exposed at the village of Brora, northern Scotland, UK, contain a marked enrichment of tellurium (Te relative to crustal mean, average world coal compositions and British Isles Carboniferous coals. The Te content of Brora coal pyrite is more than one order of magnitude higher than in sampled pyrite of Carboniferous coals. The Te enrichment coincides with selenium (Se and mercury (Hg enrichment in the rims of pyrite, and Se/Te is much lower than in pyrites of Carboniferous coals. Initial pyrite formation is attributed to early burial (syn-diagenesis, with incorporation of Te, Se, Hg and lead (Pb during later pyrite formation. The source of Te may have been a local hydrothermal system which was responsible for alluvial gold (Au in the region, with some Au in Brora headwaters occurring as tellurides. Anomalous Te is not ubiquitous in coal, but may occur locally, and is detectable by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS.

Mutagenic activities of metal compounds in bacteria

Energy Technology Data Exchange (ETDEWEB)

Nishioka, H

1975-01-01

Environmental contaminations by certain metal compounds are bringing about serious problems to human health, including genetic hazards. It has been reported that some compounds of iron, manganese and mercury induce point mutations in microorganisms. Also it has been observed that those of aluminum, antimony, arsenic, cadmium, lead and tellurium cause chromosome aberrations in plants, insects and cultured human cells. The mechanism of mutation induction by these metals remains, however, still obscure. For screening of chemical mutagens, Kada et al, recently developed a simple and efficient method named rec-assay by observing differential growth sensitivities to drugs in wild and recombination-deficient strains of Bacillus subtilis. When a chemical is more inhibitory for Rec/sup -/ than for Rec/sup +/ cells, it is reasonable to suspect mutagenicity based on its DNA-damaging capacity. In the present report, 56 metal compounds were tested by the rec-assay. Compounds showing positive results in the assay such as potassium dichromate (K/sub 2/Cr/sub 2/O/sub 7/), ammonium molybdate ((NH/sub 4/)/sub 6/Mo/sub 7/O/sub 24/) and sodium arsenite (NaAsO/sub 2/) were then examined as to their capacities to induce reversions in E. coli Trp/sup -/ strains possessing different DNA repair pathways. 11 references, 3 tables.

Effect of tellurium on viscosity and liquid structure of GaSb melts

Energy Technology Data Exchange (ETDEWEB)

Ji Leilei [School of Material Science and Engineering, Jinan University, Jinan 250022 (China); Geng Haoran [School of Material Science and Engineering, Jinan University, Jinan 250022 (China)], E-mail: mse_genghr@ujn.edu.cn; Sun Chunjing [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Teng Xinying; Liu Yamei [School of Material Science and Engineering, Jinan University, Jinan 250022 (China)

2008-04-03

The behavior of GaSb melt with tellurium addition was investigated using viscometer and differential scanning calorimetry (DSC). Normally, the viscosity of all melts measured decreased with the increasing temperature. However, anomalous transition points were observed in the temperature dependence of viscosity for Ga-Sb-Te system. Corresponded with the abnormal points on the viscosity-temperature curves, there were thermal effect peaks on the DSC curves. Furthermore, viscous activation energy and flow units of these melts and their structural features were discussed in this paper.

Ecological aspects of selenium and tellurium in human and animal health

Energy Technology Data Exchange (ETDEWEB)

Frost, D V; Ingvoldstad, D

1975-01-01

Animal and human studies indicate that selenium inadequacy, in part, underlies various chronic diseases. Epidemiologic evidence suggests that cancer and heart disease are most common where ambient Se availability is low. Plant Se uptake and Se blood levels are inverse to human cancer mortality. As the active group in glutathione peroxidase, Se/sup -2/ inhibits aberrant oxidations which lead to chronic diseases. It binds heavy metals, and with tocopherol maintains tissue integrity. Sulfur dioxide fallout from the atmosphere, resulting from fossil fuel burning, may diminish the nutritional availability of selenium by diminishing plant uptake. Intensive ruminant grazing returns unavailable Se/sup 0/ to soils. Trimethyl selenium ion, as excreted by animals, also appears to be unavailable to plants. Modern fertilization practices and the effect of buildup of sulfates in the soil, due to acid rains, both appear to lessen the availability of Se to plants. SeO/sub 2/ added to the atmosphere from combustion and volcanic activity react with SO/sub 2/ to yield Se/sup 0/. This is presumed to fall out as particles from the air. How traces of Se are otherwise carried in air, explaining its enrichment in some areas, is unknown. The New Zealand experience with Se inadequacy in animals and man may be repeated in other parts of the world. Se inadequacy is far more of a human health problem than Se toxicity. There are no known adverse health effects from tellurium, other than tellurium breath. 164 references, 5 figures, 3 tables.

The application of three-phase liquid-liquid extraction to the analysis of bismuth and tellurium in sulphide concentrates

International Nuclear Information System (INIS)

Nicholas, D.J.

1976-01-01

An extraction system consisting of one aqueous and two organic phases is described. Diantipyrylmethane (DAM) is used as the extractant for bismuth and tellurium, which are extracted into the smaller of the two organic phases from nitric acid and perchloric acid respectively. The extraction efficiency is in the range of 90 to 95 per cent, compensation for incomplete extraction being made by the technique of standard addition. Copper, lead, and zinc are not extracted in either procedure. When the solutions contain high concentrations of iron, thioglycolic acid is used as a masking agent for iron in the extraction of bismuth. Atomic-absorption spectrophotometry is used for the analysis of the third phase after it has been diluted with methanol. The precision for bismuth and tellurium is in the range of 3 to 4 per cent. The accuracy, as ascertained from comparative analyses of sulphide concentrates, is good

Tellurium stable isotope fractionation in chondritic meteorites and some terrestrial samples

Science.gov (United States)

Fehr, Manuela A.; Hammond, Samantha J.; Parkinson, Ian J.

2018-02-01

New methodologies employing a 125Te-128Te double-spike were developed and applied to obtain high precision mass-dependent tellurium stable isotope data for chondritic meteorites and some terrestrial samples by multiple-collector inductively coupled plasma mass spectrometry. Analyses of standard solutions produce Te stable isotope data with a long-term reproducibility (2SD) of 0.064‰ for δ130/125Te. Carbonaceous and enstatite chondrites display a range in δ130/125Te of 0.9‰ (0.2‰ amu-1) in their Te stable isotope signature, whereas ordinary chondrites present larger Te stable isotope fractionation, in particular for unequilibrated ordinary chondrites, with an overall variation of 6.3‰ for δ130/125Te (1.3‰ amu-1). Tellurium stable isotope variations in ordinary chondrites display no correlation with Te contents or metamorphic grade. The large Te stable isotope fractionation in ordinary chondrites is likely caused by evaporation and condensation processes during metamorphism in the meteorite parent bodies, as has been suggested for other moderately and highly volatile elements displaying similar isotope fractionation. Alternatively, they might represent a nebular signature or could have been produced during chondrule formation. Enstatite chondrites display slightly more negative δ130/125Te compared to carbonaceous chondrites and equilibrated ordinary chondrites. Small differences in the Te stable isotope composition are also present within carbonaceous chondrites and increase in the order CV-CO-CM-CI. These Te isotope variations within carbonaceous chondrites may be due to mixing of components that have distinct Te isotope signatures reflecting Te stable isotope fractionation in the early solar system or on the parent bodies and potentially small so-far unresolvable nucleosynthetic isotope anomalies of up to 0.27‰. The Te stable isotope data of carbonaceous and enstatite chondrites displays a general correlation with the oxidation state and hence might

The influence of composition of fluoride electrolytes and conditions of the electrodeposition on some properties of tellurium

International Nuclear Information System (INIS)

Bugelis, V.M.; Kum, G.N.; Abrarov, O.A.; Madumarov, A.; Navalikhin, L.V.; Ajnakulov, Eh.B.

1981-01-01

Effect of electrolytic bath content, cathode current density, illumination and temperature on specific resistance, photosensitivity, structure and chemical purity of plated tellurium coatings is studied. Deposition is realized from moderately acid fluoride electrolytes at the constant temperature with a platinum working electrode. X-ray studies of precipitates obtained are carried out

Evaluated phase diagrams of binary metal-tellurium systems of the D-block transition elements

International Nuclear Information System (INIS)

Chattopadhyay, G.; Bharadwaj, S.R.

1989-01-01

The binary phase diagrams of metal-tellurium systems for twenty seven d-block transition elements have been critically evaluated. Complete phase diagrams are presented for the elements, chromium, manganese, iron, cobalt, nickel, copper, molybdenum, palladium, silver, lanthanum, platinum and gold, whereas, for scandium, titanium, vanadium, yttrium, zirconium, niobium, technitium, ruthenium, rhodium, hafnium, tantalum, tungsten , rhenium, osmium and iridium, the phase diagrams are incomplete and tentative. (author). 20 refs., 27 tabs., 27 figs

Thermodynamic assessment of the palladium-tellurium (Pd-Te) system

International Nuclear Information System (INIS)

Gosse, S.; Gueneau, C.

2011-01-01

Among the fission products formed in nuclear fuels, the platinum-group metal palladium and the chalcogen element tellurium exhibit strong interaction. It is therefore of interest to be able to predict the chemical equilibria involving the Pd and Te fission products. A thermodynamic assessment is carried out using the Calphad (Calculation of Phase Diagram) method to investigate the behaviour of Pd-Te alloy system in nuclear fuels under irradiation and under waste disposal conditions. The Pd-Te binary description was optimized using experimental data found in literature including thermodynamic properties and phase diagram data. To validate the calculated phase diagram and thermodynamic properties, the results are compared with data from the literature. Both calculated and experimental phase diagrams and thermodynamic properties are in good agreement in the whole Pd-Te composition range. (authors)

Investigation of evaporation characteristics of polonium and its lighter homologues selenium and tellurium from liquid Pb-Bi-eutecticum

CERN Document Server

Neuhausen, J; Eichler, B

2004-01-01

The evaporation behaviour of polonium and its lighter homologues selenium and tellurium dissolved in liquid Pb-Bi-eutecticum (LBE) has been studied at various temperatures in the range from 482 K up to 1330 K under Ar/H2 and Ar/H2O-atmospheres using γ-ray spectroscopy. Polonium release in the temperature range of interest for technical applications is slow. Within short term (1h) experiments measurable amounts of polonium are evaporated only at temperatures above 973 K. Long term experiments reveal that a slow evaporation of polonium occurs at temperatures around 873 K resulting in a fractional polonium loss of the melt around 1% per day. Evaporation rates of selenium and tellurium are smaller than those of polonium. The presence of H2O does not enhance the evaporation within the error limits of our experiments. The thermodynamics and possible reaction pathways involved in polonium release from LBE are discussed.

Effect of sample preparation methods on photometric determination of the tellurium and cobalt content in the samples of copper concentrates

Directory of Open Access Journals (Sweden)

Viktoriya Butenko

2016-03-01

Full Text Available Methods of determination of cobalt and nickel in copper concentrates currently used in factory laboratories are very labor intensive and time consuming. The limiting stage of the analysis is preliminary chemical sample preparation. Carrying out the decomposition process of industrial samples with concentrated mineral acids in open systems does not allow to improve the metrological characteristics of the methods, for this reason improvement the methods of sample preparation is quite relevant and has a practical interest. The work was dedicated to the determination of the optimal conditions of preliminary chemical preparation of copper concentrate samples for the subsequent determination of cobalt and tellurium in the obtained solution using tellurium-spectrophotometric method. Decomposition of the samples was carried out by acid dissolving in individual mineral acids and their mixtures by heating in an open system as well as by using ultrasonification and microwave radiation in a closed system. In order to select the optimal conditions for the decomposition of the samples in a closed system the phase contact time and ultrasonic generator’s power were varied. Intensification of the processes of decomposition of copper concentrates with nitric acid (1:1, ultrasound and microwave radiation allowed to transfer quantitatively cobalt and tellurium into solution spending 20 and 30 min respectively. This reduced the amount of reactants used and improved the accuracy of determination by running the process in strictly identical conditions.

LIGHT INDUCED TELLURIUM ENRICHMENT ON CDZNTE CRYSTAL SURFACES DETECTED BY RAMAN SPECTROSCOPY

International Nuclear Information System (INIS)

Hawkins, S; Eliel Villa-Aleman, E; Martine Duff, M; Douglas Hunter, D

2007-01-01

Synthetic CdZnTe or 'CZT' crystals can be grown under controlled conditions to produce high quality crystals to be used as room temperature radiation detectors. Even the best crystal growth methods result in defects, such as tellurium secondary phases, that affect the crystal's performance. In this study, CZT crystals were analyzed by micro Raman spectroscopy. The growth of Te rich areas on the surface was induced by low powered lasers. The growth was observed versus time with low power Raman scattering and was observed immediately under higher power conditions. The detector response was also measured after induced Te enrichment

Equilibrium evaporation test of lead-bismuth eutectic and of tellurium in lead-bismuth

International Nuclear Information System (INIS)

Ohno, Shuji; Nishimura, Masahiro; Hamada, Hirotsugu; Miyahara, Shinya; Sasa, Toshinobu; Kurata, Yuji

2005-01-01

A series of equilibrium evaporation experiment was performed to acquire the essential and the fundamental knowledge about the transfer behavior of lead-bismuth eutectic (LBE) and impurity tellurium in LBE from liquid to gas phase. The experiments were conducted using the transpiration method in which saturated vapor in an isothermal evaporation pot was transported by inert carrier gas and collected outside of the pot. The size of the used evaporation pot is 8 cm inner diameter and 15 cm length. The weight of the LBE pool in the pot is about 500 g. The investigated temperature range was 450degC to 750degC. From this experiment and discussion using the data in literature, we have obtained several instructive and useful data on the LBE evaporation behavior such as saturated vapor pressure of LBE, vapor concentration of Pb, Bi and Bi 2 in LBE saturated gas phase, and activity coefficient of Pb in the LBE. The LBE vapor pressure equation is represented as the sum of Pb, Bi and Bi 2 vapor in the temperature range between 550degC and 750degC as logP[Pa]=10.2-10100/T[k]. The gas-liquid equilibrium partition coefficient of tellurium in LBE is in the range of 10 to 100, with no remarkable temperature dependency between 450degC and 750degC. This research was founded by the Ministry of Education, Culture, Sports, Science and Technology (MEXT). (author)

Tellurium sulfates from reactions in oleum and sulfur trioxide: syntheses and crystal structures of TeO(SO_4), Te_4O_3(SO_4)_5, and Te(S_2O_7)_2

International Nuclear Information System (INIS)

Logemann, Christian; Bruns, Joern; Schindler, Lisa Verena; Zimmermann, Vanessa; Wickleder, Mathias S.

2015-01-01

The reaction of K_2TeO_4 with fuming sulfuric acid (65 % SO_3) in sealed glass ampoules at 250 C led to colorless single crystals of TeO(SO_4) [triclinic, P anti 1, Z = 8, a = 819.89(3) pm, b = 836.95(4) pm, c = 1179.12(5) pm, α = 82.820(2) , β = 70.645(2) , γ = 81.897(2) , V = 753.11(6) x 10"6 pm"3]. A horseshoe type [Te_4O_3] fragment is the basic motif in the layer structure of the compound. The [Te_4O_3] moieties are linked to infinite chains by further oxide ions. Monomeric [Te_4O_3] horseshoes are found in the crystal structure of Te_4O_3(SO_4)_5 [trigonal, P3_221, Z = 3, a = 859.05(2) pm, c = 2230.66(7) pm, V = 1425.61(6) x 10"6 pm"3], which was obtained from TeO_2 and fuming sulfuric acid (65 % SO_3) at 200 C as colorless single crystals. By switching to neat SO_3 as reaction medium colorless crystals of Te(S_2O_7)_2 [P2_1/n, Z = 4, a = 1065.25(3) pm, b = 818.50(2) pm, c = 1206.27(3) pm, β = 102.097(1) , V = 1028.40(5) x 10"6 pm"3] form when ortho-telluric acid, H_6TeO_6, is used as the tellurium source. The compound was reported previously, however, obviously with a wrong crystallographic description. In the crystal structure the tellurium atoms are coordinated by two chelating disulfate ions. Further Te-O contacts link the [Te(S_2O_7)_2] units to an extended network. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Facile Hydrothermal Synthesis of Tellurium Nanostructures for Solar Cells

Directory of Open Access Journals (Sweden)

M. Panahi-Kalamuei

2014-10-01

Full Text Available Tellurium (Te nanostructures have been successfully synthesized via a simple hydrothermal methodfrom the reaction of a TeCl4 aqueous solution with thioglycolic acid (TGA as a reductant. TGA can be easily oxidized to the corresponding disulfide [SCH2CO2H]2, which in turn can reduce TeCl4 to Te. The obtained Te was characterized by XRD, SEM, EDS, and DRS. The effect of reducing agent on morphology and size of the products were also studied. Additionally, Te thin film was deposited on the FTO-TiO2 by Dr- blading then employed to solar cell application and measured open circuit voltage (Voc, short circuit current (Isc, and fill factor (FF were determined as well. The studies showed that particle morphology and sizes play crucial role on solar cell efficiencies.

Determination of gold, indium, tellurium and thallium in the same sample digest of geological materials by atomic-absorption spectroscopy and two-step solvent extraction

Science.gov (United States)

Hubert, A.E.; Chao, T.T.

1985-01-01

A rock, soil, or stream-sediment sample is decomposed with hydrofluoric acid, aqua regia, and hydrobromic acid-bromine solution. Gold, thallium, indium and tellurium are separated and concentrated from the sample digest by a two-step MIBK extraction at two concentrations of hydrobromic add. Gold and thallium are first extracted from 0.1M hydrobromic acid medium, then indium and tellurium are extracted from 3M hydrobromic acid in the presence of ascorbic acid to eliminate iron interference. The elements are then determined by flame atomic-absorption spectrophotometry. The two-step solvent extraction can also be used in conjunction with electrothermal atomic-absorption methods to lower the detection limits for all four metals in geological materials. ?? 1985.

Evaluation of the Content of Antimony, Arsenic, Bismuth, Selenium, Tellurium and Their Inorganic Forms in Commercially Baby Foods.

Science.gov (United States)

Ruiz-de-Cenzano, M; Rochina-Marco, A; Cervera, M L; de la Guardia, M

2017-12-01

Baby foods, from the Spanish market and prepared from meat, fish, vegetables, cereals, legumes, and fruits, were analyzed to obtain the concentration of antimony (Sb), arsenic (As), bismuth (Bi), and tellurium (Te) as toxic elements and selenium (Se) as essential element. An analytical procedure was employed based on atomic fluorescence spectroscopy which allowed to obtain accurate data at low levels of concentration. Values of 14 commercial samples, expressed in nanograms per gram fresh weight, ranged for Sb 0.66-6.9, As 4.5-242, Te 1.35-2.94, Bi 2.18-4.79, and Se 5.4-109. Additionally, speciation studies were performed based on data from a non-chromatographic screening method. It was concluded that tellurium and bismuth were mainly present as inorganic forms and selenium as organic form, and antimony and arsenic species depend on the ingredients of each baby food. Risk assessment considerations were made by comparing dietary intake of the aforementioned elements through the consumption of one baby food portion a day and recommended or tolerable guideline values.

Reactions of newly formed fission products in the gas phase

International Nuclear Information System (INIS)

Strickert, R.G.

1976-01-01

A dynamic gas-flow system was constructed which stopped fission products in the gas phase and rapidly separated (in less than 2 sec) volatile compounds from non-volatile ones. The filter assembly designed and used was shown to stop essentially all non-volatile fission products. Between 5 percent and 20 percent of tellurium fission-product isotopes reacted with several hydrocarbon gases to form volatile compounds, which passed through the filter. With carbon monoxide gas, volatile tellurium compound(s) (probably TeCO) were also formed with similar efficiencies. The upper limits for the yields of volatile compounds formed between CO and tin and antimony fission products were shown to be less than 0.3 percent, so tellurium nuclides, not their precursors, reacted with CO. It was found that CO reacted preferentially with independently produced tellurium atoms; the reaction efficiency of beta-produced atoms was only 27 +- 3 percent of that of the independently formed atoms. The selectivity, which was independent of the over-all reaction efficiency, was shown to be due to reaction of independently formed atoms in the gas phase. The gas phase reactions are believed to occur mainly at thermal energies because of the independence of the yield upon argon moderator mole-fraction (up to 80 percent). It was shown in some experiments that about one-half of the TeCO decomposed in passing through a filter and that an appreciable fraction (approximately 20 percent) of the tellurium atoms deposited on the filter reacted agin with CO. Other tellurium atoms on the filter surface (those formed by beta decay and those formed independently but not reacting in the gas phase) also reacted with CO, but probably somewhat less efficiently than atoms formed by TeCO decomposition. No evidence was found for formation of TeCO as a direct result of beta-decay

Resource recovery from urban stock, the example of cadmium and tellurium from thin film module recycling

Energy Technology Data Exchange (ETDEWEB)

Simon, F.-G., E-mail: franz-georg.simon@bam.de [BAM Federal Institute for Materials Research and Testing, Division 4.3 Contaminant Transfer and Environmental Technologies, Unter den Eichen 87, 12205 Berlin (Germany); Holm, O.; Berger, W. [BAM Federal Institute for Materials Research and Testing, Division 4.3 Contaminant Transfer and Environmental Technologies, Unter den Eichen 87, 12205 Berlin (Germany)

2013-04-15

Highlights: ► The semiconductor layer on thin-film photovoltaic modules can be removed from the glass-plate by vacuum blast cleaning. ► The separation of blasting agent and semiconductor can be performed using flotation with a valuable yield of 55%. ► PV modules are a promising source for the recovery of tellurium in the future. - Abstract: Raw material supply is essential for all industrial activities. The use of secondary raw material gains more importance since ore grade in primary production is decreasing. Meanwhile urban stock contains considerable amounts of various elements. Photovoltaic (PV) generating systems are part of the urban stock and recycling technologies for PV thin film modules with CdTe as semiconductor are needed because cadmium could cause hazardous environmental impact and tellurium is a scarce element where future supply might be constrained. The paper describes a sequence of mechanical processing techniques for end-of-life PV thin film modules consisting of sandblasting and flotation. Separation of the semiconductor material from the glass surface was possible, however, enrichment and yield of valuables in the flotation step were non-satisfying. Nevertheless, recovery of valuable metals from urban stock is a viable method for the extension of the availability of limited natural resources.

Resource recovery from urban stock, the example of cadmium and tellurium from thin film module recycling

International Nuclear Information System (INIS)

Simon, F.-G.; Holm, O.; Berger, W.

2013-01-01

Highlights: ► The semiconductor layer on thin-film photovoltaic modules can be removed from the glass-plate by vacuum blast cleaning. ► The separation of blasting agent and semiconductor can be performed using flotation with a valuable yield of 55%. ► PV modules are a promising source for the recovery of tellurium in the future. - Abstract: Raw material supply is essential for all industrial activities. The use of secondary raw material gains more importance since ore grade in primary production is decreasing. Meanwhile urban stock contains considerable amounts of various elements. Photovoltaic (PV) generating systems are part of the urban stock and recycling technologies for PV thin film modules with CdTe as semiconductor are needed because cadmium could cause hazardous environmental impact and tellurium is a scarce element where future supply might be constrained. The paper describes a sequence of mechanical processing techniques for end-of-life PV thin film modules consisting of sandblasting and flotation. Separation of the semiconductor material from the glass surface was possible, however, enrichment and yield of valuables in the flotation step were non-satisfying. Nevertheless, recovery of valuable metals from urban stock is a viable method for the extension of the availability of limited natural resources

Determination of tellurium by hydride generation with in situ trapping flame atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Matusiewicz, H.; Krawczyk, M. [Politechn Poznanska, Poznan (Poland)

2007-03-15

The analytical performance of coupled hydride generation - integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system was evaluated for determination of Te in reference material (GBW 07302 Stream Sediment), coal fly ash and garlic. Tellurium, using formation of H{sub 2}Te vapors, is atomized in air-acetylene flame-heated IAT. A new design HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangernents (a water-cooled single silica tube, double-slotted quartz tube or an 'integrated trap') was investigated. An improvement in detection limit was achieved compared with using either of the above atom trapping techniques separately. The concentration detection limit, defined as 3 times the blank standard deviation (3{sigma}), was 0.9 ng mL{sup -1} for Te. For a 2 min in situ preconcentration time (sample volume of 2 mL), sensitivity enhancement compared to flame AAS, was 222 fold, using the hydride generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision, expressed as RSD, was 7.0% (n = 6) for Te. The accuracy of the method was verified using a certified reference material (GBW 07302 Stream Sediment) by aqueous standard calibration curves. The measured Te contents of the reference material was in agreement with the information value. The method was successfully applied to the determination of tellurium in coal fly ash and garlic.

Test of irradiation of tellurium oxide for obtaining iodine-131 by dry distillation

International Nuclear Information System (INIS)

Alanis M, J.

2003-07-01

With the purpose of optimizing to the maximum independently the work of the reactor of those mathematical calculations of irradiation that are already optimized, now it corresponds to carry out irradiation tests in the different positions with their respective neutron fluxes that it counts the reactor for samples irradiation. Then, it is necessary to carry out the irradiation of the tellurium dioxide through cycles, with the purpose of observing the activity that it goes accumulating in each cycle and this way to obtain an activity of the Iodine-131 obtained when finishing the last cycle. (Author)

New radioactively labelled amines, procedure of preparation of the new compounds as well as the diagnostic preparations based on these new compounds

Energy Technology Data Exchange (ETDEWEB)

1979-02-07

This patent describes the composition and preparation of new radioactively labelled amine conpounds for use as radiopharmaceuticals, particularly for the detection and/or localization of thrombi in the body. They are not alien to the body, are used to trace the fibrin network, and lead to favourable ratios between the presence of radioactivity in the blood clot and that in the rest of the body. These new compounds have the general formula Y - (CH/sub 2/)/sub 2/-X-(CH/sub 2/)/sub 2/ - NH/sub 2/ in which X is an oxygen or sulfur atom or a methylene, ethylene or trimethylene group and Y is an organic molecule labelled with radioactive iodine, or in which X is a radioactively labelled selenium or tellurium atom and Y is an organic molecule.

Formation of defects in tellurium at various levels of gravitation

International Nuclear Information System (INIS)

Parfen'ev, R.V.; Farbshtejn, I.I.; Shul'pina, I.L.; Yakimov, S.V.; Shalimov, V.P.; Turchaninov, A.M.

2002-01-01

One investigated into effect of gravitation conditions during tellurium crystallization (ranging from microgravitation up to increased gravitation - 5g 0 ) on concentration of neutral (N D ) and electrically active (N AD ) acceptor structure defects in specimens grown both under complete remelting of parent ingot and under directed recrystallization of ingot with inoculation. N AD and N D concentrations and their distribution along the specimen depth were determined on the basis of analysis of electrical characteristics (conductivity and the Hall effect) measured along ingots within 1.6-300 K temperature range. The results were compared with characteristics of specimens grown following the similar program under normal conditions. At complete remelting under microgravitation one detected attributes of strong supercooling and spontaneous crystallization, as well as, of specimen resistance oscillation by its depth caused by N D modulation [ru

Use of Iodine-131 to Tellurium-132 Ratios for Assessing the Relationships between Human Inhaled Radioactivity and Environmental Monitoring after the Accident in Fukushima

Directory of Open Access Journals (Sweden)

Koji Uchiyama

2018-03-01

Full Text Available Significant differences in findings were seen between the intake amounts of iodine-131 that were derived from direct measurements and the estimated intake from environmental monitoring data at the Fukushima accident. To clarify these discrepancies, we have investigated the iodine-131 and tellurium-132 body burdens of five human subjects, who after being exposed to a radioactive plume, underwent 21.5 h whole body counter measurements at Fukui Prefectural Hospital, so clear intake scenario and thyroid counter measurement data were available. To determine the iodine-131 and tellurium-132 body burdens, we introduced a new method of whole body counter calibration composed of a self-consistent approach with the time-dependent correction efficiency factors concept. The ratios of iodine-131 to tellurium-132, ranging from 0.96 ± 0.05 to 2.29 ± 0.38, were consistent with results of the environmental measurements. The 24 h iodine uptake values ranging from 12.1–16.0% were within euthyroid range in Japanese people. These results suggest, even if the relatively low thyroid iodine uptake in the Japanese population was taken into consideration, that there is no doubt about the consistency between direct measurements and environmental monitoring data. Adequate intake scenario is suggested to be principally important to estimate the inhaled radioactivity in areas in or around nuclear accidents.

Exploratory studies of element substitutions in synthetic tetrahedrite. Part II. Selenium and tellurium as anions in Zn-Fe tetrahedrites

DEFF Research Database (Denmark)

Karup-Møller, Sven; Makovicky, E.

1999-01-01

-free) compositons do not materialize. The substituted Se tetrahedrite coexists with Cu3SbSe3, (iron-bearing) Cu2-xSe, Cu3SbSe4 plus/minus low Zn-sulfide melt. Selenium does not adopt the role of cation and tellurium that of anion in the tetrahedrite structure. The explanation of the severely restricted composition...

The effect of hydrostatic pressure on the anomalous sign reversal of the Hall coefficient in tellurium

International Nuclear Information System (INIS)

Balynas, V.; Dobrovolskis, Z.; Krotkus, A.; Hoerstel, W.

1981-01-01

In order to obtain information about the pressure behaviour of the higher lying second conduction band the dependences of the Hall coefficient of single crystalline tellurium on temperature (300 to 500 K) have been measured at atmospheric pressure and hydrostatic pressures of 500 and 800 MPa. The separation between the two conduction bands in Te decreases with increasing pressure. The anomalous sign reversal of the Hall coefficient can be well explained by a double-conduction band model

Revision and extension to the analysis of the third spectrum of tellurium: Te III

International Nuclear Information System (INIS)

Tauheed, A.; Naz, A.

2011-01-01

The spectrum of doubly ionized tellurium atom (Te III) has been investigated in the vacuum ultraviolet wavelength region. The ground configuration of Te III is 5s 2 5p 2 and the excited configurations are of the type 5s 2 5p nl. The core excitation leads to a 5s5p 3 configuration. Cowan's multi-configuration interaction code was utilized to predict the ion structure. The observed spectrum of tellurium was recorded on a 3-m normal incidence vacuum spectrograph of Antigonish Laboratory (Canada) in the wavelength region of 300 - 2000 A by using a triggered spark light source for the excitation of the spectrum. The 5s 2 5p 2 - [ 5s 2 5p (5d + 6d + 7d + 6s + 7s + 8s) + 5s5p 3 ] transition array has been analyzed. Previously reported levels by Joshi et al have been confirmed while the older analysis by Crooker and Joshi has been revised and extended to include the 5s 2 5p (5d, 6d, 7d, 6s,7s, 8s) and 5s5p 3 configurations. Least-squares- fitted parametric calculations were used to interpret the final results. One hundred and fifty spectral lines have been identified to establish 60 energy levels. Our wavelength accuracy for unblended and sharp lines is better than ±0.005 A. The ionization potential of Te III was found to be 224550 ± 300 cm -1 (27.841 ± 0.037eV).

Validation of a new design of tellurium dioide-irradiated target

Energy Technology Data Exchange (ETDEWEB)

Fllaoui, Aziz; Ghamad, Younes; Zoubir, Brahim; Ayaz, Zinel Abidine; El Morabiti, Aissam; Amayoud, Hafid [Centre National de l' Energie des Sciences et des Techniques Nucleaires, Rabat (Morocco); Chakir, El Mahjoub [Nuclear Physics Department, University Ibn Toufail, Kenitra (Morocco)

2016-10-15

Production of iodine-131 by neutron activation of tellurium in tellurium dioxide (TeO{sub 2}) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gas welding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ≤ 10 - 4 mbr.L/s, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to 600 .deg. C with the appearance of deformations on lids beyond 450 .deg. C. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes-convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from 4 hours of irradiation at a power level of 0.5 MW up to 35 hours (7 h/d for 5 days a week) at 1.5 MW. The results show that the irradiated targets are

Validation of a New Design of Tellurium Dioxide-Irradiated Target

Directory of Open Access Journals (Sweden)

Aziz Fllaoui

2016-10-01

Full Text Available Production of iodine-131 by neutron activation of tellurium in tellurium dioxide (TeO2 material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gas welding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ≤ 10−4 mbr.L/s, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics. To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to 600°C with the appearance of deformations on lids beyond 450°C. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes—convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from 4 hours of irradiation at a power level of 0.5 MW up to 35 hours (7 h/d for 5 days a week at 1.5 MW. The results show that the irradiated targets are

Light-Induced Tellurium Enrichment on CdZnTe Crystal Surfaces Detected by Raman Spectroscopy

International Nuclear Information System (INIS)

Hawkins, Samantha A.; Villa-Aleman, Eliel; Duff, Martine C.; Hunter, Doug B.; Burger, Arnold; Groza, Michael; Buliga, Vladimir; Black, David R.

2008-01-01

CdZnTe (CZT) crystals can be grown under controlled conditions to produce high-quality crystals to be used as room-temperature radiation detectors. Even the best crystal growth methods result in defects, such as tellurium secondary phases, that affect the crystal's performance. In this study, CZT crystals were analyzed by micro-Raman spectroscopy. The growth of Te rich areas on the surface was induced by low-power lasers. The growth was observed versus time with low-power Raman scattering and was observed immediately under higher-power conditions. The detector response was also measured after induced Te enrichment.

Synthesis and characterization of nanometer sized thermoelectric lead-antimony-silver-tellurium compounds and related materials

International Nuclear Information System (INIS)

Petri, Denis

2012-01-01

The present dissertation deals with different variants of synthesis and processing of nanocrystalline composites of various thermoelectric compounds based on lead telluride including LAST-m (AgPb m SbTe m+2 ), LASTT-m-x (AgPb m-x Sn x SbTe m+2 ), LABST-m-x (AgPb m Sb 1-x Bi x Te m+2 ), doped LAST-m and (PbTe) m (M 15 2 Te 3 ) and the characterization thereof. A new route of manufacturing nanocrystalline composites was developed. The so called co-ball milling-route includes the synthesis of bi- or multinary compounds by conventional solid state melting methods followed by combined milling of appropriate amounts in a planetary ball mill; a process related to the widely used mechanical alloying of elemental powders. The as produced powders were shortly annealed for one hour and a.erwards compacted either at room temperature followed by pressureless sintering or combined application of high pressure and elevated temperatures via spark-plasma-sintering or short-term-sintering. The ball milling yielded micron-sized agglomerates consisting of crystallites with diameters ranging from 10 to 50 nm. These crystallites exhibited complicated internal nanostructures severe crystal defects as a consequence of the high energy processing. During short-term annealing some grain coarsening occured and the crystal defects partly healed, which was confirmed by TEM and HRTEM investigations as well as profile analysis of XRD powder pattern. Local EDX-analysis showed different compositions at every point as a consequence of synthesis and decomposition of the compounds. Measurements of thermopower, electrical and thermal conductivity were carried out and the values of the figure of merit ZT and the powerfactor were calculated. In general the compounds exhibited larger thermopower than corresponding bulk materials, which might be attributed to energy filtering of charge carriers at partly oxidized grain boundaries. Due to enhanced phonon scattering at grain boundarys, nanoscopic

Synthesis, Processing, and Thermoelectric Properties of Germanium-Antimony-Tellurium Based Compounds and Alloys

Science.gov (United States)

Williams, Jared Brett

Society has become increasingly more aware of the negative impacts which nonrenewable energy sources have on the environment, and therefore the search for new and more efficient means of energy production has become an important research endeavor. Thermoelectric modules possess the unique ability to convert wasted heat into useful electrical energy via solid state processes, which could vastly improve the efficiency of a number of applications. The materials which accomplish this are typically comprised of semiconductors which exhibit high electrical conductivity, Seebeck coefficient, and thermal resistivity. Together these properties give us a gauge for the overall efficiency of the thermal to electrical energy conversion. Phase change materials are a class of materials primarily used for optical data storage in CDs, DVDs, and Blu-Ray discs. Today's state of the art phase change materials are based on alloys of GeTe and Sb2Te3. These materials have also been found to exhibit high thermoelectric efficiencies. These high efficiencies stem from their complex crystal structure and degenerate semiconducting nature. The purpose of this work was to study and engineer the thermoelectric properties of various alloys and compounds which belong to this family of materials. Specifically studied were the compounds Ge4SbTe5 and Ge17Sb2Te20. In each case various synthesis and processing strategies were implemented to increase the thermoelectric performance and better understand the fundamental electrical and thermal properties. Finally various proposals for future work on these materials are presented, all of which are based on the findings described herein.

Determination of tellurium at ultra-trace levels in drinking water by on-line solid phase extraction coupled to graphite furnace atomic absorption spectrometer

International Nuclear Information System (INIS)

Pedro, Juana; Stripekis, Jorge; Bonivardi, Adrian; Tudino, Mabel

2008-01-01

In this paper, two time-based flow injection (FI) separation pre-concentration systems coupled to graphite furnace atomic absorption spectrometry (GFAAS) for tellurium determination are studied and compared. The first alternative involves the pre-concentration of the analyte onto Dowex 1X8 employed as packaging material of a micro-column inserted in the flow system. The second set-up is based on the co-precipitation of tellurium with La(OH) 3 followed by retention onto XAD resins. Both systems are compared in terms of limit of detection, linear range, RSD%, sample throughput, micro-columns lifetime and aptitude for fully automatic operation. The features of the Dowex system are: 37% efficiency of retention and an enhancement factor of 42 for a pre-concentration time of 180 seconds (sample flow rate = 3 ml min -1 ) with acetic acid elution volumes of 80 μl. The detection limit (3 s) is 7 ng l -1 and the relative standard deviation (n = 7200 ng l -1 ) is 5.8%. The analytical performance of the XAD system is: 72% efficiency of retention and an enhancement factor of 25 for a pre-concentration time of 180 s (sample flow rate = 3 ml min -1 ) with nitric acid elution volumes of 300 μl. The detection limit is 66 ng l -1 and the relative standard deviation (n = 7200 ng l -1 ) is 8.3%. Applications to the determination of tellurium in tap water and the validation of the analytical methodology employing SRM 1643e as certified reference material are shown

Challenges in assessment of clean energy supply-chains based on byproduct minerals: A case study of tellurium use in thin film photovoltaics

International Nuclear Information System (INIS)

Bustamante, Michele L.; Gaustad, Gabrielle

2014-01-01

Highlights: • Byproduct mining presents unique challenges to quantifying energy security issues. • This case study shows Te scarcity is closely tied to Cu demand and production. • Material intensity changes over time have a significant impact on projections. • Recycling as a mitigation strategy is shown to have poor short-term results. - Abstract: Transitioning to a sustainable energy supply will be critical to meeting future economic and environmental goals. This transition will require optimizing and commercializing a portfolio of new clean energy technologies. However, many promising clean energy technologies are based on materials with inherent risks in their supply; these risks include scarcity, price volatility, criticality, and other potential supply-chain disruptions. Using tellurium use in CdTe photovoltaics as a case study, this paper presents analysis of some of the key challenges associated with modeling byproduct systems (a supply-chain where a key material is actually a byproduct of extraction of another material, copper in the case of tellurium). This work presents a novel modeling approach; the results of the case study are used to identify potential supply risks facing this clean technology, with a unique focus on sensitivity to changes in the preliminary lifecycle stages. Supply-chain sensitivities are connected with direct environmental impacts to frame the implications in a broader sustainability context and to emphasize the future role of recycling. Ultimately, it was shown that if historical supply and demand trends continue, supply gap conditions will emerge before the end of the current decade. However, improvements in byproduct yield, end-use recycling rate, and end-use material intensity exhibit significant leverage to minimize risk in the energy-critical tellurium supply-chain

Gamma Radiation Dosimetry Using Tellurium Dioxide Thin Film Structures

Directory of Open Access Journals (Sweden)

Olga Korostynska

2002-08-01

Full Text Available Thin films of Tellurium dioxide (TeO2 were investigated for γ-radiation dosimetry purposes. Samples were fabricated using thin film vapour deposition technique. Thin films of TeO2 were exposed to a 60Co γ-radiation source at a dose rate of 6 Gy/min at room temperature. Absorption spectra for TeO2 films were recorded and the values of the optical band gap and energies of the localized states for as-deposited and γ-irradiated samples were calculated. It was found that the optical band gap values were decreased as the radiation dose was increased. Samples with electrical contacts having a planar structure showed a linear increase in current values with the increase in radiation dose up to a certain dose level. The observed changes in both the optical and the electrical properties suggest that TeO2 thin film may be considered as an effective material for room temperature real time γ-radiation dosimetry.

Studies on nickel (II and palladium (II complexes with some tetraazamacrocycles containing tellurium

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Rathee Nitu

2012-01-01

Full Text Available The synthesis of 10-membered and 12-membered tellurium containing tetraazamacrocyclic complexes of divalent nickel and palladium by template condensation of diaryltellurium dichlorides, (aryl = p-hydroxyphenyl, 3-methyl-4-hydroxyphenyl, p-methoxyphenyl with 1,2-diaminoethane and 1,3-diaminopropane in the presence of metal dichloride is reported. The resulting complexes have been subjected to elemental analyses, magnetic measurements, electronic absorption, infra-red, and proton magnetic resonance spectral studies. The formation of proposed macrocyclic skeletons and their donor sites have been identified on the basis of spectral studies. Distorted octahedral structure for the nickel complexes in the solid state and squareplanar structure for the palladium complexes have been suggested.

Flavoprotein-mediated tellurite reduction: structural basis and applications to the synthesis of tellurium-containing nanostructures

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Mauricio Arenas-Salinas

2016-07-01

Full Text Available The tellurium oxyanion tellurite (TeO32- is extremely harmful for most organisms. It has been suggested that a potential bacterial tellurite resistance mechanism would consist of an enzymatic, NAD(PH-dependent, reduction to the less toxic form elemental tellurium (Te0. To date, a number of enzymes such as catalase, type II NADH dehydrogenase and terminal oxidases from the electron transport chain, nitrate reductases, and dihydrolipoamide dehydrogenase (E3, among others, have been shown to display tellurite-reducing activity. This activity is generically referred to as tellurite reductase (TR. Bioinformatic data resting on some of the abovementioned enzymes enabled the identification of common structures involved in tellurite reduction including vicinal catalytic cysteine residues and the FAD/NAD(P+-binding domain, which is characteristic of some flavoproteins. Along this line, thioredoxin reductase (TrxB, alkyl hydroperoxide reductase (AhpF, glutathione reductase (GorA, mercuric reductase (MerA, NADH: flavorubredoxin reductase (NorW, dihydrolipoamide dehydrogenase, and the putative oxidoreductase YkgC from Escherichia coli or environmental bacteria were purified and assessed for TR activity. All of them displayed in vitro TR activity at the expense of NADH or NADPH oxidation. In general, optimal reducing conditions occurred around pH 9-10 and 37 °C.Enzymes exhibiting strong TR activity produced Te-containing nanostructures (TeNS. While GorA and AhpF generated TeNS of 75 nm average diameter, E3 and YkgC produced larger structures (> 100 nm. Electron-dense structures were observed in cells over-expressing genes encoding TrxB, GorA and YkgC.

Tracing Tellurium and Its Nanostructures in Biology.

Science.gov (United States)

Zare, Bijan; Nami, Mohammad; Shahverdi, Ahmad-Reza

2017-12-01

Tellurium (Te) is a semimetal rare element in nature. Together with oxygen, sulfur (S), and selenium (Se), Te is considered a member of chalcogen group. Over recent decades, Te applications continued to emerge in different fields including metallurgy, glass industry, electronics, and applied chemical industries. Along these lines, Te has recently attracted research attention in various fields. Though Te exists in biologic organisms such as microbes, yeast, and human body, its importance and role and some of its potential implications have long been ignored. Some promising applications of Te using its inorganic and organic derivatives including novel Te nanostructures are being introduced. Before discovery and straightforward availability of antibiotics, Te had considered and had been used as an antibacterial element. Antilishmaniasis, antiinflammatory, antiatherosclerotic, and immuno-modulating properties of Te have been described for many years, while the innovative applications of Te have started to emerge along with nanotechnological advances over the recent years. Te quantum dots (QDs) and related nanostructures have proposed novel applications in the biological detection systems such as biosensors. In addition, Te nanostructures are used in labeling, imaging, and targeted drug delivery systems and are tested for antibacterial or antifungal properties. In addition, Te nanoparticles show novel lipid-lowering, antioxidant, and free radical scavenging properties. This review presents an overview on the novel forms of Te, their potential applications, as well as related toxicity profiles.

Influence of the hydrolysis conditions on the properties of tellurium coatings obtained from hydrochloric acid baths

International Nuclear Information System (INIS)

Bigelis, V.M.; Kim, G.N.; Navalikhin, L.V.; Kalanov, M.; Abrarov, O.A.

1982-01-01

The structure of tellurium coatings has been studied using the methods of activational analysis on fast neutrons, roentgenography using DRON-2. The study is carried out in electrolyte 1N TeO 2 +6NHCl+2NH 2 SO 4 at the temperatures 25 and 95 deg C in the range of current densities 10-150 mA/cm 2 with and without mixing. Atomic content of chlorine and oxygen in deposite depending on the electrolyte work is determined. Nicrohardness, density, specific resistance of the coatings investigated are determined

Near threshold electron impact ionization cross section for tellurium atoms

International Nuclear Information System (INIS)

Chipev, F.F.; Chernyshova, I.V.; Kontros, J.E.; Shpenik, O.B.

2004-01-01

Full text: Up today electron-impact ionization is one of the most intensively investigated processes in atomic and molecular physics [1]. These experiments however, are associated with difficulties: high temperatures and densities are required to produce atomic beams and monochromatic intensive electron beams. A crossed electron and atomic beams scattering geometry was employed to measure the ionization efficiency curve for tellurium atoms. Our electron spectrometer comprises two serially mounted hypocycloidal electron energy analyzers [2], the first being the monochromator and the second - the scattered electron analyzer. The whole spectrometer is immersed into the homogenous magnetic field. Great care was taken in selecting the value of the extracting potential at the electrode, mounted normally to the atomic beam direction. By careful choosing this potential as low as possible (∼1.4 V), its influence on the motion of the monochromatized electrons in the collision region was minimized and the full collection of the formed ions was reached. The atom beam was produced using a compact effusion source made of the stainless steel with a microchannel exit to minimise the angular divergency of the beam. The temperature of the microchannel plate was taken about 50 K higher than that of the metal vapour in the heated reservoir. This atomic beam source enabled to produce an atomic beam with the concentration of two orders of magnitude higher than that in the case of a standard effusion source. A typical value of the electron energy spread was 0.15 eV (FWHM) in the 0.1-15 eV energy range. The primary electron beam current was equal to 10 -7 A. Such values of electron energy spread and beam current for the primary electron beam passing through the collision chamber were chosen to provide identical conditions for carrying out all the measurements. The energy scale was calibrated with the accuracy of ± 0.05 eV. The measured ionization cross-section normalized to the results

Synthesis and structure of organoantimony(III) compounds containing antimony−selenium and −tellurium terminal bonds

Czech Academy of Sciences Publication Activity Database

Dostál, L.; Jambor, R.; Růžička, A.; Lyčka, A.; Brus, Jiří; de Proft, F.

2008-01-01

Roč. 27, č. 23 (2008), s. 6059-6062 ISSN 0276-7333 Grant - others:GA ČR(CZ) GP203/07/P094; GA MŠk(CZ) LC523 Program:LC Institutional research plan: CEZ:AV0Z40500505 Keywords : organometallic compounds Subject RIV: CA - Inorganic Chemistry Impact factor: 3.815, year: 2008

Reprint of “Extracellular production of tellurium nanoparticles by the photosynthetic bacterium Rhodobacter capsulatus”

Energy Technology Data Exchange (ETDEWEB)

Borghese, Roberto, E-mail: roberto.borghese@unibo.it [Dept. of Pharmacy and Biotechnology, University of Bologna (Italy); Brucale, Marco [Institute for the Study of Nanostructured Materials (CNR-ISMN), Rome (Italy); Fortunato, Gianuario [Dept. of Pharmacy and Biotechnology, University of Bologna (Italy); Lanzi, Massimiliano [Dept. of Industrial Chemistry “Toso Montanari”, University of Bologna (Italy); Mezzi, Alessio [Institute for the Study of Nanostructured Materials (CNR-ISMN), Rome (Italy); Valle, Francesco; Cavallini, Massimiliano [Institute for the Study of Nanostructured Materials (CNR-ISMN), Bologna (Italy); Zannoni, Davide [Dept. of Pharmacy and Biotechnology, University of Bologna (Italy)

2017-02-15

Highlights: • Tellurite is reduced by R. capsulatus as cytosolic tellurium nanoprecipitates TeNPs. • Lawsone allows R. capsulatus to produce extracellular TeNPs. • Extracellular TeNPs production depends on the carbon source used for cells growth. • Both lawsone concentration and the incubation time determine the TeNPs size. • Extracellular TeNPs are coated with extracellular polymeric substances (EPS). - Abstract: The toxic oxyanion tellurite (TeO{sub 3}{sup 2−}) is acquired by cells of Rhodobacter capsulatus grown anaerobically in the light, via acetate permease ActP2 and then reduced to Te{sup 0} in the cytoplasm as needle-like black precipitates. Interestingly, photosynthetic cultures of R. capsulatus can also generate Te{sup 0} nanoprecipitates (TeNPs) outside the cells upon addition of the redox mediator lawsone (2-hydroxy-1,4-naphtoquinone). TeNPs generation kinetics were monitored to define the optimal conditions to produce TeNPs as a function of various carbon sources and lawsone concentration. We report that growing cultures over a 10 days period with daily additions of 1 mM tellurite led to the accumulation in the growth medium of TeNPs with dimensions from 200 up to 600–700 nm in length as determined by atomic force microscopy (AFM). This result suggests that nucleation of TeNPs takes place over the entire cell growth period although the addition of new tellurium Te{sup 0} to pre-formed TeNPs is the main strategy used by R. capsulatus to generate TeNPs outside the cells. Finally, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) analysis of TeNPs indicate they are coated with an organic material which keeps the particles in solution in aqueous solvents.

Aspects of a Distinct Cytotoxicity of Selenium Salts and Organic Selenides in Living Cells with Possible Implications for Drug Design

Directory of Open Access Journals (Sweden)

Ethiene Castellucci Estevam

2015-07-01

Full Text Available Selenium is traditionally considered as an antioxidant element and selenium compounds are often discussed in the context of chemoprevention and therapy. Recent studies, however, have revealed a rather more colorful and diverse biological action of selenium-based compounds, including the modulation of the intracellular redox homeostasis and an often selective interference with regulatory cellular pathways. Our basic activity and mode of action studies with simple selenium and tellurium salts in different strains of Staphylococcus aureus (MRSA and Saccharomyces cerevisiae indicate that such compounds are sometimes not particularly toxic on their own, yet enhance the antibacterial potential of known antibiotics, possibly via the bioreductive formation of insoluble elemental deposits. Whilst the selenium and tellurium compounds tested do not necessarily act via the generation of Reactive Oxygen Species (ROS, they seem to interfere with various cellular pathways, including a possible inhibition of the proteasome and hindrance of DNA repair. Here, organic selenides are considerably more active compared to simple salts. The interference of selenium (and tellurium compounds with multiple targets could provide new avenues for the development of effective antibiotic and anticancer agents which may go well beyond the traditional notion of selenium as a simple antioxidant.

Total β-decay energies and masses of tin, antimony and tellurium isotopes in the vicinity of 50132Sn82

International Nuclear Information System (INIS)

Lund, E.; Aleklett, K.; Rudstam, G.

1977-01-01

Experimental β-decay energies for short-lived isotopes of tin, antimony and tellurium are presented. Mass-separated sources were produced at the on-line isotope separator OSIRIS. By applying β-γ coincidence methods, total β-decay energies have been determined for the following nuclides: 127-131 Sn, 128 130 131 134 Sb and 134 135 Te. The atomic mass excess has been derived for these nuclei, and comparisons are made with mass formula predictions. (Auth.)

Ab-initio study of pure sup 7 sup 7 Se and sup 1 sup 2 sup 5 Te systems and of the sup 7 sup 7 Se nuclear quadrupole interaction in tellurium

CERN Document Server

Oh, Y K; Cho, H S

1999-01-01

Using the Hartree-Fock cluster procedure, we have studied the electric-field gradient tensors at the nuclear sites of sup 7 sup 7 Se and sup 1 sup 2 sup 5 Te in pure sup 1 sup 2 sup 5 Te systems and in tellurium crystalline system's with a sup 7 sup 7 Se impurity. From the results for the pure systems, sup 7 sup 7 Se in selenium and sup 1 sup 2 sup 5 Te in tellurium, using the observed quadrupole moments: Q( sup 7 sup 7 Se) 0.75 +- 0.07 barns and Q( sup 1 sup 2 sup 5 Te) = 0.35 +- 0.04 barns. Comparison is made with earlier values obtained by different methods. Using our calculated values of Q and the results of a study of the field-gradient tensors for sup 7 sup 7 Se in tellurium, the theoretical values of the quadrupole coupling constants are found to agree, within about 7 percent, with experiment. The calculated asymmetry parameters are also found to be in reasonable agreement with the experiment values, although the agreement not as close as in the case of the quadrupole -coupling constants. Directions fo...

Molecular polarizability of organic molecules and their complexes. Communication LIV. Molar volumes of polyaryl organoelement compounds in solutions, extrapolated to infinite dilution, and steric structure of the molecules

International Nuclear Information System (INIS)

Bulgarevich, S.B.; Burdastykh, T.V.

2008-01-01

Molar volumes in various solvents were determined for organic derivatives of silicon, phosphorus, arsenic, sulfur, and tellurium, containing aryl nuclei capable to internal rotation about single bonds between them and bridging groups. Additive analysis of the molar volumes of these compounds showed that the aryl nuclei are acoplanar with respect to the bridging groups. Most probable is a conrotatory mutual orientation of the aromatic rings. Molar volumes were also determined for a series of compounds with two bridging groups, which can serve as models of an extreme case of mutual proximity of aryl ring planes in diaryl systems with one bridging group. A possibility for considerably simplifying the methods for determination of dipole moments and Kerr constants for compounds whose molar volumes can be calculated by our developed additive scheme is demonstrated [ru

Melt-gas phase equilibria and state diagrams of the selenium-tellurium system

Science.gov (United States)

Volodin, V. N.; Trebukhov, S. A.; Burabaeva, N. M.; Nitsenko, A. V.

2017-05-01

The partial pressures of saturated vapor of the components in the Se-Te system are determined and presented in the form of temperature-concentration dependences from which the boundaries of the melt-gas phase transition are calculated at atmospheric pressure and vacuums of 2000 and 100 Pa. The existence of azeotropic mixtures is revealed. It is found that the points of inseparably boiling melts correspond to 7.5 at % of Se and 995°C at 101325 Pa, 10.9 at % at 673°C and 19.5 at % at 522°C in vacuums of 2000 and 100 Pa, respectively. A complete state diagram is constructed, including the fields of gas-liquid equilibria at atmospheric and low pressures, the boundaries of which allow us to assess the behavior of selenium and tellurium upon distillation fractionation.

Simultaneous analysis of arsenic, antimony, selenium and tellurium in environmental samples using hydride generation ICPMS

International Nuclear Information System (INIS)

Jankowski, L.M.; Breidenbach, R.; Bakker, I.J.I.; Epema, O.J.

2009-01-01

Full text: A quantitative method for simultaneous analysis of arsenic, antimony, selenium and tellurium in environmental samples is being developed using hydride generation ICPMS. These elements must be first transformed into hydride-forming oxidation states. This is particularly challenging for selenium and antimony because selenium is susceptible to reduction to the non-hydride-forming elemental state and antimony requires strong reducing conditions. The effectiveness of three reducing agents (KI, thiourea, cysteine) is studied. A comparison is made between addition of reducing agent to the sample and addition of KI to the NaBH 4 solution. Best results were obtained with the latter approach. (author)

Luminescent Tellurium-Doped Cadmium Sulfide Electrodes as Probes of Semiconductor Excited-State Deactivation Processes in Photoelectrochemical Cells.

Science.gov (United States)

1980-08-12

photocurrent and emission intensity. Whereas CdS:Te electrochemistry consisted of oxidation of an electrolyte 2+ reductant, ZnO underwent photoanodic...employed n- and 1 3 2,3 3 3,4p-type GaPl’ n-type ZnO , n-type CdS , and n- and p-type GaAs. We have focussed our attention recently on n-type, tellurium...should point out that our treatment of Or and 0x is not without precedent. Both GaP- and ZnO -based PECs have been examined in this regard.l12 The

Stability studies of arsenic, selenium, antimony and tellurium species in water, urine, fish and soil extracts using HPLC/ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Lindemann, T.; Prange, A.; Neidhart, B. [GKSS Research Centre, Geesthacht (Germany). Inst. of Physical and Chemical Analysis; Dannecker, W. [Hamburg Univ. (Germany). Inst. fuer Anorganische und Angewandte Chemie

2000-10-01

The stability of arsenic, selenium, antimony and tellurium species in water and urine (NIST SRM 2670n) as well as in extracts of fish and soil certified reference materials (DORM-2 and NIST SRM 2710) has been investigated. Stability studies were carried out with As(III), As(V), arsenobetaine, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), phenylarsonic acid (PAA), Se(IV), Se(VI), selenomethionine, Sb(III), Sb(V) and Te(VI). Speciation analysis was performed by on-line coupling of anion exchange high-performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS). Best storage of aqueous mixtures of the examined species was achieved at 3 C whereas at -20 C species transformation especially of selenomethionine and Sb(V) took place and a new selenium species appeared within a period of 30 days. Losses and species transformations during extraction processes were investigated. Extraction of the spiked fish material with methanol/water led to partial conversion of Sb(III), Sb(V) and selenomethionine to two new antimony and one new selenium species. The other arsenic, selenium and tellurium species were almost quantitatively extracted. For soil spiked with MMA, PAA, Se(IV) and Sb(III), recoveries after extraction with water and sulfuric acid (0.01 mol/L) were below 20%. (orig.)

Calculations of energy levels and electromagnetic properties for tellurium pair isotopes, by unified method

International Nuclear Information System (INIS)

Teixeira, R.R.P.

1988-01-01

Calculations with the Unified Model (vibrator coupled to two particles), of the energy levels and the eletromagnetic properties have been performed and compared with the twelve pair isotopes from tellurium with A between 112 and 134. The results were analysed using as particles interaction: pairing and SDI (Surface Delta Interaction). The SDI and 3 fonons collective states were used in the fittings, and a syntematic comparison between the theoretical and experimental results was made. The dependence of the results with the model parameters was determined, through large variation sof them. Calculations using 4 fonons have been made, and the importance of the introduced variations in the results was discussed. Calculations have been made in the VAX Computer of the Pelletron at IFUSP. (author) [pt

Development of tellurium oxide and lead-bismuth oxide glasses for mid-wave infra-red transmission optics

Science.gov (United States)

Zhou, Beiming; Rapp, Charles F.; Driver, John K.; Myers, Michael J.; Myers, John D.; Goldstein, Jonathan; Utano, Rich; Gupta, Shantanu

2013-03-01

Heavy metal oxide glasses exhibiting high transmission in the Mid-Wave Infra-Red (MWIR) spectrum are often difficult to manufacture in large sizes with optimized physical and optical properties. In this work, we researched and developed improved tellurium-zinc-barium and lead-bismuth-gallium heavy metal oxide glasses for use in the manufacture of fiber optics, optical components and laser gain materials. Two glass families were investigated, one based upon tellurium and another based on lead-bismuth. Glass compositions were optimized for stability and high transmission in the MWIR. Targeted glass specifications included low hydroxyl concentration, extended MWIR transmission window, and high resistance against devitrification upon heating. Work included the processing of high purity raw materials, melting under controlled dry Redox balanced atmosphere, finning, casting and annealing. Batch melts as large as 4 kilograms were sprue cast into aluminum and stainless steel molds or temperature controlled bronze tube with mechanical bait. Small (100g) test melts were typically processed in-situ in a 5%Au°/95%Pt° crucible. Our group manufactured and evaluated over 100 different experimental heavy metal glass compositions during a two year period. A wide range of glass melting, fining, casting techniques and experimental protocols were employed. MWIR glass applications include remote sensing, directional infrared counter measures, detection of explosives and chemical warfare agents, laser detection tracking and ranging, range gated imaging and spectroscopy. Enhanced long range mid-infrared sensor performance is optimized when operating in the atmospheric windows from ~ 2.0 to 2.4μm, ~ 3.5 to 4.3μm and ~ 4.5 to 5.0μm.

Cs_7Sm_1_1[TeO_3]_1_2Cl_1_6 and Rb_7Nd_1_1[TeO_3]_1_2Br_1_6, the new tellurite halides of the tetragonal Rb_6LiNd_1_1[SeO_3]_1_2Cl_1_6 structure type

International Nuclear Information System (INIS)

Charkin, Dmitri O.; Black, Cameron; Downie, Lewis J.; Sklovsky, Dmitry E.; Berdonosov, Peter S.; Olenev, Andrei V.; Zhou, Wuzong; Lightfoot, Philip; Dolgikh, Valery A.

2015-01-01

Two new rare-earth – alkali – tellurium oxide halides were synthesized by a salt flux technique and characterized by single-crystal X-ray diffraction. The structures of the new compounds Cs_7Sm_1_1[TeO_3]_1_2Cl_1_6 (I) and Rb_7Nd_1_1[TeO_3]_1_2Br_1_6 (II) (both tetragonal, space group I4/mcm) correspond to the sequence of [MLn_1_1(TeO_3)_1_2] and [M_6X_1_6] layers and bear very strong similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted. - Graphical abstract: Two new rare-earth – alkali – tellurium oxide halides were predicted and synthesized. - Highlights: • Two new rare-earth – alkali – tellurium oxide halides were synthesized. • They adopt slab structure of rare earth-tellurium-oxygen and CsCl-like slabs. • The Br-based CsCl-like slabs have been observed first in this layered family.

Potential for improved extraction of tellurium as a byproduct of current copper mining processes

Science.gov (United States)

Hayes, S. M.; Spaleta, K. J.; Skidmore, A. E.

2016-12-01

Tellurium (Te) is classified as a critical element due to its increasing use in high technology applications, low average crustal abundance (3 μg kg-1), and primary source as a byproduct of copper extraction. Although Te can be readily recovered from copper processing, previous studies have estimated a 4 percent extraction efficiency, and few studies have addressed Te behavior during the entire copper extraction process. The goals of the present study are to perform a mass balance examining Te behavior during copper extraction and to connect these observations with mineralogy of Te-bearing phases which are essential first steps in devising ways to optimize Te recovery. Our preliminary mass balance results indicate that less than 3 percent of Te present in copper ore is recovered, with particularly high losses during initial concentration of copper ore minerals by flotation. Tellurium is present in the ore in telluride minerals (e.g., Bi-Te-S phases, altaite, and Ag-S-Se-Te phases identified using electron microprobe) with limited substitution into sulfide minerals (possibly 10 mg kg-1 Te in bulk pyrite and chalcopyrite). This work has also identified Te accumulation in solid-phase intermediate extraction products that could be further processed to recover Te, including smelter dusts (158 mg kg-1) and pressed anode slimes (2.7 percent by mass). In both the smelter dusts and anode slimes, X-ray absorption spectroscopy indicates that about two thirds of the Te is present as reduced tellurides. In anode slimes, electron microscopy shows that the remaining Te is present in an oxidized form in a complex Te-bearing oxidate phase also containing Pb, Cu, Ag, As, Sb, and S. These results clearly indicate that more efficient, increased recovery of Te may be possible, likely at minimal expense from operating copper processing operations, thereby providing more Te for manufacturing of products such as inexpensive high-efficiency solar panels.

Tellurium sulfates from reactions in oleum and sulfur trioxide: syntheses and crystal structures of TeO(SO{sub 4}), Te{sub 4}O{sub 3}(SO{sub 4}){sub 5}, and Te(S{sub 2}O{sub 7}){sub 2}

Energy Technology Data Exchange (ETDEWEB)

Logemann, Christian; Bruns, Joern; Schindler, Lisa Verena; Zimmermann, Vanessa; Wickleder, Mathias S. [Carl von Ossietzky University of Oldenburg, Institute of Chemistry (Germany)

2015-04-15

The reaction of K{sub 2}TeO{sub 4} with fuming sulfuric acid (65 % SO{sub 3}) in sealed glass ampoules at 250 C led to colorless single crystals of TeO(SO{sub 4}) [triclinic, P anti 1, Z = 8, a = 819.89(3) pm, b = 836.95(4) pm, c = 1179.12(5) pm, α = 82.820(2) , β = 70.645(2) , γ = 81.897(2) , V = 753.11(6) x 10{sup 6} pm{sup 3}]. A horseshoe type [Te{sub 4}O{sub 3}] fragment is the basic motif in the layer structure of the compound. The [Te{sub 4}O{sub 3}] moieties are linked to infinite chains by further oxide ions. Monomeric [Te{sub 4}O{sub 3}] horseshoes are found in the crystal structure of Te{sub 4}O{sub 3}(SO{sub 4}){sub 5} [trigonal, P3{sub 2}21, Z = 3, a = 859.05(2) pm, c = 2230.66(7) pm, V = 1425.61(6) x 10{sup 6} pm{sup 3}], which was obtained from TeO{sub 2} and fuming sulfuric acid (65 % SO{sub 3}) at 200 C as colorless single crystals. By switching to neat SO{sub 3} as reaction medium colorless crystals of Te(S{sub 2}O{sub 7}){sub 2} [P2{sub 1}/n, Z = 4, a = 1065.25(3) pm, b = 818.50(2) pm, c = 1206.27(3) pm, β = 102.097(1) , V = 1028.40(5) x 10{sup 6} pm{sup 3}] form when ortho-telluric acid, H{sub 6}TeO{sub 6}, is used as the tellurium source. The compound was reported previously, however, obviously with a wrong crystallographic description. In the crystal structure the tellurium atoms are coordinated by two chelating disulfate ions. Further Te-O contacts link the [Te(S{sub 2}O{sub 7}){sub 2}] units to an extended network. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synthesis and characterization of nanometer sized thermoelectric lead-antimony-silver-tellurium compounds and related materials; Synthese und Charakterisierung nanoskaliger Thermoelektrika der LAST (Lead-Antimony-Silver-Tellurium)-Familie und verwandter Verbindungen

Energy Technology Data Exchange (ETDEWEB)

Petri, Denis

2012-09-10

The present dissertation deals with different variants of synthesis and processing of nanocrystalline composites of various thermoelectric compounds based on lead telluride including LAST-m (AgPb{sub m}SbTe{sub m+2}), LASTT-m-x (AgPb{sub m-x}Sn{sub x}SbTe{sub m+2}), LABST-m-x (AgPb{sub m}Sb{sub 1-x}Bi{sub x}Te{sub m+2}), doped LAST-m and (PbTe){sub m}(M{sup 15}{sub 2}Te{sub 3}) and the characterization thereof. A new route of manufacturing nanocrystalline composites was developed. The so called co-ball milling-route includes the synthesis of bi- or multinary compounds by conventional solid state melting methods followed by combined milling of appropriate amounts in a planetary ball mill; a process related to the widely used mechanical alloying of elemental powders. The as produced powders were shortly annealed for one hour and a.erwards compacted either at room temperature followed by pressureless sintering or combined application of high pressure and elevated temperatures via spark-plasma-sintering or short-term-sintering. The ball milling yielded micron-sized agglomerates consisting of crystallites with diameters ranging from 10 to 50 nm. These crystallites exhibited complicated internal nanostructures severe crystal defects as a consequence of the high energy processing. During short-term annealing some grain coarsening occured and the crystal defects partly healed, which was confirmed by TEM and HRTEM investigations as well as profile analysis of XRD powder pattern. Local EDX-analysis showed different compositions at every point as a consequence of synthesis and decomposition of the compounds. Measurements of thermopower, electrical and thermal conductivity were carried out and the values of the figure of merit ZT and the powerfactor were calculated. In general the compounds exhibited larger thermopower than corresponding bulk materials, which might be attributed to energy filtering of charge carriers at partly oxidized grain boundaries. Due to enhanced phonon

Laser resonance ionization scheme development for tellurium and germanium at the dual Ti:Sa–Dye ISOLDE RILIS

CERN Document Server

Day Goodacre, T.; Fedosseev, V.N.; Forster, L.; Marsh, B.A.; Rossel, R.E.; Rothe, S.; Veinhard, M.

2016-01-01

The resonance ionization laser ion source (RILIS) is the principal ion source of the ISOLDE radioactive beam facility based at CERN. Using the method of in-source laser resonance ionization spectroscopy, a transition to a new autoionizing state of tellurium was discovered and applied as part of a three-step, three-resonance, photo-ionization scheme. In a second study, a three-step, two-resonance, photo-ionization scheme for germanium was developed and the ionization efficiency was measured at ISOLDE. This work increases the range of ISOLDE RILIS ionized beams to 31 elements. Details of the spectroscopy studies are described and the new ionization schemes are summarized.

Laser resonance ionization scheme development for tellurium and germanium at the dual Ti:Sa–Dye ISOLDE RILIS

Energy Technology Data Exchange (ETDEWEB)

Day Goodacre, T., E-mail: thomas.day.goodacre@cern.ch [CERN, CH-1211 Geneva 23 (Switzerland); School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Fedorov, D. [Petersburg Nuclear Physics Institute, 188350 Gatchina (Russian Federation); Fedosseev, V.N.; Forster, L.; Marsh, B.A. [CERN, CH-1211 Geneva 23 (Switzerland); Rossel, R.E. [CERN, CH-1211 Geneva 23 (Switzerland); Institut für Physik, Johannes Gutenberg Universität, D-55099 Mainz (Germany); Faculty of Design, Computer Science and Media, Hochschule RheinMain, Wiesbaden (Germany); Rothe, S.; Veinhard, M. [CERN, CH-1211 Geneva 23 (Switzerland)

2016-09-11

The resonance ionization laser ion source (RILIS) is the principal ion source of the ISOLDE radioactive beam facility based at CERN. Using the method of in-source laser resonance ionization spectroscopy, a transition to a new autoionizing state of tellurium was discovered and applied as part of a three-step, three-resonance, photo-ionization scheme. In a second study, a three-step, two-resonance, photo-ionization scheme for germanium was developed and the ionization efficiency was measured at ISOLDE. This work increases the range of ISOLDE RILIS ionized beams to 31 elements. Details of the spectroscopy studies are described and the new ionization schemes are summarized.

Intracellular Diagnostics: Hunting for the Mode of Action of Redox-Modulating Selenium Compounds in Selected Model Systems

Directory of Open Access Journals (Sweden)

Dominika Mániková

2014-08-01

Full Text Available Redox-modulating compounds derived from natural sources, such as redox active secondary metabolites, are currently of considerable interest in the field of chemoprevention, drug and phytoprotectant development. Unfortunately, the exact and occasionally even selective activity of such products, and the underlying (bio-chemical causes thereof, are often only poorly understood. A combination of the nematode- and yeast-based assays provides a powerful platform to investigate a possible biological activity of a new compound and also to explore the “redox link” which may exist between its activity on the one side and its chemistry on the other. Here, we will demonstrate the usefulness of this platform for screening several selenium and tellurium compounds for their activity and action. We will also show how the nematode-based assay can be used to obtain information on compound uptake and distribution inside a multicellular organism, whilst the yeast-based system can be employed to explore possible intracellular mechanisms via chemogenetic screening and intracellular diagnostics. Whilst none of these simple and easy-to-use assays can ultimately substitute for in-depth studies in human cells and animals, these methods nonetheless provide a first glimpse on the possible biological activities of new compounds and offer direction for more complicated future investigations. They may also uncover some rather unpleasant biochemical actions of certain compounds, such as the ability of the trace element supplement selenite to induce DNA strand breaks.

Comparative study on the bioactivation mechanisms and cytotoxicity of Te-phenyl-L-tellurocysteine, Se-phenyl-L-selenocysteine, and S-phenyl-L-cysteine

NARCIS (Netherlands)

Rooseboom, Martijn; Vermeulen, Nico P E; Durgut, Fatma; Commandeur, Jan N M

2002-01-01

Tellurium compounds are effective antioxidants and chemoprotectors, even more active than their selenium and sulfur analogues. In addition to these properties, some selenium compounds, such as selenocysteine Se-conjugates, possess significant chemopreventive and antitumor activities, and selenol

Effect of aging and temperature on alternating current conductivity of tellurium thin films

Energy Technology Data Exchange (ETDEWEB)

Tsiulyanu, D. [Technical University, Department of Physics, bul. Dacia 41, MD-2060, Chisinau (Moldova, Republic of)], E-mail: tsiu@cni.md; Marian, T.; Tiuleanu, A. [Technical University, Department of Physics, bul. Dacia 41, MD-2060, Chisinau (Moldova, Republic of); Liess, H.-D.; Eisele, I. [University of the Bundeswehr Munich, Faculty of Electrical Engineering and Information Technology, Institute of Physics, D-85577 Neubiberg (Germany)

2009-02-27

The impedance spectra of tellurium films with interdigital platinum electrodes were investigated in air at temperatures between 10 and 50 deg. C . Cole-Cole analysis made it possible to assess time constants, resistance, and capacitance of the film at characteristic frequencies and the dependence of these parameters on aging and temperature. Aging under normal conditions over 12 months led to a relative increase of only {approx} 5% in film impedance at the characteristic frequency. However, aging noticeably influences the electrical resistance of the film at high (> 500 kHz) frequencies, and capacitance diminished after 12 months by more than 50% throughout the spectrum. Scanning electron microscopy confirmed that the effect of aging is due to structural changes in the film. Temperature does not influence the capacitance of the film but uncommonly influences its resistance, which reaches a maximum at around 20 deg. C . This is ascribed to desorption of oxygen previously adsorbed from the environment.

Effect of aging and temperature on alternating current conductivity of tellurium thin films

International Nuclear Information System (INIS)

Tsiulyanu, D.; Marian, T.; Tiuleanu, A.; Liess, H.-D.; Eisele, I.

2009-01-01

The impedance spectra of tellurium films with interdigital platinum electrodes were investigated in air at temperatures between 10 and 50 deg. C . Cole-Cole analysis made it possible to assess time constants, resistance, and capacitance of the film at characteristic frequencies and the dependence of these parameters on aging and temperature. Aging under normal conditions over 12 months led to a relative increase of only ∼ 5% in film impedance at the characteristic frequency. However, aging noticeably influences the electrical resistance of the film at high (> 500 kHz) frequencies, and capacitance diminished after 12 months by more than 50% throughout the spectrum. Scanning electron microscopy confirmed that the effect of aging is due to structural changes in the film. Temperature does not influence the capacitance of the film but uncommonly influences its resistance, which reaches a maximum at around 20 deg. C . This is ascribed to desorption of oxygen previously adsorbed from the environment

Study on concentration nonlinearity of interacting acoustic flows in cadmium sulfide and tellurium

International Nuclear Information System (INIS)

Ilisavskij, Yu.V.; Kulakova, L.A.; Yakhkind, Eh.Z.

1976-01-01

The ratio of an one-mode (self-action of an external monochromatic sound wave) and a many-mode (interaction of an external wave with crystal thermal phonons) concentration nonlinearity has been experimentally investigated on sound amplification in cadmium sulphide and tellurium. It has been shown that in a strong piezoelectric the main part in the nonlinear limitation of the sound amplification in a drift field is played by the wave interaction, i.e., the transfer of the sound wave energy into the crystal sound modes starts before the nonlinear self-action of a wave. In Te characterized by a large value of the electromechanical coupling constant value at the sound frequency of about 250 MHz the threshold of many-mode nonlinearity is achieved in fields much below the critical one, and corresponds to the sound intensity as low as 10 -7 W/cm 2 , as compared with 10 -2 W/cm 2 -the threshold of the one-mode nonlinearity

Electrochemical and antimicrobial activity of tellurium oxide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Gupta, Pramod K. [Department of Applied Sciences and Humanities, Jamia Millia Islamia, New Delhi 110067 (India); Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi 110067 (India); Sharma, Prem Prakash; Sharma, Anshu [Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi 110067 (India); Khan, Zishan H., E-mail: zishan_hk@yahoo.co.in [Department of Applied Sciences and Humanities, Jamia Millia Islamia, New Delhi 110067 (India); Solanki, Pratima R., E-mail: pratimarsolanki@gmail.com [Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi 110067 (India)

2016-09-15

Highlights: • TeO{sub 2} NPs synthesized without using any catalyst by chemical vapour deposition method. • The growth temperature was 410 °C with continuous flow of O{sub 2.} • TeO{sub 2} NPs have anti-bacterial activity against E. coli, K. pneumoniae and S. aureus while enhances the growth of S. pyogenes. • TeO{sub 2} shows maximum redox current at pH 7 for phosphate buffer solution. - Abstract: Thin film of tellurium oxide (TeO{sub 2}) has been synthesized by chemical vapour deposition method onto indium tin oxide (ITO) coated glass substrate without using any catalyst. XRD pattern of TeO{sub 2} thin film suggests that the structure of TeO{sub 2} changes from amorphous to crystalline (paratellurite) on dispersing into deionized water. Zeta potential measurement reveals a positive surface potential of 28.8 mV. TEM images shows spherical shaped TeO{sub 2} nanoparticles having average particle size of 65 nm. Electrochemical studies of TeO{sub 2}/ITO electrode exhibit improved electron transfer owing to its inherent electron transfer property at pH 7.0 of phosphate buffer. Antimicrobial activity of TeO{sub 2} has been studied for gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and gram negative (Escherichia coli and Klebsiella pneumoniae) bacterial and fungal strains (Aspergillus nizer and Candida albicans). These studies suggest that the TeO{sub 2} NPs inhibit the growth of E. coli, K. pneumoniae and S. aureus bacteria, whereas the same particles enhance the growth of S. pyogenes bacteria.

Leaching of cadmium and tellurium from cadmium telluride (CdTe) thin-film solar panels under simulated landfill conditions

Science.gov (United States)

Ramos-Ruiz, Adriana; Wilkening, Jean V.; Field, James A.; Sierra-Alvarez, Reyes

2017-01-01

A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. PMID:28472709

Optical properties of tellurium-doped InxGa1-xAsySb1-y epitaxial layers studied by photoluminescence spectroscopy

International Nuclear Information System (INIS)

Diaz-Reyes, J; Cardona-Bedoya, J A; Gomez-Herrera, M L; Herrera-Perez, J L; Riech, I; Mendoza-Alvarez, J G

2003-01-01

Controlled doping of quaternary alloys of In x Ga 1-x As y Sb 1-y with tellurium is fundamental to obtain the n-type layers needed for the development of optoelectronic devices based on p-n heterojunctions. InGaAsSb epitaxial layers were grown by liquid phase epitaxy and Te doping was obtained by incorporating small Sb 3 Te 2 pellets in the growth melt. The tellurium doping levels were in the range 10 16 -10 17 cm -3 . We have used low-temperature photoluminescence (PL) spectroscopy to study the influence of the Te donor levels on the radiative transitions shown in the PL spectra. The PL measurements were done by exciting the samples with the 448 nm line of an Ar ion laser with varying excitation powers in the range from 10 to 200 mW. For the low-doped sample the PL spectrum showed a narrow exciton-related peak centred at around 610 meV with a full width at half maximum (FWHM) of about 7 meV which is evidence of the good crystalline quality of the layers. For higher Te doping, the PL spectra show the presence of band-to-band and donor-to-acceptor transitions which overlap as the Te concentration increases. The peak of the PL band shifts to higher energies as Te doping increases due to a band-filling effect as the Fermi level enters into the conduction band. From the peak energy of the PL spectra, and using a model that includes the band-filling and band-shrinkage effects due to the carriers, we have estimated the effective carrier concentration due to doping with Te in the epilayers

Ten Good Reasons for the Use of the Tellurium-Centered Anderson-Evans Polyoxotungstate in Protein Crystallography.

Science.gov (United States)

Bijelic, Aleksandar; Rompel, Annette

2017-06-20

Protein crystallography represents at present the most productive and most widely used method to obtain structural information on target proteins and protein-ligand complexes within the atomic resolution range. The knowledge obtained in this way is essential for understanding the biology, chemistry, and biochemistry of proteins and their functions but also for the development of compounds of high pharmacological and medicinal interest. Here, we address the very central problem in protein crystallography: the unpredictability of the crystallization process. Obtaining protein crystals that diffract to high resolutions represents the essential step to perform any structural study by X-ray crystallography; however, this method still depends basically on trial and error making it a very time- and resource-consuming process. The use of additives is an established process to enable or improve the crystallization of proteins in order to obtain high quality crystals. Therefore, a more universal additive addressing a wider range of proteins is desirable as it would represent a huge advance in protein crystallography and at the same time drastically impact multiple research fields. This in turn could add an overall benefit for the entire society as it profits from the faster development of novel or improved drugs and from a deeper understanding of biological, biochemical, and pharmacological phenomena. With this aim in view, we have tested several compounds belonging to the emerging class of polyoxometalates (POMs) for their suitability as crystallization additives and revealed that the tellurium-centered Anderson-Evans polyoxotungstate [TeW 6 O 24 ] 6- (TEW) was the most suitable POM-archetype. After its first successful application as a crystallization additive, we repeatedly reported on TEW's positive effects on the crystallization behavior of proteins with a particular focus on the protein-TEW interactions. As electrostatic interactions are the main force for TEW binding

From Selenium- to Tellurium-Based Glass Optical Fibers for Infrared Spectroscopies

Directory of Open Access Journals (Sweden)

Jacques Lucas

2013-05-01

Full Text Available Chalcogenide glasses are based on sulfur, selenium and tellurium elements, and have been studied for several decades regarding different applications. Among them, selenide glasses exhibit excellent infrared transmission in the 1 to 15 µm region. Due to their good thermo-mechanical properties, these glasses could be easily shaped into optical devices such as lenses and optical fibers. During the past decade of research, selenide glass fibers have been proved to be suitable for infrared sensing in an original spectroscopic method named Fiber Evanescent Wave Spectroscopy (FEWS. FEWS has provided very nice and promising results, for example for medical diagnosis. Then, some sophisticated fibers, also based on selenide glasses, were developed: rare-earth doped fibers and microstructured fibers. In parallel, the study of telluride glasses, which can have transmission up to 28 µm due to its atom heaviness, has been intensified thanks to the DARWIN mission led by the European Space Agency (ESA. The development of telluride glass fiber enables a successful observation of CO2 absorption band located around 15 µm. In this paper we review recent results obtained in the Glass and Ceramics Laboratory at Rennes on the development of selenide to telluride glass optical fibers, and their use for spectroscopy from the mid to the far infrared ranges.

Direct determination of tellurium and its redox speciation at the low nanogram level in natural waters by catalytic cathodic stripping voltammetry.

Science.gov (United States)

Biver, Marc; Quentel, François; Filella, Montserrat

2015-11-01

Tellurium is one of the elements recently identified as technologically critical and is becoming a new emergent contaminant. No reliable method exists for its determination in environmental samples such as natural waters. This gap is filled by the method described here; it allows the rapid detection of trace concentrations of Te(IV) and Te(VI) in surface waters by differential pulse cathodic stripping voltammetry. It is based on the proton reduction catalysed by the absorption of Te(IV) on the mercury electrode. Under our conditions (0.1 mol L(-1) HCl) a detection limit of about 5 ng L(-1) for a deposition time of 300 s is achieved. Organic matter does not represent a problem at low concentrations; higher concentrations are eliminated by adsorptive purification. Tellurium occurs primarily as Te(IV) and Te(VI) in natural waters. Thus, determining total Te requires the reduction of Te(VI) that it is not electroactive. A number of reduction procedures have been carefully evaluated and a method based on the addition of TiCl3 to the acidified samples has been proven to reduce Te(VI) at the trace level to Te(IV) reliably and quantitatively. Therefore, the procedure described allows the direct determination of total Te and its redox speciation. It is flexible, reliable and cost effective compared to any possible alternative method based on the common preconcentration-ICPMS approach. It is readily implementable as a routine method and can be deployed in the field with relative ease. Copyright © 2015 Elsevier B.V. All rights reserved.

Tellurium Stable Isotopes as a Paleoredox Proxy

Science.gov (United States)

Wasserman, N.; Johnson, T. M.

2017-12-01

Despite arguments for variably-oxygenated shallow waters and anoxic deep marine waters, which delayed animal development until the Neoproterozoic Oxidation Event, the magnitude of atmospheric oxygen during the Proterozoic is still uncertain [1]. The evidence for low pO2 (<0.1-1% PAL) is based on geochemical and isotopic proxies, which track the mobilization of Fe and Mn on the continents. For example, large chromium isotope shifts occur at the Neoproterozoic Oxidation Event due to the initiation of Cr redox cycling, but this proxy is insensitive to fluctuations in the lower-pO2 conditions at other times during the Proterozoic. Tellurium, a metalloid with a lower threshold to oxidation, may be sensitive to pO2 shifts in a lower range. In the reduced forms, Te(-II) and Te(0), the element is insoluble and immobile. However, in the more oxidized phases, Te(IV) and Te(VI), Te can form soluble oxyanions (though it tends to adsorb to Fe-oxyhydroxides and clays) [2]. Te stable isotopes have been shown to fractionate during abiotic or biologic reduction of Te(VI) or Te(IV) to elemental Te(0) [3, 4]. Utilizing hydride generation MC-ICP-MS, we are able to obtain high precision (2σ 0.04‰) measurements of δ128Te/125Te for natural samples containing < 10 ng of Te. A suite of Phanerozoic and Proterozoic ironstones show significant variation in δ128Te/125Te (<0.5‰), suggesting that the Te redox cycle was active during the Proterozoic. Future directions will include Te isotope measurements of Precambrian paleosols to determine natural isotope variation before the Great Oxidation Event and experiments to determine fractionation during adsorption to Fe-oxyhydroxides. [1] Planavsky et al. (2014) Science 346 (6209), pp. 635-638 [2] Qin et al. (2017) Environmental Science and Technology 51 (11), pp 6027-6035 [3] Baesman et al. (2007) Applied Environmental Microbiology 73 (7), pp 2135-2143 [4] Smithers and Krause (1968) Canadian Journal of Chemistry 46(4): pp 583-591

Determination of tellurium in gallium by alternating current stripping voltammetry with a mercury/graphite electrode

International Nuclear Information System (INIS)

Berengard, I.B.; Kaplan, B. Ya.

1986-01-01

The analytical signal in ac stripping coltammetry (ACSV) with mercury indicator electrodes depends on the weight of the electrolytically collected analyte at the electrode surface, the depth of the collection layer being equal to the effective diffusion-layer thickness. Replacement of the static mercury drop electrode (SMDE) by the mercury/graphite electrode (MGE) is of practical interest in that the analyte detection limit can be lowered by decreasing the colume of the telluriumcontaining polarographed solution; in addition, plant laboratories find it difficult to control the SDME uniformity. The work in this article was done on a PU-1 universal polarograph in a square-wave vol tage component mode using the three-electrode cell shown. The rotating mercury/graphite electrode is found by the authors to be superior to the static mercury drop electrode in that it can lower the detection limit for tellurium in gallium to 5.10 /SUP -7percent/ , due to the smaller volume of the polarographed solution

NMR spectroscopy of selenium and tellurium organic compounds

International Nuclear Information System (INIS)

Kalabin, G.A.; Projdakov, A.G.; Radchenko, S.I.

1980-01-01

13 C NMR spectra of the substituted methylthio (seleno, telluro) acetylenes, CH 3 EC 1 identity sign C 2 R, E=S, Se, Te are measured. High sensitivity of the chemical shifts of ternary bond carbons to specific effects of heteroatoms is established. The substituent nature produces considerable effect on the sensitivity of C 1 -carbon atom to these effects. Chemical shifts of the substituent carbons do not depend on heteroatoms nature

Nanoscale Device Properties of Tellurium-based Chalcogenide Compounds

Science.gov (United States)

Dahal, Bishnu R.

The great progress achieved in miniaturization of microelectronic devices has now reached a distinct bottleneck, as devices are starting to approach the fundamental fabrication and performance limit. Even if a major breakthrough is made in the fabrication process, these scaled down electronic devices will not function properly since the quantum effects can no longer be neglected in the nanoscale regime. Advances in nanotechnology and new materials are driving novel technologies for future device applications. Current microelectronic devices have the smallest feature size, around 10 nm, and the industry is planning to switch away from silicon technology in the near future. The new technology will be fundamentally different. There are several leading technologies based on spintronics, tunneling transistors, and the newly discovered 2-dimensional material systems. All of these technologies are at the research level, and are far from ready for use in making devices in large volumes. This dissertation will focus on a very promising material system, Te-based chalcogenides, which have potential applications in spintronics, thermoelectricity and topological insulators that can lead to low-power-consumption electronics. Very recently it was predicted and experimentally observed that the spin-orbit interaction in certain materials can lead to a new electronic state called topological insulating phase. The topological insulator, like an ordinary insulator, has a bulk energy gap separating the highest occupied electronic band from the lowest empty band. However, the surface states in the case of a three-dimensional or edge states in a two-dimensional topological insulator allow electrons to conduct at the surface, due to the topological character of the bulk wavefunctions. These conducting states are protected by time-reversal symmetry, and cannot be eliminated by defects or chemical passivation. The edge/surface states satisfy Dirac dispersion relations, and hence the physics of relativistic Dirac fermions becomes relevant. This results in peculiar quantum oscillations in transport measurements which make it possible to unambiguously identify surface Dirac fermions. In order to lead us towards a better understanding of topological insulators and their applications, it is, however, necessary to develop techniques that will enable high quality materials to be obtained in a routine and reliable way. However, this has been an enormous challenge so far. Since highly volatile components are involved in most topological insulators, whether in bulk single crystal or epitaxial thin films or chemical vapor deposition grown nanoribbons, maintaining near stoichiometry has proven to be very difficult. Observing the predicted transport properties of these systems, particularly surface carriers of high mobility whilst maintaining bulk insulating states, is seriously impeded by the unintentional doping of bulk carriers. Moreover, in thin films and hetrostructures, at the all-important thickness range of a few nanometers, the additional limitation of the film-substrate lattice mismatch and the resulting strain in films is a major concern. In this thesis, we have developed a synthesis technique to obtain high quality SnTe nanoribbons, which is a topological crystalline insulator and its surface states are topologically protected by mirror symmetry of the lattice. The obtained ribbons are nearly stoichiometric and show strong semiconducting behavior with a bandgap of 240 meV. This is the first time high quality SnTe nanoribbons have been synthesized. High quality SnTe nanoribbons form a potential platform to understand the magnetic topological insulating behavior. In this thesis, it is also shown that magnetic behavior can be introduced in SnTe nanoribbons by means of chromium doping. Magnetically doped topological insulators, possessing an energy gap created at the Dirac point are predicted to exhibit exotic phenomena including the quantized anomalous Hall Effect and a dissipationless transport, which facilitate the development of low-power-consumption devices using electron spins. In addition, this thesis also discusses the growth and transport properties of another Te-based chalcogenide system, CoTe with ferrimagnetic and semiconducting behavior. We have shown that the structural, electrical and magnetic properties can be tuned by controlling the amount of cobalt in the system.

Zn2(TeO3Br2

Directory of Open Access Journals (Sweden)

Mats Johnsson

2008-05-01

Full Text Available Single crystals of dizinc tellurium dibromide trioxide, Zn2(TeO3Br2, were synthesized via a transport reaction in sealed evacuated silica tubes. The compound has a layered crystal structure in which the building units are [ZnO4Br] distorted square pyramids, [ZnO2Br2] distorted tetrahedra, and [TeO3E] tetrahedra (E being the 5s2 lone pair of Te4+ joined through sharing of edges and corners to form layers of no net charge. Bromine atoms and tellurium lone pairs protrude from the surfaces of each layer towards adjacent layers. This new compound Zn2(TeO3Br2 is isostructural with the synthetic compounds Zn2(TeO3Cl2, CuZn(TeO32, Co2(TeO3Br2 and the mineral sophiite, Zn2(SeO3Cl2.

Size Controlled Synthesis of Tellurium Nanorices by Galvanic Displacement Reaction of Aluminum

International Nuclear Information System (INIS)

Wu, Tingjun; Myung, Lawrence Youngjae; Zhang, Miluo; Lee, Kyu-Hwan; Lee, Yeheun Laura; Lim, Hyo-Ryong; Kim, Bum Sung; Choa, Yong-Ho; Myung, Nosang V.

2015-01-01

ABSTRACT: Tellurium nanostructures were synthesized by galvanic displacement reaction (GDR) of aluminum in an alkaline solution containing TeO 3 2− ions. Due to negative redox potential of Al/AlO 2 − (i.e., −2.50 V vs. sat. Ag/AgCl), TeO 3 2− (+IV) can be reduced to Te 2 2− (-I) and Te 2− (-II), which resulted in the deposition of Te (0) nanostructures in the solution via chemical reaction between Te 2 2− or Te 2− and TeO 3 2− . The deposition mechanism led to the formation of unique “rice-like” nanostructures in the solution instead of branched structures on the substrate. The sharp tips of the “rice-like” nanostructures may be attributed to the high density of surface charges at the tips. The morphology, diameter and aspect ratio of Te “rice-like” nanostructures were altered by the TeO 3 2− concentration, solution pH, reaction time and the reaction temperature. Electrochemical analytical methods, including open circuit potential (OCP) and linear polarizations (LPs), were used to investigate the reaction mechanisms. The enhancement of piezoelectric constant (d 11 ) of nanorices at small diameter was probably due to a flexoelectric effect

On the cesium-rich part of the Cs-Te phase diagram

International Nuclear Information System (INIS)

Boer, R. de; Cordfunke, E.H.P.

1995-03-01

The cesium-tellurium system in the region between 33 and 55 at.% Te has been investigated with X-ray diffraction and DSC. The existence of the compounds Cs 5 Te 3 and CsTe is demonstrated. The latter compound exhibits a structural transition at elevated temperature, as does the compound Cs 2 Te. The earlier reported compounds Cs 3 Te 2 and Cs 5 Te 4 do not exist. (orig.)

The Present, Mid-Term, and Long-Term Supply Curves for Tellurium; and Updates in the Results from NREL's CdTe PV Module Manufacturing Cost Model (Presentation)

Energy Technology Data Exchange (ETDEWEB)

Woodhouse, M.; Goodrich, A.; Redlinger, M.; Lokanc, M.; Eggert, R.

2013-09-01

For those PV technologies that rely upon Te, In, and Ga, first-order observations and calculations hint that there may be resource constraints that could inhibit their successful deployment at a SunShot level. These are only first-order approximations, however, and the possibility for an expansion in global Te, In, and Ga supplies needs to be considered in the event that there are upward revisions in their demand and prices.In this study, we examine the current, mid-term, and long-term prospects of Tellurium (Te) for use in PV. We find that the current global supply base of Te would support <10 GW of annual traditional CdTe PV manufacturing production. But as for the possibility that the supply base for Te might be expanded, after compiling several preliminary cumulative availability curves we find that there may be significant upside potential in the supply base for this element - principally vis a vis increasing demand and higher prices. Primarily by reducing the Tellurium intensity in manufacturing and by increasing the recovery efficiency of Te in Cu refining processes, we calculate that it may prove affordable to PV manufacturers to expand the supply base for Te such that 100 GW, or greater, of annual CdTe PV production is possible in the 2030 - 2050 timeframe.

Zn2(TeO3)Br2

Science.gov (United States)

Zhang, Dong; Johnsson, Mats

2008-01-01

Single crystals of dizinc tellurium dibromide trioxide, Zn2(TeO3)Br2, were synthesized via a transport reaction in sealed evacuated silica tubes. The compound has a layered crystal structure in which the building units are [ZnO4Br] distorted square pyramids, [ZnO2Br2] distorted tetra­hedra, and [TeO3 E] tetra­hedra (E being the 5s 2 lone pair of Te4+) joined through sharing of edges and corners to form layers of no net charge. Bromine atoms and tellurium lone pairs protrude from the surfaces of each layer towards adjacent layers. This new compound Zn2(TeO3)Br2 is isostructural with the synthetic compounds Zn2(TeO3)Cl2, CuZn(TeO3)2, Co2(TeO3)Br2 and the mineral sophiite, Zn2(SeO3)Cl2. PMID:21202162

Lattice parameters and stability of the spinel compounds in relation to the ionic radii and electronegativities of constituting chemical elements.

Science.gov (United States)

Brik, Mikhail G; Suchocki, Andrzej; Kamińska, Agata

2014-05-19

A thorough consideration of the relation between the lattice parameters of 185 binary and ternary spinel compounds, on one side, and ionic radii and electronegativities of the constituting ions, on the other side, allowed for establishing a simple empirical model and finding its linear equation, which links together the above-mentioned quantities. The derived equation gives good agreement between the experimental and modeled values of the lattice parameters in the considered group of spinels, with an average relative error of about 1% only. The proposed model was improved further by separate consideration of several groups of spinels, depending on the nature of the anion (oxygen, sulfur, selenium/tellurium, nitrogen). The developed approach can be efficiently used for prediction of lattice constants for new isostructural materials. In particular, the lattice constants of new hypothetic spinels ZnRE2O4, CdRE2S4, CdRE2Se4 (RE = rare earth elements) are predicted in the present Article. In addition, the upper and lower limits for the variation of the ionic radii, electronegativities, and their certain combinations were established, which can be considered as stability criteria for the spinel compounds. The findings of the present Article offer a systematic overview of the structural properties of spinels and can serve as helpful guides for synthesis of new spinel compounds.

Aspects of the chemistry of boron

International Nuclear Information System (INIS)

Moellinger, H.

1976-01-01

Crystal phases of elementary boron are reviewed as well as boron-sulphur, boron-selenum, boron-tellurium, and boron-nitrogen compounds, carboranes, and boron-carbohydrate complexes. A boron cadastre of rivers and lakes serves to illustrate the role of boron in environmental protection. Technically relevant boron compounds and their uses are mentioned. (orig.) 891 HK/orig. 892 MB [de

Equilibrium evaporation behavior of polonium and its homologue tellurium in liquid lead-bismuth eutectic

International Nuclear Information System (INIS)

Ohno, Shuji; Miyahara, Shinya; Kurata, Yuji; Katsura, Ryoei; Yoshida, Shigeru

2006-01-01

Experimental study using the transpiration method investigates equilibrium evaporation behavior of radionuclide polonium ( 210 Po) generated and accumulated in liquid lead-bismuth eutectic (LBE) cooled nuclear systems. The experiment consists of two series of tests: preliminary evaporation tests for homologue element tellurium (Te) in LBE, and evaporation tests for 210 Po-accumulated LBE in which test specimens are prepared by neutron irradiation. The evaporation tests of Te in LBE provide the suggestion that Te exists in a chemical form of PbTe as well as the information for confirming the validity of technique and conditions of Po test. From the evaporation tests of 210 Po in LBE, we obtain fundamental data and empirical equations such as 210 Po vapor concentration in the gas phase, 210 Po partial vapor pressure, thermodynamic activity coefficients, and gas-liquid equilibrium partition coefficient of 210 Po in LBE in the temperature range from 450 to 750degC. Additionally, radioactivity concentration of 210 Po and 210m Bi vapor in a cover gas region of a typical LBE-cooled nuclear system is specifically estimated based on the obtained experimental results, and the importance of 210 Po evaporation behavior is quantitatively demonstrated. (author)

Iron-tellurium-selenium mixed oxide catalysts for the selective oxidation of propylene to acrolein

International Nuclear Information System (INIS)

Patel, B.M.; Price, G.L.

1990-01-01

This paper reports on iron-tellurium-selenium mixed oxide catalysts prepared by coprecipitation from aqueous solution investigated for the propylene to acrolein reaction in the temperature range 543-773 K. Infrared spectroscopy, electron dispersive X-ray analysis, X-ray diffraction, and isotopic tracer techniques have also been employed to characterize this catalytic system. Properties of the Fe-Te-Se mixed oxide catalysts have been compared with Fe-Te mixed oxides in an effort to deduce the functionality of Se. The selenium in the Fe-Te-Se-O catalyst has been found to be the hydrocarbon activating site. The activation energies for the acrolein and carbon dioxide formation are 71 and 54 kJ/mol, respectively. Reactions carried out with 18 O 2 have shown lattice oxygen to be primarily responsible for the formation of both acrolein and carbon dioxide. The initial and rate-determining step for acrolein formation is hydrogen abstraction as determined by an isotope effect associated with the C 3 D 6 reaction. No isotope effect is observed for carbon dioxide formation from C 3 D 6 suggesting that CO 2 is formed by parallel, not consecutive, oxidation of propylene

Enhanced Flexural Strength of Tellurium Nanowires/epoxy Composites with the Reinforcement Effect of Nanowires

Science.gov (United States)

Balguri, Praveen Kumar; Harris Samuel, D. G.; Aditya, D. B.; Vijaya Bhaskar, S.; Thumu, Udayabhaskararao

2018-02-01

Investigating the mechanical properties of polymer nanocomposite materials has been greatly increased in the last decade. In particular, flexural strength plays a major role in resisting bending and shear loads of a composite material. Here, one dimensional (1D) tellurium nanowires (TeNWs) reinforced epoxy composites have been prepared and the flexural properties of resulted TeNWs/epoxy nanocomposites are studied. The diameter and length of the TeNWs used to make TeNWs/epoxy nanocomposites are 21±2.5 nm and 697±87 nm, respectively. Plain and TeNWs/epoxy nanocomposites are characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). Furthermore, significant enhancement in the flexural strength of TeNWs/epoxy nanocomposite is observed in comparison to plain epoxy composite, i.e. flexural strength is increased by 65% with the addition of very little amount of TeNWs content (0.05 wt.%) to epoxy polymer. Structural details of plain and TeNWs/epoxy at micrometer scale were examined by scanning electron microscopy (SEM). We believe that our results provide a new type of semiconductor nanowires based high strength epoxy polymer nanocomposites.

Principles for prevention of toxic effects from metals

DEFF Research Database (Denmark)

Landrigan, Philip J.; Kotelchuk, David; Grandjean, Philippe

2007-01-01

of the Toxic Effects of Metals Aluminum Antimony Arsenic Barium Beryllium Bismuth Cadmium Chromium Cobalt Copper Gallium and Semiconductor Compounds Germanium Indium Iron Lead Manganese Mercury Molybdenum Nickel Palladium Platinum Selenium Silver Tellurium Thallium Tin Titanium Tungsten Uranium Vanadium Zinc...

Raman and DSC studies of fragility in tellurium-zinc oxide glass formers

International Nuclear Information System (INIS)

Stavrou, Elissaios; Kripotou, Sotiria; Raptis, Constantine; Turrell, Sylvia; Syassen, Karl

2011-01-01

Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out in four mixed (TeO 2 ) 1-x (ZnO) x (x = 0.1, 0.2, 0.3, 0.4) glasses at high temperatures (Raman and DSC through the glass transition) and high pressures (Raman) with the aim of determining the fragility of these glass forming oxides. Four different criteria, corresponding to four parameters, were applied to assess the fragility of the glasses. From the DSC studies, we have obtained the fragility parameter m which corresponds to the slopes of Arrhenius (lnQ vs. 1/T g , were Q is the heating rate) plots, and the glass transition width ΔT g . Also, from the low-frequency Raman scattering, and in particular the boson peak intensity of the glasses at T g , we have estimated the fragility ratio r R (T g ) = I min /I max whose value serves as another (empirical) fragility criterion. Finally, from high pressure Raman measurements on the glasses, we have estimated the Grueneisen parameter γ T for each glass, which constitutes the fourth fragility parameter adopted in this work. Considering the four parameters ΔT g , m, r (T g ) and γ T and the generally accepted (empirical) fragility criteria, we conclude that the mixed tellurium-zinc oxides constitute strong-to-intermediate glass formers (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

ThP05 Biogeneration of Volatile Selenium Compounds in Biosolids/Biofuels and Quantification by VD/GC/ICPMS

Science.gov (United States)

A noval analytical approach that uses VD/GC/ICPMS for the on-line extraction and quantificationof volatile organopmetalloids is described. Several species of arsenic, selenium, antimony, bismuth and tellurium are amenable to this technique. Preliminary results of a study on the...

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Electronic switching in amorphous chalcogenide semiconductors has been observed and studied for nearly forty years. Technological exploitation of this phenomenon has most recently emerged in DVD's where GST, a compound of germanium, antimony, and tellurium, is used to store information. We explain how GST ...

Test of irradiation of tellurium oxide for obtaining iodine-131 by dry distillation; Prueba de irradiacion de dioxido de telurio para obtener yodo-131 por destilacion seca

Energy Technology Data Exchange (ETDEWEB)

Alanis M, J. [ININ, Departamento de Materiales Radiactivos, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2003-07-15

With the purpose of optimizing to the maximum independently the work of the reactor of those mathematical calculations of irradiation that are already optimized, now it corresponds to carry out irradiation tests in the different positions with their respective neutron fluxes that it counts the reactor for samples irradiation. Then, it is necessary to carry out the irradiation of the tellurium dioxide through cycles, with the purpose of observing the activity that it goes accumulating in each cycle and this way to obtain an activity of the Iodine-131 obtained when finishing the last cycle. (Author)

Structural Fluctuation and Thermophysical Properties of Molten II-VI Compounds

Science.gov (United States)

2003-01-01

The objectives of the project is to conduct ground-based experimental and theoretical research on the structural fluctuations and thermophysical properties of molten II-VI compounds to enhance the basic understanding of the existing flight experiments in microgravity materials science programs and to study the fundamental heterophase fluctuations phenomena in these melts by: 1) Conducting neutron scattering analysis and measuring quantitatively the relevant thermophysical properties of the II-VI melts such as viscosity, electrical conductivity, thermal diffusivity and density as well as the relaxation characteristics of these properties to advance the understanding of the structural properties and the relaxation phenomena in these melts and 2) Performing theoretical analyses on the melt systems to interpret the experimental results. All the facilities required for the experimental measurements have been procured, installed and tested. A relaxation phenomenon, which shows a slow drift of the measured thermal conductivity toward the equilibrium value after cooling of the sample, was observed for the first time. An apparatus based on the transient torque induced by a rotating magnetic field has been developed to determine the viscosity and electrical conductivity of semiconducting liquids. Viscosity measurements on molten tellurium showed similar relaxation behavior as the measured diffusivity. Neutron scattering experiments were performed on the HgTe and HgZnTe melts and the results on pair distribution showed better resolution than previous reported.

Growth of PbTe nanorods controlled by polymerized tellurium anions and metal(II) amides via composite-hydroxide-mediated approach

International Nuclear Information System (INIS)

Wan Buyong; Hu Chenguo; Liu Hong; Xiong Yufeng; Li Feiyun; Xi Yi; He Xiaoshan

2009-01-01

The pure face-centered-cubic PbTe nanorods have been synthesized by the composite-hydroxide-mediated approach using hydrazine as a reducing agent. The method is based on reaction among reactants in the melts of potassium hydroxide and sodium hydroxide eutectic at 170-220 deg. C and normal atmosphere without using any organic dispersant or surface-capping agent. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy were used to characterize the structure, morphology and composition of the samples. The diameters of nanorods are almost fixed, while the lengths can be tunable under different growth time and temperatures. The growth mechanism of PbTe nanorods is investigated via UV-vis absorption, demonstrating that polymerized tellurium anions and metal(II) amides in the hydrazine hydroxide melts could control the crystallization and growth process of PbTe nanostructures. The band gap of as-synthesized PbTe nanorods has been calculated based on UV-vis-NIR optical diffuse reflectance spectra data.

Growth of PbTe nanorods controlled by polymerized tellurium anions and metal(II) amides via composite-hydroxide-mediated approach

Energy Technology Data Exchange (ETDEWEB)

Wan Buyong [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); College of Physics and Information Technology, Chongqing Normal University, Chongqing 400047 (China); Hu Chenguo, E-mail: hucg@cqu.edu.cn [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); Liu Hong [State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Xiong Yufeng [National Center for Nanoscience and Technology, Beijing 100080 (China); Li Feiyun; Xi Yi; He Xiaoshan [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China)

2009-09-15

The pure face-centered-cubic PbTe nanorods have been synthesized by the composite-hydroxide-mediated approach using hydrazine as a reducing agent. The method is based on reaction among reactants in the melts of potassium hydroxide and sodium hydroxide eutectic at 170-220 deg. C and normal atmosphere without using any organic dispersant or surface-capping agent. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy were used to characterize the structure, morphology and composition of the samples. The diameters of nanorods are almost fixed, while the lengths can be tunable under different growth time and temperatures. The growth mechanism of PbTe nanorods is investigated via UV-vis absorption, demonstrating that polymerized tellurium anions and metal(II) amides in the hydrazine hydroxide melts could control the crystallization and growth process of PbTe nanostructures. The band gap of as-synthesized PbTe nanorods has been calculated based on UV-vis-NIR optical diffuse reflectance spectra data.

Effect of increasing tellurium content on the electronic and optical properties of cadmium selenide telluride alloys CdSe{sub 1-x}Te{sub x}: An ab initio study

Energy Technology Data Exchange (ETDEWEB)

Reshak, Ali Hussain, E-mail: maalidph@yahoo.co.uk [Institute of Physical Biology-South Bohemia University, Nove Hrady 37333 (Czech Republic); School of Material Engineering, Malaysia University of Perlis, P.O Box 77, d/a Pejabat Pos Besar, 01007 Kangar, Perlis (Malaysia); Kityk, I.V. [Electrical Engineering Department, Technical University of Czestochowa, Al. Armii Krajowej 17/19, Czestochowa (Poland); Khenata, R. [Laboratoire de Physique Quantique et de Modelisation Mathematique de la Matiere (LPQ3 M), universite de Mascara, Mascara 29000 (Algeria); Department of Physics and Astronomy, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Auluck, S. [National Physical Laboratory Dr. K S Krishnan Marg, New Delhi 110012 (India)

2011-06-16

Highlights: > Theoretical study of effect of vary Te content on band structure, density of states, linear and nonlinear optical susceptibilities of CdSe{sub 1-x}Te{sub x}. > Increasing Te content leads to a decrease in the energy band gap. > Significant enhancement of the electronic properties as a function of tellurium concentration - Abstract: An all electron full potential linearized augmented plane wave method, within a framework of GGA (EV-GGA) approach, has been used for an ab initio theoretical study of the effect of increasing tellurium content on the band structure, density of states, and the spectral features of the linear and nonlinear optical susceptibilities of the cadmium-selenide-telluride ternary alloys CdSe{sub 1-x}Te{sub x} (x = 0.0, 0.25, 0.5, 0.75 and 1.0). Our calculations show that increasing Te content leads to a decrease in the energy band gap. We find that the band gaps are 0.95 (1.76), 0.89 (1.65), 0.83 (1.56), 0.79 (1.44) and 0.76 (1.31) eV for x = 0.0, 0.25, 0.5, 0.75 and 1.0 in the cubic structure. As these alloys are known to have a wurtzite structure for x less than 0.25, the energy gaps are 0.8 (1.6) eV and 0.7 (1.55) eV for the wurtzite structure (x = 0.0, 0.25) for the GGA (EV-GGA) exchange correlation potentials. This reduction in the energy gaps enhances the functionality of the CdSe{sub 1-x}Te{sub x} alloys, at least for these concentrations, leading to an increase in the effective second-order susceptibility coefficients from 16.75 pm/V (CdSe) to 18.85 pm/V (CdSe{sub 0.75}Te{sub 0.25}), 27.23 pm/V (CdSe{sub 0.5}Te{sub 0.5}), 32.25 pm/V (CdSe{sub 0.25}Te{sub 0.75}), and 37.70 pm/V (CdTe) for the cubic structure and from 12.65 pm/V (CdSe) to 21.11 pm/V (CdSe{sub 0.75}Te{sub 0.25}) in the wurtzite structure. We find a nonlinear relationship between the absorption/emission energies and composition, and a significant enhancement of the electronic properties as a function of tellurium concentration. This variation will help in

Enhancement of Thermoelectric Properties of PEDOT:PSS and Tellurium-PEDOT:PSS Hybrid Composites by Simple Chemical Treatment

Science.gov (United States)

Jin Bae, Eun; Hun Kang, Young; Jang, Kwang-Suk; Yun Cho, Song

2016-01-01

The thermoelectric properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and tellurium-PEDOT:PSS (Te-PEDOT:PSS) hybrid composites were enhanced via simple chemical treatment. The performance of thermoelectric materials is determined by their electrical conductivity, thermal conductivity, and Seebeck coefficient. Significant enhancement of the electrical conductivity of PEDOT:PSS and Te-PEDOT:PSS hybrid composites from 787.99 and 11.01 to 4839.92 and 334.68 S cm-1, respectively was achieved by simple chemical treatment with H2SO4. The power factor of the developed materials could be effectively tuned over a very wide range depending on the concentration of the H2SO4 solution used in the chemical treatment. The power factors of the developed thermoelectric materials were optimized to 51.85 and 284 μW m-1 K-2, respectively, which represent an increase of four orders of magnitude relative to the corresponding parameters of the untreated thermoelectric materials. Using the Te-PEDOT:PSS hybrid composites, a flexible thermoelectric generator that could be embedded in textiles was fabricated by a printing process. This thermoelectric array generates a thermoelectric voltage of 2 mV using human body heat.

Luminescent converter of neodymium laser radiation

International Nuclear Information System (INIS)

Ryba-Romanowski, W.; Golab, S.

1992-01-01

The new luminescent converter of neodymium laser radiation has been worked out. Activated inorganic compounds of ytterbium and erbium ions has been used as luminescent agent. The multi-component inorganic glass containing tellurium oxide as well as boron, sodium, magnesium and zinc oxides has been applied as a converter matrix

Production and characterization Te-peptide by induced autolysis of Saccharomyces cerevisiae.

Science.gov (United States)

Morya, V K; Dong, Shin Jae; Kim, Eun-ki

2014-04-01

Recently, the interest in mimicking functions of chalcogen-based catalytic antioxidants like selenoenzymes, has been increased. Various attempts had been done with selenium, but very few attempts were carried out with tellurium. Bio-complex formation and characterization of tellurium was not tried earlier by using any organism. The present study was focused on tellurium peptide production, characterization, and bioactivity assessment especially Mimetic to glutathione peroxidase (GPx). The production was achieved by the autolysis of total proteins obtained from Saccharomyces cerevisiae ATCC 7752 grown with inorganic tellurium. The GPx-like activity of the hydrolyzed tellurium peptide was increased when prepared by autolysis, but decreased when prepared by acid hydrolysis. Tellurium peptide produced by autolysis of the yeast cell showed increased GPx-like activity as well as tellurium content. Tellurium peptide showed little toxicity, compared to highly toxic inorganic tellurium. The results showed the potential of tellurium peptide as an antioxidant that can be produced by simple autolysis of yeast cells.

Comparative Analysis of Supply Risk-Mitigation Strategies for Critical Byproduct Minerals: A Case Study of Tellurium.

Science.gov (United States)

Bustamante, Michele L; Gaustad, Gabrielle; Alonso, Elisa

2018-01-02

Materials criticality assessment is a screening framework increasingly applied to identify materials of importance that face scarcity risks. Although these assessments highlight materials for the implicit purpose of informing future action, the aggregated nature of their findings make them difficult to use for guidance in developing nuanced mitigation strategy and policy response. As a first step in the selection of mitigation strategies, the present work proposes a modeling framework and accompanying set of metrics to directly compare strategies by measuring effectiveness of risk reduction as a function of the features of projected supply demand balance over time. The work focuses on byproduct materials, whose criticality is particularly important to understand because their supplies are inherently less responsive to market balancing forces, i.e., price feedbacks. Tellurium, a byproduct of copper refining, which is critical to solar photovoltaics, is chosen as a case study, and three commonly discussed byproduct-relevant strategies are selected: dematerialization of end-use product, byproduct yield improvement, and end-of-life recycling rate improvement. Results suggest that dematerialization will be nearly twice as effective at reducing supply risk as the next best option, yield improvement. Finally, due to its infrequent use at present and its dependence upon long product lifespans, recycling end-of-life products is expected to be the least effective option despite potentially offering other benefits (e.g., cost savings and environmental impact reduction).

Enrichment mechanisms of tellurium in ferromanganese crusts

Science.gov (United States)

Sakaguchi, A.; Sugiyama, T.; Usui, A.; Takahashi, Y.

2012-04-01

Marine ferromanganese crusts (FMCs) consist of iron (Fe) hydroxides and manganese (Mn) oxides with various minor and trace elements. Especially for tellurium (Te), which is recognized as one of the rare metals, it has been reported that this element is concentrated about 105 times in FMCs compared with earth's crust, and the host phase might be Fe (oxy)hydroxide (Hein et al., 2003). Actually, in our previous study, the high concentration of Te in very surface layers of FMCs was found from the top to halfway down of a seamount in the Pacific Ocean. However, the concentration of Te in surface layers through the seamount showed good correlation with that of Mn instead of Fe. In this study, we attempted to clarify the enrichment mechanism of Te in FMCs with some methods including X-ray absorption fine structure (XAFS) technique for synthesised /natural samples. Seventeen FMC samples were collected from the Takuyo-Daigo seamount, from 950 m (summit) to 3000 m in water depth, with hyper-dolphin (remotely operated vehicle) equipped with live video camera and manipulators. The growth rates of all FMC samples were estimated to be about 3 mm/Ma. Very surface layer (less than 1 mm) of all FMC was analyzed with XRD and XAFS to confirm the mineral composition and speciation of Te. Furthermore, to serve as an aid to clarify the adsorption mechanism of Te on FMCs, distribution coefficients (Kd) and oxidation states were determined through the adsorption experiments of Te(IV) and Te(VI) on ferrihydrite and δ-MnO2. In all the experiments, pH and ionic strength were adjusted to pH 7.5 and 0.7 M, respectively. The oxidation state of Te in water phase was determined with HPLC-ICP-MS. As for the analysis of oxidation and adsorption states on the solid phase, XAFS was employed. The major mineral composition of Fe and Mn had no significant variation through the water depth of Takuyo-Daigo seamount. The oxidation state of Te in all samples showed hexavalent, and there was no significant

Acousto-optic control of internal acoustic reflection in tellurium dioxide crystal in case of strong elastic energy walkoff [Invited].

Science.gov (United States)

Voloshinov, Vitaly; Polikarpova, Nataliya; Ivanova, Polina; Khorkin, Vladimir

2018-04-01

Peculiar cases of acoustic wave propagation and reflection may be observed in strongly anisotropic acousto-optical crystals. A tellurium dioxide crystal serves as a prime example of such media, since it possesses record indexes of acoustic anisotropy. We studied one of the unusual scenarios of acoustic incidence and reflection from a free crystal-vacuum boundary in paratellurite. The directions of the acoustic waves in the (001) plane of the crystal were determined, and their basic characteristics were calculated. The carried-out acousto-optic experiment at the wavelength of light 532 nm and the acoustic frequency 73 MHz confirmed the theoretical predictions. The effects examined in the paper include the acoustic wave propagation with the record walkoff angle 74°. We also observed the incidence of the wave on the boundary at the angle exceeding 90°. Finally, we registered the close-to-back reflection of acoustic energy following the incidence. One of the stunning aspects is the distribution of energy between the incident and the back-reflected wave. The unusual features of the acoustic wave reflections pointed out in the paper are valuable for their possible applications in acousto-optic devices.

A laser system for the spectroscopy on highly charged ions, tellurium molecules, and Rydberg states of rubidium atoms; Ein Lasersystem zur Spektroskopie von hochgeladenen Ionen, Tellurmolekuelen und Rubidium-Rydberg-Zustaenden

Energy Technology Data Exchange (ETDEWEB)

Albrecht, Sebastian

2014-08-15

Optical measuring methods allow the detection and identification of the atomic structure with extraordinary precision. Deviations to theoretical predictions can indicate unknown physical effects. Therefore, precise measurements on the atomic structure continue to be of large relevance. In this work, a laser system for precision spectroscopy on Bismuth ({sup 209}Bi{sup 82+}), Tellurium ({sup 130}Te{sub 2}) and Rydberg states of Rubidium ({sup 85}Rb) has been built and characterized. Spectroscopic measurements on Tellurium and Rubidium have been achieved with this setup. The system consists of a two-stage frequency doubled diode laser, stabilized via a cavity and an RF-offsetlock to arbitrary wavelengths with absolute high stability. The setup of the laser system will be presented and the systematic error caused by the refractive index of air inside the transfer cavity will be discussed. A stability of better then 6.14 MHz at 244 nm is obtained for planned experiments on the ground state hyperfine splitting of {sup 209}Bi{sup 82+}. This will allow an increase in precision of more then four orders of magnitude for this measurement. Further increase in precision can be achieved by using an evacuated cavity. The obtained stability is measured by comparison of the laser frequency to absorption lines of Tellurium ({sup 130}Te{sub 2}). Eight reference lines, known from literature, spanning the region from 613720.717 GHz to 616803.545 GHz have been measured. The frequency measurements of three lines, coinciding with the emission spectrum of an argon-ion-laser, show deviations with respect to the published frequencies. Further inconsistencies in literature are cleared. Part of this work is also the precise measurement of 843 Doppler-free {sup 130}Te{sub 2} reference lines spanning the frequency range from 613881.150 GHz to 616614.258 GHz at a precision of better then 4 MHz for most lines. Additionally, measurements on electromagnetically induced transparency (EIT) using

Raman scattering boson peak and differential scanning calorimetry studies of the glass transition in tellurium-zinc oxide glasses.

Science.gov (United States)

Stavrou, E; Tsiantos, C; Tsopouridou, R D; Kripotou, S; Kontos, A G; Raptis, C; Capoen, B; Bouazaoui, M; Turrell, S; Khatir, S

2010-05-19

Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out on four mixed tellurium-zinc oxide (TeO(2))(1 - x)(ZnO)(x) (x = 0.1, 0.2, 0.3, 0.4) glasses under variable temperature, with particular attention being given to the respective glass transition region. From the DSC measurements, the glass transition temperature T(g) has been determined for each glass, showing a monotonous decrease of T(g) with increasing ZnO content. The Raman study is focused on the low-frequency band of the glasses, the so-called boson peak (BP), whose frequency undergoes an abrupt decrease at a temperature T(d) very close to the respective T(g) values obtained by DSC. These results show that the BP is highly sensitive to dynamical effects over the glass transition and provides a means for an equally reliable (to DSC) determination of T(g) in tellurite glasses and other network glasses. The discontinuous temperature dependence of the BP frequency at the glass transition, along with the absence of such a behaviour by the high-frequency Raman bands (due to local atomic vibrations), indicates that marked changes of the medium range order (MRO) occur at T(g) and confirms the correlation between the BP and the MRO of glasses.

Raman scattering boson peak and differential scanning calorimetry studies of the glass transition in tellurium-zinc oxide glasses

International Nuclear Information System (INIS)

Stavrou, E; Tsiantos, C; Tsopouridou, R D; Kripotou, S; Kontos, A G; Raptis, C; Capoen, B; Bouazaoui, M; Turrell, S; Khatir, S

2010-01-01

Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out on four mixed tellurium-zinc oxide (TeO 2 ) 1-x (ZnO) x (x = 0.1, 0.2, 0.3, 0.4) glasses under variable temperature, with particular attention being given to the respective glass transition region. From the DSC measurements, the glass transition temperature T g has been determined for each glass, showing a monotonous decrease of T g with increasing ZnO content. The Raman study is focused on the low-frequency band of the glasses, the so-called boson peak (BP), whose frequency undergoes an abrupt decrease at a temperature T d very close to the respective T g values obtained by DSC. These results show that the BP is highly sensitive to dynamical effects over the glass transition and provides a means for an equally reliable (to DSC) determination of T g in tellurite glasses and other network glasses. The discontinuous temperature dependence of the BP frequency at the glass transition, along with the absence of such a behaviour by the high-frequency Raman bands (due to local atomic vibrations), indicates that marked changes of the medium range order (MRO) occur at T g and confirms the correlation between the BP and the MRO of glasses.

Tetrabromido[4-(triphenylphosphanyloxybutyl]tellurium acetonitrile monosolvate

Directory of Open Access Journals (Sweden)

Sari M. Närhi

2013-02-01

Full Text Available In the title compound, [TeBr4(C22H23OP]·CH3CN, the Te atom exhibits a square-pyramidal coordination with an apical Te—C bond and four basal Te—Br bonds. The conformation of the aliphatic C—C—C—C chain is gauche [torsion angle = −67.7 (8°]. A weak C—H...Br interaction helps to establish the conformation. In the crystal, there is a weak secondary bonding interaction [Te...N = 3.456 (11 Å] between the Te atom and the N atom of the solvent molecule, which completes a distorted TeNCBr4 octahedron. Inversion dimers linked by pairs of C—H...Br interactions are also observed.

Calculation of 125Te NMR Chemical Shifts at the Full Four-Component Relativistic Level with Taking into Account Solvent and Vibrational Corrections: A Gateway to Better Agreement with Experiment.

Science.gov (United States)

Rusakova, Irina L; Rusakov, Yuriy Yu; Krivdin, Leonid B

2017-06-29

Four-component relativistic calculations of 125 Te NMR chemical shifts were performed in the series of 13 organotellurium compounds, potential precursors of the biologically active species, at the density functional theory level under the nonrelativistic and four-component fully relativistic conditions using locally dense basis set scheme derived from relativistic Dyall's basis sets. The relativistic effects in tellurium chemical shifts were found to be of as much as 20-25% of the total calculated values. The vibrational and solvent corrections to 125 Te NMR chemical shifts are about, accordingly, 6 and 8% of their total values. The PBE0 exchange-correlation functional turned out to give the best agreement of calculated tellurium shifts with their experimental values giving the mean absolute percentage error of 4% in the range of ∼1000 ppm, provided all corrections are taken into account.

Statistical thermodynamics -- A tool for understanding point defects in intermetallic compounds

International Nuclear Information System (INIS)

Ipser, H.; Krachler, R.

1996-01-01

The principles of the derivation of statistical-thermodynamic models to interpret the compositional variation of thermodynamic properties in non-stoichiometric intermetallic compounds are discussed. Two types of models are distinguished: the Bragg-Williams type, where the total energy of the crystal is taken as the sum of the interaction energies of all nearest-neighbor pairs of atoms, and the Wagner-Schottky type, where the internal energy, the volume, and the vibrational entropy of the crystal are assumed to be linear functions of the numbers of atoms or vacancies on the different sublattices. A Wagner-Schottky type model is used for the description of two examples with different crystal structures: for β'-FeAl (with B2-structure) defect concentrations and their variation with composition are derived from the results of measurements of the aluminum vapor pressure, the resulting values are compared with results of other independent experimental methods; for Rh 3 Te 4 (with an NiAs-derivative structure) the defect mechanism responsible for non-stoichiometry is worked out by application of a theoretical model to the results of tellurium vapor pressure measurements. In addition it is shown that the shape of the activity curve indicates a certain sequence of superstructures. In principle, there are no limitations to the application of statistical thermodynamics to experimental thermodynamic data as long as these are available with sufficient accuracy, and as long as it is ensured that the distribution of the point defects is truly random, i.e. that there are no aggregates of defects

Sorption of V and VI group metalloids (As, Sb, Te on modified peat sorbents

Directory of Open Access Journals (Sweden)

Ansone-Bertina Linda

2016-01-01

Full Text Available The present work investigates arsenic, antimony and tellurium sorption using iron modified peat. The results were obtained using batch tests and the sorption was studied as a function of initial metalloid concentration, pH and sorption time, as well as the presence of competing substances. The obtained results indicate that modification of peat with Fe compounds significantly enhances the sorption capacity of the sorbents used for sorption of arsenic, antimony and tellurium. The optimal pH interval for the sorption of Sb(III is 6.5–9 and for As(V and Sb(V – 3–6, while As(III and tellurium sorption using Fe-modified peat is favourable in a wider interval of 3–9. The presence of competing ions as well as HA affect sorption of metalloids on Fe-modified peat. A minor impact on the reduction of metalloid sorption was detected in the presence of nitrate, sulphate, carbonate and tartrate ions, while in the presence of phosphate and HA the sorption ability of metalloids can be considerably reduced. The obtained results of kinetic experiments indicate that sorption of metalloids on Fe-modified peat mainly occurs relying on mechanisms of physical sorption processes.

On the study of proton-irradiated Tellurium targets relevant for production of medical radioisotopes 123I and 124I

International Nuclear Information System (INIS)

Imam Kambali; Hari Suryanto; Daya Agung Sarwono; Cahyana Amiruddin

2014-01-01

The energy loss distribution and range of energetic proton beams in tellurium (Te) target have been simulated using the Stopping and Range of Ion in Matter (SRIM 2013) codes. The calculated data of the proton's range were then used to determine the optimum thickness of Te targets for future production of 123 I and 124 I from 123 Te(p,n) 123 I, 124 Te(p,n) 124 I and 124 Te(p,2n) 123 I nuclear reactions using the BATAN's Cs-30 cyclotron. It was found that for an incidence angle of 0° with respect to the target normal, the optimum thickness of 123 Te and 124 Te targets for 123 I production should be 644 µm and 1.8 mm respectively, whereas a 649 µm thick 124 Te target would be Required for 124 I production. In addition, the thickness should be decreased with increasing incidence angle. The EOB yield could theoretically reach up to 13.62 Ci of 123 I at proton energy of 22 Me V and beam current of 30 µA if the 124 Te is irradiated over a period of 3 hours. The theoretical EOB yield is comparable to the experimental data with accuracy within 10%. (author)

Chemical processes for the extreme enrichment of tellurium into marine ferromanganese oxides

Science.gov (United States)

Kashiwabara, Teruhiko; Oishi, Yasuko; Sakaguchi, Aya; Sugiyama, Toshiki; Usui, Akira; Takahashi, Yoshio

2014-04-01

Tellurium, an element of growing economic importance, is extremely enriched in marine ferromanganese oxides. We investigated the mechanism of this enrichment using a combination of spectroscopic analysis and adsorption/coprecipitation experiments. X-ray Absorption Near-Edge Structure (XANES) analysis showed that in adsorption/coprecipitation systems, Te(IV) was oxidized on δ-MnO2 and not oxidized on ferrihydrite. Extended X-ray Absorption Fine Structure (EXAFS) analysis showed that both Te(IV) and Te(VI) were adsorbed on the surface of δ-MnO2 and ferrihydrite via formation of inner-sphere complexes. In addition, Te(VI) can be structurally incorporated into the linkage of Fe octahedra through a coprecipitation process because of its molecular geometry that is similar to the Fe octahedron. The largest distribution coefficient obtained in the adsorption/coprecipitation experiments was for the Te(VI)/ferrihydrite coprecipitation system, and it was comparable to those calculated from the distribution between natural ferromanganese oxides and seawater. Our XAFS and micro-focused X-ray fluorescence (μ-XRF) mapping of natural ferromanganese oxides showed that Te was structurally incorporated as Te(VI) in Fe (oxyhydr)oxide phases. We conclude that the main process for the enrichment of Te in ferromanganese oxides is structural incorporation of Te(VI) into Fe (oxyhydr)oxide phases through coprecipitation. This mechanism can explain the unique degree of enrichment of Te compared with other oxyanions, which are mainly enriched via adsorption on the surface of the solid structures. In particular, the great contrast in the distributions of Te and Se is caused by their oxidized species: (i) the similar geometry of the Te(VI) molecule to Fe octahedron, and (ii) quite soluble nature of Se(VI). Coexisting Mn oxide phases may promote structural incorporation of Te(VI) by oxidation of Te(IV), although the surface oxidation itself may not work as the critical enrichment process as

Assessment of the consequences of the Fukushima accident on the environment in Japan, one year after the accident; Bilan des consequences de l'accident de Fukushima sur l'environnement au Japon, un an apres l'accident

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-02-28

Illustrated by several maps and figures, this document proposes and discusses quantitative assessments of radioactive releases in the air (rare gases, iodine, tellurium compounds, caesium), of the atmospheric dispersion of releases, of the contamination of soils by radioactive deposits (dry and humid deposits), of the contamination of food products in Japan (vegetable productions, animal productions like meat, milk, eggs and so on), and of the contamination of the marine environment

Assessment of the consequences of the Fukushima accident on the environment in Japan, one year after the accident

International Nuclear Information System (INIS)

2012-01-01

Illustrated by several maps and figures, this document proposes and discusses quantitative assessments of radioactive releases in the air (rare gases, iodine, tellurium compounds, caesium), of the atmospheric dispersion of releases, of the contamination of soils by radioactive deposits (dry and humid deposits), of the contamination of food products in Japan (vegetable productions, animal productions like meat, milk, eggs and so on), and of the contamination of the marine environment

Leaching of cadmium and tellurium from cadmium telluride (CdTe) thin-film solar panels under simulated landfill conditions.

Science.gov (United States)

Ramos-Ruiz, Adriana; Wilkening, Jean V; Field, James A; Sierra-Alvarez, Reyes

2017-08-15

A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1mgL -1 ), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005mgL -1 ). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. Copyright © 2017 Elsevier B.V. All rights reserved.

Formation of tellurium nanocrystals during anaerobic growth of bacteria that use Te oxyanions as respiratory electron acceptors

Science.gov (United States)

Baesman, S.M.; Bullen, T.D.; Dewald, J.; Zhang, Dongxiao; Curran, S.; Islam, F.S.; Beveridge, T.J.; Oremland, R.S.

2007-01-01

Certain toxic elements support the metabolism of diverse prokaryotes by serving as respiratory electron acceptors for growth. Here, we demonstrate that two anaerobes previously shown to be capable of respiring oxyanions of selenium also achieve growth by reduction of either tellurate [Te(VI)] or tellurite [Te(IV)] to elemental tellurium [Te(0)]. This reduction achieves a sizeable stable-Te-isotopic fractionation (isotopic enrichment factor [??] = -0.4 to -1.0 per ml per atomic mass unit) and results in the formation of unique crystalline Te(0) nanoarchitectures as end products. The Te(0) crystals occur internally within but mainly externally from the cells, and each microorganism forms a distinctly different structure. Those formed by Bacillus selenitireducens initially are nanorods (???10-nm diameter by 200-nm length), which cluster together, forming larger (???1,000-nm) rosettes composed of numerous individual shards (???100-nm width by 1,000-nm length). In contrast, Sulfurospirillium barnesii forms extremely small, irregularly shaped nanospheres (diameter < 50 nm) that coalesce into larger composite aggregates. Energy-dispersive X-ray spectroscopy and selected area electron diffraction indicate that both biominerals are composed entirely of Te and are crystalline, while Raman spectroscopy confirms that they are in the elemental state. These Te biominerals have specific spectral signatures (UV-visible light, Raman) that also provide clues to their internal structures. The use of microorganisms to generate Te nanomaterials may be an alternative for bench-scale syntheses. Additionally, they may also generate products with unique properties unattainable by conventional physical/chemical methods. Copyright ?? 2007, American Society for Microbiology. All Rights Reserved.

The actinides

International Nuclear Information System (INIS)

Bagnall, K.W.

1987-01-01

This chapter of coordination compound chemistry is devoted to the actinides and starts with a general survey. Most of the chapter relates to thorium and uranium but protactinium, neptunium and plutonium are included. There are sections on nitrogen, phosphorus, sulfur, selenium, tellurium and halogen ligands of the metals in their +3, +4, +5 and +6 oxidation states and of the transplutonium elements in their +2, +3, +4, and +5 oxidation states. (UK)

Crystal growth and characterization of Ir-Te compounds

Energy Technology Data Exchange (ETDEWEB)

Kurzhals, Philipp; Weber, Frank; Zocco, Diego; Adelmann, Peter; Merz, Michael; Wolf, Thomas; Kuntz, Sebastian; Grube, Kai [Karlsruhe Institute of Technology, Institute for Solid State Physics, Karlsruhe (Germany)

2016-07-01

IrTe{sub 2} is distinguished by a structural phase transition whose origin is not understood up to the present day. We grew crystals using the self-flux method starting from the reagents iridium and tellurium and got specimen with varying amounts of IrTe{sub 2} and Ir{sub 3}Te{sub 8}, analyzed by x-ray powder diffraction. We studied the transition near T = 280 K in magnetization measurements down to T = 1.8 K probing also for superconductivity, which was reported for intercalated samples. Results indicate that the structural transition happens over an extended range in temperature and superconductivity is absent in our samples. Ir{sub 3}Te{sub 8} is not studied to such an extent as IrTe{sub 2}. In previous publications a structural phase transition is reported. We characterized the transition by performing magnetization measurements and X-ray diffraction.

Thermoelectric properties of ternary phases of thallium-tin-tellurium system

Energy Technology Data Exchange (ETDEWEB)

Dichi, E. [Equipe materiaux et sante, faculte de pharmacie, universite Paris XI, 5, rue J.B, EA 401, Clement 92296 Chatenay-Malabry (France)], E-mail: emma.dichi@cep.u-psud.fr; Sghaier, M. [Equipe materiaux et sante, faculte de pharmacie, universite Paris XI, 5, rue J.B, EA 401, Clement 92296 Chatenay-Malabry (France); Kra, G. [Laboratoire de chimie minerale, universite de Cocody, 22, BP 582, Abidjan 22, Cote d' Ivoire (France)

2008-06-30

In this paper, we present the measurements of conductivity and of thermoelectric power. Measurements were taken for the temperature range of 100-330 K for the three ternary phases of Tl-Sn-Te system. The potential of these compounds as thermoelectric materials was studied.

Electronic, structural, and optical properties of host materials for inorganic phosphors

International Nuclear Information System (INIS)

Alemany, Pere; Moreira, Ibério de P.R.; Castillo, Rodrigo; Llanos, Jaime

2012-01-01

Highlights: ► We performed a first-principles DFT study of the electronic structures of several wide band gap insulators (La 2 O 3 , La 2 O 2 S, Y 2 O 3 Y 2 O 2 S, La 2 TeO 6 , and Y 2 TeO 6 ) used as host materials for inorganic phosphors. ► The electronic, structural, and optical properties calculated for these compounds are in good agreement with the available experimental data. ► The electronic structure of the M 2 TeO 6 phases exhibits distinct features that could allow a fine tuning of the optical properties of luminescent materials obtained by doping with rare earth metals. - Abstract: A family of large gap insulators used as host materials for inorganic phosphors (La 2 O 3 , La 2 O 2 S, Y 2 O 3 , Y 2 O 2 S, La 2 TeO 6 , and Y 2 TeO 6 ) have been studied by first-principles DFT based calculations. We have determined electronic, structural, and optical properties for all these compounds both at the LDA and GGA levels obtaining, in general, a good agreement with available experimental data and previous theoretical studies. The electronic structure for the M 2 TeO 6 phases, addressed in this work for the first time, reveals some significant differences with respect to the other compounds, especially in the region of the lower conduction band, where the appearance of a group of four isolated oxygen/tellurium based bands below the main part of the La (Y) centered conduction band is predicted to lead to significant changes in the optical properties of the two tellurium containing compounds with respect to the rest of compounds in the series.

Resonant ionization by laser beams: application to ions sources and to study the nuclear structure of radioactive tellurium isotopes

International Nuclear Information System (INIS)

Sifi, R.

2007-07-01

The radioactive ion beams that are produced through current isotope separators are well separated according to the A mass but not according to the Z parameter. The resonant ionization through laser beams applied to ion sources allows the production of radioactive ion beam in a very selective and efficient way by eliminating the isobaric contamination. The first chapter is dedicated to the resonant ionization by laser beams, we describe the principle, the experimental setting, the lasers used, the ionization schemes and the domain of application. The second chapter deals with the application of resonant ionization to laser ion sources for the production of radioactive ion beams. We present experimental tests performed for getting copper ion beams. Resonant ionization through laser is also used in the spectroscopy experiments performed at the Isolde (isotope separation on-line device) installation in CERN where more than 20 elements are ionized very efficiently. The technique is based on a frequency scanning around the excitation transition of the atoms in order to probe the hyperfine structure. Laser spectroscopy allows the determination of the hyperfine structure as well as the isotopic shift of atoms. In the third chapter the method is applied to the spectroscopy of tellurium atoms. First, we define the 2 parameters on which the extraction is based: charge radius and nuclear moments, then we present several theoretical models that we have used to assess our experimental results. (A.C.)

Electrical properties of tellurium clusters on the void sublattice of an opal crystal the important role played by the Te-SiO$_{2}$ interface

CERN Document Server

Berezovets, V A; Farbshtein, I I; Nizhankovskii, V I

2002-01-01

The temperature dependences of electrical resistivity and of the Hall effect of nanocluster tellurium crystals obtained by filling the voids in a dielectric (opal) matrix with a melt of pure and doped Te were studied. The Hall hole concentration p/sub eff/ was found to increase anomalously (by more than two orders of magnitude) in a sample prepared from pure Te and cooled to helium temperatures. At T = 1.45 K, the hole concentration in this sample was p/sub eff/ = equivalent to 6 * 10/sup 17/ cm/sup -3/. At the same time, the Hall effect in this sample was observed to reverse sign at T equivalent to 200 K from positive for T < 200 K to negative at higher temperatures. This implies a low impurity concentration (N/sub A/ is less than at least 10/sup 15/ cm/sup -3/). A nanocluster crystal of doped Te does not exhibit this anomaly; here, we have p/sub eff/ equivalent to 6 * 10/sup 17/ cm/sup -3/ throughout the temperature region covered, as in the original Te. These features are assigned to the formation of a ...

Organotellurium ligands – designing and complexation reactions

Indian Academy of Sciences (India)

Unknown

membered rings it is negative and ~30 ppm only. Keywords. Organotellurium ligands; hybrid telluroether; platinum metal complexes; tellurium-125 NMR. 1. Introduction. Tellurium is the noblest metalloid which may act as a Lewis acid as well as Lewis base. The ligand chemistry of tellurium, which acts as a 'soft' donor, was ...

Thin film heterojunction photovoltaic cells and methods of making the same

Science.gov (United States)

Basol, Bulent M.; Tseng, Eric S.; Rod, Robert L.

1983-06-14

A method of fabricating a thin film heterojunction photovoltaic cell which comprises depositing a film of a near intrinsic or n-type semiconductor compound formed of at least one of the metal elements of Class II B of the Periodic Table of Elements and at least tellurium and then heating said film at a temperature between about 250.degree. C. and 500.degree. C. for a time sufficient to convert said film to a suitably low resistivity p-type semiconductor compound. Such film may be deposited initially on the surface of an n-type semiconductor substrate. Alternatively, there may be deposited on the converted film a layer of n-type semiconductor compound different from the film semiconductor compound. The resulting photovoltaic cell exhibits a substantially increased power output over similar cells not subjected to the method of the present invention.

Bis(ethyleneglycolato-κ2O,O′tellurium(IV

Directory of Open Access Journals (Sweden)

Neil R. Brooks

2013-07-01

Full Text Available The title compound, C4H8O4Te, crystallized from a solution of Te4+ in ethylene glycol. The TeIV atom is in a distorted seesaw coordination defined by four O atoms from two different ethyleneglycate ligands. The C atoms of the ethyleneglycate ligands are disorderd over two positions, with population parameters of 50.3 (6 and 49.7 (6% indicating a statistical distribution. Due to the possibility to transform the primitive monoclinic unit cell into a metrically orthorhombic C unit cell, the data are twinned and were refined with the twin law -100/0-10/101 with the relative scale factor refining to 1.82 (4% for the minor component.

Development of Low Surge Vacuum Contact with Te

Energy Technology Data Exchange (ETDEWEB)

Kim, B. S.; Lee, H. W.; Woo, B. C.; Kim, B. G. [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

1996-12-01

The purpose of this study is to develop of low surge Te contact for vacuum circuit breaker. The vacuum circuit breaker have various advantages such that it is free from maintenance, does not bring about public pollution, is excellent in its current breaking property, and so forth, on account of which the extent of its application has become broadened rapidly. For the characteristics of the contact material for the vacuum circuit breaker to satisfy, there may be enumerated: (1)large current breaking capacity; (2)high voltage withstand; (3)small contact resistance; (4)small melt-adhesive force; (5)low chopping current value; (6)good workability; (7)sufficient mechanical strength; and so forth. In this study we used cobalt for based refractory material having high melting temperature and intermetallic material between tellurium and silver to reduce chopping current. The contact materials were produced in accordance with the powder metallurgy using the method of infiltration. Production of the contact material was carried out in such a method that cobalt powder having average particle size of 50{mu}m, pre sintered in H{sub 2} atmosphere, 900 degree C , 2 hour. Ag ingot and Te(Se) were alloyed using high frequency furnaced in vacuum. And then Ag-Te(Se) alloy was infiltrated to Co skeleton in H{sub 2} atmosphere, 1000 degree C , 1 hour. The melting of the alloy to be infiltrated was carried out in a vacuum sealed quartz tube and be analysed by X-ray diffraction, scanning electron microscope, optical microscope and energy dispersive energy spectrometer. In the alloying of silver and tellurium, tellurium does not exist in single element but Ag{sub 2}Te intermetallic compound. And In Ag and Se, Se does not exist in single element but Ag{sub 2}Se intermetallic compound. We also produced the test vacuum interruptor to evaluate the electrode properties in vacuum atmosphere. The electrical properties of Co-(Ag-Se) electrode have better value than that of Co-(Ag-Te) electrode

Cs7Sm11[TeO3]12Cl16 and Rb7Nd11[TeO3]12Br16, the new tellurite halides of the tetragonal Rb6LiNd11[SeO3]12Cl16 structure type

Science.gov (United States)

Charkin, Dmitri O.; Black, Cameron; Downie, Lewis J.; Sklovsky, Dmitry E.; Berdonosov, Peter S.; Olenev, Andrei V.; Zhou, Wuzong; Lightfoot, Philip; Dolgikh, Valery A.

2015-12-01

Two new rare-earth - alkali - tellurium oxide halides were synthesized by a salt flux technique and characterized by single-crystal X-ray diffraction. The structures of the new compounds Cs7Sm11[TeO3]12Cl16 (I) and Rb7Nd11[TeO3]12Br16 (II) (both tetragonal, space group I4/mcm) correspond to the sequence of [MLn11(TeO3)12] and [M6X16] layers and bear very strong similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted.

Bis(tetraphenylphosphonium di-μ-iodido-bis[diiodidotellurate(II

Directory of Open Access Journals (Sweden)

Risto S. Laitinen

2008-12-01

Full Text Available The structure of the title compound, (C24H20P2[Te2I6], is composed of discrete PPh4+ cations and centrosymmetric [Te2I6]2− anions. The tellurium(II atom shows a sligthly distorted square-planar TeI4 geometry and is coordinated to two bridging and two terminal iodine atoms. The planar [Te2I6]2− ions are isolated by the cations and no intermolecular tellurium–halogen or halogen–halogen interactions are present.

Separation of 99Mo from 132Te using thiourea as complexing agent. Application to the separation of 99Mo from the fission products

International Nuclear Information System (INIS)

Mestnik, S.A.C.

1987-01-01

A radiochemical method to isolate 99 Mo from 132 Te both produced in the fission of 235 U has been developed. The method is based on the formation of a cationic complex of tellurium with thiourea in acid medium wich is retained (98.7+-0.5) % on a cation exchange resin (Dowex 50W-X8, 100-200 mesh) wile (99.8+-0.05)% 99 Mo passes through it, due to the non formation of such complex in the same experimental conditions. The radiochemical purity of the separated 99 Mo verified by using gamma spectrometry was found to be suitable for the preparation of 99 Mo- 99m Tc generators. The retention of 99 Mo on an alumina column as function of pH was investigated. The best pH range for this purpose was found to be between 4.0-4.5. Yellow crystals with melting point of 115 0 C were formed when non-irradiated tellurium reacted with thiourea. Elemental analysis, ultra-violet and infra-red absorption spectrophotometry as well as thermogravimetry were used to characterize the complex formed. In the studies made in order to characterize the compound it has been observed: 1. the most probable chemical composition of the complex studied is [Te(SCN 2 H 4 ) 4 ] (SO 4 ) 2 ; 2. the coordination takes place between tellurium and sulphur atoms; 3. the maximum absorption in the ultra-violet region occurs near 310nm. The thermogravimetric curves obtained allowed to propose the concerned thermodecomposition mechanism. (author) [pt

Effect of composition on the degree of anisotropy of thermal expansion and electric resistance of cermet specimens of GeTe

International Nuclear Information System (INIS)

Barbakadze, K.G.; Vekua, T.S.; Ioseliani, M.I.; Kvitsiniya, K.M.

1988-01-01

A study was made on α temperature coefficient of thermal expansion and ρ specific electric resistance of cermet germanium telluride for alloys close to stoichiometric composition. It is shown that anisotropy of thermal expansion of cermet germanium telluride depends sufficiently on its composition. This dependence is clearly pronounced if tellurium content in alloys equals 50.4-51.2 at.%. The maximal anisotropy is observed in the alloy containing 50.8 at.% of tellurium. The temperature of extreme value of temperature coefficient of linear expansion decreases from 440 down to 373 deg.C for alloys with 49-50.8 at.% of tellurium, and grows from 373 up to 405 deg.C if tellurium content equals 50.8-52 at.%

Isotopically modified compounds

International Nuclear Information System (INIS)

Kuruc, J.

2009-01-01

In this chapter the nomenclature of isotopically modified compounds in Slovak language is described. This chapter consists of following parts: (1) Isotopically substituted compounds; (2) Specifically isotopically labelled compounds; (3) Selectively isotopically labelled compounds; (4) Non-selectively isotopically labelled compounds; (5) Isotopically deficient compounds.

NMR spectroscopy of organic compounds of selenium and tellurium. Communication 9. Chemical shifts of /sup 13/C in isological series of unsaturated ethers, sulfides, selenides and tellurides

Energy Technology Data Exchange (ETDEWEB)

Kalabin, G.A.; Bzhezovskii, V.M.; Kushnarev, D.F.; Proidakov, A.G. (Irkutskii Gosudarstvennyj Univ. (USSR))

1981-06-01

The effects of heteroatoms Eh(Eh=O, S, Se, Te) on /sup 13/C chemical shifts in eleven isological series of R/sup 1/-Eh-R/sup 2/ unsaturated compounds are compared. A linear relation between /sup 13/C nuclei screening and tEh electronegativity is observed. An assumption is suggested that both likeness of the effects of 6A and 7A group elements on /sup 13/C chemical shifts of R/sup 1/ and R/sup 2/ substituents and their difference for elements of the 4A group are caused by unbonded interactions of the substituents with unshared electron pairs of heteroatoms.

The Natural Carotenoid Crocetin and the Synthetic Tellurium Compound AS101 Protect the Ovary against Cyclophosphamide by Modulating SIRT1 and Mitochondrial Markers

Directory of Open Access Journals (Sweden)

Giovanna Di Emidio

2017-01-01

Full Text Available Cancer therapies are associated with increased infertility risk due to accelerated reproductive aging. Oxidative stress (OS is a potential mechanism behind ovarian toxicity by cyclophosphamide (CPM, the most ovotoxic anticancer drug. An important sensor of OS is SIRT1, a NAD+-dependent deacetylase which regulates cellular defence and cell fate. This study investigated whether the natural carotenoid crocetin and the synthetic compound AS101 protect the ovary against CPM by modulating SIRT1 and mitochondrial markers. We found that the number of primordial follicles of female CD1 mice receiving crocetin plus CPM increased when compared with CPM alone and similar to AS101, whose protective effects are known. SIRT1 increased in CPM mouse ovaries revealing the occurrence of OS. Similarly, mitochondrial SIRT3 rose, whilst SOD2 and the mitochondrial biogenesis activator PGC1-α decreased, suggesting the occurrence of mitochondrial damage. Crocetin and AS101 administration prevented SIRT1 burst suggesting that preservation of redox balance can help the ovary to counteract ovarian damage by CPM. Decreased SIRT3 and increased SOD2 and PGC1-α in mice receiving crocetin or AS101 prior to CPM provide evidence for mitochondrial protection. Present results improve the knowledge of ovarian damage by CPM and may help to develop interventions for preserving fertility in cancer patients.

Fission product thermodynamic data: technical progress report 1 January-30 June 1991

International Nuclear Information System (INIS)

Ball, R.G.J.; Yates, A.D.; Bowsher, B.R.; Dickinson, S.; Freemantle, N.E.; Day, T.; Ogden, J.S.

1991-07-01

Thermodynamic data are being determined for a number of compounds formed from specific fission products and reactor materials. The compounds selected for experimental study and critical assessment were chosen because their thermodynamic data were inadequate or did not exist, as assessed and recommended at a specialists' meeting. These data can be used in the appropriate computer code so that the speciation and transport properties of the fission products can be predicted during a severe reactor accident. Experimental studies have focussed on the vaporization of tellurium dioxide, caesium ruthenate, strontium borate and indium hydroxide. Critical evaluations have begun for a number of tellurides of importance in severe accident assessments, and preliminary analyses have been made of the Fe-Te, Ni-Te and Cr-Te systems. (author)

Fabrication and application of amorphous semiconductor devices

International Nuclear Information System (INIS)

Kumurdjian, Pierre.

1976-01-01

This invention concerns the design and manufacture of elecric switching or memorisation components with amorphous semiconductors. As is known some compounds, particularly the chalcogenides, have a resistivity of the semiconductor type in the amorphous solid state. These materials are obtained by the high temperature homogeneisation of several single elements such as tellurium, arsenic, germanium and sulphur, followed by water or air quenching. In particular these compounds have useful switching and memorisation properties. In particular they have the characteristic of not suffering deterioration when placed in an environment subjected to nuclear radiations. In order to know more about the nature and properties of these amorphous semiconductors the French patent No. 71 28048 of 30 June 1971 may be consulted with advantage [fr

Crystal structure of ammonium divanadium(IV,V tellurium(IV heptaoxide

Directory of Open Access Journals (Sweden)

William T. A. Harrison

2014-07-01

Full Text Available The polyhedral building blocks of the layered inorganic network in the mixed-valence title compound, (NH4(VIVO2(VVO2(TeO3, are vertex-sharing VVO4 tetrahedra, distorted VIVO6 octahedra and TeO3 pyramids, which are linked by V—O—V and V—O—Te bonds, forming double layers lying parallel to (100. The presumed TeIV lone-pairs of electrons appear to be directed inwards into cavities in the double layers. The charge-balancing ammonium cations lie between the layers and probably interact with them via N—H...O hydrogen bonds.

Regenerable antioxidants-introduction of chalcogen substituents into tocopherols.

Science.gov (United States)

Poon, Jia-Fei; Singh, Vijay P; Yan, Jiajie; Engman, Lars

2015-02-02

To improve the radical-trapping capacity of the natural antioxidants, alkylthio-, alkylseleno-, and alkyltelluro groups were introduced into all vacant aromatic positions in β-, γ- and δ-tocopherol. Reaction of the tocopherols with electrophilic chalcogen reagents generated by persulfate oxidation of dialkyl dichalcogenides provided convenient but low-yielding access to many sulfur and selenium derivatives, but failed in the case of tellurium. An approach based on lithiation of the appropriate bromo-tocopherol, insertion of chalcogen into the carbon-lithium bond, air-oxidation to a dichalcogenide, and final borohydride reduction/alkylation turned out to be generally applicable to the synthesis of all chalcogen derivatives. Whereas alkylthio- and alkylseleno analogues were generally poorer quenchers of lipid peroxyl radicals than the corresponding parents, all tellurium compounds showed a substantially improved radical-trapping activity. Introduction of alkyltelluro groups into the tocopherol scaffold also caused a dramatic increase in the regenerability of the antioxidant. In a two-phase lipid peroxidation system containing N-acetylcysteine as a water-soluble co-antioxidant the inhibition time was up to six-fold higher than that recorded for the natural antioxidants. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sanskrit Compound Processor

Science.gov (United States)

Kumar, Anil; Mittal, Vipul; Kulkarni, Amba

Sanskrit is very rich in compound formation. Typically a compound does not code the relation between its components explicitly. To understand the meaning of a compound, it is necessary to identify its components, discover the relations between them and finally generate a paraphrase of the compound. In this paper, we discuss the automatic segmentation and type identification of a compound using simple statistics that results from the manually annotated data.

Thermodynamics of post-growth annealing of cadmium zinc telluride nuclear radiation detectors

Science.gov (United States)

Adams, Aaron Lee

Nuclear Radiation Detectors are used for detecting, tracking, and identifying radioactive materials which emit high-energy gamma and X-rays. The use of Cadmium Zinc Telluride (CdZnTe) detectors is particularly attractive because of the detector's ability to operate at room temperature and measure the energy spectra of gamma-ray sources with a high resolution, typically less than 1% at 662 keV. While CdZnTe detectors are acceptable imperfections in the crystals limit their full market potential. One of the major imperfections are Tellurium inclusions generated during the crystal growth process by the retrograde solubility of Tellurium and Tellurium-rich melt trapped at the growth interface. Tellurium inclusions trap charge carriers generated by gamma and X-ray photons and thus reduce the portion of generated charge carriers that reach the electrodes for collection and conversion into a readable signal which is representative of the ionizing radiation's energy and intensity. One approach in resolving this problem is post-growth annealing which has the potential of removing the Tellurium inclusions and associated impurities. The goal of this project is to use experimental techniques to study the thermodynamics of Tellurium inclusion migration in post-growth annealing of CdZnTe nuclear detectors with the temperature gradient zone migration (TGZM) technique. Systematic experiments will be carried out to provide adequate thermodynamic data that will inform the engineering community of the optimum annealing parameters. Additionally, multivariable correlations that involve the Tellurium diffusion coefficient, annealing parameters, and CdZnTe properties will be analyzed. The experimental approach will involve systematic annealing experiments (in Cd vapor overpressure) on different sizes of CdZnTe crystals at varying temperature gradients ranging from 0 to 60°C/mm (used to migrate the Tellurium inclusion to one side of the crystal), and at annealing temperatures ranging

Local order in molten Sesub(1-x)Tesub(x)

International Nuclear Information System (INIS)

Bellissent, R.; Tourand, G.

1980-04-01

In this paper a study of the short range order and of the coordination number in liquid Selenium-Tellurium systems is presented. The first part deals with neutron diffraction measurements of the structure factors of liquid Sesub(1-x)Tesub(x) in the whole concentration range, at 475 C, performed at EL3 reactor in Saclay using a 640 cell multidetector. From these data the radial distribution functions have been calculated. In a second part a structural model based on random chains for Selenium and on a quasicrystalline behavior of Tellurium is presented. For Se-rich melts it is assumed that Tellurium enters the Selenium chains by substitution. In the Te-rich range it is assumed that the local order is represented by substituted SeTe chains in a Tellurium matrix. This model provides with a good representation of the various structure factors. Moreover the coordination number for each concentration in the model has been calculated and the results are consistent with the experimental data. The 2 fold coordination of Se and the 3 valency of Te in the liquid state are emphasized and they can be associated with the metallisation of liquid Tellurium whereas Selenium remains a semiconductor

Contact-resonance atomic force microscopy for nanoscale elastic property measurements: Spectroscopy and imaging

International Nuclear Information System (INIS)

Stan, G.; Krylyuk, S.; Davydov, A.V.; Vaudin, M.D.; Bendersky, L.A.; Cook, R.F.

2009-01-01

Quantitative measurements of the elastic modulus of nanosize systems and nanostructured materials are provided with great accuracy and precision by contact-resonance atomic force microscopy (CR-AFM). As an example of measuring the elastic modulus of nanosize entities, we used the CR-AFM technique to measure the out-of-plane indentation modulus of tellurium nanowires. A size-dependence of the indentation modulus was observed for the investigated tellurium nanowires with diameters in the range 20-150 nm. Over this diameter range, the elastic modulus of the outer layers of the tellurium nanowires experienced significant enhancement due to a pronounced surface stiffening effect. Quantitative estimations for the elastic moduli of the outer and inner parts of tellurium nanowires of reduced diameter are made with a core-shell structure model. Besides localized elastic modulus measurements, we have also developed a unique CR-AFM imaging capability to map the elastic modulus over a micrometer-scale area. We used this CR-AFM capability to construct indentation modulus maps at the junction between two adjacent facets of a tellurium microcrystal. The clear contrast observed in the elastic moduli of the two facets indicates the different surface crystallography of these facets.

Synthesis and structure of aromatic and heterocyclic tellurium compounds 33. Synthesis of [2-(aryltelluro)vinyl]aldehydes and ketones and stereochemistry of nucleophilic substitution under vinyl atom of carbon

International Nuclear Information System (INIS)

Sadekov, I.D.; Rivkin, B.B.; Zakharov, A.V.; Minkin, V.I.

1996-01-01

By means of interaction of (2-vinylchlorida) carbonyl compounds and (2-acylvinyl) triethylammonium chlorides and arenetellurolate-anions certain, [2-(aryltelluro)vinyl]ketones and [2-(aryltelluro)vinyl]aldehydes have been synthesized, while by means of reaction between 2-aroylvinyl chlorides and Li 2 Te some di(2-aroylvinyl)tellurides have been prepared. Interaction of (2-vinylchloride)ketones with arenetellurolate-anions always gives rise to Z-isomers of [2-(aryltelluro)vinyl]ketones as a result of stabilization of intermediate carbanion by intramolecular coordination O→Te. Nucleophilic addition of arenetellurolate-anions to α-acetylene aldehydes and ketones occurs as trans-addition. 36 refs., 2 figs., 1 tab

Studies on Cd1Se0.6Te0.4 Thin Films by Spectroscopic and Diffractometer Characterization

Directory of Open Access Journals (Sweden)

Cliff Orori Mosiori

2017-09-01

Full Text Available Cadmium selenide tellurium is a compound containing cadmium, tellurium and selenium elements forming a combined solid. Hall measurements suggest that it is an n-type semiconductor. Related optical studies indicate that is transparent to infra-red radiation. Structural studies clearly show that it has a wurtzite, sphalerite crystalline forms. Cadmium is a toxic heavy metal, and selenium is only toxic in large amounts or doses. By this toxicity, cadmium selenide is a known to be carcinogen to humans; however, this does not stop investigating it for optoelectronic applications. Current research has narrowed down to investigating cadmium selenide when in the form of nanoparticles. Cadmium selenide finds applications has found applications in opto-electronic devices like laser diodes, biomedical imaging, nano-sensing, high-efficiency solar cells and thin-film transistors. By chemical bath deposition, Cd1Se0.6Te0.4 thin films were grown onto glass. Tellurium was gradually introduced as an impurity and its crystalline structure and optical properties were investigated by XRD and UV-VIS spectroscopy. The main Cd1Se0.6Te0.4/glass characteristics were correlated with the conditions of growing and post-growth treatment and it was found out that films were homogeneous films with controllable thickness onto the glass substrate and suitable for n-type “sandwich” heterostructures applications. Comparison of the intensities of equivalent reflexions provided a test for the internal consistency of the measurements. Equivalent reflexions in two specimens differed on average by 1.4 % and 0.6% from the mean measured intensity, attesting to the high internal consistency of measurements from extended-face crystals. By comparison from data obtained from all samples showed their average deviation from the mean to be 0.9 %.

New studies on mustard gold from the Dongping Mines, Hebei Province, China: The tellurian, plumbian, manganoan and mixed varieties

DEFF Research Database (Denmark)

Li, Jiuling; Makovicky, Emil

2001-01-01

geologi, Dongping gold tellurite deposit, mustard gold, calaverite, Fe-Pb-Te minerals, alteration, tellurium, filling in micro-porous, composite varieties, particles of gold......geologi, Dongping gold tellurite deposit, mustard gold, calaverite, Fe-Pb-Te minerals, alteration, tellurium, filling in micro-porous, composite varieties, particles of gold...

Organolanthanoid compounds

International Nuclear Information System (INIS)

Schumann, H.

1984-01-01

Up to little more than a decade ago organolanthanoid compounds were still a curiosity. Apart from the description of an isolated number of cyclopentadienyl and indenyl derivatives, very few significant contributions had been made to this interesting sector of organometallic chemistry. However, subsequent systematic studies using modern preparative and analytical techniques, together with X-ray single crystal structure determinations, enabled the isolation and characterization of a large number of very interesting homoleptic and heteroleptic compounds in which the lanthanoid is bound to hydrogen, to substituted or unsubstituted cyclopentadienyl groups, to allyl or alkynyl groups, or even to phosphorus ylides, trimethylsilyl, and carbonylmetal groups. These compounds, which are all extremely sensitive to oxygen and water, open up new possibilities in the field of catalysis and have great potential in organic synthesis - as recent studies with pentamethylcyclopentadienyl derivatives, organolanthanoid(II) compounds, and hexamethyllanthanoid complexes have already shown. (orig.) [de

The formation of lithium diarylargentates from arylsilver compounds and the corresponding aryllithium compounds

NARCIS (Netherlands)

Blenkers, J.; Hofstee, H.K.; Boersma, J.; Kerk, G.J.M. van der

1979-01-01

Diarylsilverlithium compounds of the type Ar2AgLi are formed by treating arylsilver compounds with the corresponding aryllithium compounds. Cryoscopy in benzene shows that the Ar2AgLi compounds are associated into dimers. NMR spectroscopic data indicate that only one type of aryl group is present in

Semiconducting III-V compounds

CERN Document Server

Hilsum, C; Henisch, Heinz R

1961-01-01

Semiconducting III-V Compounds deals with the properties of III-V compounds as a family of semiconducting crystals and relates these compounds to the monatomic semiconductors silicon and germanium. Emphasis is placed on physical processes that are peculiar to III-V compounds, particularly those that combine boron, aluminum, gallium, and indium with phosphorus, arsenic, and antimony (for example, indium antimonide, indium arsenide, gallium antimonide, and gallium arsenide).Comprised of eight chapters, this book begins with an assessment of the crystal structure and binding of III-V compounds, f

Selenium-75-labelled foliate compounds

International Nuclear Information System (INIS)

1974-01-01

A saturation method to analyze a foliate is presented; it uses competitive reaction of the compound to be measured and of a radioactive-labelled version of this compound with a reagent specific to this compound present in insufficient quantity to combine with the whole of the compound and its labelled version, separation of the bound compound from its non-bound homologue and measurement of the radioactivity concentration in the bound compound, the non-bound compound or both. The radioactive isotope used in the labelled foliate is selenium 75 [fr

Rubber compounding and processing

CSIR Research Space (South Africa)

John, MJ

2014-06-01

Full Text Available This chapter presents an overview on the compounding and processing techniques of natural rubber compounds. The introductory portion deals with different types of rubbers and principles of rubber compounding. The primary and secondary fillers used...

Multi-angle compound imaging

DEFF Research Database (Denmark)

Jespersen, Søren Kragh; Wilhjelm, Jens Erik; Sillesen, Henrik

1998-01-01

This paper reports on a scanning technique, denoted multi-angle compound imaging (MACI), using spatial compounding. The MACI method also contains elements of frequency compounding, as the transmit frequency is lowered for the highest beam angles in order to reduce grating lobes. Compared to conve......This paper reports on a scanning technique, denoted multi-angle compound imaging (MACI), using spatial compounding. The MACI method also contains elements of frequency compounding, as the transmit frequency is lowered for the highest beam angles in order to reduce grating lobes. Compared...... to conventional B-mode imaging MACI offers better defined tissue boundaries and lower variance of the speckle pattern, resulting in an image with reduced random variations. Design and implementation of a compound imaging system is described, images of rubber tubes and porcine aorta are shown and effects...... on visualization are discussed. The speckle reduction is analyzed numerically and the results are found to be in excellent agreement with existing theory. An investigation of detectability of low-contrast lesions shows significant improvements compared to conventional imaging. Finally, possibilities for improving...

Physical and optical properties of size-selective CdTe nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Fok, Alice [Department of Chemistry, The City College of New York, CUNY New York, NY 10031 (United States); Morales, Jorge [Department of Biology, City College of New York, CUNY New York, NY 10031 (United States); Sohel, Mohammad [Natural Sciences Department, Hostos College, CUNY Bronx, NY 10451 (United States)

2010-06-15

Physical and optical properties of colloidal cadmium telluride nanocrystals (CdTe NCs) were investigated. The CdTe NCs were synthesized by reacting elemental tellurium dissolved in tributylphosphine with a mixture of cadmium oxide, octadecene, and oleic acid. These NCs, which were characterized by transmission electron microscopy (TEM) are spherical and ranged from 5 to 7 nm in diameter. The identity of the compound post-synthesis was confirmed by X-Ray diffraction (XRD) patterns. UV-Vis and photoluminescence (PL) properties as grown and pure CdTe samples were investigated. Bright excitonic photoluminescence emission was observed (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Iodine-131 production by a dry method using reactor-irradiated elementary tellurium. Part 1 - Conditions for obtaining iodine emanation and its capture. Part 2 - comparative study of preparation conditions using Pyrex, stainless steel and alumina equipment. Part 3 - production on a semi-industrial scale; Production de l'iode 131 par voie seche a partir de tellure elementaire irradie a la pile. 1ere partie - Etudes des conditions pour obtenir l'emanation de l'iode et le capter. 2eme partie - Etude comparee des conditions pour effectuer cette preparation avec des appareils en Pyrex, en acier inoxydable et en alumine. 3eme partie - production a l'echelle semi-industrielle

Energy Technology Data Exchange (ETDEWEB)

Bardy, A; Beydon, J; Murthy, T S; Doyen, J B; Lefrancois, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-04-15

A previous report has described how iodine 131 can be prepared from elementary tellurium by a dry method which consists in treating irradiated tellurium at 400 degrees in argon. The possibility of carrying out this treatment in a stainless steel or alumina apparatus has been considered. The behavior of gaseous iodine 131 towards these materials has thus been studied. If the adsorption of iodine on stainless steel is superficial desorption is rapid at 250 degrees in oxygen or 400 degrees in argon. If the adsorption is chemical in nature it becomes necessary to heat to higher temperatures. Adsorption of iodine on alumina is very weak and the iodine can be desorbed rapidly. With these materials tests have been carried out on 300 gms of tellurium containing 41 curies of iodine 131; the yields were very satisfactory ( 98 per cent). (author) [French] La methode de preparation de l iode 131 par voie seche a partir de tellure elementaire decrite dans un precedent rapport consiste a traiter le tellure irradie a 400 degres sous argon. Nous avons examine la possibilite d effectuer ce traitement dans un appareil en acier inoxidable ou en alumine. Le comportement de l iode 131 gazeux vis a vis de ces materiaux a donc ete etudie. Si l adsorption de l iode sur l acier inoxidable est superficielle la desorption est rapide a 250 degres sous oxygene ou 400 degres sous argon. Si la fixation est de nature chimique il est necessaire de chauffer a des temperatures plus elevees. L adsorption de l iode sur l alumine est res faible et l iode peut etre desorbe rapideemnt. En employant ces materiaux des essais ont ete obtenus sur 300 g de tellure contenant 41 curies d iode 131 avec un bon rendement (98 pour cent). (auteur00.

Micro-Raman spectroscopy studies of bulk and thin films of CuInTe2

International Nuclear Information System (INIS)

Ananthan, M R; Mohanty, Bhaskar Chandra; Kasiviswanathan, S

2009-01-01

Micro-Raman spectroscopy measurements were made on polycrystalline and amorphous thin films of CuInTe 2 as well as bulk polycrystalline CuInTe 2 . Various vibrational modes exhibited by the bulk and polycrystalline thin films were attributed to those expected for single crystal CuInTe 2 . Raman spectra of amorphous films presented a broad spectrum, decomposition of which revealed the presence of elemental tellurium on the film surface. Laser-induced changes on CuInTe 2 thin films were studied by acquiring spectra with higher laser beam power. Modes due to tellurium appeared when the spectra were acquired during laser–sample interaction, indicating tellurium segregation. The Raman spectra measured from polycrystalline films during high laser power irradiation did not show decrease in the intensity of the A 1 mode of CuInTe 2 in spite of loss of tellurium from the lattice. This has been interpreted as related to an increased contribution from the undistorted subsurface CuInTe 2 region at higher excitation power

Phenolic Molding Compounds

Science.gov (United States)

Koizumi, Koji; Charles, Ted; de Keyser, Hendrik

Phenolic Molding Compounds continue to exhibit well balanced properties such as heat resistance, chemical resistance, dimensional stability, and creep resistance. They are widely applied in electrical, appliance, small engine, commutator, and automotive applications. As the focus of the automotive industry is weight reduction for greater fuel efficiency, phenolic molding compounds become appealing alternatives to metals. Current market volumes and trends, formulation components and its impact on properties, and a review of common manufacturing methods are presented. Molding processes as well as unique advanced techniques such as high temperature molding, live sprue, and injection/compression technique provide additional benefits in improving the performance characterisitics of phenolic molding compounds. Of special interest are descriptions of some of the latest innovations in automotive components, such as the phenolic intake manifold and valve block for dual clutch transmissions. The chapter also characterizes the most recent developments in new materials, including long glass phenolic molding compounds and carbon fiber reinforced phenolic molding compounds exhibiting a 10-20-fold increase in Charpy impact strength when compared to short fiber filled materials. The role of fatigue testing and fatigue fracture behavior presents some insight into long-term reliability and durability of glass-filled phenolic molding compounds. A section on new technology outlines the important factors to consider in modeling phenolic parts by finite element analysis and flow simulation.

Nomenclature on an inorganic compound

International Nuclear Information System (INIS)

1998-10-01

This book contains eleven chapters : which mention nomenclature of an inorganic compound with introduction and general principle on nomenclature of compound. It gives the description of grammar for nomenclature such as brackets, diagonal line, asterisk, and affix, element, atom and groups of atom, chemical formula, naming by stoichiometry, solid, neutral molecule compound, ion, a substituent, radical and name of salt, oxo acid and anion on introduction and definition of oxo acid, coordination compound like symbol of stereochemistry , boron and hydrogen compound and related compound.

Lasing transition at 1.06 μm emission in Nd3+ -doped borate-based tellurium calcium zinc niobium oxide glasses for high-power solid-state lasers.

Science.gov (United States)

Ravi, O; Prasad, K; Jain, Rajiv; Venkataswamy, M; Chaurasia, Shivanand; Deva Prasad Raju, B

2017-08-01

The spectroscopic properties of Tellurium Calcium Zinc Niobium oxide Borate (TCZNB) glasses of composition (in mol%) 10TeO 2  + 15CaO + 5ZnO + 10 Nb 2 O 5  + (60 - x)B 2 O 3  + Nd 2 O 3 (x = 0.1, 0.5, 1.0 or 1.5 mol%) have been investigated experimentally. The three phenomenological intensity parameters Ω 2 , Ω 4, Ω 6 have been calculated using the Judd-Ofelt theory and in turn radiative properties such as radiative transition probabilities, emission cross-sections, branching ratios and radiative lifetimes have been estimated. The trend found in the JO intensity parameter is Ω 2  > Ω 6  > Ω 4 If Ω 6  > Ω 4 , the glass system is favourable for the laser emission 4 F 3 /2  →  4 I 11 /2 in the infrared (IR) wavelength. The experimental values of branching ratio of 4 F 3 /2  →  4 I 11 /2 transition indicate favourable lasing action with low threshold power. The evaluated total radiative transition probabilities (A T ), stimulated emission cross-section (σ e ) and gain bandwidth parameters (σ e  × Δλ p ) were compared with earlier reports. An energy level analysis has been carried out considering the experimental energy positions of the absorption and emission bands. Copyright © 2016 John Wiley & Sons, Ltd.

Raman scattering in transition metal compounds: Titanium and compounds of titanium

Energy Technology Data Exchange (ETDEWEB)

Jimenez, J.; Ederer, D.L.; Shu, T. [Tulane Univ., New Orleans, LA (United States)] [and others

1997-04-01

The transition metal compounds form a very interesting and important set of materials. The diversity arises from the many states of ionization the transition elements may take when forming compounds. This variety provides ample opportunity for a large class of materials to have a vast range of electronic and magnetic properties. The x-ray spectroscopy of the transition elements is especially interesting because they have unfilled d bands that are at the bottom of the conduction band with atomic like structure. This group embarked on the systematic study of transition metal sulfides and oxides. As an example of the type of spectra observed in some of these compounds they have chosen to showcase the L{sub II, III} emission and Raman scattering in some titanium compounds obtained by photon excitation.

Antioxidant Phenolic Compounds from Pu-erh Tea

Directory of Open Access Journals (Sweden)

Shu Shan Du

2012-11-01

Full Text Available Eight compounds were isolated from the water extract of Pu-erh tea and their structures were elucidated by NMR and MS as gallic acid (1, (+-catechin (2, (−-epicatechin (3, (−-epicatechin-3-O-gallate (4, (−-epigallocatechin-3-O-gallate (5, (−-epiafzelechin- 3-O-gallate (6, kaempferol (7, and quercetin (8. Their in vitro antioxidant activities were assessed by the DPPH and ABTS scavenging methods with microplate assays. The relative order of DPPH scavenging capacity for these compounds was compound 8 > compound 7 > compound 1 > compound 6 > compound 4 ≈ compound 5 > compound 2 > VC (reference > compound 3, and that of ABTS scavenging capacity was compound 1 > compound 2 > compound 7 ≈ compound 8 > compound 6 > compound 5 > compound 4 > VC (reference > compound 3. The results showed that these phenolic compounds contributed to the antioxidant activity of Pu-erh tea.

Partial purification of endogenous digitalis-like compound(s) in cord blood

Energy Technology Data Exchange (ETDEWEB)

Balzan, S.; Ghione, S.; Biver, P.; Gazzetti, P.; Montali, U. (C.N.R. Institute of Clinical Physiology, Pisa (Italy))

1991-02-01

Increasing evidence indicates the presence of endogenous digitalis-like compound(s) in human body fluids. In this preliminary report, we describe a study of the partial purification by HPLC of these compounds in the plasma of neonates (who have particularly high concentrations of this substance) and adults. Plasma samples from neonates (cord blood) and adults, lyophilized and extracted with methanol, were applied on a 300 x 3.9 mm C18 Nova Pak column and eluted with a mobile phase of acetonitrile/methanol/water (17/17/66 or 14/14/72 by vol) and, after 30 min, with 100% methanol. We assayed eluted fractions for inhibitory activity of 86Rb uptake and for digoxin-like immunoreactivity. The elution profile revealed a first peak of inhibitory activity of 86Rb uptake at the beginning of the chromatography; another peak was eluted with the 100% methanol. The two peaks also cross-reacted with antidigoxin antibodies. Because the second peak could possibly reflect the nonspecific interference of various lipophilic compounds, we focused our attention on the first peak. For these fractions dose-response curves for 86Rb uptake and for displacement of digoxin were parallel, respectively, to those of ouabain and digoxin, suggesting similarities of digoxin-like immunoreactive substance to cardiac glycosides. Similar chromatographic profiles were also obtained for plasma from adults, suggesting that the endogenous glycoside-like compound(s) in the neonate may be the same as those in the adult.

Synthesis and reactivity of 10-alkylphenotellurazines

International Nuclear Information System (INIS)

Sadekov, I.D.; Abakarov, G.M.; Panov, V.B.; Ukhin, L.Yu.; Garnovskii, A.D.; Minkin, V.I.

1985-01-01

The reaction of N-alkyl-2,2'-dilithium diphenylamines with tellurium diiodide yields derivatives of a new heterocyclic system, phenotellurazine. 10-Alkyl-phenotellurazines readily form derivatives containing tetra- and tricoordinated tellurium, form complexes with metal salts and rhodium(I) carbonyl chloride and by bromination and nitration give 3,7-dibromo- or 3-nitro-, 3,7-dinitro, and 1,3,7,9-tetranitro derivatives

Radionuclides in diffusion probing of inorganic materials based on chalcogenides

International Nuclear Information System (INIS)

Firsova, L.P.

1994-01-01

Migration of tellurium-125m, selenium-75, sulfur-35 radionuclides in solid solutions Pb 1-y (Se 0.08 Te 0.92 ) y and (Pb 1-x Sn x ) y Te 1-y , where x=0.1 and 0.2, has been studied, the results are presented. Data on dependence of selenium and tellurium self-diffusion coefficients on temperature in the range of 600-750 deg C are given. The results of the study of self-diffusion coefficient isothermal dependences on lead and tellurium vapour pressure in equilibrium with solid phases have been considered. It is ascertained that a change in the temperature and p-n transitions initiate the change in self-diffusion mechanisms of chalcogenide atoms. 8 refs., 3 tabs

Investigations on organogermanium compounds XII. Reactions of trialkylgermylalkalimetal compounds in hexamethylphosphoric triamide (HMPT) with some inorganic and organic compounds

NARCIS (Netherlands)

Bulten, E.J.; Noltes, J.G.

1971-01-01

Trialkylgermyl alkali metal compounds in HMPT have been found to be highly reactive nucleophiles. Reactions with some inorganic and organic compounds, such as oxygen, carbon dioxide, inorganic and orgaanic halides, aldehydes, ketones, epoxides and lactones are described. Several new

NATURAL POLYACETYLENE COMPOUNDS

Directory of Open Access Journals (Sweden)

A. M. Nasukhova

2014-01-01

Full Text Available In article the review of the initial stage of researches of natural polyacetylene compounds is resulted. The high reactionary ability leading to fast oxidation and degradation of these compounds, especially at influence of Uf-light, oxygen of air, pH and other factors, has caused the serious difficulties connected with an establishment of structure and studying of their physical and chemical properties. Therefore the greatest quantity of works of this stage is connected with studying of essential oils of plants from families Apiaceae, Araliaceae, Asteraceae, Campanulaceae, Olacaceae, Pittosporaceae and Santalaceae where have been found out, basically, diacetylene compounds. About development of physical and chemical methods of the analysis of possibility of similar researches have considerably extended. More than 2000 polyacetylenes are known today, from them more than 1100 are found out in plants fam. Asteraceae. Revolution in the field of molecular biology has allowed to study processes of biosynthesis of these compounds intensively.

Nuclear medicine. Progress report for quarter ending June 30, 1982

Energy Technology Data Exchange (ETDEWEB)

Knapp, F.F. Jr.; Ambrose, K.R.; Butler, T.A.; Goodman, M.M.; Hoeschele, J.D.; Srivastava, P.C.

1982-09-01

The oxidation products of tellurium and selenium fatty acids were shown to differ and may relate to the unique prolonged retention of tellurium fatty acids in the heart. The studies suggest that the trapping of tellurium fatty acids in the heart may result from the formation of an insoluble oxidation product after entry into the cells of the heart muscle. Also described in this report is the synthesis of several barbituric acid analogues for evaluation as potential cerebral perfusion agents. The present studies indicate that the iodovinyl-alkyl barbiturates cross the intact blood-brain barrier but undergo in vivo deiodination as measured by a high uptake of radioiodine in the thyroid. During this period four /sup 191/Os-osmate shipments were made to Medical Cooperative investigators for evaluation of the ultrashort-lived /sup 191//sup m/Ir (T/sub 1/2/ = 4.9 sec) obtained from the /sup 191//sup m/Ir generator. Seven shipments of the /sup 195//sup m/Pt-labeled cis-dichlorodiammineplatinum(II) antitumor drug were made to collaborators and fice shipments of radiolabeled tellurium fatty acids were made to the Massachusetts General Hospital.

Progress in decontamination by halophilic microorganisms in saline wastewater and soil

International Nuclear Information System (INIS)

Zhuang Xuliang; Han Zhen; Bai Zhihui; Zhuang Guoqiang; Shim Hojae

2010-01-01

Environments with high-salt concentrations are often populated by dense microbial communities. Halophilic microorganisms can be isolated from different saline environments and different strains even belonging to the same genus have various applications. Wastewater and soil rich in both organic matter and salt are difficult to treat using conventional microorganisms typically found in wastewater treatment and soil bioremediation facilities. Studies on decontaminative capabilities and decontamination pathways of organic contaminants (i.e., aromatic compounds benzoate, cinnamate, 3-phenylpropionate, 4-hydroxybenzoic acid), heavy metals (i.e., tellurium, vanadium), and nutrients in the biological treatment of saline wastewater and soil by halophilic microorganisms are discussed in this review. - Review on the decontaminative capabilities of halophilic microorganisms in saline wastewater and soil.

Progress in decontamination by halophilic microorganisms in saline wastewater and soil

Energy Technology Data Exchange (ETDEWEB)

Zhuang Xuliang, E-mail: xlzhuang@rcees.ac.c [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085 (China); Bureau of Science and Technology for Resources and Environment, Chinese Academy of Sciences, Beijing 100864 (China); Han Zhen [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Bai Zhihui; Zhuang Guoqiang [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085 (China); Shim Hojae [Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau (China)

2010-05-15

Environments with high-salt concentrations are often populated by dense microbial communities. Halophilic microorganisms can be isolated from different saline environments and different strains even belonging to the same genus have various applications. Wastewater and soil rich in both organic matter and salt are difficult to treat using conventional microorganisms typically found in wastewater treatment and soil bioremediation facilities. Studies on decontaminative capabilities and decontamination pathways of organic contaminants (i.e., aromatic compounds benzoate, cinnamate, 3-phenylpropionate, 4-hydroxybenzoic acid), heavy metals (i.e., tellurium, vanadium), and nutrients in the biological treatment of saline wastewater and soil by halophilic microorganisms are discussed in this review. - Review on the decontaminative capabilities of halophilic microorganisms in saline wastewater and soil.

Multipurpose Compound

Science.gov (United States)

1983-01-01

Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

Molecular modeling of inorganic compounds

National Research Council Canada - National Science Library

Comba, Peter; Hambley, Trevor W; Martin, Bodo

2009-01-01

... mechanics to inorganic and coordination compounds. Initially, simple metal complexes were modeled, but recently the field has been extended to include organometallic compounds, catalysis and the interaction of metal ions with biological macromolecules. The application of molecular mechanics to coordination compounds is complicated by the numbe...

Structural studies of novel coordination compounds run in the Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences

International Nuclear Information System (INIS)

Antipin, M.Yu.; Starikova, Z.A.; Yanovskij, A.I.; Dolgushin, F.M.; Lysenko, K.A.; Khrustalev, V.N.; Vorontsov, I.I.; Korlyukov, A.A.; Andreev, G.B.; Neretin, I.S.

2001-01-01

The results of the investigation into structural chemistry of coordination compounds taking place in the X-ray Laboratory of the Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences are given. The review gives an idea on the tendencies to structural researches of complexes of varying categories of coordination compounds, among which are lithium, strontium, cadmium compounds, rare earth compounds, transuranium compounds, transition element compounds, carboranes, fullerenes. An attempt was made to prove the structure and reveal the novel structural and crystallochemical regularities in the studied series of relative compounds. The outlooks for the following progress of studies on this field are determined [ru

Transport properties of fission product vapors

International Nuclear Information System (INIS)

Im, K.H.; Ahluwalia, R.K.

1983-07-01

Kinetic theory of gases is used to calculate the transport properties of fission product vapors in a steam and hydrogen environment. Provided in tabular form is diffusivity of steam and hydrogen, viscosity and thermal conductivity of the gaseous mixture, and diffusivity of cesium iodide, cesium hydroxide, diatomic tellurium and tellurium dioxide. These transport properties are required in determining the thermal-hydraulics of and fission product transport in light water reactors

Devices for collecting chemical compounds

Science.gov (United States)

Scott, Jill R; Groenewold, Gary S

2013-12-24

A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

2. Intermetallic compounds with lanthanides

International Nuclear Information System (INIS)

Elemans, J.B.A.A.

1975-01-01

Theoretical considerations are given concerning the structures of intermetallic compounds of the lanthanides and thorium (R) on the one hand, and with Fe, Co or Ni (M) on the other. They all derive from the parent composition RM 5 with the CaCu 5 hexagonal structure. This consists of alternate layers in which the M atoms are distinguished as M 1 and M 2 . The other compounds whose structures are studied are obtained by systematic replacement of R by M, or vice versa. In the first type, every third R is replaced by two M's yielding R 2 M 17 compounds. The substitution may be truly random or structured in two ways: so that either the hexagonal structure is maintained or that it is converted into a rhombihedral one. In the second type, one M (in a M 1 position) out of every five is replaced by one R, giving rise to RM 2 compounds which form Laves phases. In the third type, the M 1 's are replaced by R's, resulting in compounds RM 3 . In the fourth type, every third M is replaced by R, yielding R 2 M 7 compounds. With M = Co and R a light lanthanide, the compounds are ferromagnets; with R yttrium, thorium, or a heavy lanthanide, they are ferrimagnets. The preparation of the compounds in an arc-melting apparatus under an Ar-atmosphere followed by annealing is described

Design and construction of a prototype to obtain TeO2

International Nuclear Information System (INIS)

Roque H, I.

1997-01-01

At the National Institute of Nuclear Research is developed the process to produce the radioisotope Iodine 131 which is employed in medicine with therapeutical purposes. The raw material to produce iodine 131 is tellurium dioxide (TeO 2 ). TeO 2 is intended to be produced from a prototype being this aim of this thesis named D esign and construction of a prototype to obtain TeO 2 . The TeO 2 obtained must have specific physicochemical characteristics, being necessary an special design of a prototype which will guarantee the quality of tellurium dioxide obtention. Design and building the final prototype project, was developed in to three stages. At the first stage, the TeO 2 was obtained at the laboratory, this allows to know the basic reaction characteristics. The second stage purpose, was to work with an former prototype which allowed to produce 100 g of tellurium dioxide. In the last stage a depurated chemical process parameters was made and the prototype was refined in regard to its mechanical design, giving us as result the final prototype. With this final prototype, the production reaches 2 Kg/week of tellurium dioxide with the best physicochemical properties which is to be employed as raw material in order to produce iodine 131. (Author)

Out-of-pile experiments of fuel-cladding chemical interaction, (2)

International Nuclear Information System (INIS)

Konashi, Kenji; Yato, Tadao; Kaneko, Hiromitsu; Honda, Yutaka

1980-01-01

Cesium seems to be one of the most important fission products in the fuel-cladding chemical interaction of fuel pins for LMFBRs. However the FCCI under irradiation cannot always be explained by considering only cesium-oxygen system as the corrosive, since attack does not occur in the cesium-oxygen system unless oxygen potential is sufficiently high. Cesium-tellurium-oxygen system has been proposed to account for heavy cladding attack which was sometimes found in hypostoichiometric mixed oxide fuel pins. In this paper, the experiment on the reaction of liquid tellurium with stainless steel is reported. The type 316 stainless steel claddings for Monju type fuel pins were used as the test specimens. Tellurium was contained into the cladding tubes with end plugs. The temperature dependence of the attack by tellurium was examined in the range from 450 to 900 deg C for 30 min, and the heating time dependence was examined from 5 min to 200 hr at 725 deg C. An infrared lamp furnace was used for the experiment within 7 hr, and a resistance furnace for longer experiment. The character of corrosion was matrix attack, and the reaction products on the stainless steel surfaces consisted of chrome rich inner phase and iron and nickel rich outer phase. The results are reported. (Kako, I.)

Compounding around the world.

Science.gov (United States)

Vail, Jane

2008-01-01

Pharmaceutical compounding is universal in its prevalence. Variations in disease patterns, culture, and tradition; the role of government in health care; and the availability of essential equipment and required agents shape a compounding profile unique to each country worldwide. In the following reflections, pharmacists form Argentina, Belgium, Colombia, Germany, Puerto Rico, Spain, and the United States describe their experiences in the compounding setting unique to their practice and their nation. The unifying theme in their comments is the dedication of each contributor to enabling recovery and ensuring the good health of his or her clients.

Volatile flavor compounds in yogurt: a review.

Science.gov (United States)

Cheng, Hefa

2010-11-01

Considerable knowledge has been accumulated on the volatile compounds contributing to the aroma and flavor of yogurt. This review outlines the production of the major flavor compounds in yogurt fermentation and the analysis techniques, both instrumental and sensory, for quantifying the volatile compounds in yogurt. The volatile compounds that have been identified in plain yogurt are summarized, with the few key aroma compounds described in detail. Most flavor compounds in yogurt are produced from lipolysis of milkfat and microbiological transformations of lactose and citrate. More than 100 volatiles, including carbonyl compounds, alcohols, acids, esters, hydrocarbons, aromatic compounds, sulfur-containing compounds, and heterocyclic compounds, are found in yogurt at low to trace concentrations. Besides lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone contribute most to the typical aroma and flavor of yogurt. Extended storage of yogurt causes off-flavor development, which is mainly attributed to the production of undesired aldehydes and fatty acids during lipid oxidation. Further work on studying the volatile flavor compounds-matrix interactions, flavor release mechanisms, and the synergistic effect of flavor compounds, and on correlating the sensory properties of yogurt with the compositions of volatile flavor compounds are needed to fully elucidate yogurt aroma and flavor.

Terahertz and infrared transmission of an organic/inorganic hybrid thermoelectric material

International Nuclear Information System (INIS)

Heyman, J. N.; Alebachew, B. A.; Kaminski, Z. S.; Nguyen, M. D.; Coates, N. E.; Urban, J. J.

2014-01-01

We report terahertz and infrared transmission measurements of a high-performance thermoelectric material containing tellurium nanowires in a conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) matrix. The DC electrical conductivity of the hybrid material (41 S/cm) is approximately one hundred times that of pure PEDOT:PSS and more than 400 times that of a film of pure tellurium nanowires, while the terahertz-frequency (THz) conductivity of PEDOT:PSS and the hybrid material are comparable at f ∼ 2THz. A frequency-dependent conductivity model indicates that the increased DC conductivity of the hybrid material results from an increase in the DC charge mobility rather than in the free charge density. We suggest that the increased DC conductivity of the hybrid material results from an increase in linkage between PEDOT domains by the tellurium nanowires

Terahertz and infrared transmission of an organic/inorganic hybrid thermoelectric material

Energy Technology Data Exchange (ETDEWEB)

Heyman, J. N., E-mail: heyman@macalester.edu; Alebachew, B. A.; Kaminski, Z. S.; Nguyen, M. D. [Physics Department, Macalester College, St. Paul, Minnesota 55105 (United States); Coates, N. E.; Urban, J. J. [The Molecular Foundry, Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2014-04-07

We report terahertz and infrared transmission measurements of a high-performance thermoelectric material containing tellurium nanowires in a conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) matrix. The DC electrical conductivity of the hybrid material (41 S/cm) is approximately one hundred times that of pure PEDOT:PSS and more than 400 times that of a film of pure tellurium nanowires, while the terahertz-frequency (THz) conductivity of PEDOT:PSS and the hybrid material are comparable at f ∼ 2THz. A frequency-dependent conductivity model indicates that the increased DC conductivity of the hybrid material results from an increase in the DC charge mobility rather than in the free charge density. We suggest that the increased DC conductivity of the hybrid material results from an increase in linkage between PEDOT domains by the tellurium nanowires.

Stable isotopes labelled compounds

International Nuclear Information System (INIS)

1982-09-01

The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

Organic electronic devices using phthalimide compounds

Science.gov (United States)

Hassan, Azad M.; Thompson, Mark E.

2010-09-07

Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

Organometallic compounds in the environment

National Research Council Canada - National Science Library

Craig, P. J

2003-01-01

... of Organometallic Species in the Environment 20 1.10 Stability of Organometallic Compounds in Biological Systems 1.11 G eneral Comments on the Toxicities of Organometallic Compounds 22 1.12 General Considerations on Environmental R eactivity of Organometallic Compounds 24 1.13 Microbial Biotransformation of Metals and M etalloids 25 1.13.1 Introduction 25 1...

II-VI semiconductor compounds

CERN Document Server

1993-01-01

For condensed matter physicists and electronic engineers, this volume deals with aspects of II-VI semiconductor compounds. Areas covered include devices and applications of II-VI compounds; Co-based II-IV semi-magnetic semiconductors; and electronic structure of strained II-VI superlattices.

Occurency and aqueous processing of tellurides from Sonora (Mexico)

International Nuclear Information System (INIS)

Aguayo, S.; Perez, E.; Ecinas, M.A.

1996-01-01

Tellurium production is limited mainly to that obtained from the treatment of electrolyte muds from copper refineries. however, there are several other sources from which the precious metal tellurides are potentially attractive. This work presents a review of the main localitiesin Sonora (Mexico), where tellurides have been found. In addition, based upon the physical chemistry fundamentals for tellurium and precious metal tellurides, the aqueous extraction and recovery routes are discussed. (Author) 51 refs

Bioavailability of dietary phenolic compounds: Review

Directory of Open Access Journals (Sweden)

Erick Gutiérrez-Grijalva Paul Gutiérrez-Grijalva

2015-12-01

Full Text Available Phenolic compounds are ubiquitous in plant-based foods. High dietary intake of fruits, vegetables and cereals is related to a decreased rate in chronic diseases. Phenolic compounds are thought to be responsible, at least in part, for those health effects. Nonetheless, phenolic compounds bioaccessibility and biotransformation is often not considered in these studies; thus, a precise mechanism of action of phenolic compounds is not known. In this review we aim to present a comprehensive knowledge of the metabolic processes through which phenolic compounds go after intake.

Compound Semiconductor Radiation Detectors

CERN Document Server

Owens, Alan

2012-01-01

Although elemental semiconductors such as silicon and germanium are standard for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by their physical limitations, namely the need for ancillary cooling, their modest stopping powers, and radiation intolerance. Compound semiconductors, on the other hand, encompass such a wide range of physical and electronic properties that they have become viable competitors in a number of applications. Compound Semiconductor Radiation Detectors is a consolidated source of information on all aspects of the use of compound semiconductors for radiation detection and measurement. Serious Competitors to Germanium and Silicon Radiation Detectors Wide-gap compound semiconductors offer the ability to operate in a range of hostile thermal and radiation environments while still maintaining sub-keV spectral resolution at X-ray wavelengths. Narrow-gap materials offer the potential of exceeding the spectral resolutio...

The Onium Compounds

Science.gov (United States)

Tsarevsky, Nicolay V.; Slaveykova, Vera; Manev, Stefan; Lazarov, Dobri

1997-06-01

The onium salts are of a big interest for theoretical and structural chemistry, and for organic synthesis. Some representatives of the group (e.g. ammonium salts) were known from the oldest times. Many onium salts are met the nature: ammonium salts (either as inorganic salts, and organic derivatives, e.g. aminoacids, salts of biogenic amines and alkaloids, etc.); oxonium salts (plant pigments as anthocyans are organic oxonium compounds), etc. In 1894 C. Hartmann and V. Meyer prepared the first iodonium salts - 4-iododiphenyliodonium hydrogensulfate and diphenyliodonium salts, and suggested the ending -onium for all compounds with properties similar to those of ammonium salts. Nowadays onium compounds of almost all nonmetals are synthesised and studied. A great variety of physical methods: diffraction (e.g. XRD) and spectral methods (IR-, NMR-, and UV-spectra), as well as the chemical properties and methods of preparation of onium salts have been used in determination of the structure of these compounds. The application of different onium salts is immense. Ammonium, phosphonium and sulfonium salts are used as phase-transfer catalysts; diazonium salts - for the preparation of dyes, metalochromic and pH-indicators. All the onium salts and especially diazonium and iodonium salts are very useful reagents in organic synthesis.

Peroxide organometallic compounds and their transformations

International Nuclear Information System (INIS)

Razuvaev, G.A.; Brilkina, T.G.

1976-01-01

A survey is given experimental works on synthesis and reactions of peroxide organometallic compounds. Reactions have been considered of organometallic compounds with oxygen and organic peroxides which result in formation of both peroxide and non-peroxide products. Possible routes and mechanisms of chemical transformations of peroxide organometallic compounds have been discussed. Reactions of organometallic compounds with oxygen and peroxides have been considered

Catalytic properties of niobium compounds

International Nuclear Information System (INIS)

Tanabe, K.; Iizuka, T.

1983-04-01

The catalytic activity and selectivity of niobium compounds including oxides, salts, organometallic compounds and others are outlined. The application of these compounds as catalysts to diversified reactions is reported. The nature and action of niobium catalysts are characteristic and sometimes anomalous, suggesting the necessity of basic research and the potential use as catalysts for important processes in the chemical industry. (Author) [pt

Aroma compounds in sweet whey powder.

Science.gov (United States)

Mahajan, S S; Goddik, L; Qian, M C

2004-12-01

Aroma compounds in sweet whey powder were investigated in this study. Volatiles were isolated by solvent extraction followed by solvent-assisted flavor evaporation. Fractionation was used to separate acidic from nonacidic volatiles. Gas chromatography/mass spectrometry and gas chromatography/olfactometry were used for the identification of aroma compounds. Osme methodology was applied to assess the relative importance of each aroma compound. The most aroma-intense free fatty acids detected were acetic, propanoic, butanoic, hexanoic, heptanoic, octanoic, decanoic, dodecanoic, and 9-decenoic acids. The most aroma-intense nonacidic compounds detected were hexanal, heptanal, nonanal, phenylacetaldehyde, 1-octen-3-one, methional, 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, 2,3-dimethylpyrazine, 2,3,5-trimethylpyrazine, furfuryl alcohol, p-cresol, 2-acetylpyrrole, maltol, furaneol, and several lactones. This study suggested that the aroma of whey powder could comprise compounds originating from milk, compounds generated by the starter culture during cheese making, and compounds formed during the manufacturing process of whey powder.

Natural compounds with herbicidal activity

Directory of Open Access Journals (Sweden)

Mariano Fracchiolla

2007-12-01

Full Text Available Research about phytotoxic activity of natural compounds could lead both to find new herbicidal active ingredients and to plan environmental friendly weed control strategies. Particularly, living organisms could be a source of compounds that are impossible, for their complexity, to synthesize artificially. More over, they could have alternative sites of action respect to the known chemical herbicides and, due to their origin, they should be more environmental safe. Many living organism, such as bacteria, fungi, insects, lichens and plants, are able to produce bioactive compounds. They generally are secondary metabolites or simply waste molecules. In this paper we make a review about these compounds, highlighting potential and constraints.

Natural compounds with herbicidal activity

Directory of Open Access Journals (Sweden)

Pasquale Montemurro

2011-02-01

Full Text Available Research about phytotoxic activity of natural compounds could lead both to find new herbicidal active ingredients and to plan environmental friendly weed control strategies. Particularly, living organisms could be a source of compounds that are impossible, for their complexity, to synthesize artificially. More over, they could have alternative sites of action respect to the known chemical herbicides and, due to their origin, they should be more environmental safe. Many living organism, such as bacteria, fungi, insects, lichens and plants, are able to produce bioactive compounds. They generally are secondary metabolites or simply waste molecules. In this paper we make a review about these compounds, highlighting potential and constraints.

New uranium compounds preparation and use as catalyst for hydrogenation of non-saturated organic compounds

International Nuclear Information System (INIS)

Arnaudet, L.; Folcher, G.

1985-01-01

Preparation of new organic uranium compounds and their use as catalysts for hydrogenation of non-saturated organic compounds are described. These compounds include Uranium III, a cyclopentadienic group, an alkyl group and an acetylenic derivative C 6 H 5 C triple bonds CR fixed by a π bond. Catalysts can be prepared with depleted uanium for hydrogenation of olefins for example [fr

Analysis of isoelectron isonuclear series of holovalent tetraelectron compounds as a system of bicomponent chemical compounds

International Nuclear Information System (INIS)

Vigdorovich, V.N.; Dzhuraev, T.D.

1985-01-01

Analogs and prototypes of the compounds supplementing the system of isoelectron isonuclear series of holovalent tetraelectron compounds by Gorunova are revealed. The investigation of all series of tetraelectron ovalenthol compounds allows one to supplement the variety of known series used for regular tracing and forecasting of compound properties (series of cation and anion substitutions by isonuclear series of the A 4 B 4 , A 3 B 5 , A 1 B 7 type and others compounds. The above series for medium ordinal numbers anti Z equal 10, 14, 18, 23 and 36 permit to illustrate the possibility of existence of such analogs or series, for example for the compounds of the type A 3 -- B 5 :AlN-BP or Z=1(f AlP-ScN-BV (for Z=14), ScP-AlV (for Z=18), GaP-AlAs-YN-BNb ( for Z=23) and YAs-GaNb-InV-ScSb-LaP-AlPr (for Z=36)

Studying the propensity of compounds to supersaturate

DEFF Research Database (Denmark)

Palmelund, Henrik; Madsen, Cecilie Maria; Christensen, Jakob Plum

2016-01-01

Supersaturating drug delivery systems can enhance the oral bioavailability of poorly soluble drug compounds. Supersaturation of such compounds has been studied in many different ways; however, a more standardized method is required. The rationale of choosing suitable concentrations of supersatura......Supersaturating drug delivery systems can enhance the oral bioavailability of poorly soluble drug compounds. Supersaturation of such compounds has been studied in many different ways; however, a more standardized method is required. The rationale of choosing suitable concentrations...... of supersaturation to study has previously been very inconsistent. This makes comparisons between studies and compounds difficult, as the propensity of compounds to supersaturate varies greatly. This study presents a standardized method to study the supersaturation of drug compounds. The method allows, both......, for a ranking of compounds according to their supersaturation propensity and the effectiveness of precipitation inhibitors. The time-concentration profile of supersaturation and precipitation was studied in situ for 4 different concentrations for 6 model compounds (albendazole, aprepitant, danazol, felodipine...

Potent antifouling compounds produced by marine Streptomyces

KAUST Repository

Xu, Ying

2010-02-01

Biofouling causes huge economic loss and a recent global ban on organotin compounds as antifouling agents has increased the need for safe and effective antifouling compounds. Five structurally similar compounds were isolated from the crude extract of a marine Streptomyces strain obtained from deep-sea sediments. Antifouling activities of these five compounds and four other structurally-related compounds isolated from a North Sea Streptomyces strain against major fouling organisms were compared to probe structure-activity relationships of compounds. The functional moiety responsible for antifouling activity lies in the 2-furanone ring and that the lipophilicity of compounds substantially affects their antifouling activities. Based on these findings, a compound with a straight alkyl side-chain was synthesized and proved itself as a very effective non-toxic, anti-larval settlement agent against three major fouling organisms. The strong antifouling activity, relatively low toxicity, and simple structures of these compounds make them promising candidates for new antifouling additives. © 2009 Elsevier Ltd. All rights reserved.

Method for purifying bidentate organophosphorus compounds

International Nuclear Information System (INIS)

Schulz, W.W.

1977-01-01

Bidentate organophosphorus compounds useful for extracting actinide elements from acidic nuclear waste solutions are purified of undesirable acidic impurities by contacting the compounds with ethylene glycol which preferentially extracts the impurities found in technical grade bidentate compounds

Solid-phase synthesis of compounds of europium and terbium with nitrogen-containing heterocyclic compounds under mechanical activation

International Nuclear Information System (INIS)

Kalinovskaya, I.V.; Karasev, V.E.

2000-01-01

Effect of solvents and parameters of mechanical treatment on basic regularities of synthesis of rare earth compounds with nitrogen-containing heterocyclic compounds is studied. It is shown that interaction on europium (3) and terbium (3) nitrates with nitrogen-containing heterocyclic compounds leads to formation of compounds of Ln(NO 3 )·2D composition, where Ln=Eu, Tb; D=2,2-dipyridyl, 1,10-phenanthroline, diphenylguanidine. Effect of conditions of mechanical treatment and different additions on process and yield of products is studied. Compounds prepared are characterized by the methods of chemical element analysis, IR spectroscopy and luminescent spectroscopy [ru

Affixation and compounding in Hakka

OpenAIRE

Ungsitipoonporn, Siriopen

2014-01-01

This paper aims to present the internal structures of words in the Hakka language. Similar to other languages, affixation and compounding are outstanding in Hakka. In general, prefixes and suffixes are bound morphemes which do not occur independently, but in Hakka they sometimes appear as independent forms. Apart from single words, identifying compound words is of particular interest. Compound nouns can be made up of two or three words (characters) which ...

Compound-heterozygous Marfan syndrome

NARCIS (Netherlands)

van Dijk, F. S.; Hamel, B. C.; Hilhorst-Hofstee, Y.; Mulder, B. J. M.; Timmermans, J.; Pals, G.; Cobben, J. M.

2009-01-01

We report two families in which the probands have compound-heterozygous Marfan syndrome (MFS). The proband of family I has the R2726W FBN1 mutation associated with isolated skeletal features on one allele and a pathogenic FBN1 mutation on the other allele. The phenotype of the compound-heterozygous

Polishing compound for plastic surfaces

Science.gov (United States)

Stowell, M.S.

1991-01-01

This invention is comprised of a polishing compound for plastic materials. The compound includes approximately by approximately by weight 25 to 80 parts at least one petroleum distillate lubricant, 1 to 12 parts mineral spirits, 50 to 155 parts abrasive paste, and 15 to 60 parts water. Preferably, the compound includes approximately 37 to 42 parts at least one petroleum distillate lubricant, up to 8 parts mineral spirits, 95 to 110 parts abrasive paste, and 50 to 55 parts water. The proportions of the ingredients are varied in accordance with the particular application. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC), and similar plastic materials whenever a smooth, clear polished surface is desired.

Crystallographic properties of fertilizer compounds

Energy Technology Data Exchange (ETDEWEB)

Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

1991-02-01

This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA's fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

Combustion synthesis and characterization of uranium and thorium tellurides

International Nuclear Information System (INIS)

Czechowicz, D.G.

1985-10-01

This report describes an investigation of the chemical systems uranium-tellurium and thorium-tellurium. A novel synthesis technique, combustion synthesis, which uses the exothermic heat of reaction rather than externally supplied heat, was utilized to form the phases UTe, U 3 Te 4 , and UTe 2 in the U-Te system and the phases ThTe, Th 2 Te 3 , and ThTe 2 in the Th-Te system from reactions of the type U/sub x/ + Te/sub y/ = U/sub x/Te/sub y/. With this synthetic method, U-Te and Th-Te products could be formed in a matter of seconds, and the purity of the products was often greater than that of the starting materials used. Control over final product stoichiometry was found to be very difficult. The product phase distribution observed in combustion products, as determined by x-ray diffraction, electron microprobe, and optical metallographic methods, was found to be spatially complex. Lattice constants were calculated from x-ray diffraction patterns for the compounds UTe, U 3 Te 4 , and ThTe. SOLGASMIX thermodynamic equilibrium calculations were performed using available and estimated thermodynamic data on the system U-Te-O in an attempt to understand the products formed by combustion. Adiabatic combustion reaction temperatures for specific U-Te and Th-Te reactions were also calculated utilizing available and estimated thermodynamic data. 71 refs., 31 figs., 15 tabs

Novel method of producing radioactive iodine

International Nuclear Information System (INIS)

Shikata, E.; Amano, H.

1976-01-01

Radioactive iodine(I-131) is easily obtained by heating, at a temperature ranging from 600 0 C to 650 0 C, a tellurium oxide intermediate which was obtained by heating telluric acid or tellurium trioxide at a temperature from about 400 0 C to 560 0 C and was irradited with a neutron flux. Thus, pure I-131 is obtained without the complicated operations required in a conventional process for separation and/or purification of the product. 4 claims

Single crystal growth and structure refinements of CsMxTe2-xO6 (M = Al, Ga, Ge, In) pyrochlores

International Nuclear Information System (INIS)

Siritanon, Theeranun; Sleight, A.W.; Subramanian, M.A.

2011-01-01

Graphical abstract: Single crystals of CsM x Te 2-x O 6 pyrochlores with M = Al, Ga, Ge, and In have been grown and structure refinements indicate deviations from ideal stoichiometry presumably related to mixed valency of tellurium. Highlights: → Single crystals of CsM x Te 2-x O 6 pyrochlores with M = Al, Ga, Ge, and In have been grown. → Structure refinements from single crystal X-ray diffraction data confirm e structure. → Deviations from ideal stoichiometry suggest mixed valency of tellurium and hence conductivity. -- Abstract: Single crystals of CsM x Te 2-x O 6 pyrochlores with M = Al, Ga, Ge, and In have been grown from a TeO 2 flux. Structure refinements from single crystal X-ray diffraction data are reported. These results are used to discuss deviations from ideal stoichiometry that result in electronic conductivity presumably related to mixed valency of tellurium.

A Multiplexed Assay That Monitors Effects of Multiple Compound Treatment Times Reveals Candidate Immune-Enhancing Compounds.

Science.gov (United States)

Zhao, Ziyan; Henowitz, Liza; Zweifach, Adam

2018-05-01

We previously developed a flow cytometry assay that monitored lytic granule exocytosis in cytotoxic T lymphocytes stimulated by contacting beads coated with activating anti-CD3 antibodies. That assay was multiplexed in that responses of cells that did or did not receive the activating stimulus were distinguished via changes in light scatter accompanying binding of cells to beads, allowing us to discriminate compounds that activate responses on their own from compounds that enhance responses in cells that received the activating stimulus, all within a single sample. Here we add a second dimension of multiplexing by developing means to assess in a single sample the effects of treating cells with test compounds for different times. Bar-coding cells before adding them to test wells lets us determine compound treatment time while also monitoring activation status and response amplitude at the point of interrogation. This multiplexed assay is suitable for screening 96-well plates. We used it to screen compounds from the National Cancer Institute, identifying several compounds that enhance anti-LAMP1 responses. Multiple-treatment-time (MTT) screening enabled by bar-coding and read via high-throughput flow cytometry may be a generally useful method for facilitating the discovery of compounds of interest.

Process for obtaining oxygen doped zinc telluride monocrystals and scintillator crystals obtained by this process

International Nuclear Information System (INIS)

Schneider, Maurice; Moreau, Roland; D'Haenen, J.-P.; Merenda, Pierre.

1976-01-01

A process is described for obtaining oxygen doped zinc telluride monocrystals, for use as scintillator crystals for ionising radiation detectors. The following operations are carried out in succession: one or several zinc telluride crystals are introduced into a silica ampoule together with a ternary mixture of zinc tellurium and oxygen, as an oxide or hydroxide of these elements; the ampoule is pumped down to a high vacuum and sealed; the sealed ampoule containing the mixture and monocrystals is placed in a kiln and brought to a uniform temperature sufficient to make the mixture three-phased, depending on its composition; the zinc telluride crystalline compound remains solid; the ampoule is then tempered to bring it quickly back to ambient temperature [fr

Characterization of selected volatile organic compounds, polycyclic aromatic hydrocarbons and carbonyl compounds at a roadside monitoring station

Science.gov (United States)

Ho, K. F.; Lee, S. C.; Chiu, Gloria M. Y.

Volatile organic compounds (VOCs), PAHs and carbonyl compounds are the major toxic components in Hong Kong. Emissions from motor vehicles have been one of the primary pollution sources in the metropolitan areas throughout Hong Kong for a long time. A 1-yr monitoring program for VOCs, PAHs and carbonyl compounds had been performed at a roadside urban station at Hong Kong Polytechnic University in order to determine the variations and correlations of each selected species (VOCs, PAHs and carbonyl compounds). This study is aimed to analyze toxic volatile organic compounds (benzene, toluene, ethylbenzene and xylene), two carbonyl compounds (formaldehyde, acetaldehyde), and selective polycyclic aromatic hydrocarbons. The monitoring program started from 16 April 1999 to 30 March 2000. Ambient VOC concentrations, many of which originate from the same sources as particulate PAHs and carbonyls compounds, show significant quantities of benzene, toluene and xylenes. Correlations and multivariate analysis of selected gaseous and particulate phase organic pollutants were performed. Source identification by principle component analysis and hierarchical cluster analysis allowed the identification of four sources (factors) for the roadside monitoring station. Factor 1 represents the effect of diesel vehicle exhaust. Factor 2 shows the contribution of aromatic compounds. Factor 3 explains photochemical products—formaldehyde and acetaldehyde. Factor 4 explains the effect of gasoline vehicle exhaust.

Response of Bioluminescent Bacteria to Alkyltin Compounds.

Science.gov (United States)

1987-12-01

found in the butyltiri series of compounds; tributyltin was (’Stimes more toxic than dibutyltin and (- 50 times more toxic than (mono)butyltin. When...correlations between compounds, tributyltin was -35 tine more Kicrotxit and fish bLoessays for pure toxic than dibutyltin end -750 times More compounds and...the compounds as a decrease in toxicity (5) tributyltin compounds ea -150 tines more and a method to study synergistic andtoxic than trinethyltia

Analysis of isoelectron isonuclear series of holovalent tetraelectron compounds as a system of bicomponent chemical compounds

Energy Technology Data Exchange (ETDEWEB)

Vigdorovich, V.N.; Dzhuraev, T.D.

1985-03-01

Analogs and prototypes of the compounds supplementing the system of isoelectron isonuclear series of holovalent tetraelectron compounds by Gorunova are revealed. The investigation of all series of tetraelectron ovalenthol compounds allows one to supplement the variety of known series used for regular tracing and forecasting of compound properties (series of cation and anion substitutions by isonuclear series of the A/sup 4/B/sup 4/, A/sup 3/B/sup 5/, A/sup 1/B/sup 7/ type and others compounds. The above series for medium ordinal numbers anti Z equal 10, 14, 18, 23 and 36 permit to illustrate the possibility of existence of such analogs or series, for example for the compounds of the type A/sup 3/-- B/sup 5/:AlN-BP or Z=1(f AlP-ScN-BV (for Z=14), ScP-AlV (for Z=18), GaP-AlAs-YN-BNb (for Z=23) and YAs-GaNb-InV-ScSb-LaP-AlPr (for Z=36).

Chemical compounds in teak

Directory of Open Access Journals (Sweden)

Fernanda Viana da Silva Leonardo

2015-09-01

Full Text Available Quinone compounds are largely generated at extractive fraction of the woods in a complex and variable biological system. The literature has indications for many segments from food industry to pharmaceutical industry. Within the field of industrial use of wood, they are less desirable since they are treated only as incidental substances in production strings of pulp, paper, charcoal, and sawmill. In spite of its small amount, compared to other chemical compounds called essential, these substances have received special attention from researchers revealing a diverse range of offerings to market products textiles, pharmaceuticals, colorants, and other polymers, for which are being tested and employed. Quinones are found in fungi, lichens, and mostly in higher plants. Tectona grandis, usually called teak, is able to biosynthesize anthraquinones, which is a quinone compound, byproduct of secondary metabolism. This species provides wood that is much prized in the furniture sector and can also be exploited for metabolites to supply the market in quinone compounds and commercial development of new technologies, adding value to the plantations of this species within our country.

Fig volatile compounds--a first comparative study.

Science.gov (United States)

Grison-Pigé, Laure; Hossaert-McKey, Martine; Greeff, Jaco M; Bessière, Jean-Marie

2002-09-01

We analysed the compounds of volatile blends released by receptive figs of twenty Ficus species to attract their specific pollinating wasps. In all, 99 different compounds were identified. The compounds are mainly terpenoids, aliphatic compounds and products from the shikimic acid pathway. In each species blend, there are few major compounds, which are generally common among floral fragrances. Most species blends also include rare compounds, but generally their proportion in the blend is low. A possible basis for species-specificity of Ficus-wasp interactions is discussed in relation to the patterns of volatiles found in this interspecies comparison. Copyright 2002 Elsevier Science Ltd.

Phenolic compounds in Ross Sea water

Science.gov (United States)

Zangrando, Roberta; Barbaro, Elena; Gambaro, Andrea; Barbante, Carlo; Corami, Fabiana; Kehrwald, Natalie; Capodaglio, Gabriele

2016-04-01

Phenolic compounds are semi-volatile organic compounds produced during biomass burning and lignin degradation in water. In atmospheric and paleoclimatic ice cores studies, these compounds are used as biomarkers of wood combustion and supply information on the type of combusted biomass. Phenolic compounds are therefore indicators of paleoclimatic interest. Recent studies of Antarctic aerosols highlighted that phenolic compounds in Antarctica are not exclusively attributable to biomass burning but also derive from marine sources. In order to study the marine contribution to aerosols we developed an analytical method to determine the concentration of vanillic acid, vanillin, p-coumaric acid, syringic acid, isovanillic acid, homovanillic acid, syringaldehyde, acetosyringone and acetovanillone present in dissolved and particle phases in Sea Ross waters using HPLC-MS/MS. The analytical method was validated and used to quantify phenolic compounds in 28 sea water samples collected during a 2012 Ross Sea R/V cruise. The observed compounds were vanillic acid, vanillin, acetovanillone and p-coumaric acid with concentrations in the ng/L range. Higher concentrations of analytes were present in the dissolved phase than in the particle phase. Sample concentrations were greatest in the coastal, surficial and less saline Ross Sea waters near Victoria Land.

Semiconducting compounds and devices incorporating same

Science.gov (United States)

Marks, Tobin J.; Facchetti, Antonio; Boudreault, Pierre-Luc; Miyauchi, Hiroyuki

2016-01-19

Disclosed are molecular and polymeric compounds having desirable properties as semiconducting materials. Such compounds can exhibit desirable electronic properties and possess processing advantages including solution-processability and/or good stability. Organic transistor and photovoltaic devices incorporating the present compounds as the active layer exhibit good device performance.

Compound Odontoma in young girl

Directory of Open Access Journals (Sweden)

Nurwahida Nurwahida

2017-08-01

Full Text Available Introduction. Odontomas are the most common type of odontogenic tumors and generally they are asymptomatic. These tumors are formed from enamel and dentin, and can have variable amounts of cement and pulp tissues. According to radiographic, microscopic, and clinical features, two types of odontomas are recognized: Complex and compound odontomas. Complex odontomas occur mostly in the posterior part of the mandible and compound odontomas in the anterior maxilla. Case Report. A young girl patient, 9 years old came to Department of Oral and Maxillofacial Surgery with a slow growing and asymptomatic swelling in her left posterior mandible for 5 years in his history taking. The panoramic radiograph show  a radioopacity and radiolucent lesion at the lower second molar region, with well-corticated limits. An insisional biopsi   confirmed  as compound odontoma. The surgery  performed with simple enucleation and curettage under general anaesthesia. Discussion. Compound odontomas are usually located in the anterior maxilla, over the crowns of unerupted teeth, or between the roots of erupted teeth. In this case report, Compound odontomas are found in the posterior mandible. Conclusion. Compound odontomas in the posterior mandible is a rare. The treatment of odontomas depends on the size of the lesion. The early diagnosis, the treatment of choice is conservative surgical enucleation and curettage and prognosis is excellent.

Prioritizing pesticide compounds for analytical methods development

Science.gov (United States)

Norman, Julia E.; Kuivila, Kathryn; Nowell, Lisa H.

2012-01-01

The U.S. Geological Survey (USGS) has a periodic need to re-evaluate pesticide compounds in terms of priorities for inclusion in monitoring and studies and, thus, must also assess the current analytical capabilities for pesticide detection. To meet this need, a strategy has been developed to prioritize pesticides and degradates for analytical methods development. Screening procedures were developed to separately prioritize pesticide compounds in water and sediment. The procedures evaluate pesticide compounds in existing USGS analytical methods for water and sediment and compounds for which recent agricultural-use information was available. Measured occurrence (detection frequency and concentrations) in water and sediment, predicted concentrations in water and predicted likelihood of occurrence in sediment, potential toxicity to aquatic life or humans, and priorities of other agencies or organizations, regulatory or otherwise, were considered. Several existing strategies for prioritizing chemicals for various purposes were reviewed, including those that identify and prioritize persistent, bioaccumulative, and toxic compounds, and those that determine candidates for future regulation of drinking-water contaminants. The systematic procedures developed and used in this study rely on concepts common to many previously established strategies. The evaluation of pesticide compounds resulted in the classification of compounds into three groups: Tier 1 for high priority compounds, Tier 2 for moderate priority compounds, and Tier 3 for low priority compounds. For water, a total of 247 pesticide compounds were classified as Tier 1 and, thus, are high priority for inclusion in analytical methods for monitoring and studies. Of these, about three-quarters are included in some USGS analytical method; however, many of these compounds are included on research methods that are expensive and for which there are few data on environmental samples. The remaining quarter of Tier 1

Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria

Directory of Open Access Journals (Sweden)

Nelson L. Brock

2013-05-01

Full Text Available Members of the marine Roseobacter clade can degrade dimethylsulfoniopropionate (DMSP via competing pathways releasing either methanethiol (MeSH or dimethyl sulfide (DMS. Deuterium-labeled [2H6]DMSP and the synthetic DMSP analogue dimethyltelluriopropionate (DMTeP were used in feeding experiments with the Roseobacter clade members Phaeobacter gallaeciensis DSM 17395 and Ruegeria pomeroyi DSS-3, and their volatile metabolites were analyzed by closed-loop stripping and solid-phase microextraction coupled to GC–MS. Feeding experiments with [2H6]DMSP resulted in the incorporation of a deuterium label into MeSH and DMS. Knockout of relevant genes from the known DMSP demethylation pathway to MeSH showed in both species a residual production of [2H3]MeSH, suggesting that a second demethylation pathway is active. The role of DMSP degradation pathways for MeSH and DMS formation was further investigated by using the synthetic analogue DMTeP as a probe in feeding experiments with the wild-type strain and knockout mutants. Feeding of DMTeP to the R. pomeroyi knockout mutant resulted in a diminished, but not abolished production of demethylation pathway products. These results further corroborated the proposed second demethylation activity in R. pomeroyi. Isotopically labeled [2H3]methionine and 34SO42−, synthesized from elemental 34S8, were tested to identify alternative sulfur sources besides DMSP for the MeSH production in P. gallaeciensis. Methionine proved to be a viable sulfur source for the MeSH volatiles, whereas incorporation of labeling from sulfate was not observed. Moreover, the utilization of selenite and selenate salts by marine alphaproteobacteria for the production of methylated selenium volatiles was explored and resulted in the production of numerous methaneselenol-derived volatiles via reduction and methylation. The pathway of selenate/selenite reduction, however, proved to be strictly separated from sulfate reduction.

Antifouling Compounds from Marine Invertebrates

OpenAIRE

Qi, Shu-Hua; Ma, Xuan

2017-01-01

In this review, a comprehensive overview about the antifouling compounds from marine invertebrates is described. In total, more than 198 antifouling compounds have been obtained from marine invertebrates, specifically, sponges, gorgonian and soft corals.

Antifouling Compounds from Marine Invertebrates.

Science.gov (United States)

Qi, Shu-Hua; Ma, Xuan

2017-08-28

In this review, a comprehensive overview about the antifouling compounds from marine invertebrates is described. In total, more than 198 antifouling compounds have been obtained from marine invertebrates, specifically, sponges, gorgonian and soft corals.

The demise of compound houses

DEFF Research Database (Denmark)

Andreasen, Jørgen; Eskemose Andersen, Jørgen

2006-01-01

of compound housing and analyses the advantages and disadvantages of life within such housing in Kumasi. Issues of privacy, image and communal life are usually cited by occupants dissatiesfied with life in compound houses, and the difficulty of extending them without spoiling the open spaces...... perceptions of what is acceptable urban life to the growing cohort of young African households. In addition, there is a need to explore innovative forms of tenure in order to secure the majority of Kumasi's population access to land for housing.......The compound house has long provided the accomodation required by low income households in West African cities. In Kumasi, Ghana, evidence suggests that no new compounds are being built. Instead, the city is being ringed by relatively affluent villa-style development while neighbourhoods dominated...

Use of labeled compounds in tracer experiments

International Nuclear Information System (INIS)

Anon.

1991-01-01

The use of radiotracers in research has become common. This chapter looks at some of the underlying assumptions and advantages of labeled compounds: advantages of radiotracers; availability of suitable tracers and labeled compounds; purity of labeled compounds; autoradiolysis; storage of labeled compounds; detection systems for chromatography and electrophoretic methods. 14 refs., 2 figs

Fluorine-18 labelled compounds

International Nuclear Information System (INIS)

Kleijn, J.P. de

1978-01-01

The work presented in this thesis deals with the problems involved in the adaption of reactor-produced fluorine-18 to the synthesis of 18 F-labelled organic fluorine compounds. Several 18 F-labelling reagents were prepared and successfully applied. The limitations to the synthetic possibilities of reactor-produced fluoride- 18 become manifest in the last part of the thesis. An application to the synthesis of labelled aliphatic fluoro amino acids has appeared to be unsuccessful as yet, although some other synthetic approaches can be indicated. Seven journal articles (for which see the availability note) are used to compose the four chapters and three appendices. The connecting text gives a survey of known 18 F-compounds and methods for preparing such compounds. (Auth.)

Resistance to phenicol compounds following adaptation to quaternary ammonium compounds in Escherichia coli.

Science.gov (United States)

Soumet, C; Fourreau, E; Legrandois, P; Maris, P

2012-07-06

Bacterial adaptation to quaternary ammonium compounds (QACs) is mainly documented for benzalkonium chloride (BC) and few data are available for other QACs. The aim of this study was to assess the effects of repeated exposure to different quaternary ammonium compounds (QACs) on the susceptibility and/or resistance of bacteria to other QACs and antibiotics. Escherichia coli strains (n=10) were adapted by daily exposure to increasingly sub-inhibitory concentrations of a QAC for 7 days. Three QACs were studied. Following adaptation, we found similar levels of reduction in susceptibility to QACs with a mean 3-fold increase in the minimum inhibitory concentration (MIC) compared to initial MIC values, whatever the QAC used during adaptation. No significant differences in antibiotic susceptibility were observed between the tested QACs. Antibiotic susceptibility was reduced from 3.5- to 7.5-fold for phenicol compounds, β lactams, and quinolones. Increased MIC was associated with a shift in phenotype from susceptible to resistant for phenicol compounds (florfenicol and chloramphenicol) in 90% of E. coli strains. Regardless of the QAC used for adaptation, exposure to gradually increasing concentrations of this type of disinfectant results in reduced susceptibility to QACs and antibiotics as well as cross-resistance to phenicol compounds in E. coli strains. Extensive use of QACs at sub-inhibitory concentrations may lead to the emergence of antibiotic-resistant bacteria and may represent a public health risk. Published by Elsevier B.V.

THE COMPOUND NOUNS BETWEEN ENGLISH AND ALBANIAN LANGUAGE

OpenAIRE

Shkelqim Millaku; Xhevahire Topanica

2016-01-01

The compound words are all the words that are compound from two or more words and both of them creative the new words with the new meaning. In linguistics, a compound is a lexeme (less precisely, a word) that consists of more than one stem. Compounding or composition is the word-formation that creates compound lexemes (the other word-formation process being derivation). Compounding or Word-compounding refers to the faculty and device of language to form new words by combining or putting toget...

Constitutional studies in the palladium-rhodium-tellurium (-oxygen) system. A contribution to elucidate the behaviour of Pd, Rh and Te in the vitrification process of high-level waste concentrates (HLWC)

International Nuclear Information System (INIS)

Hartmann, T.

1996-01-01

In the vitrification process of high-level waste concentrates (HLWC) from the reprocessing of nuclear spent fuel elements, about 30 different elements have to be immobilized in a solid matrix consisting of an alkali borosilicate glass. Most of the waste oxides are dissolved in the alkali borosilicate melt and become structural elements of the glasses when cooled. This, however, applies only partly to the platinum metals Ru, which forms RuO 2 , and palladium and rhodium, which deposit as sparingly soluble and electrically conducting tellurides. This might considerably impair the technical process of HLWC vitrification. Therefore, constitutional studies on the Pd-Rh-Te system became necessary. The phase diagram of the Pd-Rh-Te ternary system at temperatures of 1150, 1100, 1050, 1000, 950, 900 and 750 C was determined under inertial conditions. Oxygen exerts a major influence on the system. Already under limited availability of oxygen, the rhodium contents of the solid solution phases α 1 and α 2 are clearly diminished. Rhodium of the phases becomes oxidized selectively. The three-phase field α 1 +α 2 +L is shifted to higher palladium and tellurium contents, even oxygen is available to a limited extend only. With the oxygen in the air, the extension of the three-phase space is reduced markedly. The complex process chemistry of Pf, Rh and Te during the vitrification can be described by the state of the Pd-Rh-Te ternary system after annealing in (air) oxygen for limited periods of time. (orig./MM) [de

Insecticidal Activity of Cyanohydrin and Monoterpenoid Compounds

Directory of Open Access Journals (Sweden)

Joel R. Coats

2000-04-01

Full Text Available The insecticidal activities of several cyanohydrins, cyanohydrin esters and monoterpenoid esters (including three monoterpenoid esters of a cyanohydrin were evaluated. Topical toxicity to Musca domestica L. adults was examined, and testing of many compounds at 100 mg/fly resulted in 100% mortality. Topical LD50 values of four compounds for M. domestica were calculated. Testing of many of the reported compounds to brine shrimp (Artemia franciscana Kellog resulted in 100% mortality at 10 ppm, and two compounds caused 100% mortality at 1 ppm. Aquatic LC50 values were calculated for five compounds for larvae of the yellow fever mosquito (Aedes aegypti (L.. Monoterpenoid esters were among the most toxic compounds tested in topical and aquatic bioassays.

Bis(1,3-dithiole) Compounds

DEFF Research Database (Denmark)

Andersen, Jan Rud; Engler, E. M.; Green, D. C.

1977-01-01

There is described the preparation of bis-1,3-dithiole compounds (I) which are key synthetic precursors for the preparation of new polymeric metal bis(dithiolene) (i.e., II) and tetrathiafulvalene compounds (i.e., III): (Image Omitted)...

Molecular mechanism of radiosensitization by nitro compounds

International Nuclear Information System (INIS)

Kagiya, T.; Wada, T.; Nishimoto, S.I.

1984-01-01

In this chapter a molecular mechanism of radiosensitization by electron-affinic nitro compounds is discussed, mainly on the basis of the results of the radiation-induced chemical studies of DNA-related compounds in aqueous solutions. In Section II the general aspects of the radiation chemistry of organic compounds in the absence and presence of oxygen in aqueous solution are shown in order to demonstrate characteristic differences between radiation chemical reactions in hypoxic and oxic cells. The effects of nitro compounds on the radiolysis yields of DNA-related compounds in aqueous solutions are described in Section III. In Section IV the retardation effects of misonidazole on the radiation chemical processes of DNA-related compounds are shown along with the reaction characteristics of misonidazole with hydroxyl radical ( . OH) and hydrated electron (e/sub aq/-bar) produced by the radiolysis of water. The promotion of radiation-induced oxidation of thymine into thymine glycol (TG) by nitro radiosensitizers in deoxygenated solution and the relations between the activity of nitro compound for the thymine glycol formation and the enhancement activity measured in vitro are described in Section V. Finally, the protection against radiation-induced damage of thymine by a sulfhydryl compound of glutathione and the ability of electron-affinic compounds to decompose the intracellular radioprotector are described in Section VI

Evaluation of radioactive wastes in Instituto de Energia Atomica (Sao Paulo-Brazil)

International Nuclear Information System (INIS)

Sawakuchi, R.S.

1978-01-01

An evaluation of present and future production of radioactive waste in several departments of the Instituto de Energia Atomica has been done. Taking into account this evaluation, the criteria for disposal and convenient treatment technique have been studied. The most critical form of liquid radioactive waste is that of 131 I processing because high concentration of radiotellurium always accompanies this form of waste. Ion exchange and precipitation techniques were used to study this waste processing. Two kinds of resins were used by the ion exchange method: the strong anionic and the stron cationic. Quantitative tellurium retention has not been attained by the ion exchange method using either resins. The technique of precipitation of radioactive tellurium as ammonium tellurate was also used, allowing us to obtain more than 99% of tellurium removal. The remaining radioactive wastes can be eliminated using the storage for decay criteria with further release to the sewers in the case of liquids and burial in the case of solids. (Author) [pt

Thin films of mixed metal compounds

Science.gov (United States)

Mickelsen, Reid A.; Chen, Wen S.

1985-01-01

A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.

Quinoline-Based Hybrid Compounds with Antimalarial Activity

Directory of Open Access Journals (Sweden)

Xhamla Nqoro

2017-12-01

Full Text Available The application of quinoline-based compounds for the treatment of malaria infections is hampered by drug resistance. Drug resistance has led to the combination of quinolines with other classes of antimalarials resulting in enhanced therapeutic outcomes. However, the combination of antimalarials is limited by drug-drug interactions. In order to overcome the aforementioned factors, several researchers have reported hybrid compounds prepared by reacting quinoline-based compounds with other compounds via selected functionalities. This review will focus on the currently reported quinoline-based hybrid compounds and their preclinical studies.

Four new compounds from Imperata cylindrica.

Science.gov (United States)

Liu, Xuan; Zhang, Bin-Feng; Yang, Li; Chou, Gui-Xin; Wang, Zheng-Tao

2014-04-01

Four new compounds, impecylone (1), deacetylimpecyloside (2), seguinoside K 4-methylether (3) and impecylenolide (4), were isolated from Imperata cylindrica along with two known compounds, impecyloside (5) and seguinoside K (6). Their structures were elucidated mainly by spectroscopic analyses including 1D- and 2D-NMR techniques, and the absolute configuration of 1 was confirmed by X-ray diffraction analysis. In calcium assay, the result indicated that compounds 1, 2, 4 and 5 cannot obviously inhibit the calcium peak value compared with the negative control, and suggested that the four compounds could not have anti-inflammatory activity.

Genetic effects of organic mercury compounds

Energy Technology Data Exchange (ETDEWEB)

Ramel, C

1967-01-01

Organic mercury compounds have a c-mitotic effect on plant cells that cause polyploidi. Studies were performed on Allium root cells. These investigations involved methyl mercury dicyandiamide, methyl mercury hydroxide, and phenyl mercury hydroxide. The lowest concentration necessary for a cytologically observable effect was about 0.05 ppM Hg for the methyl compounds. For the phenyl compound, the value was lower. Experiments were performed on Drosophila melanogaster. The question was whether the mercury would reach the gonads. Experimental data with mercury treated larvae indicated a chromosome disjunction. Data indicated a preferential segregation at the meiotic division might be involved. Experiments are being performed on mice inbred (CBA) in order to investigate teratogenic effects and dominant lethality caused by organic mercury compounds. The mutagenic effects of these compounds are studied on Neurospora Drosophila. No conclusive data is now available.

Chloric organic compound

International Nuclear Information System (INIS)

Moalem, F.

2000-01-01

Since many years ago, hazardous and toxic refuses which are results of human activities has been carelessly without any Biological and Engineering facts and knowledge discharged into our land and water. The effects of discharging those materials in environment are different. Some of refuse materials shows short and other has long-time adverse effects in our environment, Among hazardous organic chemical materials, chlorine, consider, to be the main element. Organic materials with chlorine is called chlorine hydrocarbon as a hazardous compound. This paper discuss the hazardous materials especially chloric organic compound and their misuse effects in environment and human being

Radiolysis of other organic compounds

International Nuclear Information System (INIS)

Pikaev, A.K.

1986-01-01

Peculiarities of radiolysis of organic halogen, phosphorus, sulfur and nitrogen (including amines, amides, nitriles et al.) compounds in liquid phase are discussed. Intermediate and stable finish products of radiolysis of the given compounds, properties and radiochemical yields of these products are considered

Xenobiotic organic compounds in wastewater

DEFF Research Database (Denmark)

Eriksson, Eva; Baun, Anders; Henze, Mogens

2002-01-01

hundred of XOCs, among them mainly originating from hygiene products: chlorophenols, detergents and phthalates. Several compounds not deriving from hygiene products were also identified e.g. flame-retardants and drugs. A environmental hazard identification showed that a large number of compounds with high...

Two new acetylenic compounds from Asparagus officinalis.

Science.gov (United States)

Li, Xue-Mei; Cai, Jin-Long; Wang, Wen-Xiang; Ai, Hong-Lian; Mao, Zi-Chao

2016-01-01

Two new acetylenic compounds, asparoffins A (1) and B (2), together with two known compounds, nyasol (3) and 3″-methoxynyasol (4), were isolated from stems of Asparagus officinalis. The structures of two new compounds were elucidated on the basis of detailed spectroscopic analyses (UV, IR, MS, 1D, and 2D NMR). All compounds were evaluated for their cytotoxicities against three human cancer cell lines.

Phenolic Compounds in Brassica Vegetables

Directory of Open Access Journals (Sweden)

Pablo Velasco

2010-12-01

Full Text Available Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables.

Compound cueing in free recall

Science.gov (United States)

Lohnas, Lynn J.; Kahana, Michael J.

2013-01-01

According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cueing in free recall. Specifically, the temporal contiguity effect should be greater when the two most recently recalled items were studied in contiguous list positions. A meta-analysis of published free recall experiments demonstrates evidence for compound cueing in both conditional response probabilities and inter-response times. To help rule out a rehearsal-based account of these compound cueing effects, we conducted an experiment with immediate, delayed and continual-distractor free recall conditions. Consistent with retrieved context theory but not with a rehearsal-based account, compound cueing was present in all conditions, and was not significantly influenced by the presence of interitem distractors. PMID:23957364

Compound cuing in free recall.

Science.gov (United States)

Lohnas, Lynn J; Kahana, Michael J

2014-01-01

According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cuing in free recall. Specifically, the temporal contiguity effect should be greater when the 2 most recently recalled items were studied in contiguous list positions. A meta-analysis of published free recall experiments demonstrates evidence for compound cuing in both conditional response probabilities and interresponse times. To help rule out a rehearsal-based account of these compound cuing effects, we conducted an experiment with immediate, delayed, and continual-distractor free recall conditions. Consistent with retrieved context theory but not with a rehearsal-based account, compound cuing was present in all conditions, and was not significantly influenced by the presence of interitem distractors.

Unlock your Compound Management

OpenAIRE

Steffen Eller

2016-01-01

Pharmaceutical industry faces the increased demand for innovative medicines against various diseases. In this regard, the compound library in pharmaceutical industry is the most valuable asset. However, the compound distribution from the library into the screening plates is often still done manually and binds highly qualified resources to very time-consuming, tedious and error-prone tasks. To overcome these challenges, Chemspeed launched the first automated true one-to-one gravimetric "pi...

Carbonyl Compounds Generated from Electronic Cigarettes

Directory of Open Access Journals (Sweden)

Kanae Bekki

2014-10-01

Full Text Available Electronic cigarettes (e-cigarettes are advertised as being safer than tobacco cigarettes products as the chemical compounds inhaled from e-cigarettes are believed to be fewer and less toxic than those from tobacco cigarettes. Therefore, continuous careful monitoring and risk management of e-cigarettes should be implemented, with the aim of protecting and promoting public health worldwide. Moreover, basic scientific data are required for the regulation of e-cigarette. To date, there have been reports of many hazardous chemical compounds generated from e-cigarettes, particularly carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, and glyoxal, which are often found in e-cigarette aerosols. These carbonyl compounds are incidentally generated by the oxidation of e-liquid (liquid in e-cigarette; glycerol and glycols when the liquid comes in contact with the heated nichrome wire. The compositions and concentrations of these compounds vary depending on the type of e-liquid and the battery voltage. In some cases, extremely high concentrations of these carbonyl compounds are generated, and may contribute to various health effects. Suppliers, risk management organizations, and users of e-cigarettes should be aware of this phenomenon.

Applying Quality by Design Concepts to Pharmacy Compounding.

Science.gov (United States)

Timko, Robert J

2015-01-01

Compounding of medications is an important part of the practice of the pharmacy profession. Because compounded medications do not have U.S. Food and Drug Administration approval, a pharmacist has the responsibility to ensure that compounded medications are of suitable quality, safety, and efficacy. The Federal Government and numerous states have updated their laws and regulations regarding pharmacy compounding as a result of recent quality issues. Compounding pharmacists are expected to follow good preparation prodecures in their compounding practices in much the same way pharmaceutical manufacturers are required to follow Current Good Manufacturing Procedures as detailed in the United States Code of Federal Regulations. Application of Quality by Design concepts to the preparation process for a compounded medication can help in understanding the potential pitfalls and the means to mitigate their impact. The goal is to build quality into the compounding process to ensure that the resultant compounded prescription meets the human or animal patients' requirements.

Neurotoxicity of fragrance compounds: A review.

Science.gov (United States)

Pinkas, Adi; Gonçalves, Cinara Ludvig; Aschner, Michael

2017-10-01

Fragrance compounds are chemicals belonging to one of several families, which are used frequently and globally in cosmetics, household products, foods and beverages. A complete list of such compounds is rarely found on the ingredients-list of such products, as "fragrance mixtures" are defined as "trade secrets" and thus protected by law. While some information regarding the general toxicity of some of these compounds is available, their neurotoxicity is known to a lesser extent. Here, we discuss the prevalence and neurotoxicity of fragrance compounds belonging to the three most common groups: phthalates, synthetic musks and chemical sensitizers. Copyright © 2017 Elsevier Inc. All rights reserved.

Mesoionic Compounds

Indian Academy of Sciences (India)

Organic Chemistry. Kamatak University,. Dharwad. Her research interests are synthesis, reactions and synthetic utility of sydnones. She is currently working on electrochemical and insecticidal/antifungal activities for some of these compounds. Keywords. Aromaticity, mesoionic hetero- cycles, sydnones, tandem re- actions.

EPR investigations on technetium compounds

International Nuclear Information System (INIS)

Abram, U.; Munze, R.; Kirmse, R.; Stach, J.

1986-01-01

Stimulated by the widespread use of the isotope /sup 99m/Tc in the field of nuclear medicine, there has been a substantial growth of interest in the chemistry of this man-made element. A particular need emerges for analytical methods allowing solution investigations of coordination compounds of technetium with low substance use. Considering these facts, Electron Paramagnetic Resonance Spectroscopy (EPR) appears to be a very suitable method because only very small amounts of the compounds are needed (lower than 1 mg). The resulting spectra give information regarding the valence state, symmetry and bonding properties of the compounds under study

Diazo compounds in the chemistry of fullerenes

International Nuclear Information System (INIS)

Tuktarov, Airat R; Dzhemilev, Usein M

2010-01-01

Experimental and theoretical data on the reactions of different diazo compounds (diazomethane, its derivatives, cyclic diazo compounds and diazocarbonyl compounds) with fullerenes are summarized. The structures and stereochemistry of cycloadducts formed in these reactions are considered.

Diazo compounds in the chemistry of fullerenes

Science.gov (United States)

Tuktarov, Airat R.; Dzhemilev, Usein M.

2010-09-01

Experimental and theoretical data on the reactions of different diazo compounds (diazomethane, its derivatives, cyclic diazo compounds and diazocarbonyl compounds) with fullerenes are summarized. The structures and stereochemistry of cycloadducts formed in these reactions are considered.

Diazo compounds in the chemistry of fullerenes

Energy Technology Data Exchange (ETDEWEB)

Tuktarov, Airat R; Dzhemilev, Usein M [Institute of Petrochemistry and Catalysis, Russian Academy of Sciences, Ufa (Russian Federation)

2010-09-14

Experimental and theoretical data on the reactions of different diazo compounds (diazomethane, its derivatives, cyclic diazo compounds and diazocarbonyl compounds) with fullerenes are summarized. The structures and stereochemistry of cycloadducts formed in these reactions are considered.

Extraterrestrial Organic Compounds in Meteorites

Science.gov (United States)

Botta, Oliver; Bada, Jeffrey L.; Meyer, Michael (Technical Monitor)

2003-01-01

Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

Vanadium Compounds as PTP Inhibitors

Directory of Open Access Journals (Sweden)

Elsa Irving

2017-12-01

Full Text Available Phosphotyrosine signaling is regulated by the opposing actions of protein tyrosine kinases (PTKs and protein tyrosine phosphatases (PTPs. Here we discuss the potential of vanadium derivatives as PTP enzyme inhibitors and metallotherapeutics. We describe how vanadate in the V oxidized state is thought to inhibit PTPs, thus acting as a pan-inhibitor of this enzyme superfamily. We discuss recent developments in the biological and biochemical actions of more complex vanadium derivatives, including decavanadate and in particular the growing number of oxidovanadium compounds with organic ligands. Pre-clinical studies involving these compounds are discussed in the anti-diabetic and anti-cancer contexts. Although in many cases PTP inhibition has been implicated, it is also clear that many such compounds have further biochemical effects in cells. There also remain concerns surrounding off-target toxicities and long-term use of vanadium compounds in vivo in humans, hindering their progress through clinical trials. Despite these current misgivings, interest in these chemicals continues and many believe they could still have therapeutic potential. If so, we argue that this field would benefit from greater focus on improving the delivery and tissue targeting of vanadium compounds in order to minimize off-target toxicities. This may then harness their full therapeutic potential.

Properties of tritium and its compounds

International Nuclear Information System (INIS)

Belovodskij, L.F.; Gaevoj, V.K.; Grishmanovskij, V.I.

1985-01-01

Ways of tritium preparation and different aspects of its application are considered. Physicochemical properties of this isotope and some compounds of it - tritium oxides, lithium, titanium, zirconium, uranium tritides, tritium organic compounds - are discussed. In particular, diffusion of tritium and its oxide through different materials, tritium oxidation processes, decomposition of tritium-containing compounds under the action of self-radiation are considered. Main radiobiological tritium properties are described

Antibacterial Compounds from Red Seaweeds (Rhodophyta)

OpenAIRE

Noer Kasanah; Triyanto Triyanto; Drajad Sarwo Seto; Windi Amelia; Alim Isnansetyo

2015-01-01

Seaweeds produce great variety of metabolites benefit for human. Red seaweeds (Rhodophyta) are well known as producer of phycocolloids such agar, agarose, carragenan and great variety of secondary metabolites. This review discusses the red algal secondary metabolites with antibacterial activity. The chemical constituents of red algae are steroid, terpenoid, acetogenin and dominated by halogenated compounds mainly brominated compounds. Novel compounds with intriguing skeleton are also reported...

Toxicology of perfluorinated compounds

Energy Technology Data Exchange (ETDEWEB)

Stahl, Thorsten [Hessian State Laboratory, Wiesbaden (Germany); Mattern, Daniela; Brunn, Hubertus [Hessian State Laboratory, Giessen (Germany)

2011-12-15

Perfluorinated compounds [PFCs] have found a wide use in industrial products and processes and in a vast array of consumer products. PFCs are molecules made up of carbon chains to which fluorine atoms are bound. Due to the strength of the carbon/fluorine bond, the molecules are chemically very stable and are highly resistant to biological degradation; therefore, they belong to a class of compounds that tend to persist in the environment. These compounds can bioaccumulate and also undergo biomagnification. Within the class of PFC chemicals, perfluorooctanoic acid and perfluorosulphonic acid are generally considered reference substances. Meanwhile, PFCs can be detected almost ubiquitously, e.g., in water, plants, different kinds of foodstuffs, in animals such as fish, birds, in mammals, as well as in human breast milk and blood. PFCs are proposed as a new class of 'persistent organic pollutants'. Numerous publications allude to the negative effects of PFCs on human health. The following review describes both external and internal exposures to PFCs, the toxicokinetics (uptake, distribution, metabolism, excretion), and the toxicodynamics (acute toxicity, subacute and subchronic toxicities, chronic toxicity including carcinogenesis, genotoxicity and epigenetic effects, reproductive and developmental toxicities, neurotoxicity, effects on the endocrine system, immunotoxicity and potential modes of action, combinational effects, and epidemiological studies on perfluorinated compounds). (orig.)

Kinetics of molybdenum(6) complexation with o,o'-dihydroxyazo compounds or heterocyclic azo compounds in the presence of hydroxylamine

International Nuclear Information System (INIS)

Kochelaeva, G.A.; Degtyarev, M.Yu.; Ivanov, V.M.; Prokhorova, G.V.; Figurovskaya, V.N.

1999-01-01

The kinetics of complexation in the system molybdenum(6)-azo compound-hydroxylamine was studied. Azo compounds of the types o,o'-dihydroxyazo compounds, such as Lyumogallion IREA and Magneson IREA, and heterocyclic azo compounds, such as 4-(2-pyridylazo)resorcinol and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol, were studied. The formation of mixed-ligand complexes with the ratio of component 1 : 1 : 1 was detected. Rate constants, activation energies, and stability constants of the forming compounds were evaluated. It was concluded that the reagents under study are promising for the analytical chemistry of molybdenum [ru

Calorimetric investigations of UPb{sub 3} compound

Energy Technology Data Exchange (ETDEWEB)

Agarwal, Renu, E-mail: arenu@barc.gov.in; Samui, Pradeep; Mukerjee, S.K.

2016-08-10

Highlights: • First time reporting of enthalpy increment and heat capacity data of UPb{sub 3} compound. • First time reporting of high temperature calorimetric determination of enthalpy of formation of UPb{sub 3} compound. • Miedema model was used to calculate enthalpies of formation of UPb{sub 3} and UPb. • Thermodynamic table of the compound UPb{sub 3} was generated. - Abstract: Interaction of uranium based metallic fuels and lead coolant can lead to formation of intermetallic compounds of U-Pb system. To understand U-Pb interactions, it is important to know thermodynamic properties of intermetallic compounds present in this system, UPb{sub 3} and UPb. In the present work, enthalpy increment, heat capacity and enthalpy of formation of UPb{sub 3} intermetallic compound were determined. The enthalpy increment was determined by high temperature Calvet calorimeter and heat capacity was determined using DSC. The heat capacity data was used to calculate thermodynamic parameters of the compound as a function of temperature. The enthalpy of formation at 843 K was determined using successive precipitation method, by direct reaction calorimetry. The enthalpy of formation at 843 K, from Pb(l) and U(l), was −28.9 kJ at-mol{sup −1} and after adjusting enthalpy increments of pure elements and compound, the enthalpy of formation of the compound at 298 K, from Pb(s) and U(α) was found to be −20.0 kJ at-mol{sup −1}.

Screening and identification of phytotoxic volatile compounds in medicinal plants and characterizations of a selected compound, eucarvone.

Science.gov (United States)

Sunohara, Yukari; Baba, Yohei; Matsuyama, Shigeru; Fujimura, Kaori; Matsumoto, Hiroshi

2015-07-01

Screening and identification of phytotoxic volatile compounds were performed using 71 medicinal plant species to find new natural compounds, and the characterization of the promising compound was investigated to understand the mode of action. The volatile compounds from Asarum sieboldii Miq. showed the strongest inhibitory effect on the hypocotyl growth of lettuce seedlings (Lactuca sativa L.cv. Great Lakes 366), followed by those from Schizonepeta tenuifolia Briquet and Zanthoxylum piperitum (L.) DC.. Gas chromatography-mass spectrometry (GC/MS) identified four volatile compounds, α-pinene (2,6,6-trimethylbicyclo[3.1.1]hept-2-ene), β-pinene (6,6-dimethyl-2-methylenebicyclo[3.1.1]heptane), 3-carene (3,7,7-trimethylbicyclo[4.1.0]hept-3-ene), and eucarvone (2,6,6-trimethy-2,4-cycloheptadien-1-one), from A. sieboldii, and three volatile compounds, limonene (1-methyl-4-(1-methylethenyl)-cyclohexene), menthone (5-methyl-2-(propan-2-yl)cyclohexan-1-one), and pulegone (5-methyl-2-propan-2-ylidenecyclohexan-1-one), from S. tenuifolia. Among these volatile compounds, eucarvone, menthone, and pulegone exhibited strong inhibitory effects on both the root and shoot growth of lettuce seedlings. Eucarvone-induced growth inhibition was species-selective. Cell death, the generation of reactive oxygen species (ROS), and lipid peroxidation were induced in susceptible finger millet seedlings by eucarvone treatment, whereas this compound (≤158 μM) did not cause the increase of lipid peroxidation and ROS production in tolerant maize. The results of the present study show that eucarvone can have strong phytotoxic activity, which may be due to ROS overproduction and subsequent oxidative damage in finger millet seedlings.

An introduction to the chemistry of complex compounds

CERN Document Server

Grinberg, Aleksander Abramovich; Trimble, R F

1962-01-01

An Introduction to the Chemistry of Complex Compounds discusses the fundamental concepts that are essential in understanding the underlying principles of complex compounds. The coverage of the book includes the compounds of the hexa, penta, and tetrammine type; compounds of the tri, dl, monoamine and hexacido types for the coordination number of 6; and complex compounds with a coordination number of 4. The text also covers the effects and chemical properties of complex compounds, such as the nature of the force of complex formation; the mutual effects of coordinated groups; and acid-base prope

Detection of chlorinated aromatic compounds

Science.gov (United States)

Ekechukwu, A.A.

1996-02-06

A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

Medicinal gold compounds

International Nuclear Information System (INIS)

Parish, R.V.; Cottrill, S.M.

1987-01-01

A major use of gold compounds in the pharmaceutical industry is for anti-arthritic agents. The disease itself is not understood and little is known about the way in which the drugs act, but detailed pictures of the distribution of gold in the body are available, and some of the relevant biochemistry is beginning to emerge. The purpose of this article is to give a survey of the types of compounds presently employed in medicine, of the distribution of gold in the body which results from their use, and of some relevant chemistry. Emphasis is placed on results obtained in the last few years

Xerogel-Sequestered Silanated Organochalcogenide Catalysts for Bromination with Hydrogen Peroxide and Sodium Bromide

Directory of Open Access Journals (Sweden)

Caitlyn M. Gatley

2015-05-01

Full Text Available While H2O2 is a powerful oxidant, decomposing into environmentally benign H2O and O2, a catalyst is often required for reactions with H2O2 to proceed at synthetically useful rates. Organotellurium and organoselenium compounds catalyze the oxidation of halide salts to hypohalous acids using H2O2. When sequestered into xerogel monoliths, the xerogel-chalcogenide combinations have demonstrated increased catalytic activity relative to the organochalcogen compound alone in solution for the oxidation of halide salts to hypohalous acids with H2O2. Diorganotellurides, diorganoselenides, and diorganodiselenides bearing triethoxysilane functionalities were sequestered into xerogel monoliths and their catalytic activity and longevity were investigated. The longevity of the catalyst-xerogel combinations was examined by isolating and recycling the catalyst-xerogel combination. It was found tellurium-containing catalyst 3 and selenium-containing catalyst 8 maintained their catalytic activity through three recycling trials and adding electron-donating substituents to catalyst 3 also increased the catalytic rate. The presence of organotellurium and organoselenium groups in the +4 oxidation state was determined by X-ray photoelectron spectroscopy.

Chemistry

International Nuclear Information System (INIS)

Ferris, L.M.

1975-01-01

The chemical research and development efforts related to the design and ultimate operation of molten-salt breeder reactor systems are concentrated on fuel- and coolant-salt chemistry, including the development of analytical methods for use in these systems. The chemistry of tellurium in fuel salt is being studied to help elucidate the role of this element in the intergranular cracking of Hastelloy N. Studies were continued of the effect of oxygen-containing species on the equilibrium between dissolved UF 3 and dissolved UF 4 , and, in some cases, between the dissolved uranium fluorides and graphite, and the UC 2 . Several aspects of coolant-salt chemistry are under investigation. Hydroxy and oxy compounds that could be formed in molten NaBF 4 are being synthesized and characterized. Studies of the chemistry of chromium (III) compounds in fluoroborate melts were continued as part of a systematic investigation of the corrosion of structural alloys by coolant salt. An in-line voltammetric method for determining U 4+ /U 3+ ratios in fuel salt was tested in a forced-convection loop over a six-month period. (LK)

Nitrogen compounds behavior under irradiation environment

International Nuclear Information System (INIS)

Ichikawa, Nagayoshi; Takagi, Junichi; Yotsuyanagi, Tadasu

1991-01-01

Laboratory experiments were performed to evaluate nitrogen compounds behavior in liquid phase under irradiation environments. Nitrogen compounds take a chemical form of ammonium ion under reducing condition by gamma irradiation, whereas ammonium ions are rather stable even under oxidizing conditions. Key reactions were pointed out and their reaction rate constants and activation energies were estimated through computer code simulation. A reaction scheme for nitrogen compounds including protonate reaction was proposed. (author)

Thermoelectric properties of P-type Sb2Te3 thick film processed by a screen-printing technique and a subsequent annealing process

International Nuclear Information System (INIS)

Kim, Sun Jin; We, Ju Hyung; Kim, Jin Sang; Kim, Gyung Soo; Cho, Byung Jin

2014-01-01

Highlights: • We report on thermoelectric properties of screen-printed Sb 2 Te 3 thick film. • Subsequent annealing process determines thermoelectric properties of Sb 2 Te 3 film. • Annealing in tellurium powder ambient contributes to tellurium-rich Sb 2 Te 3 film. • Annealing in tellurium powder ambient enhances carrier mobility of Sb 2 Te 3 film. -- Abstract: We herein report the thermoelectric properties of Sb 2 Te 3 thick film fabricated by a screen-printing technique and a subsequent annealing process. Each step of the screen-printing fabrication process of Sb 2 Te 3 thick film is described in detail. It was found that the subsequent annealing process must be carefully designed to achieve good thermoelectric properties of the screen-printed film. The results show that the annealing of the screen-printed Sb 2 Te 3 thick film together with tellurium powder in the same process chamber significantly improves the carrier mobility by increasing the average scattering time of the carrier in the film, resulting in a large improvement of the power factor. By optimizing the annealing process, we achieved a maximum thermoelectric figure-of-merit, ZT, of 0.32 at room temperature, which is slightly higher than that of bulk Sb 2 Te 3 . Because screen-printing is a simple and low-cost process and given that it is easy to scale up to large sizes, this result will be useful for the realization of large, film-type thermoelectric devices

Neoclassical compounds and final combining forms in English

Directory of Open Access Journals (Sweden)

Ana Díaz-Negrillo

2014-12-01

Full Text Available English neoclassical compounds rely on a distinct vocabulary stock and present morphological features which raise a number of theoretical questions. Generalisations about neoclassical compounds are also problematic because the output is by no means homogeneous, that is, defining features of neoclassical compounds sometimes co-exist with features that are not prototypical of these formations. The paper looks at neoclassical compounds with a view to exploring patterns of morphological behaviour and development in this class of compounds. The approach is both synchronic and diachronic: it researches whether the morphological behaviour of recently formed compounds is different from that of earlier compounds and, if so, in which respects. This is assessed on data from the BNC with respect to some of the features that are cited in the literature as defining properties of neoclassical compounds, specifically, their internal configuration, the occurrence or not of a linking vowel, and their productivity.

Ultrasound assisted extraction of bioactive compounds

Directory of Open Access Journals (Sweden)

Helena Drmić

2010-01-01

Full Text Available Many novel and innovative techniques are nowadays researched and explored in order to replace or improve classical, thermal processing technologies. One of newer technique is technique of minimal food processing, under what we assume ultrasound processing. Ultrasound technology can be very useful for minimal food processing because transmission of acoustic energy through product is fast and complete, which allows reduction in total processing time, and therefore lower energy consumption. Industrial processing is growing more and more waste products, and in desire of preservation of global recourses and energy efficiency, several ways of active compounds extraction techniques are now explored. The goal is to implement novel extraction techniques in food and pharmaceutical industry as well in medicine. Ultrasound assisted extraction of bioactive compounds offers increase in yield, and reduction or total avoiding of solvent usage. Increase in temperature of treatment is controlled and restricted, thereby preserving extracted bioactive compounds. In this paper, several methods of ultrasound assisted extraction of bioactive compounds from plant materials are shown. Ultrasound can improve classic mechanisms of extraction, and thereby offer novel possibilities of commercial extraction of desired compounds. Application of sonochemistry (ultrasound chemistry is providing better yield in desired compounds and reduction in treatment time.

CRYSTAL-QUASICHEMICAL ANALYSIS OF DEFECT SUBSYSTEM OF DOPED PbTe: Sb CRYSTALS AND Pb-Sb-Te SOLID SOLUTIONS

Directory of Open Access Journals (Sweden)

D.M. Freik

2014-05-01

Full Text Available Within crystalquasichemical formalism models of point defects of crystals in the Pb-Sb-Te system were specified. Based on proposed crystalquasichemical formulae of antimony doped crystals PbTe:Sb amphoteric dopant effect was explained. Mechanisms of solid solution formation for РbТе-Sb2Те3: replacement of antimony ions lead sites  with the formation of cation vacancies  (I or neutral interstitial tellurium atoms  (II were examined. Dominant point defects in doped crystals PbTe:Sb and РbТе-Sb2Те3 solid solutions based on p-PbTe were defined. Dependences of concentration of dominant point defects, current carriers and Hall concentration on content of dopant compound and the initial deviation from stoichiometry in the basic matrix were calculated.

Formation and filtration characteristics of solids generated in a high level liquid waste treatment process. Solids formation behavior from simulated high level liquid waste

International Nuclear Information System (INIS)

Kondo, Y.; Kubota, M.

1997-01-01

The solids formation behavior in a simulated high level liquid waste (HLLW) was experimentally examined, when the simulated HLLW was treated in the ordinary way of actual HLLW treatment process. Solids formation conditions and mechanism were closely discussed. The solids formation during a concentration step can be explained by considering the formation of zirconium phosphate, phosphomolybdic acid and precipitation of strontium and barium nitrates and their solubilities. For the solids formation during the denitration step, at least four courses were observed; formation of an undissolved material by a chemical reaction with each other of solute elements (zirconium, molybdenum, tellurium) precipitation by reduction (platinum group metals) formation of hydroxide or carbonate compounds (chromium, neodymium, iron, nickel, strontium, barium) and a physical adsorption to stable solid such as zirconium molybdate (nickel, strontium, barium). (author)

Synthesis and characterization of the [Te(SCN2H4)4] (SO4)2 complex. Application to the separation of 99Mo from fission products

International Nuclear Information System (INIS)

Mestnik, S.A.C.; Silva, C.P.G. da.

1988-10-01

Thiourea reacts with tellurium-IV ions, in sulfuric medium, to form cationic complex which is strongly retained on cationic ion exchanger. The method was applied to separate 99 Mo from 132 Te obtained in the fission of 235 U since molybdenum does not form such complex and passes throught the cationic exchanger column in the molibdate form. In this paper, the procedure of the tellurium-thiourea complex preparation and its characterization are described. Elemental analysis, ultraviolet and infra-red absorption spectrophotometry as well as thermogravimetry were used to characterize the complex. (author) [pt

Synthesis, spectroscopic, structural and thermal characterizations of [(C7H6NO42TeBr6·4H2O

Directory of Open Access Journals (Sweden)

S. Smaoui

2018-02-01

Full Text Available Tellurium (IV complexes with pyridine-2,6-dicarboxylate ligand were synthesized by slow evaporation from aqueous solutions yielding a new compound: [(C7H6NO42TeBr6·4H2O]. The structure of this compound was solved and refined by single-crystal X-ray diffraction. The compound is centrosymmetric P21/c (N°: 14 with the parameters a = 8.875(5 Å, b = 15.174(5 Å, c = 10.199(5 Å, β = 94.271° (5 and Z = 2. The structure consists of isolated H2O, isolated [TeBr6]2− octahedral anions and (pyridine-2,6-dicarboxylate [C7H6NO4]+ cations. The stability of the structure was ensured by ionic and hydrogen bonding contacts (N–H⋯Br and O–H⋯Br and Van-Der Walls interaction. The thermal decomposition of the compound was studied by thermogravimetric analysis (TGA and differential scanning calorimetry (DSC. The FTIR and Raman spectroscopy at different temperatures confirm the existence of vibrational modes that correspond to the organic, inorganic and water molecular groups. Additionally, the UV–Vis diffuse reflectance spectrum was recorded in order to investigate the band gap nature. The measurements show that this compound exhibits a semiconducting behavior with an optical band gap of 2.66 eV.

Neutron activation analysis of manganese-mercury telluride

International Nuclear Information System (INIS)

Sadykov, I. I.

2003-01-01

The triple semiconductor compound Mn x Hg 1-x Te is a worthwhile material for the development of infra-red detectors. It's properties, as well as other semiconductors ones depend on impurity elements content. So, analytical Purity control of Mn x Hg 1-x Te is required. Some procedures of the neutron activation analysis of Te[1], Hg [2] and that of their compounds (Cd x Hg 1-x Te [3], for instance) have been developed recently. However, no papers on the NAA of Mn x Hg 1-x Te have been found. This paper describes the procedure of the NAA of Mn x Hg 1-x Te based on anion-exchange chromatographic separation of impurity and matrix elements. Experimental The following reagents were used: commerciality available strongly based anion-exchange resin AW-17 (50-100 meash), hydrochloride hydrasine of analytical grade, solutions of HCl and HNO 3 prepared from concentrated acids of reagent grade. Separation processes were studied by radioactive tracers. The gamma-activity was measured on a HPGe detector GC1518 (efficiency 15 %, resolution 1,7 keV at 1332,5 keV line of 6 0C o) using DSA-1000 digital multichannel analyzer (Canberra, USA). Radioactive tracers were produced by irradiation of metals, salts or oxides of corresponding elements in WWR-SM water-water nuclear reactor. Irradiation of Mn x Hg 1-x Te samples and standards was carried out in a channel of WWR-SM reactor with a neutron flux density of 1.10 14 cm 2 .s -1 for 10 h. Solutions of manganese and mercury were prepared by dissolving their oxides in concentric hydrochloric acid. Solutions of tellurium were prepared by dissolving metallic tellurium in HCl:HNO 3 (3:1) mixture. Solution obtained was evaporated to dryness, the reside was dissolved in conc. HCl. To reduce tellurium to Te(IV) 1-2 mg of hydrazine were dissolved in solution at slight heating. Then, distilled water was added in a required quantities to get a desired concentration of HCl. The chromatographic behaviour of matrix and impurity elements was studied

Drug-likeness analysis of traditional Chinese medicines: 2. Characterization of scaffold architectures for drug-like compounds, non-drug-like compounds, and natural compounds from traditional Chinese medicines.

Science.gov (United States)

Tian, Sheng; Li, Youyong; Wang, Junmei; Xu, Xiaojie; Xu, Lei; Wang, Xiaohong; Chen, Lei; Hou, Tingjun

2013-01-21

In order to better understand the structural features of natural compounds from traditional Chinese medicines, the scaffold architectures of drug-like compounds in MACCS-II Drug Data Report (MDDR), non-drug-like compounds in Available Chemical Directory (ACD), and natural compounds in Traditional Chinese Medicine Compound Database (TCMCD) were explored and compared. First, the different scaffolds were extracted from ACD, MDDR and TCMCD by using three scaffold representations, including Murcko frameworks, Scaffold Tree, and ring systems with different complexity and side chains. Then, by examining the accumulative frequency of the scaffolds in each dataset, we observed that the Level 1 scaffolds of the Scaffold Tree offer advantages over the other scaffold architectures to represent the scaffold diversity of the compound libraries. By comparing the similarity of the scaffold architectures presented in MDDR, ACD and TCMCD, structural overlaps were observed not only between MDDR and TCMCD but also between MDDR and ACD. Finally, Tree Maps were used to cluster the Level 1 scaffolds of the Scaffold Tree and visualize the scaffold space of the three datasets. The analysis of the scaffold architectures of MDDR, ACD and TCMCD shows that, on average, drug-like molecules in MDDR have the highest diversity while natural compounds in TCMCD have the highest complexity. According to the Tree Maps, it can be observed that the Level 1 scaffolds present in MDDR have higher diversity than those presented in TCMCD and ACD. However, some representative scaffolds in MDDR with high frequency show structural similarities to those in TCMCD and ACD, suggesting that some scaffolds in TCMCD and ACD may be potentially drug-like fragments for fragment-based and de novo drug design.

Data-Driven Derivation of an "Informer Compound Set" for Improved Selection of Active Compounds in High-Throughput Screening.

Science.gov (United States)

Paricharak, Shardul; IJzerman, Adriaan P; Jenkins, Jeremy L; Bender, Andreas; Nigsch, Florian

2016-09-26

Despite the usefulness of high-throughput screening (HTS) in drug discovery, for some systems, low assay throughput or high screening cost can prohibit the screening of large numbers of compounds. In such cases, iterative cycles of screening involving active learning (AL) are employed, creating the need for smaller "informer sets" that can be routinely screened to build predictive models for selecting compounds from the screening collection for follow-up screens. Here, we present a data-driven derivation of an informer compound set with improved predictivity of active compounds in HTS, and we validate its benefit over randomly selected training sets on 46 PubChem assays comprising at least 300,000 compounds and covering a wide range of assay biology. The informer compound set showed improvement in BEDROC(α = 100), PRAUC, and ROCAUC values averaged over all assays of 0.024, 0.014, and 0.016, respectively, compared to randomly selected training sets, all with paired t-test p-values agnostic fashion. This approach led to a consistent improvement in hit rates in follow-up screens without compromising scaffold retrieval. The informer set is adjustable in size depending on the number of compounds one intends to screen, as performance gains are realized for sets with more than 3,000 compounds, and this set is therefore applicable to a variety of situations. Finally, our results indicate that random sampling may not adequately cover descriptor space, drawing attention to the importance of the composition of the training set for predicting actives.

Thermal conductivity of REIn3 compounds

International Nuclear Information System (INIS)

Mucha, J

2006-01-01

The results of measurements of the thermal conductivity of REIn 3 (RE Pr, Nd, Dy, Ho, Tm) compounds as a function of the temperature in the interval 4-300 K in the absence and in the presence of an external magnetic field of 8 T are presented. Except for PRIn 3 all the compounds are antiferromagnetic. YIn 3 was also measured as a reference compound. The results were analysed in the paramagnetic phase, where an influence of the crystalline electric field on the thermal conductivity was found. Drastic changes in the thermal conductivity were observed and analysed in the vicinity of the Neel temperature and in the antiferromagnetic phases of the compounds. Below the Neel temperature an additional magnon contribution to the thermal conductivity was separated out

Compound Option Pricing under Fuzzy Environment

Directory of Open Access Journals (Sweden)

Xiandong Wang

2014-01-01

Full Text Available Considering the uncertainty of a financial market includes two aspects: risk and vagueness; in this paper, fuzzy sets theory is applied to model the imprecise input parameters (interest rate and volatility. We present the fuzzy price of compound option by fuzzing the interest and volatility in Geske’s compound option pricing formula. For each α, the α-level set of fuzzy prices is obtained according to the fuzzy arithmetics and the definition of fuzzy-valued function. We apply a defuzzification method based on crisp possibilistic mean values of the fuzzy interest rate and fuzzy volatility to obtain the crisp possibilistic mean value of compound option price. Finally, we present a numerical analysis to illustrate the compound option pricing under fuzzy environment.

Structure Modification of an Active Azo-Compound as a Route to New Antimicrobial Compounds

Directory of Open Access Journals (Sweden)

Simona Concilio

2017-05-01

Full Text Available Some novel (phenyl-diazenylphenols 3a–g were designed and synthesized to be evaluated for their antimicrobial activity. A previously synthesized molecule, active against bacteria and fungi, was used as lead for modifications and optimization of the structure, by introduction/removal or displacement of hydroxyl groups on the azobenzene rings. The aim of this work was to evaluate the consequent changes of the antimicrobial activity and to validate the hypothesis that, for these compounds, a plausible mechanism could involve an interaction with protein receptors, rather than an interaction with membrane. All newly synthesized compounds were analyzed by 1H-NMR, DSC thermal analysis and UV-Vis spectroscopy. The in vitro minimal inhibitory concentrations (MIC of each compound was determined against Gram-positive and Gram-negative bacteria and Candida albicans. Compounds 3b and 3g showed the highest activity against S. aureus and C. albicans, with remarkable MIC values of 10 µg/mL and 3 µg/mL, respectively. Structure-activity relationship studies were capable to rationalize the effect of different substitutions on the phenyl ring of the azobenzene on antimicrobial activity.

Magnesium compounds

Science.gov (United States)

Kramer, D.A.

2007-01-01

Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

Prediction model of biocrude yield and nitrogen heterocyclic compounds analysis by hydrothermal liquefaction of microalgae with model compounds.

Science.gov (United States)

Sheng, Lili; Wang, Xin; Yang, Xiaoyi

2018-01-01

The model of biocrude yield and the nitrogen heterocyclic compounds in biocrude of microalgae hydrothermal liquefaction are two of the most concerned issues in this field at present. This study explored a hydrothermal liquefaction biocrude yield model involved in the interaction among biochemical compounds in microalgae and analysed nitrogen heterocyclic compounds in biocrude. The model compound (castor oil, soya protein and glucose) and Nanochloropsis were liquefied at 280°C for 1h. The products were analyzed by GC-MS, element analysis and FTIR. The results suggested that interactions among different components in microalgae enhanced biocrude yield. The biocrude yield prediction model involved cross-interactions performed more accurate than previous models.When the ratio of protein and carbohydrate around 3, the cross-interaction and nitrogen heterocyclic compounds in biocrude would both reach the highest extent. Copyright © 2017. Published by Elsevier Ltd.

Separation of compounds differing in isotopic composition

International Nuclear Information System (INIS)

Sievers, R.E.; Brooks, J.J.

1975-01-01

Compounds differing in isotopic composition are separated by introducing a mixture of the compounds into a chromatographic column containing a lanthanide chelate as a stationary phase and eluting from the column a fraction that is at least enriched with one of the compounds of the mixture. (U.S.)

Compound Wiretap Channels

Directory of Open Access Journals (Sweden)

Kramer Gerhard

2009-01-01

Full Text Available Abstract This paper considers the compound wiretap channel, which generalizes Wyner's wiretap model to allow the channels to the (legitimate receiver and to the eavesdropper to take a number of possible states. No matter which states occur, the transmitter guarantees that the receiver decodes its message and that the eavesdropper is kept in full ignorance about the message. The compound wiretap channel can also be viewed as a multicast channel with multiple eavesdroppers, in which the transmitter sends information to all receivers and keeps the information secret from all eavesdroppers. For the discrete memoryless channel, lower and upper bounds on the secrecy capacity are derived. The secrecy capacity is established for the degraded channel and the semideterministic channel with one receiver. The parallel Gaussian channel is further studied. The secrecy capacity and the secrecy degree of freedom ( are derived for the degraded case with one receiver. Schemes to achieve the for the case with two receivers and two eavesdroppers are constructed to demonstrate the necessity of a prefix channel in encoder design. Finally, the multi-antenna (i.e., MIMO compound wiretap channel is studied. The secrecy capacity is established for the degraded case and an achievable is given for the general case.

Thermoelectric performance of tellurium-reduced quaternary p-type lead–chalcogenide composites

International Nuclear Information System (INIS)

Aminorroaya Yamini, Sima; Wang, Heng; Gibbs, Zachary M.; Pei, Yanzhong; Mitchell, David R.G.; Dou, Shi Xue; Snyder, G. Jeffrey

2014-01-01

Graphical abstract: - Abstract: A long-standing technological challenge to the widespread application of thermoelectric generators is obtaining high-performance thermoelectric materials from abundant elements. Intensive study on PbTe alloys has resulted in a high figure of merit for the single-phase ternary PbTe–PbSe system through band structure engineering, and the low thermal conductivity achieved due to nanostructuring leads to high thermoelectric performance for ternary PbTe–PbS compounds. Recently, the single-phase p-type quaternary PbTe–PbSe–PbS alloys have been shown to provide thermoelectric performance superior to the binary and ternary lead chalcogenides. This occurs via tuning of the band structure and from an extraordinary low thermal conductivity resulting from high-contrast atomic mass solute atoms. Here, we present the thermoelectric efficiency of nanostructured p-type quaternary PbTe–PbSe–PbS composites and compare the results with corresponding single-phase quaternary lead chalcogenide alloys. We demonstrate that the very low lattice thermal conductivity achieved is attributed to phonon scattering at high-contrast atomic mass solute atoms rather than from the contribution of secondary phases. This results in a thermoelectric efficiency of ∼1.4 over a wide temperature range (650–850 K) in a p-type quaternary (PbTe) 0.65 (PbSe) 0.1 (PbS) 0.25 composite that is lower than that of single-phase (PbTe) 0.85 (PbSe) 0.1 (PbS) 0.05 alloy without secondary phases

Compound-specific radiocarbon analysis - Analytical challenges and applications

Science.gov (United States)

Mollenhauer, G.; Rethemeyer, J.

2009-01-01

Within the last decades, techniques have become available that allow measurement of isotopic compositions of individual organic compounds (compound-specific isotope measurements). Most often the carbon isotopic composition of these compounds is studied, including stable carbon (δ13C) and radiocarbon (Δ14C) measurements. While compound-specific stable carbon isotope measurements are fairly simple, and well-established techniques are widely available, radiocarbon analysis of specific organic compounds is a more challenging method. Analytical challenges include difficulty obtaining adequate quantities of sample, tedious and complicated laboratory separations, the lack of authentic standards for measuring realistic processing blanks, and large uncertainties in values of Δ14C at small sample sizes. The challenges associated with sample preparation for compound-specific Δ14C measurements will be discussed in this contribution. Several years of compound-specific radiocarbon analysis have revealed that in most natural samples, purified organic compounds consist of heterogeneous mixtures of the same compound. These mixtures could derive from multiple sources, each having a different initial reservoir age but mixed in the same terminal reservoir, from a single source but mixed after deposition, or from a prokaryotic organism using variable carbon sources including mobilization of ancient carbon. These processes not only represent challenges to the interpretation of compound-specific radiocarbon data, but provide unique tools for the understanding of biogeochemical and sedimentological processes influencing the preserved organic geochemical records in marine sediments. We will discuss some examples where compound-specific radiocarbon analysis has provided new insights for the understanding of carbon source utilization and carbon cycling.

Separation of compounds differing in isotopic composition

International Nuclear Information System (INIS)

Sievers, R.E.; Brooks, J.J.

1976-01-01

Compounds differing in isotopic composition are separated by introducing a mixture of the compounds into a chromatographic column containing a lanthanide chelate as a stationary phase and eluting from the column a fraction which is at least enriched with one of the compounds of the mixture. 17 claims, no drawings

Mini-review: Molecular mechanisms of antifouling compounds

KAUST Repository

Qian, Pei-Yuan

2013-04-01

Various antifouling (AF) coatings have been developed to protect submerged surfaces by deterring the settlement of the colonizing stages of fouling organisms. A review of the literature shows that effective AF compounds with specific targets are ones often considered non-toxic. Such compounds act variously on ion channels, quorum sensing systems, neurotransmitters, production/release of adhesive, and specific enzymes that regulate energy production or primary metabolism. In contrast, AF compounds with general targets may or may not act through toxic mechanisms. These compounds affect a variety of biological activities including algal photosynthesis, energy production, stress responses, genotoxic damage, immunosuppressed protein expression, oxidation, neurotransmission, surface chemistry, the formation of biofilms, and adhesive production/release. Among all the targets, adhesive production/release is the most common, possibly due to a more extensive research effort in this area. Overall, the specific molecular targets and the molecular mechanisms of most AF compounds have not been identified. Thus, the information available is insufficient to draw firm conclusions about the types of molecular targets to be used as sensitive biomarkers for future design and screening of compounds with AF potential. In this review, the relevant advantages and disadvantages of the molecular tools available for studying the molecular targets of AF compounds are highlighted briefly and the molecular mechanisms of the AF compounds, which are largely a source of speculation in the literature, are discussed. © 2013 Copyright Taylor and Francis Group, LLC.

Polymer compound

NARCIS (Netherlands)

1995-01-01

A Polymer compound comprising a polymer (a) that contains cyclic imidesgroups and a polymer (b) that contains monomer groups with a 2,4-diamino-1,3,5-triazine side group. According to the formula (see formula) whereby themole percentage ratio of the cyclic imides groups in the polymer compoundwith

Butyl Rubber: Compound Development and Characterization

National Research Council Canada - National Science Library

Sloan, James

2000-01-01

...), to develop the standard butyl rubber compound. The strategy of this work was to compound- and compression-mold high-quality, uniform butyl rubber experimental sheets and to evaluate their cure properties, mechanical properties...

Radioactive decay and labeled compounds

International Nuclear Information System (INIS)

Anon.

1991-01-01

This chapter on radioactive decay and labeled compounds has numerous intext equations and worked, sample problems. Topics covered include the following: terms and mathematics of radioactive decay; examples of calculations; graphs of decay equations; radioactivity or activity; activity measurements; activity decay; half-life determinations; labeled compounds. A 20 problem set is also included. 1 ref., 4 figs., 1 tab

Microbial growth on C1 compounds: proceedings

International Nuclear Information System (INIS)

Crawford, R.L.; Hanson, R.S.

1984-01-01

This book contains individual papers prepared for the 4th International Symposium on Microbial Growth on One Carbon Compounds. Individual reports were abstracted and indexed for EDB. Topics presented were in the areas of the physiology and biochemistry of autotraps, physiology and biochemistry of methylotrophs and methanotrops, physiology and biochemistry of methanogens, genetics of microbes that use C 1 compounds, taxonomy and ecology of microbes tht grow on C 1 compounds, applied aspects of microbes that grow on C 1 compounds, and new directions in C 1 metabolism. (DT)

IRIS Toxicological Review of Thallium and Compounds ...

Science.gov (United States)

Thallium compounds are used in the semiconductor industry, the manufacture of optic lenses and low-melting glass, low-temperature thermometers, alloys, electronic devices, mercury lamps, fireworks, and imitation germs, and clinically as an imaging agent in the diagnosis of certain tumors. EPA's assessment of noncancer health effects and carcinogenic potential of thallium compounds was last prepared and added to the IRIS database between 1988 and 1990. The IRIS program is preparing an assessment that will incorporate current health effects information available for thallium and compounds, and current risk assessment methods. The IRIS assessment for thallium compounds will consist of a Toxicological Review and IRIS Summary. The Toxicological Review is a critical review of the physiochemical and toxicokinetic properties of a chemical, and its toxicity in humans and experimental systems. The assessment will present reference values for the noncancer effects of thallium compounds (RfD and Rfc), and a cancer assessment. The Toxicological Review and IRIS Summary have been subject to Agency review, Interagency review, and external scientific peer review. The final product will reflect the Agency opinion on the overall toxicity of thallium and compounds. EPA is undertaking an Integrated Risk Information System (IRIS) health assessment for thallium and compounds. IRIS is an EPA database containing Agency scientific positions on potential adverse human health effec

Spin polarization in rare earth intermetallic compounds

International Nuclear Information System (INIS)

Steenwijk, F.J. van

1976-01-01

In this thesis the results of Moessbauer experiments performed on a series of intermetallic compounds of europium and gadolinium are reported. For each of these compounds the magnetic hyperfine field, the electric field gradient at the nuclear site and the isomer shift were determined. For most of the compounds the magnetic ordering temperature was also measured. For some of the europium compounds (e.g. EuAu 5 , EuAg 5 , and EuCu 5 ) it could be derived from the measurements that the easy direction of magnetization falls along the crystallographic c-axis. In a number of compounds (e.g. EuCu 5 , EuZn 5 , EuAu 2 and GdCu 5 ), the various contributions to the magnetic hyperfine field were disentangled by the investigation of suitable pseudobinary compounds that are dilute in Eu. The neighbour contribution Hsub(N) and the paramagnetic Curie temperature thetasub(p) were compared with each other in terms of the RKKY model for EuCu 5 and GdCu 5 . Since the correspondence was found to be poor it was concluded that the magnetic behaviour in these compounds cannot be described by a simple free electron picture as is the basis for the RKKY model

Prediction of intermetallic compounds

International Nuclear Information System (INIS)

Burkhanov, Gennady S; Kiselyova, N N

2009-01-01

The problems of predicting not yet synthesized intermetallic compounds are discussed. It is noted that the use of classical physicochemical analysis in the study of multicomponent metallic systems is faced with the complexity of presenting multidimensional phase diagrams. One way of predicting new intermetallics with specified properties is the use of modern processing technology with application of teaching of image recognition by the computer. The algorithms used most often in these methods are briefly considered and the efficiency of their use for predicting new compounds is demonstrated.

Food applications of natural antimicrobial compounds

Science.gov (United States)

Lucera, Annalisa; Costa, Cristina; Conte, Amalia; Del Nobile, Matteo A.

2012-01-01

In agreement with the current trend of giving value to natural and renewable resources, the use of natural antimicrobial compounds, particularly in food and biomedical applications, becomes very frequent. The direct addition of natural compounds to food is the most common method of application, even if numerous efforts have been made to find alternative solutions to the aim of avoiding undesirable inactivation. Dipping, spraying, and coating treatment of food with active solutions are currently applied to product prior to packaging as valid options. The aim of the current work is to give an overview on the use of natural compounds in food sector. In particular, the review will gather numerous case-studies of meat, fish, dairy products, minimally processed fruit and vegetables, and cereal-based products where these compounds found application. PMID:23060862

Food applications of natural antimicrobial compounds.

Science.gov (United States)

Lucera, Annalisa; Costa, Cristina; Conte, Amalia; Del Nobile, Matteo A

2012-01-01

In agreement with the current trend of giving value to natural and renewable resources, the use of natural antimicrobial compounds, particularly in food and biomedical applications, becomes very frequent. The direct addition of natural compounds to food is the most common method of application, even if numerous efforts have been made to find alternative solutions to the aim of avoiding undesirable inactivation. Dipping, spraying, and coating treatment of food with active solutions are currently applied to product prior to packaging as valid options. The aim of the current work is to give an overview on the use of natural compounds in food sector. In particular, the review will gather numerous case-studies of meat, fish, dairy products, minimally processed fruit and vegetables, and cereal-based products where these compounds found application.

Food applications of natural antimicrobial compounds

Directory of Open Access Journals (Sweden)

Matteo Alessandro eDel Nobile

2012-08-01

Full Text Available In agreement with the current trend of giving value to natural and renewable resources, the use of natural antimicrobial compounds, particularly in food and biomedical applications, becomes very frequent. The direct addition of natural compounds to food is the most common method of application, even if numerous efforts have been made to find alternative solutions to the aim of avoiding undesirable inactivation. Dipping, spraying and coating treatment of food with active solutions are currently applied to product prior to packaging as valid options. The aim of the current work is to give an overview on the use of natural compounds in food sector. In particular, the review will gather numerous case-studies of meat, fish, dairy products, minimally processed fruit and vegetables and cereal-based products where these compounds found application.

Biochemical studies on certain biologically active nitrogenous compounds

International Nuclear Information System (INIS)

Abdel kader, S.M.; El Sayed, M.M.; El Malt, E.A.; Shaker, E.S.; Abdel Aziz, H.G.

2010-01-01

Certain biologically active nitrogenous compounds such as alkaloids are widely distributed in many wild and medicinal plants such as peganum harmala L. (Phycophyllaceae). However, less literature cited on the natural compounds was extracted from the aerial parts of this plant; therefore this study was conducted on harmal leaves using several solvents. Data indicated that methanol extract was the inhibitoriest effect against some pathogenic bacteria, particularly Streptococcus pyogenus. Chromatographic separation illustrated that presence of four compounds; the most active one was the third compound (3). Elementary analysis (C, H, N) revealed that the primary chemical structure of the active antibacterial compound (C3) was: C17 H21 N3 O7 S with molecular weight 411. Spectroscopic analysis proved that coninical structure was = 1- thioformyl, 8?- D glucoperanoside- Bis- 2, 3 dihydroisopyridino pyrrol. This new compound is represented as a noval ?- carboline alkaloid compound

Multi-Phase Equilibrium and Solubilities of Aromatic Compounds and Inorganic Compounds in Sub- and Supercritical Water: A Review.

Science.gov (United States)

Liu, Qinli; Ding, Xin; Du, Bowen; Fang, Tao

2017-11-02

Supercritical water oxidation (SCWO), as a novel and efficient technology, has been applied to wastewater treatment processes. The use of phase equilibrium data to optimize process parameters can offer a theoretical guidance for designing SCWO processes and reducing the equipment and operating costs. In this work, high-pressure phase equilibrium data for aromatic compounds+water systems and inorganic compounds+water systems are given. Moreover, thermodynamic models, equations of state (EOS) and empirical and semi-empirical approaches are summarized and evaluated. This paper also lists the existing problems of multi-phase equilibria and solubility studies on aromatic compounds and inorganic compounds in sub- and supercritical water.

Genetic effects of organic mercury compounds

Energy Technology Data Exchange (ETDEWEB)

Ramel, C

1967-01-01

Studies on the genetic and developmental effects of organic mercury compounds on lilies, drosophila, and ice were carried out. It was found that chromosomal and developmental abnormalities were correlated with the administration of mercury compounds.

Integrated modelling of two xenobiotic organic compounds

DEFF Research Database (Denmark)

Lindblom, Erik Ulfson; Gernaey, K.V.; Henze, Mogens

2006-01-01

This paper presents a dynamic mathematical model that describes the fate and transport of two selected xenobiotic organic compounds (XOCs) in a simplified representation. of an integrated urban wastewater system. A simulation study, where the xenobiotics bisphenol A and pyrene are used as reference...... compounds, is carried out. Sorption and specific biological degradation processes are integrated with standardised water process models to model the fate of both compounds. Simulated mass flows of the two compounds during one dry weather day and one wet weather day are compared for realistic influent flow...... rate and concentration profiles. The wet weather day induces resuspension of stored sediments, which increases the pollutant load on the downstream system. The potential of the model to elucidate important phenomena related to origin and fate of the model compounds is demonstrated....

UV-absorbing compounds in subarctic herbarium bryophytes

Energy Technology Data Exchange (ETDEWEB)

Huttunen, S. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland)]. E-mail: satu.huttunen@oulu.fi; Lappalainen, N.M. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland); Turunen, J. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland)

2005-01-01

The UV-B-absorbing compounds of herbarium specimens of 10 subarctic bryophyte species collected during the years 1926-1996 and available at the Botanical Museum, University of Oulu, were studied. We studied whether herbarium specimens reflect changes in the past radiation climate through their methanol-extractable compounds. The order of gametophytes based on the average amount of total compounds (sum of A{sub 280-320nm}) per mass from the lowest to the highest was Polytrichum commune, Pleurozium schreberi, Hylocomium splendens, Sphagnum angustifolium, Dicranum scoparium, Funaria hygrometrica, Sphagnum fuscum, Sphagnum warnstorfii, Sphagnum capillifolium and Polytrichastrum alpinum, and the amount of UV-B-absorbing compounds per specific surface area correlated with the summertime daily global radiation and latitude. P. alpinum, F. hygrometrica and three Sphagnum species seem to be good indicators for further studies. The amount of UV-B-absorbing compounds revealed no significant trends from the 1920s till the 1990s, with the exception of S. capillifolium, which showed a significant decreasing trend. - UV-B-absorbing compounds in subarctic herbarium bryophytes indicate the radiation climate of the collecting site and time.

UV-absorbing compounds in subarctic herbarium bryophytes

International Nuclear Information System (INIS)

Huttunen, S.; Lappalainen, N.M.; Turunen, J.

2005-01-01

The UV-B-absorbing compounds of herbarium specimens of 10 subarctic bryophyte species collected during the years 1926-1996 and available at the Botanical Museum, University of Oulu, were studied. We studied whether herbarium specimens reflect changes in the past radiation climate through their methanol-extractable compounds. The order of gametophytes based on the average amount of total compounds (sum of A 280-320nm ) per mass from the lowest to the highest was Polytrichum commune, Pleurozium schreberi, Hylocomium splendens, Sphagnum angustifolium, Dicranum scoparium, Funaria hygrometrica, Sphagnum fuscum, Sphagnum warnstorfii, Sphagnum capillifolium and Polytrichastrum alpinum, and the amount of UV-B-absorbing compounds per specific surface area correlated with the summertime daily global radiation and latitude. P. alpinum, F. hygrometrica and three Sphagnum species seem to be good indicators for further studies. The amount of UV-B-absorbing compounds revealed no significant trends from the 1920s till the 1990s, with the exception of S. capillifolium, which showed a significant decreasing trend. - UV-B-absorbing compounds in subarctic herbarium bryophytes indicate the radiation climate of the collecting site and time

Degradation of based EPDM dielectric compounds

International Nuclear Information System (INIS)

Galembeck, F.

1988-01-01

The stability of an EPDM compound used as power cables insulation was studied under various conditions of thermal stress. Changes in the dielectric and tensile strenght of the samples were found after the aging. Samples of the EPDM compound were analysed by spectroscopic (photoacoustic, IR) methods showing alterations in its components: Pb 3 O 4 is reduced to PbO and exsuded paraffin is oxidized. Methane is prevalent in the gaseous mixture released by the heated compound and analysed by Gas Chromatography. (author) [pt

Compounds in dictionary-based Cross-language information retrieval_revised

Directory of Open Access Journals (Sweden)

2002-01-01

Full Text Available Compound words form an important part of natural language. From the cross-lingual information retrieval (CLIR point of view it is important that many natural languages are highly productive with compounds, and translation resources cannot include entries for all compounds. Also, compounds are often content bearing words in a sentence. In Swedish, German and Finnish roughly one tenth of the words in a text prepared for information retrieval purposes are compounds. Important research questions concerning compound handling in dictionary-based cross-language information retrieval are 1 compound splitting into components, 2 normalisation of components, 3 translation of components and 4 query structuring for compounds and their components in the target language. The impact of compound processing on the performance of the cross-language information retrieval process is evaluated in this study and the results indicate that the effect is clearly positive.

Medical Applications and Toxicities of Gallium Compounds

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Christopher R. Chitambar

2010-05-01

Full Text Available Over the past two to three decades, gallium compounds have gained importance in the fields of medicine and electronics. In clinical medicine, radioactive gallium and stable gallium nitrate are used as diagnostic and therapeutic agents in cancer and disorders of calcium and bone metabolism. In addition, gallium compounds have displayed anti-inflammatory and immunosuppressive activity in animal models of human disease while more recent studies have shown that gallium compounds may function as antimicrobial agents against certain pathogens. In a totally different realm, the chemical properties of gallium arsenide have led to its use in the semiconductor industry. Gallium compounds, whether used medically or in the electronics field, have toxicities. Patients receiving gallium nitrate for the treatment of various diseases may benefit from such therapy, but knowledge of the therapeutic index of this drug is necessary to avoid clinical toxicities. Animals exposed to gallium arsenide display toxicities in certain organ systems suggesting that environmental risks may exist for individuals exposed to this compound in the workplace. Although the arsenic moiety of gallium arsenide appears to be mainly responsible for its pulmonary toxicity, gallium may contribute to some of the detrimental effects in other organs. The use of older and newer gallium compounds in clinical medicine may be advanced by a better understanding of their mechanisms of action, drug resistance, pharmacology, and side-effects. This review will discuss the medical applications of gallium and its mechanisms of action, the newer gallium compounds and future directions for development, and the toxicities of gallium compounds in current use.

Compound semiconductor device physics

CERN Document Server

Tiwari, Sandip

2013-01-01

This book provides one of the most rigorous treatments of compound semiconductor device physics yet published. A complete understanding of modern devices requires a working knowledge of low-dimensional physics, the use of statistical methods, and the use of one-, two-, and three-dimensional analytical and numerical analysis techniques. With its systematic and detailed**discussion of these topics, this book is ideal for both the researcher and the student. Although the emphasis of this text is on compound semiconductor devices, many of the principles discussed will also be useful to those inter

A survey of synthetic and natural phytotoxic compounds and phytoalexins as potential antimalarial compounds.

Science.gov (United States)

Bajsa, Joanna; Singh, Kshipra; Nanayakkara, Dhammika; Duke, Stephen Oscar; Rimando, Agnes Mamaril; Evidente, Antonio; Tekwani, Babu Lal

2007-09-01

The apicomplexan parasites pathogens such as Plasmodium spp. possess an apicoplast, a plastid organelle similar to those of plants. The apicoplast has some essential plant-like metabolic pathways and processes, making these parasites susceptible to inhibitors of these functions. The main objective of this paper is to determine if phytotoxins with plastid target sites are more likely to be good antiplasmodial compounds than are those with other modes of action. The antiplasmodial activities of some compounds with established phytotoxic action were determined in vitro on a chloroquine (CQ) sensitive (D6, Sierra Leone) strain of Plasmodium falciparum. In this study, we provide in vitro activities of almost 50 such compounds, as well as a few phytoalexins against P. falciparum. Endothall, anisomycin, and cerulenin had sufficient antiplasmodial action to be considered as new lead antimalarial structures. Some derivatives of fusicoccin possessed markedly improved antiplasmodial action than the parent compound. Our results suggest that phytotoxins with plastid targets may not necessarily be better antiplasmodials than those that act at other molecular sites. The herbicides, phytotoxins and the phytoalexins reported here with significant antiplasmodial activity may be useful probes for identification of new antimalarial drug targets and may also be used as new lead structures for new antiplasmodial drug discovery.

Characterization of ToxCast Phase II compounds disruption of ...

Science.gov (United States)

The development of multi-well microelectrode array (mwMEA) systems has increased in vitro screening throughput making them an effective method to screen and prioritize large sets of compounds for potential neurotoxicity. In the present experiments, a multiplexed approach was used to determine compound effects on both neural function and cell health in primary cortical networks grown on mwMEA plates following exposure to ~1100 compounds from EPA’s Phase II ToxCast libraries. On DIV 13, baseline activity (40 min) was recorded prior to exposure to each compound at 40 µM. DMSO and the GABAA antagonist bicuculline (BIC) were included as controls on each mwMEA plate. Changes in spontaneous network activity (mean firing rate; MFR) and cell viability (lactate dehydrogenase; LDH and CellTiter Blue; CTB) were assessed within the same well following compound exposure. Activity calls (“hits”) were established using the 90th and 20th percentiles of the compound-induced change in MFR (medians of triplicates) across all tested compounds; compounds above (top 10% of compounds increasing MFR), and below (bottom 20% of compounds decreasing MFR) these thresholds, respectively were considered hits. MFR was altered beyond one of these thresholds by 322 compounds. Four compound categories accounted for 66% of the hits, including: insecticides (e.g. abamectin, lindane, prallethrin), pharmaceuticals (e.g. haloperidol, reserpine), fungicides (e.g. hexaconazole, fenamidone), and h

Diazo Compounds: Versatile Tools for Chemical Biology.

Science.gov (United States)

Mix, Kalie A; Aronoff, Matthew R; Raines, Ronald T

2016-12-16

Diazo groups have broad and tunable reactivity. That and other attributes endow diazo compounds with the potential to be valuable reagents for chemical biologists. The presence of diazo groups in natural products underscores their metabolic stability and anticipates their utility in a biological context. The chemoselectivity of diazo groups, even in the presence of azido groups, presents many opportunities. Already, diazo compounds have served as chemical probes and elicited novel modifications of proteins and nucleic acids. Here, we review advances that have facilitated the chemical synthesis of diazo compounds, and we highlight applications of diazo compounds in the detection and modification of biomolecules.

Electronic structure of A15 compounds

International Nuclear Information System (INIS)

Pickett, W.E.

1980-01-01

For the past twenty-five years compounds with the A15 crystal structure have dominated the class of high temperature superconductors. The crystal structure of an A15 compound A 3 B is cubic (space group O/sub h/ 3 ). However, the site symmetry (D/sub 2d/) of the A atoms is much lower than cubic, an unusual occurrence in cubic binary compounds. Variations on this theme have supplied the basis of many theoretical models of the anomalous temperature (T) dependence of normal state properties and the low temperature cubic reversible tetragonal structural transformations which accompany high values of T/sub c/ in A15 compounds. In this paper results of self-consistent pseudopotential band structure calculations are used to assess some important aspects of the unique and unusual behavior in A15 compounds: (1) the role of the B atom in determining the overall electronic structure will be shown to be important; (2) the effect of the low site symmetry of the A atom on the charge density and potential will be assessed; and (3) the bonding will be shown to be metallic-covalent with no significant A-B charge transfer

Atmospheric Chemistry of Micrometeoritic Organic Compounds

Science.gov (United States)

Kress, M. E.; Belle, C. L.; Pevyhouse, A. R.; Iraci, L. T.

2011-01-01

Micrometeorites approx.100 m in diameter deliver most of the Earth s annual accumulation of extraterrestrial material. These small particles are so strongly heated upon atmospheric entry that most of their volatile content is vaporized. Here we present preliminary results from two sets of experiments to investigate the fate of the organic fraction of micrometeorites. In the first set of experiments, 300 m particles of a CM carbonaceous chondrite were subject to flash pyrolysis, simulating atmospheric entry. In addition to CO and CO2, many organic compounds were released, including functionalized benzenes, hydrocarbons, and small polycyclic aromatic hydrocarbons. In the second set of experiments, we subjected two of these compounds to conditions that simulate the heterogeneous chemistry of Earth s upper atmosphere. We find evidence that meteor-derived compounds can follow reaction pathways leading to the formation of more complex organic compounds.

Antiviral Screening of Multiple Compounds against Ebola Virus.

Science.gov (United States)

Dowall, Stuart D; Bewley, Kevin; Watson, Robert J; Vasan, Seshadri S; Ghosh, Chandradhish; Konai, Mohini M; Gausdal, Gro; Lorens, James B; Long, Jason; Barclay, Wendy; Garcia-Dorival, Isabel; Hiscox, Julian; Bosworth, Andrew; Taylor, Irene; Easterbrook, Linda; Pitman, James; Summers, Sian; Chan-Pensley, Jenny; Funnell, Simon; Vipond, Julia; Charlton, Sue; Haldar, Jayanta; Hewson, Roger; Carroll, Miles W

2016-10-27

In light of the recent outbreak of Ebola virus (EBOV) disease in West Africa, there have been renewed efforts to search for effective antiviral countermeasures. A range of compounds currently available with broad antimicrobial activity have been tested for activity against EBOV. Using live EBOV, eighteen candidate compounds were screened for antiviral activity in vitro. The compounds were selected on a rational basis because their mechanisms of action suggested that they had the potential to disrupt EBOV entry, replication or exit from cells or because they had displayed some antiviral activity against EBOV in previous tests. Nine compounds caused no reduction in viral replication despite cells remaining healthy, so they were excluded from further analysis (zidovudine; didanosine; stavudine; abacavir sulphate; entecavir; JB1a; Aimspro; celgosivir; and castanospermine). A second screen of the remaining compounds and the feasibility of appropriateness for in vivo testing removed six further compounds (ouabain; omeprazole; esomeprazole; Gleevec; D-LANA-14; and Tasigna). The three most promising compounds (17-DMAG; BGB324; and NCK-8) were further screened for in vivo activity in the guinea pig model of EBOV disease. Two of the compounds, BGB324 and NCK-8, showed some effect against lethal infection in vivo at the concentrations tested, which warrants further investigation. Further, these data add to the body of knowledge on the antiviral activities of multiple compounds against EBOV and indicate that the scientific community should invest more effort into the development of novel and specific antiviral compounds to treat Ebola virus disease.

Antiviral Screening of Multiple Compounds against Ebola Virus

Directory of Open Access Journals (Sweden)

Stuart D. Dowall

2016-10-01

Full Text Available In light of the recent outbreak of Ebola virus (EBOV disease in West Africa, there have been renewed efforts to search for effective antiviral countermeasures. A range of compounds currently available with broad antimicrobial activity have been tested for activity against EBOV. Using live EBOV, eighteen candidate compounds were screened for antiviral activity in vitro. The compounds were selected on a rational basis because their mechanisms of action suggested that they had the potential to disrupt EBOV entry, replication or exit from cells or because they had displayed some antiviral activity against EBOV in previous tests. Nine compounds caused no reduction in viral replication despite cells remaining healthy, so they were excluded from further analysis (zidovudine; didanosine; stavudine; abacavir sulphate; entecavir; JB1a; Aimspro; celgosivir; and castanospermine. A second screen of the remaining compounds and the feasibility of appropriateness for in vivo testing removed six further compounds (ouabain; omeprazole; esomeprazole; Gleevec; D-LANA-14; and Tasigna. The three most promising compounds (17-DMAG; BGB324; and NCK-8 were further screened for in vivo activity in the guinea pig model of EBOV disease. Two of the compounds, BGB324 and NCK-8, showed some effect against lethal infection in vivo at the concentrations tested, which warrants further investigation. Further, these data add to the body of knowledge on the antiviral activities of multiple compounds against EBOV and indicate that the scientific community should invest more effort into the development of novel and specific antiviral compounds to treat Ebola virus disease.

Antibacterial Compounds from Red Seaweeds (Rhodophyta

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Noer Kasanah

2015-07-01

Full Text Available Seaweeds produce great variety of metabolites benefit for human. Red seaweeds (Rhodophyta are well known as producer of phycocolloids such agar, agarose, carragenan and great variety of secondary metabolites. This review discusses the red algal secondary metabolites with antibacterial activity. The chemical constituents of red algae are steroid, terpenoid, acetogenin and dominated by halogenated compounds mainly brominated compounds. Novel compounds with intriguing skeleton are also reported such as bromophycolides and neurymenolides. In summary, red seaweeds are potential sources for antibacterial agents and can serve as lead in synthesis of new natural medicines.

Antifouling Compounds from Marine Macroalgae.

Science.gov (United States)

Dahms, Hans Uwe; Dobretsov, Sergey

2017-08-28

Marine macroalgae produce a wide variety of biologically-active metabolites that have been developed into commercial products, such as antibiotics, immunosuppressive, anti-inflammatory, cytotoxic agents, and cosmetic products. Many marine algae remain clean over longer periods of time, suggesting their strong antifouling potential. Isolation of biogenic compounds and the determination of their structure could provide leads for the development of environmentally-friendly antifouling paints. Isolated substances with potent antifouling activity belong to fatty acids, lipopeptides, amides, alkaloids, lactones, steroids, terpenoids, and pyrroles. It is unclear as yet to what extent symbiotic microorganisms are involved in the synthesis of these compounds. Algal secondary metabolites have the potential to be produced commercially using genetic and metabolic engineering techniques. This review provides an overview of publications from 2010 to February 2017 about antifouling activity of green, brown, and red algae. Some researchers were focusing on antifouling compounds of brown macroalgae, while metabolites of green algae received less attention. Several studies tested antifouling activity against bacteria, microalgae and invertebrates, but in only a few studies was the quorum sensing inhibitory activity of marine macroalgae tested. Rarely, antifouling compounds from macroalgae were isolated and tested in an ecologically-relevant way.

Compound Wiretap Channels

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Shlomo Shamai (Shitz

2009-01-01

Full Text Available This paper considers the compound wiretap channel, which generalizes Wyner's wiretap model to allow the channels to the (legitimate receiver and to the eavesdropper to take a number of possible states. No matter which states occur, the transmitter guarantees that the receiver decodes its message and that the eavesdropper is kept in full ignorance about the message. The compound wiretap channel can also be viewed as a multicast channel with multiple eavesdroppers, in which the transmitter sends information to all receivers and keeps the information secret from all eavesdroppers. For the discrete memoryless channel, lower and upper bounds on the secrecy capacity are derived. The secrecy capacity is established for the degraded channel and the semideterministic channel with one receiver. The parallel Gaussian channel is further studied. The secrecy capacity and the secrecy degree of freedom (s.d.o.f. are derived for the degraded case with one receiver. Schemes to achieve the s.d.o.f. for the case with two receivers and two eavesdroppers are constructed to demonstrate the necessity of a prefix channel in encoder design. Finally, the multi-antenna (i.e., MIMO compound wiretap channel is studied. The secrecy capacity is established for the degraded case and an achievable s.d.o.f. is given for the general case.

Compounds interaction on biodegradation of toluene and methyl ...

African Journals Online (AJOL)

MEK) mixtures in a composite bead biofilter was investigated. The biodegradation rate of two compounds in the exponential growth phase and stationary phase for the single compound and two compounds mixing systems was determined.

The Generation of Diazo Compounds in Continuous-Flow.

Science.gov (United States)

Hock, Katharina J; Koenigs, Rene M

2018-03-25

Toxic, cancerogenic and explosive - these attributes are typically associated with diazo compounds. Nonetheless, diazo compounds are nowadays a highly demanded class of reagents for organic synthesis, yet the concerns with regards to safe and scalable transformations of these compounds are still exceptionally high. Lately, the research area of the continuous-flow synthesis of diazo compounds attracted significant interest and a whole variety of protocols for their "on-demand" preparation have been realized to date. This concept article focuses on the recent developments using continuous-flow technologies to access diazo compounds; thus minimizing risks and hazards when working with this particular class of compounds. In this article we discuss these concepts and highlight different pre-requisites to access and to perform downstream functionalization reaction. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurement of loss rates of organic compounds in snow using in situ experiments and isotopically labelled compounds

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Erika von Schneidemesser

2012-07-01

Full Text Available Organic molecular marker compounds are widely used to identify emissions from anthropogenic and biogenic air pollution sources in atmospheric samples and in deposition. Specific organic compounds have been detected in polar regions, but their fate after deposition to snow is poorly characterized. Within this context, a series of exposure experiments were carried out to observe the post-depositional processing of organic compounds under real-world conditions in snow on the surface of the Greenland Ice Sheet, at the Summit research station. Snow was prepared from water spiked with isotopically labelled organic compounds, representative of typical molecular marker compounds emitted from anthropogenic activities. Reaction rate constants and reaction order were determined based on a decrease in concentration to a stable, non-zero, threshold concentration. Fluoranthene-d10, docosane-d46, hexadecanoic acid-d31, docosanoic acid-d43 and azelaic acid-d14 were estimated to have first order loss rates within surface snow with reaction rate constants of 0.068, 0.040, 0.070, 0.067 and 0.047 h−1, respectively. No loss of heptadecane-d36 was observed. Overall, these results suggest that organic contaminants are archived in polar snow, although significant post-depositional losses of specific organic compounds occur. This has implications for the environmental fate of organic contaminants, as well as for ice-core studies that seek to use organic molecular markers to infer past atmospheric loadings, and source emissions.

Pre-compound emission in low-energy heavy-ion interactions

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Kumar Sharma Manoj

2017-01-01

Full Text Available Recent experimental studies have shown the presence of pre-compound emission component in heavy ion reactions at low projectile energy ranging from 4 to 7 MeV/nucleons. In earlier measurements strength of the pre-compound component has been estimated from the difference in forward-backward distributions of emitted particles. Present measurement is a part of an ongoing program on the study of reaction dynamics of heavy ion interactions at low energies aimed at investigating the effect of momentum transfer in compound, precompound, complete and incomplete fusion processes in heavy ion reactions. In the present work on the basis of momentum transfer the measurement of the recoil range distributions of heavy residues has been used to decipher the components of compound and pre-compound emission processes in the fusion of 16O projectile with 159Tb and 169Tm targets. The analysis of recoil range distribution measurements show two distinct linear momentum transfer components corresponding to pre-compound and compound nucleus processes are involved. In order to obtain the mean input angular momentum associated with compound and pre-compound emission processes, an online measurement of the spin distributions of the residues has been performed. The analysis of spin distribution indicate that the mean input angular momentum associated with pre-compound products is found to be relatively lower than that associated with compound nucleus process. The pre-compound components obtained from the present analysis are consistent with those obtained from the analysis of excitation functions.

Pre-compound emission in low-energy heavy-ion interactions

Science.gov (United States)

Sharma, Manoj Kumar; Shuaib, Mohd.; Sharma, Vijay R.; Yadav, Abhishek; Singh, Pushpendra P.; Singh, Devendra P.; Unnati; Singh, B. P.; Prasad, R.

2017-11-01

Recent experimental studies have shown the presence of pre-compound emission component in heavy ion reactions at low projectile energy ranging from 4 to 7 MeV/nucleons. In earlier measurements strength of the pre-compound component has been estimated from the difference in forward-backward distributions of emitted particles. Present measurement is a part of an ongoing program on the study of reaction dynamics of heavy ion interactions at low energies aimed at investigating the effect of momentum transfer in compound, precompound, complete and incomplete fusion processes in heavy ion reactions. In the present work on the basis of momentum transfer the measurement of the recoil range distributions of heavy residues has been used to decipher the components of compound and pre-compound emission processes in the fusion of 16O projectile with 159Tb and 169Tm targets. The analysis of recoil range distribution measurements show two distinct linear momentum transfer components corresponding to pre-compound and compound nucleus processes are involved. In order to obtain the mean input angular momentum associated with compound and pre-compound emission processes, an online measurement of the spin distributions of the residues has been performed. The analysis of spin distribution indicate that the mean input angular momentum associated with pre-compound products is found to be relatively lower than that associated with compound nucleus process. The pre-compound components obtained from the present analysis are consistent with those obtained from the analysis of excitation functions.

Synthesis of novel ionic liquids from lignin-derived compounds

Science.gov (United States)

Socha, Aaron; Singh, Seema; Simmons, Blake A.; Bergeron, Maxime

2017-09-19

Methods and compositions are provided for synthesizing ionic liquids from lignin derived compounds comprising: contacting a starting material comprising lignin with a depolymerization agent to depolymerize the lignin and form a mixture of aldehyde containing compounds; contacting the mixture of aldehyde containing compounds with an amine under conditions suitable to convert the mixture of aldehyde containing compounds to a mixture of amine containing compounds; and contacting the mixture of amine containing compounds with an acid under conditions suitable to form an ammonium salt, thereby preparing the ionic liquid.

Chemistry of tin compounds and environment

International Nuclear Information System (INIS)

Ali, S.; Mazhar, M.; Mahmood, S.; Bhatti, M.H.; Chaudhary, M.A.

1997-01-01

Of the large volume of tin compounds reported in the literature, possible only 100 are commercially important. Tin compounds are a wide variety of purposes such as catalysts, stabilizers for many materials including polymer, biocidal agents, bactericides, insecticides, fungicides, wood preservatives, acaricides and anti fouling agents in paints, anticancer and antitumour agents, ceramic opacifiers, as textile additives, in metal finishing operations, as food additives and in electro conductive coating. All these applications make the environment much exposed to tin contamination. The application of organotin compounds as biocides account for about 30% of total tin consumption suggesting that the main environmental effects are likely to originate from this sector. Diorgano tins and mono-organo tins are used mainly in plastic industry which is the next big source for environmental pollution. In this presentation all environmental aspects of the use of tin compounds and the recommended preventive measures are discussed. (author)

Behaviour of mercury compounds in soil

Energy Technology Data Exchange (ETDEWEB)

Booer, J R

1944-01-01

The uses of inorganic compounds of mercury for the control of plant pests is reviewed, and a summary of the relevant chemical and physical properties of the compounds concerned is given. On chemical evidence a working hypothesis is propounded showing that all compounds may be expected to decompose into metallic mercury. A pot technique is described by means of which a correlation can be obtained between the effective mercury content of a given soil sample and the rate of growth of wheat seedlings. The mathematical treatment of the results is described, and the validity of the pot technique is verified by statistical analysis of results. Using the pot technqiue it is shown that volatilization losses are insignificant but that mercury is slowly rendered ineffective by the formation of mercuric sulphide. The effect of sulphur-reducing bacteria is considered and the influence of Vibrio desulphuricans on mercury is studied in detail. Experimental evidence obtained by the pot technique is produced to show that mercurous chloride slowly decomposes in the soil giving mercury and mercuric chloride, mercuric chloride rapidly decomposes into mercury and mercurous chloride, and other inorganic compounds decompose directly into mercury. The working hypothesis is substantiated in all major aspects. The uses and properties of the organo-mercury compounds are then discussed. Type compounds selected are ethyl mercury phosphate, phenyl mercury acetate and methoxyethyl mercury acetate. Using the pot technique it is shown that the formation of organo-mercury clays takes place and that these clays decompose giving metallic mercury. A mechanism is suggested.

Antiviral lead compounds from marine sponges

KAUST Repository

Sagar, Sunil

2010-10-11

Marine sponges are currently one of the richest sources of pharmacologically active compounds found in the marine environment. These bioactive molecules are often secondary metabolites, whose main function is to enable and/or modulate cellular communication and defense. They are usually produced by functional enzyme clusters in sponges and/or their associated symbiotic microorganisms. Natural product lead compounds from sponges have often been found to be promising pharmaceutical agents. Several of them have successfully been approved as antiviral agents for clinical use or have been advanced to the late stages of clinical trials. Most of these drugs are used for the treatment of human immunodeficiency virus (HIV) and herpes simplex virus (HSV). The most important antiviral lead of marine origin reported thus far is nucleoside Ara-A (vidarabine) isolated from sponge Tethya crypta. It inhibits viral DNA polymerase and DNA synthesis of herpes, vaccinica and varicella zoster viruses. However due to the discovery of new types of viruses and emergence of drug resistant strains, it is necessary to develop new antiviral lead compounds continuously. Several sponge derived antiviral lead compounds which are hopedto be developed as future drugs are discussed in this review. Supply problems are usually the major bottleneck to the development of these compounds as drugs during clinical trials. However advances in the field of metagenomics and high throughput microbial cultivation has raised the possibility that these techniques could lead to the cost-effective large scale production of such compounds. Perspectives on biotechnological methods with respect to marine drug development are also discussed. 2010 by the authors; licensee MDPI.

Organic compounds in radiation fogs in Davis (California)

Science.gov (United States)

Herckes, Pierre; Hannigan, Michael P.; Trenary, Laurie; Lee, Taehyoung; Collett, Jeffrey L.

New stainless steel active fogwater collectors were designed and used in Davis (CA, USA) to collect fogwater for the speciation of organic matter. Organic compounds in fog samples were extracted by liquid-liquid extraction and analyzed by gas chromatography coupled to mass spectrometry. Numerous organic compounds, including various alkanes, polycyclic aromatic hydrocarbons (PAH) and alkanoic acids, have been identified in the fogwater samples. Higher molecular weight (MW) compounds are preferentially associated with an insoluble phase inside the fog drops, whereas lower molecular weight and more polar compounds are found predominantly in the dissolved phase. Concentrations in the dissolved phase were sometimes much higher than estimated by the compounds' aqueous solubilities.

Biodegradable compounds: Rheological, mechanical and thermal properties

Science.gov (United States)

Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

2015-12-01

Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

Evolutionary Structure Prediction of Stoichiometric Compounds

Science.gov (United States)

Zhu, Qiang; Oganov, Artem

2014-03-01

In general, for a given ionic compound AmBn\\ at ambient pressure condition, its stoichiometry reflects the valence state ratio between per chemical specie (i.e., the charges for each anion and cation). However, compounds under high pressure exhibit significantly behavior, compared to those analogs at ambient condition. Here we developed a method to solve the crystal structure prediction problem based on the evolutionary algorithms, which can predict both the stable compounds and their crystal structures at arbitrary P,T-conditions, given just the set of chemical elements. By applying this method to a wide range of binary ionic systems (Na-Cl, Mg-O, Xe-O, Cs-F, etc), we discovered a lot of compounds with brand new stoichimetries which can become thermodynamically stable. Further electronic structure analysis on these novel compounds indicates that several factors can contribute to this extraordinary phenomenon: (1) polyatomic anions; (2) free electron localization; (3) emergence of new valence states; (4) metallization. In particular, part of the results have been confirmed by experiment, which warrants that this approach can play a crucial role in new materials design under extreme pressure conditions. This work is funded by DARPA (Grants No. W31P4Q1210008 and W31P4Q1310005), NSF (EAR-1114313 and DMR-1231586).

Medicinal Uses of Inorganic Compounds - 2

Indian Academy of Sciences (India)

In the first part of this article, we described medicinal uses of inorganic compounds relating to cancer care, infection and diabetic control, neurological, cardiovascular and in- flammatory diseases. This article contains further infor- mation on the medicinal uses of inorganic compounds as therapeutic and diagnostic in ...

Bioactive compounds in whole grain wheat

NARCIS (Netherlands)

Mateo Anson, N.

2010-01-01

Bread can be healthier! Consuming whole-grain foods can prevent cardiovascular diseases, type-2 diabetes and metabolic syndrome. This is due to bioactive compounds in whole grain, such as antioxidants and anti-inflammatory compounds. We found that the different fractions of a wheat grain vary much

Pickpocket compounds from Latin to Romance

NARCIS (Netherlands)

Nielsen Whitehead, Benedicte

2012-01-01

This thesis discusses the development in Proto–Indo–European, Latin and Romance of a word–formation pattern which the most adequate terminology in use dubs ‘verbal government compounds with a governing first member’; I use the shorthand ‘pickpocket compounds’. The first member of such compounds

Volatile sulfur compounds in tropical fruits

Directory of Open Access Journals (Sweden)

Robert J. Cannon

2018-04-01

Full Text Available Global production and demand for tropical fruits continues to grow each year as consumers are enticed by the exotic flavors and potential health benefits that these fruits possess. Volatile sulfur compounds (VSCs are often responsible for the juicy, fresh aroma of tropical fruits. This poses a challenge for analytical chemists to identify these compounds as most often VSCs are found at low concentrations in most tropical fruits. The aim of this review is to discuss the extraction methods, enrichment techniques, and instrumentation utilized to identify and quantify VSCs in natural products. This will be followed by a discussion of the VSCs reported in tropical and subtropical fruits, with particular attention to the odor and taste attributes of each compound. Finally, the biogenesis and enzymatic formation of specific VSCs in tropical fruits will be highlighted along with the contribution each possesses to the aroma of their respective fruit. Keywords: Tropical fruits, Volatile sulfur compounds, Extraction methods

Moessbauer spectroscopy in neptunium compounds

Energy Technology Data Exchange (ETDEWEB)

Nakamoto, Tadahiro; Nakada, Masami; Masaki, Nobuyuki; Saeki, Masakatsu [Japan Atomic Energy Research Inst., Tokyo (Japan)

1997-03-01

Moessbauer effects are observable in seven elements of actinides from {sup 232}Th to {sup 247}Cm and Moesbauer spectra have been investigated mainly with {sup 237}Np and {sup 238}U for the reasons of availability and cost of materials. This report describes the fundamental characteristics of Moessbauer spectra of {sup 237}Np and the correlation between the isomer shift and the coordination number of Np(V) compounds. The isomer shifts of Np(V) compounds had a tendency to increase as an increase of coordination number and the isomer shifts of Np(V) compounds showed broad distribution as well as those of Np(VI) but {delta} values of the compounds with the same coordination number were distributed in a narrow range. The {delta} values of Np(VI) complexes with O{sub x} donor set suggest that the Np atom in its hydroxide (NpO{sub 2}(OH){center_dot}4H{sub 2}O)might have pentagonal bipyramidal structure and at least, pentagonal and hexagonal bipyramidal structures might coexist in its acetate and benzoate. Really, such coexistence has been demonstrated in its nitrate, (NpO{sub 2}){sub 2}(NO{sub 3}){sub 2}{center_dot}5H{sub 2}O. (M.N.)

Techniques for Analysis of Plant Phenolic Compounds

Directory of Open Access Journals (Sweden)

Thomas H. Roberts

2013-02-01

Full Text Available Phenolic compounds are well-known phytochemicals found in all plants. They consist of simple phenols, benzoic and cinnamic acid, coumarins, tannins, lignins, lignans and flavonoids. Substantial developments in research focused on the extraction, identification and quantification of phenolic compounds as medicinal and/or dietary molecules have occurred over the last 25 years. Organic solvent extraction is the main method used to extract phenolics. Chemical procedures are used to detect the presence of total phenolics, while spectrophotometric and chromatographic techniques are utilized to identify and quantify individual phenolic compounds. This review addresses the application of different methodologies utilized in the analysis of phenolic compounds in plant-based products, including recent technical developments in the quantification of phenolics.

Site preferences of actinide cations in [NZP] compounds

Science.gov (United States)

Hawkins, H. T.; Spearing, D. R.; Smith, D. M.; Hampel, F. G.; Veirs, D. K.; Scheetz, B. E.

2000-07-01

Compounds adopting the sodium dizirconium tris(phosphate) (NaZr2(PO4)3) structure type belong to the [NZP] structural family of compounds. [NZP] compounds possess desirable properties that would permit their application as hosts for the actinides. These properties include compositional flexibility (i.e., three structural sites that can accommodate a variety of different cations), high thermal stability, negligible thermal expansion, and resistance to radiation damage. Experimental data indicate that [NZP] compounds resist dissolution and release of constituents over a wide range of experimental conditions. Moreover, [NZP] compounds may be synthesized by both conventional and novel methods and may be heat treated or sintered at modest temperatures (800 °C-1350 °C) in open or restricted systems.

Antimicrobial susceptibility assessment of compound from ...

African Journals Online (AJOL)

Ethyl acetate extract of the culture filtrate of Aspergillus fumigatus on chromatographic analysis has led to the isolation of the compound, AF-1 which exhibited a significant in vitro antimicrobial activity against the tested pathogenic microorganism. The structure of the isolated compound, AF-1 was identified as ...

Biodegradation of NSO-compounds under different redox-conditions

DEFF Research Database (Denmark)

Dyreborg, S.; Arvin, E.; Broholm, K.

1997-01-01

Laboratory experiments were carried out to investigate the potential of groundwater microorganisms to degrade selected heterocyclic aromatic compounds containing nitrogen, sulphur, or oxygen (NSO-compounds) under four redox-conditions over a period of 846 days. Eight compounds (pyrrole, 1...... anaerobic conditions, even though the microorganisms present in the anaerobic microcosms were active throughout the incubation period. A high variability in the lag period among the NSO-compounds was observed under aerobic conditions. While quinoline, indole, and carbazole were degraded with a lag period...

Thermodynamic stability studies of Ce-Sb compounds with Fe

Science.gov (United States)

Xie, Yi; Zhang, Jinsuo; Benson, Michael T.; Mariani, Robert D.

2018-02-01

Lanthanide fission products can migrate to the fuel periphery and react with cladding, causing fuel-cladding chemical interaction (FCCI). Adding a fuel additive dopant, such as Sb, can bind lanthanide, such as Ce, into metallic compounds and thus prevent migration. The present study focuses on the thermodynamic stability of Ce-Sb compounds when in contact with the major cladding constituent Fe by conducting diffusion couple tests. Ce-Sb compounds have shown high thermodynamic stability as they did not react with Fe. When Fe-Sb compounds contacted with Ce, Sb was separated out of Fe-Sb compounds and formed the more stable Ce-Sb compounds.

Aeration Controls the Reduction and Methylation of Tellurium by the Aerobic, Tellurite-Resistant Marine Yeast Rhodotorula mucilaginosa▿

Science.gov (United States)

Ollivier, Patrick R. L.; Bahrou, Andrew S.; Church, Thomas M.; Hanson, Thomas E.

2011-01-01

We previously described a marine, tellurite-resistant strain of the yeast Rhodotorula mucilaginosa that both precipitates intracellular Te(0) and volatilizes methylated Te compounds when grown in the presence of the oxyanion tellurite. The uses of microbes as a “green” route for the production of Te(0)-containing nanostructures and for the remediation of Te-oxyanion wastes have great potential, and so a more thorough understanding of this process is required. Here, Te precipitation and volatilization catalyzed by R. mucilaginosa were examined in continuously aerated and sealed (low oxygen concentration) batch cultures. Continuous aeration was found to strongly promote Te volatilization while inhibiting Te(0) precipitation. This differs from the results in sealed batch cultures, for which tellurite reduction to Te(0) was found to be very efficient. We show also that volatile Te species may be degraded rapidly in medium and converted to the particulate form by biological activity. Further experiments revealed that Te(0) precipitates produced by R. mucilaginosa can be further transformed to volatile and dissolved Te species. However, it was not clearly determined whether Te(0) is a required intermediate for Te volatilization. Based on these results, we conclude that low oxygen concentrations will be the most efficient for production of Te(0) nanoparticles while limiting the production of toxic volatile Te species, although the production of these compounds may never be completely eliminated. PMID:21602387

Method for conversion of .beta.-hydroxy carbonyl compounds

Science.gov (United States)

Lilga, Michael A.; White, James F.; Holladay, Johnathan E.; Zacher, Alan H.; Muzatko, Danielle S.; Orth, Rick J.

2010-03-30

A process is disclosed for conversion of salts of .beta.-hydroxy carbonyl compounds forming useful conversion products including, e.g., .alpha.,.beta.-unsaturated carbonyl compounds and/or salts of .alpha.,.beta.-unsaturated carbonyl compounds. Conversion products find use, e.g., as feedstock and/or end-use chemicals.

Hexavalent Chromium Compounds

Science.gov (United States)

Learn about chromium, exposure to which can increase your risk of lung cancer and cancer of the paranasal sinuses and nasal cavity. Hexavalent chromium compounds have been used as corrosion inhibitors in a wide variety of products and processes.

Experience with compound words influences their processing: An eye movement investigation with English compound words.

Science.gov (United States)

Juhasz, Barbara J

2016-11-14

Recording eye movements provides information on the time-course of word recognition during reading. Juhasz and Rayner [Juhasz, B. J., & Rayner, K. (2003). Investigating the effects of a set of intercorrelated variables on eye fixation durations in reading. Journal of Experimental Psychology: Learning, Memory and Cognition, 29, 1312-1318] examined the impact of five word recognition variables, including familiarity and age-of-acquisition (AoA), on fixation durations. All variables impacted fixation durations, but the time-course differed. However, the study focused on relatively short, morphologically simple words. Eye movements are also informative for examining the processing of morphologically complex words such as compound words. The present study further examined the time-course of lexical and semantic variables during morphological processing. A total of 120 English compound words that varied in familiarity, AoA, semantic transparency, lexeme meaning dominance, sensory experience rating (SER), and imageability were selected. The impact of these variables on fixation durations was examined when length, word frequency, and lexeme frequencies were controlled in a regression model. The most robust effects were found for familiarity and AoA, indicating that a reader's experience with compound words significantly impacts compound recognition. These results provide insight into semantic processing of morphologically complex words during reading.

Antifungal compounds from cyanobacteria.

Science.gov (United States)

Shishido, Tânia K; Humisto, Anu; Jokela, Jouni; Liu, Liwei; Wahlsten, Matti; Tamrakar, Anisha; Fewer, David P; Permi, Perttu; Andreote, Ana P D; Fiore, Marli F; Sivonen, Kaarina

2015-04-13

Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders.

Antifungal Compounds from Cyanobacteria

Directory of Open Access Journals (Sweden)

Tânia K. Shishido

2015-04-01

Full Text Available Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders.

Organic halogen compounds in the environment

International Nuclear Information System (INIS)

1979-07-01

There are 20 research reports on selected problems concerning the analysis, the occurence, and the behaviour of a wide spectrum of organic halogen compounds. The work was carried out in the framework of the project 'Organic Halogen Compounds in the Environment', financed by the BMFT, between 1975 and 1978. (orig.) [de

Carbohydrate degradation mechanisms and compounds from pretreated biomass

DEFF Research Database (Denmark)

Rasmussen, Helena

The formation of inhibitors during pretreatment of lignocellulosic feedstocks is a persistent problem, and notably the compounds that retard enzymatic cellulose conversion represent an obstacle for achieving optimal enzymatic productivity and high glucose yields. Compounds with many chemical...... pretreated wheat straw after enzymatic treatment. It was found that formation of the oligophenolic degradation compounds were common across biomass sources as sugar cane bagasse and oil palm empty fruit bunches. These findings were in line with that the oligophenolic compounds arise from reactions involving...... functionalities are formed during biomass pretreatment, which gives possibilities for various chemical reactions to take place and hence formation of many new potential inhibitor compounds. This somehow overlooked contemplation formed the basis for the main hypothesis investigated in this work: Hypothesis 1...

Device for collecting chemical compounds and related methods

Science.gov (United States)

Scott, Jill R.; Groenewold, Gary S.; Rae, Catherine

2013-01-01

A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from the fixed surfaces so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

Assessment of A Simple Compound-Saving Method To Study Insecticidal Activity of Natural Extracts and Pure Compounds Against Mosquito Larvae.

Science.gov (United States)

Falkowski, Michaël; Jahn-Oyac, Arnaud; Ferrero, Emma; Issaly, Jean; Eparvier, Véronique; Girod, Romain; Rodrigues, Alice M S; Stien, Didier; Houël, Emeline; Dusfour, Isabelle

2016-12-01

Research on natural insecticides has intensified with the spread of resistance to chemicals among insects, particularly disease vectors. To evaluate compounds, the World Health Organization (WHO) has published standardized procedures. However, those may be excessively compound-consuming when it comes to assessing the activity of natural extracts and pure compounds isolated in limited amount. As part of our work on the discovery of new mosquito larvicides from Amazonian plants, we developed a compound-saving assay in 5-ml glass tubes instead of WHO larval 100-ml cups. Comparing activity of synthetic and natural chemicals validated the glass tube assay. Raw data, lethal doses that kill 50% (LD 50 ) and 90% (LD 90 ) at 24 and 48 h, were highly correlated (0.68 natural extracts and molecules, identifying active compounds using 10 times less material than in the WHO protocol.

Toxicity prediction of compounds from turmeric (Curcuma longa L).

Science.gov (United States)

Balaji, S; Chempakam, B

2010-10-01

Turmeric belongs to the ginger family Zingiberaceae. Currently, cheminformatics approaches are not employed in any of the spices to study the medicinal properties traditionally attributed to them. The aim of this study is to find the most efficacious molecule which does not have any toxic effects. In the present study, toxicity of 200 chemical compounds from turmeric were predicted (includes bacterial mutagenicity, rodent carcinogenicity and human hepatotoxicity). The study shows out of 200 compounds, 184 compounds were predicted as toxigenic, 136 compounds are mutagenic, 153 compounds are carcinogenic and 64 compounds are hepatotoxic. To cross validate our results, we have chosen the popular curcumin and found that curcumin and its derivatives may cause dose dependent hepatotoxicity. The results of these studies indicate that, in contrast to curcumin, few other compounds in turmeric which are non-mutagenic, non-carcinogenic, non-hepatotoxic, and do not have any side-effects. Hence, the cost-effective approach presented in this paper could be used to filter toxic compounds from the drug discovery lifecycle. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Protonation sites of aromatic compounds in (+) atmospheric pressure photoionization

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Hwan; Ahmed, Arif [Dept. of Chemistry, Kyungpoo k National University, Daegu (Korea, Republic of)

2017-02-15

Reaction enthalpy of hydrogen transfer reactions of aromatic compounds has been observed to be greatly affected by the exact location of the protonation site. Therefore, to clearly identify the protonation location, each candidate protonation site for 43 aromatic compounds were theoretically determined and their location was compared with that determined based on experimental MS data. Only the basic nitrogen atom is favorable as a protonation site for pyridine-type aromatic compounds, whereas carbon atoms are preferable for the protonation of pyrrole-type compounds. The most favorable protonation sites for aniline or methylated aniline-type aromatic compounds are either the nitrogen atom in the amine group or the carbon atom at the para-position to the amine group. Like pyrrole-type compounds, aromatic compounds with amine groups also favor protonation at the carbon atom instead of at the nitrogen atom. In addition, hydrocarbons having an anthracene structural motif without heteroatoms produced higher or equal percentages of protonated ions compared to that achieved with molecular ions. The results of this study can be used to improve the analyses of aromatic compounds.

Complex fragment emission from hot compound nuclei

International Nuclear Information System (INIS)

Moretto, L.G.

1986-03-01

The experimental evidence for compound nucleus emission of complex fragments at low energies is used to interpret the emission of the same fragments at higher energies. The resulting experimental picture is that of highly excited compound nuclei formed in incomplete fusion processes which decay statistically. In particular, complex fragments appear to be produced mostly through compound nucleus decay. In the appendix a geometric-kinematic theory for incomplete fusion and the associated momentum transfer is outlined. 10 refs., 19 figs

Gel chromatography of sup(99m)Tc-labelled compounds

International Nuclear Information System (INIS)

Vilcek, S.; Machan, V.; Kalincak, M.

1976-01-01

The present state of gel chromatography of sup(99m)Tc-labelled compounds is reviewed. Examples are given of gel chromatography for preparing labelled compounds and for quality control analysis and the development of new types of sup(99m)Tc-labelled compounds. The factors which influence the gel chromatography of these compounds are discussed, i.e., the nature of the elution agent, the duration of the contact of the gel and the preparation the gel type, the nature of the labelled compound. The GCS method (gel chromatography scanning) is briefly described. The advantages of gel chromatography as compared with other chromatographic techniques for sup(99m)Tc-labelled compounds are summarized. (author)

Improvements in or relating to compounds

International Nuclear Information System (INIS)

Woodhead, J.L.

1983-01-01

The invention provides a process for the preparation of a dispersible product containing a cerium compound which comprises heating a cerium (IV) oxide hydrate in the presence of a salt to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate and produce a dispersible product containing a cerium compound. (author)

46 CFR 153.1025 - Motor fuel antiknock compounds.

Science.gov (United States)

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Motor fuel antiknock compounds. 153.1025 Section 153... Cargo Procedures § 153.1025 Motor fuel antiknock compounds. (a) No person may load or carry any other cargo in a containment system approved for motor fuel antiknock compounds containing lead alkyls except...

Cannabinoid-like anti-inflammatory compounds from flax fiber.

Science.gov (United States)

Styrczewska, Monika; Kulma, Anna; Ratajczak, Katarzyna; Amarowicz, Ryszard; Szopa, Jan

2012-09-01

Flax is a valuable source of fibers, linseed and oil. The compounds of the latter two products have already been widely examined and have been proven to possess many health-beneficial properties. In the course of analysis of fibers extract from previously generated transgenic plants overproducing phenylpropanoids a new terpenoid compound was discovered.The UV spectra and the retention time in UPLC analysis of this new compound reveal similarity to a cannabinoid-like compound, probably cannabidiol (CBD). This was confirmed by finding two ions at m/z 174.1 and 231.2 in mass spectra analysis. Further confirmation of the nature of the compound was based on a biological activity assay. It was found that the compound affects the expression of genes involved in inflammatory processes in mouse and human fibroblasts and likely the CBD from Cannabis sativa activates the specific peripheral cannabinoid receptor 2 (CB2) gene expression. Besides fibers, the compound was also found in all other flax tissues. It should be pointed out that the industrial process of fabric production does not affect CBD activity.The presented data suggest for the first time that flax products can be a source of biologically active cannabinoid-like compounds that are able to influence the cell immunological response. These findings might open up many new applications for medical flax products, especially for the fabric as a material for wound dressing with anti-inflammatory properties.

Process for production of a borohydride compound

Science.gov (United States)

Allen, Nathan Tait; Butterick, III, Robert; Chin, Arthur Achhing; Millar, Dean Michael; Molzahn, David Craig

2014-08-19

A process for production of a borohydride compound M(BH.sub.4).sub.y. The process has three steps. The first step combines a compound of formula (R.sup.1O).sub.yM with aluminum, hydrogen and a metallic catalyst containing at least one metal selected from the group consisting of titanium, zirconium, hafnium, niobium, vanadium, tantalum and iron to produce a compound of formula M(AlH.sub.3OR.sup.1).sub.y, wherein R.sup.1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group; M is an alkali metal, Be or Mg; and y is one or two; wherein the catalyst is present at a level of at least 200 ppm based on weight of aluminum. The second step combines the compound of formula M(AlH.sub.3OR.sup.1).sub.y with a borate, boroxine or borazine compound to produce M(BH.sub.4).sub.y and a byproduct mixture containing alkali metal and aluminum aryloxides. The third step separates M(BH.sub.4).sub.y from the byproduct mixture.