The concepts of liquid metal of IV generation

International Nuclear Information System (INIS)

Carbonnier, J. L.

2005-01-01

The concepts of liquid metals, due to their large spectrum, show important possibility of sustainable development: two concepts of liquid metal (Sodium and Lead) were engaged in the frame of the IV generation. The reactors with sodium benefit from considerable background of experience and of important work on projects to aim at the price diminution and the increase of safety (EFR, JSFR). The commitment of Japan as a leader of this concept and the support by France allow to contemplate an industrial deployment from 2015. The lead reactors offer some advantages in the domain of safety but otherwise require a highly important research and development binded to the control of the corrosion, the perspective of deployment of this concept are more hypothetical

Complexation ion-exchange chromatography of some metal ions on papers impregnated with Ti(IV)-based inorganic ion exchangers.

Science.gov (United States)

Sharma, S D; Gupta, R

2000-02-01

The chromatographic behavior of 40 metal ions is studied on titanium (IV) arsenate, titanium (IV) phosphate-, titanium (IV) molybdate-, titanium(IV) tungstate-, and titanium(IV) selenite-impregnated papers in 0.1M oxalic, citric, and tartaric acid as mobile phases. Similar studies are carried out on Whatman No. 1 papers for comparison. The ion-exchange capacity of these papers is determined, and their selectivity for different cations is discussed. The mechanism of migration is explained in terms of ion-exchange, precipitation, and adsorption. The prediction of elution sequence from RF values is also checked. The average Ri is found to be almost linearly dependent on the charge of the metal ions. The effect of the pKa of complexing acids on average RF values of 3d series metal ions is explained. A number of binary and ternary separations are achieved.

Organodioxygen complexes of some group 4B metal ions

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Akhter Hossain; Gino Mariotto

2003-09-01

Organodioxygen complexes of some group 4B metal ions, viz., zirconium(IV), tin(IV) and lead(II) containing monodentate, bidentate and tridentate ligands were synthesized and characterized. The complexes have the compositions of [Zr(O)(O 2 )2C 5 H 5 N.H 2 O], [Zr(O)(O 2 - ) 2 .2OPPh 3 ], [Sn(O 2 )(C 9 H 6 NO) 2 ], [Sn(0 2 ) 2 .(CH 2 ) 2 (NH 2 ) 2 ], [Pb(O 2 - )(C 5 H 5 N) 2 NO 3 ], [Pb(O 2 )(C 8 H 6 NOH)], [Pb(O 2 - )(det)NO 3 ] and [PbO 2 - ) (C 5 H 4 NCOOH)NO 3 .H 2 O]. Because of apparent linearity of M- O 2 grouping, the V 1 (O-O) stretching modes were only Raman active, giving bands at 810- 841 cm 1 for the peroxo complexes (1, 3, ,4 and 6), while the bands in the superoxo complexes (2, 5, 7 and 8) appeared at 1020- 1100 cm -1 . The peroxo complex of Zr(IV) containing monodentate ligands were found to oxidize trans-stilbene to trans-stilbene oxide under stoichiometric conditions. The organoperoxo complexes of tin and lead were insensitive to oxidative processes. (author)

Role of the Water–Metal Ion Bridge in Mediating Interactions between Quinolones and Escherichia coli Topoisomerase IV

Science.gov (United States)

2015-01-01

Although quinolones have been in clinical use for decades, the mechanism underlying drug activity and resistance has remained elusive. However, recent studies indicate that clinically relevant quinolones interact with Bacillus anthracis (Gram-positive) topoisomerase IV through a critical water–metal ion bridge and that the most common quinolone resistance mutations decrease drug activity by disrupting this bridge. As a first step toward determining whether the water–metal ion bridge is a general mechanism of quinolone–topoisomerase interaction, we characterized drug interactions with wild-type Escherichia coli (Gram-negative) topoisomerase IV and a series of ParC enzymes with mutations (S80L, S80I, S80F, and E84K) in the predicted bridge-anchoring residues. Results strongly suggest that the water–metal ion bridge is essential for quinolone activity against E. coli topoisomerase IV. Although the bridge represents a common and critical mechanism that underlies broad-spectrum quinolone function, it appears to play different roles in B. anthracis and E. coli topoisomerase IV. The water–metal ion bridge is the most important binding contact of clinically relevant quinolones with the Gram-positive enzyme. However, it primarily acts to properly align clinically relevant quinolones with E. coli topoisomerase IV. Finally, even though ciprofloxacin is unable to increase levels of DNA cleavage mediated by several of the Ser80 and Glu84 mutant E. coli enzymes, the drug still retains the ability to inhibit the overall catalytic activity of these topoisomerase IV proteins. Inhibition parallels drug binding, suggesting that the presence of the drug in the active site is sufficient to diminish DNA relaxation rates. PMID:25115926

Alkali metals and group IIA metals

International Nuclear Information System (INIS)

Fenton, D.E.

1987-01-01

This chapter on the coordination complexes of the alkali metals of group IIA starts with a historical perspective of their chemistry, from simple monodentate ligands, metal-β-diketonates to the macrocyclic polyethers which act as ligands to the alkali and akaline earth metals. Other macrocyclic ligands include quarterenes, calixarenes, porphyrins, phthalocyanines and chlorophylls. A section on the naturally occurring ionophores and carboxylic ionophores is included. (UK)

Development of supported noble metal catalyst for U(VI) to U(IV) reduction

International Nuclear Information System (INIS)

Tyagi, Deepak; Varma, Salil; Bhattacharyya, K.; Tripathi, A.K.; Bharadwaj, S.R.; Jain, V.K.; Sahu, Avinash; Vincent, Tessy; Jagatap, B.N.; Wattal, P.K.

2015-01-01

Uranium-plutonium separation is an essential step in the PUREX process employed in spent nuclear fuel reprocessing. This partitioning in the PUREX process is achieved by selective reduction of Pu(IV) to Pu(III) using uranous nitrate as reductant and hydrazine as stabilizer. Currently in our Indian reprocessing plants, the requirement of uranous nitrate is met by electrolytic reduction of uranyl nitrate. This process, however, suffers from a major drawback of incomplete reduction with a maximum conversion of ~ 60%. Catalytic reduction of U(VI) to U(IV) is being considered as one of the promising alternatives to the electro-reduction process due to fast kinetics and near total conversion. Various catalysts involving noble metals like platinum (Adams catalyst, Pt/Al 2 O 3 , Pt/SiO 2 etc.) have been reported for the reduction. Sustained activity and stability of the catalyst under harsh reaction conditions are still the issues that need to be resolved. We present here the results on zirconia supported noble metal catalyst that is developed in BARC for reduction of uranyl nitrate to uranous nitrate. Supported noble metal catalysts with varying metal loadings (0.5 - 2 wt%) were prepared via support precipitation and noble metal impregnation. The green catalysts were reduced either by chemical reduction using hydrazine hydrate or by heating in hydrogen flow or combination of both the steps. These catalysts were characterized by various techniques such as, XRD, SEM, TEM, N 2 adsorption and H 2 chemisorption. Performance of these catalysts was evaluated for U(VI) to U(IV) reduction with uranyl nitrate feed using hydrazine as reductant. The results with the most active catalyst are named as 'BARC-CAT', which was developed in our lab. (author)

Structure and magnetism in novel group IV element-based magnetic materials

Energy Technology Data Exchange (ETDEWEB)

Tsui, Frank [Univ. of North Carolina, Chapel Hill, NC (United States)

2013-08-14

The project is to investigate structure, magnetism and spin dependent states of novel group IV element-based magnetic thin films and heterostructures as a function of composition and epitaxial constraints. The materials systems of interest are Si-compatible epitaxial films and heterostructures of Si/Ge-based magnetic ternary alloys grown by non-equilibrium molecular beam epitaxy (MBE) techniques, specifically doped magnetic semiconductors (DMS) and half-metallic Heusler alloys. Systematic structural, chemical, magnetic, and electrical measurements are carried out, using x-ray microbeam techniques, magnetotunneling spectroscopy and microscopy, and magnetotransport. The work is aimed at elucidating the nature and interplay between structure, chemical order, magnetism, and spin-dependent states in these novel materials, at developing materials and techniques to realize and control fully spin polarized states, and at exploring fundamental processes that stabilize the epitaxial magnetic nanostructures and control the electronic and magnetic states in these complex materials. Combinatorial approach provides the means for the systematic studies, and the complex nature of the work necessitates this approach.

View from... Group IV Photonics: Industry meets academia

Science.gov (United States)

Pile, David

2012-12-01

Silicon photonics and devices based on group IV elements are overcoming the tough economic downturns that have rocked industry over the past 12 years. Cross fertilization between academia and industry may lead to new devices that are both innovative and profitable.

Covalently-controlled properties by design in group IV graphane analogues.

Science.gov (United States)

Jiang, Shishi; Arguilla, Maxx Q; Cultrara, Nicholas D; Goldberger, Joshua E

2015-01-20

CONSPECTUS: The isolation of graphene has sparked a renaissance in the study of two-dimensional materials. This led to the discovery of new and unique phenomena such as extremely high carrier mobility, thermal conductivity, and mechanical strength not observed in the parent 3D structure. While the emergence of these phenomena has spurred widespread interest in graphene, the paradox between the high-mobility Fermi-Dirac electronic structure and the need for a sizable band gap has challenged its application in traditional semiconductor devices. While graphene is a fascinating and promising material, the limitation of its electronic structure has inspired researchers to explore other 2D materials beyond graphene. In this Account, we summarize our recent work on a new family of two-dimensional materials based on sp(3)-hybridized group IV elements. Ligand-terminated Si, Ge, and Sn graphane analogues are an emerging and unique class of two-dimensional materials that offer the potential to tailor the structure, stability, and properties. Compared with bulk Si and Ge, a direct and larger band gap is apparent in group IV graphane analogues depending on the surface ligand. These materials can be synthesized in gram-scale quantities and in thin films via the topotactic deintercalation of layered Zintl phase precursors. Few layers and single layers can be isolated via manual exfoliation and deintercalation of epitaxially grown Zintl phases on Si/Ge substrates. The presence of a fourth bond on the surface of the layers allows various surface ligand termination with different organic functional groups achieved via conventional soft chemical routes. In these single-atom thick materials, the electronic structure can be systematically controlled by varying the identities of the main group elements and by attaching different surface terminating ligands. In contrast to transition metal dichalcogenides, the weaker interlayer interaction allows the direct band gap single layer

3D continuum phonon model for group-IV 2D materials

DEFF Research Database (Denmark)

Willatzen, Morten; Lew Yan Voon, Lok C.; Gandi, Appala Naidu

2017-01-01

. In this paper, we use the model to not only compare the phonon spectra among the group-IV materials but also to study whether these phonons differ from those of a compound material such as molybdenum disulfide. The origin of quadratic modes is clarified. Mode coupling for both graphene and silicene is obtained......, contrary to previous works. Our model allows us to predict the existence of confined optical phonon modes for the group-IV materials but not for molybdenum disulfide. A comparison of the long-wavelength modes to density-functional results is included....

Direct complexonometric determination of thorium (IV), uranium (IV), neptunium (IV), plutonium (IV) by titration of diethylenetriaminepentaacetic acid with xylenol orange as indicator

International Nuclear Information System (INIS)

Rykov, A.G.; Piskunov, E.M.; Timofeev, G.A.

1975-01-01

The purpose of the present work was to develop a method of determining Th(IV), U(IV), Np(N) and Pu(IV) in acid solutions by titration with diethylenetriamine pentacetic acid, the indicator being xylenol orange. It has been established that Th, U, Np and Pu can be determined to within 0.5-1.5%. Th and U in quantities of tens of milligrams can be determined with greater accuracy, attaining hundredths of one per cent. During titration the determination is not hindered by singly- and doubly-charged metal ions, trivalent lanthanides and actinides, except plutonium. The proposed method can be used to determine U(IV) in the presence of considerable quantities of U(VI) and Np(IV) in the presence of Np(V). Total concentrations of uranium or neptunium are determined by reducing uranium (VI) or neptunium (V) by a standard method (for example, using metallic lead, cadmium or zinc amalgam) to the tetravalent state and applying the method described in the paper. (E.P.)

Oxidation of sulfur (IV by oxygen in aqueous solution: role of some metal ions

Directory of Open Access Journals (Sweden)

Martins Claudia R.

1999-01-01

Full Text Available Catalytic effect of metal ions: Cr(VI, Cr(III, Cd(II, V(V and chloride anion, on the oxidation of S(IV in aqueous solution, at concentrations of metal ions and S(IV usually found in urban atmospheres, were studied under controlled experimental conditions (pH (2.1 - 4,5, T (25.0 - 35.0 °C, air flow rate, concentration of reactants, etc.... The kinetic constant determined at 25.0 °C and pH range (2.1 - 4.5, using ultra pure water was 8.0 ± 0.5 x 10-4 s-1. This value was considered as a reference for the oxidation reaction rate. The kinetic constants determined in the presence of Cr(VI revealed that the oxidation reaction of S(IV is quite influenced by the acidity. At pH = 2.1 (K = 2.3 x 10-2 mg-1 L s-1 the reaction is carried out with a rate five times greater when compared to pH = 2.6 (K = 4.3 x 10-3 mg-1 L s-1 and thirty times greater when compared to pH = 3.4 (K= 8.0 x 10 -4 mg-1 L s-1. The following rate expression was obtained at pH = 2.6: -r(S(IV =K [Cr(VI] [S(IV] and the activation energy found was: Ea =70.3KJ/mol. No catalytic effects were observed for Cd(II or chloride ion, while inhibitory effects were observed for Cr(III and V(V ions.

Explorations of new selenites of the group IIIA and IVA metals

International Nuclear Information System (INIS)

Kong Fang; Li Peicin; Zhang Suyun; Mao Jianggao

2012-01-01

Systematic explorations of new phases in the Ga III /In III /Ge IV –Se IV –O systems by hydrothermal syntheses or solid-state reactions at high-temperature led to six new ternary compounds, namely, M 2 Se 2 O 7 (M=Ga 1, In 2), M(OH)(SeO 3 ) (M=Ga 3, In 4), α-Ge(SeO 3 ) 2 5 and β-Ge(SeO 3 ) 2 6. Ga 2 Se 2 O 7 1 displays a 3D open framework composed of 2D gallium oxide layers being further bridged and capped by SeO 3 groups. In 2 Se 2 O 7 2 features a 3D indium oxide framework formed by corner- and edge- sharing InO 6 octahedra with SeO 3 groups attached on the cavities and the 8-member ring tunnels of the structure. The isostructural of M(OH)(SeO 3 ) (M=Ga 3, In 4) exhibit a 2D metal selenite layer composed of 1D edge-sharing MO 6 octahedral chains that are interconnected by SeO 3 groups. α-Ge(SeO 3 ) 2 (P2 1 /n) 5 displays a 3D open framework with 1D 8-member ring tunnels along the a-axis while β-Ge(SeO 3 ) 2 (Pa-3) 6 exhibits a condensed 3D network. - Graphical abstract: Highlights: ► Up to now, selenites of the group IIIA and IVA metals are still rare. ► Hydrothermal or solid state reactions yielded six new compounds in this system. ► They are M 2 Se 2 O 7 (M=Ga, In), M(OH)(SeO 3 ) (M=Ga, In), α-Ge(SeO 3 ) 2 and β-Ge(SeO 3 ) 2 . ► They exhibit four different 3D and one 2D structural types. ► α-Ge(SeO 3 ) 2 and β-Ge(SeO 3 ) 2 represent the first examples of germanium selenites.

77 FR 16508 - National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins...

Science.gov (United States)

2012-03-21

... National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins; Pesticide... Hazardous Air Pollutant Emissions: Group IV Polymers and Resins; National Emission Standards for Hazardous... proposed rule titled, National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers...

Transferable tight-binding model for strained group IV and III-V materials and heterostructures

Science.gov (United States)

Tan, Yaohua; Povolotskyi, Michael; Kubis, Tillmann; Boykin, Timothy B.; Klimeck, Gerhard

2016-07-01

It is critical to capture the effect due to strain and material interface for device level transistor modeling. We introduce a transferable s p3d5s* tight-binding model with nearest-neighbor interactions for arbitrarily strained group IV and III-V materials. The tight-binding model is parametrized with respect to hybrid functional (HSE06) calculations for varieties of strained systems. The tight-binding calculations of ultrasmall superlattices formed by group IV and group III-V materials show good agreement with the corresponding HSE06 calculations. The application of the tight-binding model to superlattices demonstrates that the transferable tight-binding model with nearest-neighbor interactions can be obtained for group IV and III-V materials.

Valley–spin Seebeck effect in heavy group-IV monolayers

International Nuclear Information System (INIS)

Zhai, Xuechao; Wang, Shengdong; Zhang, Yan

2017-01-01

Akin to electron spin, the valley has become another highly valued degree of freedom in modern electronics, specifically after tremendous studies on monolayers of group-IV materials, i.e. graphene, silicene, germanene and stanene. Except for graphene, the other heavy group-IV monolayers have observable intrinsic spin–orbit interactions due to their buckled structures. Distinct from the usual electric or optical control of valley and spin, we here employ a temperature difference to drive electron motion in ferromagnetic heavy group-IV monolayers via designing a caloritronic device locally modulated by an interlayer electric (E z ) field. A unique valley–spin Seebeck (VSS) effect is discovered, with the current contributed only by one (the other) valley and one (the other) spin moving along one (the opposite) direction. This effect is suggested to be detected below the critical temperature about 18 K for silicene, 200 K for germanene and 400 K for stanene, arising from the characteristic valley–spin nondegenerate band structures tuned by the E z field, but cannot be driven in graphene without spin–orbit interaction. Above the critical temperature, the VSS effect is broken by overlarge temperature broadening. Besides the temperature, it is also found that the E z field can drive a transition between the VSS effect and the normal spin Seebeck effect. Further calculations indicate that the VSS effect is robust against many realistic perturbations. Our research represents a conceptually but substantially major step towards the study of the Seebeck effect. These findings provide a platform for encoding information simultaneously by the valley and spin quantum numbers of electrons in future thermal-logic circuits and energy-saving devices. (paper)

Special quasirandom structures for binary/ternary group IV random alloys

KAUST Repository

Chroneos, Alexander I.; Jiang, Chao; Grimes, Robin W.; Schwingenschlö gl, Udo

2010-01-01

Simulation of defect interactions in binary/ternary group IV semiconductor alloys at the density functional theory level is difficult due to the random distribution of the constituent atoms. The special quasirandom structures approach is a

SDSS-IV MaNGA: modelling the metallicity gradients of gas and stars - radially dependent metal outflow versus IMF

Science.gov (United States)

Lian, Jianhui; Thomas, Daniel; Maraston, Claudia; Goddard, Daniel; Parikh, Taniya; Fernández-Trincado, J. G.; Roman-Lopes, Alexandre; Rong, Yu; Tang, Baitian; Yan, Renbin

2018-05-01

In our previous work, we found that only two scenarios are capable of reproducing the observed integrated mass-metallicity relations for the gas and stellar components of local star-forming galaxies simultaneously. One scenario invokes a time-dependent metal outflow loading factor with stronger outflows at early times. The other scenario uses a time-dependent initial mass function (IMF) slope with a steeper IMF at early times. In this work, we extend our study to investigate the radial profile of gas and stellar metallicity in local star-forming galaxies using spatially resolved spectroscopic data from the SDSS-IV MaNGA survey. We find that most galaxies show negative gradients in both gas and stellar metallicity with steeper gradients in stellar metallicity. The stellar metallicity gradients tend to be mass dependent with steeper gradients in more massive galaxies while no clear mass dependence is found for the gas metallicity gradient. Then we compare the observations with the predictions from a chemical evolution model of the radial profiles of gas and stellar metallicities. We confirm that the two scenarios proposed in our previous work are also required to explain the metallicity gradients. Based on these two scenarios, we successfully reproduce the radial profiles of gas metallicity, stellar metallicity, stellar mass surface density, and star formation rate surface density simultaneously. The origin of the negative gradient in stellar metallicity turns out to be driven by either radially dependent metal outflow or IMF slope. In contrast, the radial dependence of the gas metallicity is less constrained because of the degeneracy in model parameters.

Synthesis and Properties of Group IV Graphane Analogues

Science.gov (United States)

Goldberger, Joshua

Similar to how carbon networks can be sculpted into low-dimensional allotropes such as fullerenes, nanotubes, and graphene with fundamentally different properties, it is possible to create similar ligand terminated sp3-hybridized honeycomb graphane derivatives containing Ge or Sn that feature unique and tunable properties. Here, we will describe our recent success in the creation of hydrogen and organic-terminated group IV graphane analogues, from the topochemical deintercalation of precursor Zintl phases, such as CaGe2. We will discuss how the optical, electronic, and thermal properties of these materials can be systematically controlled by substituting either the surface ligand or via alloying with other Group IV elements. Additionally, we have also developed an epitopotaxial approach for integrating precise thicknesses of germanane layers onto Ge wafers that combines the epitaxial deposition of CaGe2 precursor phases with the topotactic interconversion into the 2D material. Finally, we will describe our recent efforts on the synthesis and crystal structures of Sn-containing graphane alloys in order to access novel topological phenomena predicted to occur in these graphanes.

Incorporation of sulfate or selenate groups into oxotellurates(IV). I. Calcium, cadmium, and strontium compounds

International Nuclear Information System (INIS)

Weil, Matthias; Shirkhanlou, Mahdi

2017-01-01

Seven new mixed oxochalcogenate compounds in the systems M II /X VI /Te IV /O/(H), (M II = Ca, Cd, Sr; X VI = S, Se) were obtained under hydrothermal conditions (210 C, one week). Crystal structure determinations based on single-crystal X-ray diffraction data revealed the compositions Ca 3 (SeO 4 )(TeO 3 ) 2 , Ca 3 (SeO 4 )(Te 3 O 8 ), Cd 3 (SeO 4 )(Te 3 O 8 ), Cd 3 (H 2 O)(SO 4 )(Te 3 O 8 ), Cd 4 (SO 4 )(TeO 3 ) 3 , Cd 5 (SO 4 ) 2 (TeO 3 ) 2 (OH) 2 , and Sr 3 (H 2 O) 2 (SeO 4 )(TeO 3 ) 2 for these phases. Peculiar features of the crystal structures of Ca 3 (SeO 4 )(TeO 3 ) 2 , Ca 3 (SeO 4 )(Te 3 O 8 ), Cd 3 (SeO 4 )(Te 3 O 8 ), Cd 3 (H 2 O)(SO 4 )(Te 3 O 8 ), and Sr 3 (H 2 O) 2 (SeO 4 )(TeO 3 ) 2 are metal-oxotellurate(IV) layers connected by bridging XO 4 tetrahedra and/or by hydrogen-bonding interactions involving hydroxyl or water groups, whereas Cd 4 (SO 4 )(TeO 3 ) 3 and Cd 5 (SO 4 ) 2 (TeO 3 ) 2 (OH) 2 crystallize as framework structures. Common to all crystal structures is the stereoactivity of the Te IV electron lone pair for each oxotellurate(IV) unit, pointing either into the inter-layer space, or into channels and cavities in the crystal structures. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

About the structure and stability of complex carbonates of thorium (IV), cerium (IV), zirconium (IV), hafnium (IV)

International Nuclear Information System (INIS)

Dervin, Jacqueline

1972-01-01

This research thesis addressed the study of complex carbonates of cations of metals belonging to the IV A column, i.e. thorium (IV), zirconium (IV), hafnium (IV), and also cerium (IV) and uranium (VI), and more particularly focused on ionic compounds formed in solution, and also on the influence of concentration and nature of cations on stability and nature of the formed solid. The author first presents methods used in this study, discusses their precision and scope of validity. She reports the study of the formation of different complex ions which have been highlighted in solution, and the determination of their formation constants. She reports the preparation and study of the stability domain of solid complexes. The next part reports the use of thermogravimetric analysis, IR spectrometry, and crystallography for the structural study of these compounds

Transferable tight binding model for strained group IV and III-V heterostructures

Science.gov (United States)

Tan, Yaohua; Povolotskyi, Micheal; Kubis, Tillmann; Boykin, Timothy; Klimeck, Gerhard

Modern semiconductor devices have reached critical device dimensions in the range of several nanometers. For reliable prediction of device performance, it is critical to have a numerical efficient model that are transferable to material interfaces. In this work, we present an empirical tight binding (ETB) model with transferable parameters for strained IV and III-V group semiconductors. The ETB model is numerically highly efficient as it make use of an orthogonal sp3d5s* basis set with nearest neighbor inter-atomic interactions. The ETB parameters are generated from HSE06 hybrid functional calculations. Band structures of strained group IV and III-V materials by ETB model are in good agreement with corresponding HSE06 calculations. Furthermore, the ETB model is applied to strained superlattices which consist of group IV and III-V elements. The ETB model turns out to be transferable to nano-scale hetero-structure. The ETB band structures agree with the corresponding HSE06 results in the whole Brillouin zone. The ETB band gaps of superlattices with common cations or common anions have discrepancies within 0.05eV.

Separation method for ions of elements of the III., IV., VI. and VIII. groups of periodical system

International Nuclear Information System (INIS)

Marhol, M.

1973-01-01

The method is presented of separating the ions of the elements of the periodic system groups III, IV, and VIII by ion exchangers. The ions are complex-bonded to a new type of ion exchanger consisting of the polycondensates of phenol with aldehydes or ketones and containing an atom of phosphorus, arsenic or antimony with an atom of sulphur or oxygen in a complex bond. The polymers of compounds containing a double bond, e.g., of butadiene, polyvinyl alcohol, polyethylene, polypropylene, and the compounds of styrene with fural may also be used for this purpose. The method is demonstrated on a case of uranium and heavy metal concentration and the separation thereof from waste waters. (L.K.)

Coordination and solvent extraction behaviour of oxozirconium(IV), thorium(IV) and dioxouranium(VI)

International Nuclear Information System (INIS)

Dash, K.C.

1989-01-01

The systematic liquid-liquid extraction behaviour of oxozirconium (IV), thorium(IV) and dioxouranium(VI) have been investigated using a number of synthesised and commercial chelating extractants. The synergism or antagonism for these processes in presence of neutral donor ligands have also been identified and the conditions for separation and isolation of pure individual metal ions have been established. The coordination behaviour of oxozirconium(IV), thorium(IV) and dioxouranium(VI) with a large number of mono- and polydentate ligands have been studied. With oxozirconium(IV), invariably always a cyclic, tetranuclear species is obtained, derived from the tetrameric structure of the parent ZrOCl 2 .8H 2 O which is actually (Zr 4 (OH) 8 (H 2 O) 16 )Cl 8 .12H 2 O. No simple, monomeric oxozirconium(IV) complex was obtained. Uranium(VI) and thorium(IV) form a wide variety of complexes of higher coordination numbers and several bi- and trinuclear complexes were also characterised where the two adjacent metal centres are joined to each other by a double hydroxo-bridge. (author). 69 refs., 3 figs., 4 tabs

Structural features and electronic properties of group-III-, group-IV-, and group-V-doped Si nanocrystallites

International Nuclear Information System (INIS)

Ramos, L E; Degoli, Elena; Cantele, G; Ossicini, Stefano; Ninno, D; Furthmueller, J; Bechstedt, F

2007-01-01

We investigate the incorporation of group-III (B and Al), group-IV (C and Ge), and group-V (N and P) impurities in Si nanocrystallites. The structural features and electronic properties of doped Si nanocrystallites, which are faceted or spherical-like, are studied by means of an ab initio pseudopotential method including spin polarization. Jahn-Teller distortions occur in the neighborhood of the impurity sites and the bond lengths show a dependence on size and shape of the nanocrystallites. We find that the acceptor (group-III) and donor (group-V) levels become deep as the nanocrystallites become small. The energy difference between the spin-up and spin-down levels of group-III and group-V impurities decreases as the size of the Si nanocrystallite increases and tends to the value calculated for Si bulk. Doping with carbon introduces an impurity-related level in the energy gap of the Si nanocrystallites

Platinum-group metals from nuclear reactions as a possible resource

International Nuclear Information System (INIS)

Jensen, G.A.

1985-03-01

Spent nuclear fuels contain significant quantities of three of the platinum-group metals (ruthenium, rhodium, and palladium), and a related element technetium, which is nearly absent in nature. Applications for ruthenium, rhodium, and palladium are well established. Since the supply of these and other platinum metals is largely from foreign sources, they are considered strategic materials. Existing and future spent nuclear fuels contain quantities of these platinum metals that exceed the United States reserve base. Technetium has properties similar to platinum metals and has unique, useful properties of its own. The technical feasibility of recovering and using fission product platinum metals (and technetium) extensively in industry depends on: thoroughly decontaminating platinum-group metals from all other radioactive materials in the waste stream; separating platinum-group metals from one another in very high purity; using applications where appropriate control of the residual radioactivity is possible; and whether or not the United States will recover or process spent fuel prior to repository storage. If the radioactivity must be removed, isotope separation or long term storage to allow decay of the contained radioisotopes may be possible. 7 figs., 7 tabs

3D continuum phonon model for group-IV 2D materials

KAUST Repository

Willatzen, Morten

2017-06-30

A general three-dimensional continuum model of phonons in two-dimensional materials is developed. Our first-principles derivation includes full consideration of the lattice anisotropy and flexural modes perpendicular to the layers and can thus be applied to any two-dimensional material. In this paper, we use the model to not only compare the phonon spectra among the group-IV materials but also to study whether these phonons differ from those of a compound material such as molybdenum disulfide. The origin of quadratic modes is clarified. Mode coupling for both graphene and silicene is obtained, contrary to previous works. Our model allows us to predict the existence of confined optical phonon modes for the group-IV materials but not for molybdenum disulfide. A comparison of the long-wavelength modes to density-functional results is included.

Extraction complexes of Pu(IV) with carbamoylmethylphosphine oxide ligands. A relativistic density functional study

International Nuclear Information System (INIS)

Wang, Cong-Zhi; Lan, Jian-Hui; Feng, Yi-Xiao; Zhao, Yu-Liang; Chai, Zhi-Fang; Shi, Wei-Qun; Wei, Yue-Zhou

2014-01-01

The extraction complexes of Pu(IV) with n-octyl(phenyl)-N,N-diisobutyl-methylcarbamoyl phosphine oxide (CMPO) and diphenyl-N,N-diisobutyl carbamoyl phosphine oxide (Ph 2 CMPO) have been studied by using density functional theory (DFT) combined with relativistic small-core pseudopotentials. For most complexes, the CMPO and Ph 2 CMPO molecules are coordinated as bidentate chelating ligands through the carbonyl oxygen and phosphoric oxygen atoms. The metal-ligand bonding is mainly ionic for all of these complexes. The neutral PuL(NO 3 ) 4 and PuL 2 (NO 3 ) 4 complexes are predicted to be the most thermodynamically stable molecules according to the metal-ligand complexation reactions. In addition, hydration energies may also play a significant role in the extractability of CMPO and Ph 2 CMPO for the plutonium cations. In most cases, the complexes with CMPO possess qualitatively similar geometries and electron structures to those with Ph 2 CMPO, and they also have comparable metal-ligand binding energies. Thus, replacement of alkyl groups by phenyl groups at the phosphorus atom of CMPO seems to have no obvious influence on the extraction of Pu(IV). (orig.)

Equilibrium Adsorption of heavy Metals from Aqueous Solutions onto Poly aniline Stannic(IV) Phosphate Composite

International Nuclear Information System (INIS)

El-Zahhar, A.A.; EI-Shourbagy, M.M.; Shady, S.A.

2012-01-01

An adsorbent material has been prepared by immobilization of stannic(IV) phosphate within poly aniline composite. The produced adsorbent exhibit a high adsorption potential for Pb(II), Cd(Il) and Zn(lI) from aqueous solutions. The influence of initial metal ion concentration, adsorbent dose, ph and temperature on metal ion removal has been studied. The process was found to follow a first order rate kinetics. Thc intra-particle diffusion of metal ions through pores in the adsorbent was to be the main rate limiting step. The equilibrium data fit well with Langmuir adsorption isotherm model. The selectivity order of the adsorbent towards the metal ions was Pb(Il) > Cd(Il) >Zn(II). The adsorption rate constant and thermodynamic parameters were also given to predict the nature of adsorption

HIGH-REDSHIFT METALS. I. THE DECLINE OF C IV AT z > 5.3

International Nuclear Information System (INIS)

Becker, George D.; Rauch, Michael; Sargent, Wallace L. W.

2009-01-01

We present the results from our search for C IV absorption systems at redshifts z = 5.3-6.0. We have observed four z ∼ 6 QSOs with Keck/NIRSPEC in echelle mode. The data are the most sensitive yet taken to search for C IV at these redshifts, being 50% complete at column densities log N CIV ∼ 13.4(cm -2 ). We find no clear C IV systems in any of the four sight lines. Taking into account our completeness, this translates into a decline in the number density of C IV absorbers in the range 13.2 CIV < 15.0 of at least a factor ∼4.1 (95% confidence) from z ∼ 2-4.5, over which the number density is relatively constant. We use our lack of detections, along with results from previous studies, to set limits on the slope and normalization of the column density distribution at z = 5.3-6.0. The rapid evolution of C IV at these redshifts suggests that the decrease in the number density may largely be due to ionization effects, in which case many of the metals in the z ∼ 4.5 intergalactic medium (IGM) could already be in place at z ∼ 5.3, but in lower ionization states. The lack of weak systems in our data, combined with the presence of strong C IV absorbers along at least one other sight line, further suggests that there may be large-scale variations in the enrichment and/or ionization state of the z ∼ 6 IGM. Alternatively, the known C IV absorbers at these redshifts may not reside in the general IGM, but may be associated with rare, UV-bright star-forming galaxies.

Syntheses and characterization of one-dimensional alkali metal antimony(III) thiostannates(IV), A{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} (A=K, Rb, Cs)

Energy Technology Data Exchange (ETDEWEB)

Yohannan, Jinu P.; Vidyasagar, Kanamaluru, E-mail: kvsagar@iitm.ac.in

2015-01-15

Three new isostructural quaternary antimony(III) thiostannates(IV), A{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} (A=K, Rb, Cs) have been synthesized by using alkali metal thiosulfate flux and structurally characterized by X-ray diffraction. Their structures contain A{sup +} ions around the [Sb{sub 2}Sn{sub 3}S{sub 10}]{sup 2−} chains, which are built from SbS{sub 3} pyramids, SnS{sub 6} octahedra and SnS{sub 4} tetrahedra. Raman and Mössbauer spectroscopic measurements corroborate the oxidation states and coordination environments of Sb(III) and Sn(IV). All three compounds are wide band gap semiconductors. Potassium compound undergoes partial exchange with strontium, cadmium and lead ions. - Graphical abstract: Syntheses, crystal structure, spectroscopic and partial ion-exchange studies of new one-dimensional alkali metal antimony(III) thiostannates(IV), A{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} (A=K, Rb, Cs) are described. - Highlights: • Syntheses of new alkali metal antimony(III) thiostannates(IV), A{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} (A=K, Rb, Cs). • Wide band gap semiconductors with one-dimensional structure. • Topotactic partial exchange of K{sup +} ions of K{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} with Sr{sup 2+}, Cd{sup 2+} and Pb{sup 2+} ions.

Synthesis of Group IVB Metals Oxicarbides by Carboreduction Reactions

Directory of Open Access Journals (Sweden)

A.D. Mazzoni

2002-10-01

Full Text Available The metals of the group IV B (Ti, Zr, Hf present a series of carbides and oxicarbides with scientific and technological interest. Many of these compounds belong to the subsystem "MO - MC" of the pseudoternary "MO - MN - MC" system (where M = Ti, Zr or Hf. In this work carboreduction reactions of TiO2 and ZrO2 were performed in argon atmosphere, using temperatures from 1250° to 1650° and reaction times of 120 min. The oxicarbides obtained were in the range TiC0.16O0.84 to TiC0.73O0.27 and ZrC0.46O0.54 to ZrC0.90O0.10. respectively. The reaction products were characterized by X-ray diffraction (XRD, with the calculation of their cell constants by means of the Rietveld method. Scanning Electron Microscopy (SEM was used in the characterization of powdered materials. Additionally, the carborreduction reaction was followed by weight loss.

Lithium adsorption and migration in group IV-VI compounds and GeS/graphene heterostructures: a comparative study.

Science.gov (United States)

Hao, Kuan-Rong; Fang, Lincan; Yan, Qing-Bo; Su, Gang

2018-04-18

By means of first-principles calculations, the adsorption and transport properties of lithium (Li) in orthorhombic group IV-VI compounds MX (M = Ge, Sn; X = S, Se) and GeS/graphene heterostructures have been systematically investigated. Strong interactions and distinct charge transfer between Li and compounds MX are observed. The Li diffusion barriers along the zigzag direction are found to be much lower than that along the armchair direction in monolayer and bulk MX, showing distinct anisotropic diffusion features. In particular, monolayer GeS has a lowest barrier of 0.173 eV (zigzag) among them and it will transit from a semiconductor to a metallic state after Li intercalation, indicating fast Li and electron transport properties. As a comparison, the addition of graphene in a GeS/graphene heterostructure could enhance its binding with Li, decrease the Li diffusion barrier and inhibit the volume expansion dramatically, suggesting a potential performance improvement. Our study not only reveals the directional transport properties of Li in MX, but also improves the understanding of the role of graphene in the MX/graphene heterostructure, and shows great potential application in the field of electrode materials.

Generic process for preparing a crystalline oxide upon a group IV semiconductor substrate

Science.gov (United States)

McKee, Rodney A.; Walker, Frederick J.; Chisholm, Matthew F.

2000-01-01

A process for growing a crystalline oxide epitaxially upon the surface of a Group IV semiconductor, as well as a structure constructed by the process, is described. The semiconductor can be germanium or silicon, and the crystalline oxide can generally be represented by the formula (AO).sub.n (A'BO.sub.3).sub.m in which "n" and "m" are non-negative integer repeats of planes of the alkaline earth oxides or the alkaline earth-containing perovskite oxides. With atomic level control of interfacial thermodynamics in a multicomponent semiconductor/oxide system, a highly perfect interface between a semiconductor and a crystalline oxide can be obtained.

Improvements in DC Current-Ioltage (I-V) Characteristics of n-GaN Schottky Diode using Metal Overlap Edge Termination

International Nuclear Information System (INIS)

Munir, T.; Aziz, A. A.; Abdullah, M. J.; Ain, M. F.

2010-01-01

Practical design of GaN Schottky diodes incorporating a field plate necessitates an understanding of how the addition of such plate affects the diode performance. In this paper, we investigated the effects on DC current-voltage (I-V) characteristics of n-GaN schottky diode by incorporating metal overlap edge termination. The thickness of the oxide film varies from 0.001 to 1 micron. Two-dimensional Atlas/Blaze simulations revealed that severe electric field crowding across the metal semiconductor contact will cause reliability concern and limit device breakdown voltage. DC current-voltage (I-V) measurements indicate that the forward currents are higher for thinner oxide film schottky diodes with metal overlap edge termination than those of unterminated schottky diodes. The forward current increased due to formation of an accumulation layer underneath the oxide layer. Extending the field plate to beyond periphery regions of schottky contact does not result in any significant increase in forward current. The new techniques of ramp oxide metal overlap edge termination have been implemented to increase the forward current of n-GaN schottky diode. In reverse bias, breakdown voltage increased with edge termination oxide up to a certain limit of oxide thickness.

The architecture of metal coordination groups in proteins.

Science.gov (United States)

Harding, Marjorie M

2004-05-01

A set of tables is presented and a survey given of the architecture of metal coordination groups in a representative set of protein structures from the Protein Data Bank [Bernstein et al. (1977), J. Mol. Biol. 112, 535-542; Berman et al. (2000), Nucleic Acids Res. 28, 235-242]. The structures have been determined to a resolution of 2.5 A or better; the metals considered are Ca, Mg, Mn, Fe, Cu, Zn, Na and K, with particular emphasis on Ca and Zn and the exclusion of haem groups and Fe/S clusters; the proteins are a representative set in which none has more than 30% sequence identity with any other. In them the metal is coordinated by several donor groups from different amino-acid residues in the protein chain and often also by water or other small molecules. The tables, for approximately 600 metal coordination groups, include information on the conformations of the protein chain in the region around the metal and reliability indicators. They illustrate the wide variety of coordination numbers, chelate-loop sizes and other properties and the different characteristics of different metals. They show that glycine has a particular significance in the position adjacent to a donor residue, especially in Ca coordination groups. They also show that metal coordination does not appear to lead to significant distortions of the torsion angles phi, psi from their normally allowed values. Very few metal coordination groups occur more than once in the representative set and when they do they are usually related in fold and function; they have similar but not necessarily identical conformations. However, individual chelate loops, for example Zn(-C-X-X'-C-), in which both cysteines are coordinated to Zn through S, and X and X' are any amino acids, are repeated frequently in many different and unrelated proteins. Not all chelate loops with the same composition have the same conformation, but for smaller loops there are usually one or two strongly preferred and well defined

Diversity of the Germination Apparatus in Clostridium botulinum Groups I, II, III and IV

Directory of Open Access Journals (Sweden)

Jason Brunt

2016-10-01

Full Text Available Clostridium botulinum is a highly dangerous pathogen that forms very resistant endospores that are ubiquitous in the environment, and which, under favourable conditions germinate to produce vegetative cells that multiply and form the exceptionally potent botulinum neurotoxin. To improve the control of botulinum neurotoxin-forming clostridia, it is important to understand the mechanisms involved in spore germination. Here we present models for spore germination in C. botulinum based on comparative genomics analyses, with C. botulinum Groups I and III sharing similar pathways, which differ from those proposed for C. botulinum Groups II and IV. All spores germinate in response to amino acids interacting with a germinant receptor, with four types of germinant receptor identified (encoded by various combinations of gerA, gerB and gerC genes (gerX. There are three gene clusters with an ABC-like configuration; ABC gerX1, ABABCB gerX2 and ACxBBB gerX4, and a single CA-B gerX3 gene cluster. Subtypes have been identified for most germinant receptors types, and the individual GerX subunits of each cluster show similar grouping in phylogenetic trees. C. botulinum Group I contained the largest variety of gerX subtypes, with three gerX1, three gerX2 and one gerX3 subtypes, while C. botulinum Group III contained two gerX1 types and one gerX4. C. botulinum Groups II and IV contained a single germinant receptor, gerX3 and gerX1, respectively. It is likely that all four C. botulinum Groups include a SpoVA channel involved in DPA release. The cortex lytic enzymes present in C. botulinum Groups I and III appear to be CwlJ and SleB, while in C. botulinum Groups II and IV, SleC appears to be important.

SDSS IV MaNGA - metallicity and nitrogen abundance gradients in local galaxies

Science.gov (United States)

Belfiore, Francesco; Maiolino, Roberto; Tremonti, Christy; Sánchez, Sebastian F.; Bundy, Kevin; Bershady, Matthew; Westfall, Kyle; Lin, Lihwai; Drory, Niv; Boquien, Médéric; Thomas, Daniel; Brinkmann, Jonathan

2017-07-01

We study the gas phase metallicity (O/H) and nitrogen abundance gradients traced by star-forming regions in a representative sample of 550 nearby galaxies in the stellar mass range 109-1011.5 M⊙ with resolved spectroscopic data from the Sloan Digital Sky Survey IV Mapping Nearby Galaxies at Apache Point Observatory survey. Using strong-line ratio diagnostics (R23 and O3N2 for metallicity and N2O2 for N/O) and referencing to the effective (half-light) radius (Re), we find that the metallicity gradient steepens with stellar mass, lying roughly flat among galaxies with log (M⋆/M⊙) = 9.0 but exhibiting slopes as steep as -0.14 dex R_e^{-1} at log (M⋆/M⊙) = 10.5 (using R23, but equivalent results are obtained using O3N2). At higher masses, these slopes remain typical in the outer regions of our sample (R > 1.5Re), but a flattening is observed in the central regions (R 2.0Re), we detect a mild flattening of the metallicity gradient in stacked profiles, although with low significance. The N/O ratio gradient provides complementary constraints on the average chemical enrichment history. Unlike the oxygen abundance, the average N/O profiles do not flatten out in the central regions of massive galaxies. The metallicity and N/O profiles both depart significantly from an exponential form, suggesting a disconnect between chemical enrichment and stellar mass surface density on local scales. In the context of inside-out growth of discs, our findings suggest that central regions of massive galaxies today have evolved to an equilibrium metallicity, while the nitrogen abundance continues to increase as a consequence of delayed secondary nucleosynthetic production.

U(IV) chalcogenolates synthesized via oxidation of uranium metal by dichalcogenides.

Science.gov (United States)

Gaunt, Andrew J; Scott, Brian L; Neu, Mary P

2006-09-04

Treatment of uranium metal with dichalcogenides in the presence of a catalytic amount of iodine in pyridine affords molecular U(IV) chalcogenolates that do not require stabilizing ancillary ligands. Oxidation of U(0) by PhEEPh yields monomeric seven-coordinate U(EPh)4(py)3 (E = S(1), Se(2)). The dimeric eight-coordinate complexes [U(EPh)2(mu2-EPh)2(CH3CN)2]2 (E = S(3), Se(4)) are obtained by crystallization from solutions of 1 and 2 dissolved in acetonitrile. Oxidation of U(0) by pySSpy and crystallization from thf yields nine-coordinate U(Spy)4(thf) (5). Incorporation of elemental selenium into the oxidation of U(0) by PhSeSePh results in the isolation of [U(py)2(SePh)(mu3-Se)(mu2-SePh)]4.4py (6), a tetrameric cluster in which each U(IV) ion is eight-coordinate and the U4Se4 core forms a distorted cube. The compounds were analyzed spectroscopically and the single-crystal X-ray structures of 1 and 3-6 were determined. The isolation of 1-6 represents six new examples of actinide chalcogenolates and allows insight into the nature of "hard" actinide ion-"soft" chalcogen donor interactions.

Synthesis and characterization of αzirconium (IV) hydrogenphosphate containing metallic copper clusters

International Nuclear Information System (INIS)

Souza, Alexilda Oliveira de; Rangel, Maria do Carmo; Alves, Oswaldo Luiz

2005-01-01

The α-zirconium (IV) hydrogenphosphate (α-ZrP) has received great attention in the last years due to its properties like ion exchange, intercalation, ionic conductivity and catalytic activity. This work reports a method to produce metallic copper clusters on α-ZrP to be used as catalysts in petrochemical processes. It was found that the solids were non-crystalline regardless of the uptake of copper and the reduction. The specific surface area increased as a consequence of the increase of the interlayer distance to accept the copper ions between the layers. During the reduction, big clusters of copper (0,5-11μ) with different sizes and shapes were produced. (author)

Fuel research for subcritical and critical GEN-IV systems cooled by heavy liquid metal

International Nuclear Information System (INIS)

Sobolev, V.; Verwerft, M.

2009-01-01

The participation of the Belgian Nuclear Research Centre SCK-CEN in the worldwide GEN-IV research can be considered as an opportunity. Today's GEN-IV research at SCK-CEN is mainly driven by the interests of the project MYRRHA (Multipurpose hYbrid Research Reactor for High-tech Applications). The main goal of this project is to build at SCK-CEN in Mol a new generation fast spectrum, subcritical, research and materials testing reactor MYRRHA driven by a high-energy proton accelerator. This GEN-IV MTR is cooled by heavy liquid metal (Pb-Bi) and will be used for the ADS concept demonstration, testing and qualification of new fuels, transmutation targets and innovative materials. On the European scale, MYRRHA is integrated in the Euratom FP6 Integrated Project (IP) EUROTRANS (EUROpean research programme for TRANSmutation of high level nuclear waste in an accelerator driven system), as the small-scale experimental machine for transmutation demonstration called XT-ADS. Last but not least, this experimental facility will also demonstrate the technological feasibility of the LFR (Lead-cooled Fast Reactor) GEN-IV concept; in EU the LFR design studies are performed in the framework of the Euratom FP6 ELSY (European Lead-cooled SYstem) project, where SCK-CEN is a partner. Among the research needed to ensure a safe and reliable operation of the MYRRHA/XT ADS reactor, the development and qualification of fuel and cladding materials have been recognized as one of the main key issues to be addressed

Group IV nanotube transistors for next generation ubiquitous computing

KAUST Repository

Fahad, Hossain M.

2014-06-04

Evolution in transistor technology from increasingly large power consuming single gate planar devices to energy efficient multiple gate non-planar ultra-narrow (< 20 nm) fins has enhanced the scaling trend to facilitate doubling performance. However, this performance gain happens at the expense of arraying multiple devices (fins) per operation bit, due to their ultra-narrow dimensions (width) originated limited number of charges to induce appreciable amount of drive current. Additionally arraying degrades device off-state leakage and increases short channel characteristics, resulting in reduced chip level energy-efficiency. In this paper, a novel nanotube device (NTFET) topology based on conventional group IV (Si, SiGe) channel materials is discussed. This device utilizes a core/shell dual gate strategy to capitalize on the volume-inversion properties of an ultra-thin (< 10 nm) group IV nanotube channel to minimize leakage and short channel effects while maximizing performance in an area-efficient manner. It is also shown that the NTFET is capable of providing a higher output drive performance per unit chip area than an array of gate-all-around nanowires, while maintaining the leakage and short channel characteristics similar to that of a single gate-all-around nanowire, the latter being the most superior in terms of electrostatic gate control. In the age of big data and the multitude of devices contributing to the internet of things, the NTFET offers a new transistor topology alternative with maximum benefits from performance-energy efficiency-functionality perspective. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Incorporation of sulfate or selenate groups into oxotellurates(IV). I. Calcium, cadmium, and strontium compounds

Energy Technology Data Exchange (ETDEWEB)

Weil, Matthias; Shirkhanlou, Mahdi [Institute for Chemical Technologies and Analytics, Division Structural Chemistry, TU Wien, Vienna (Austria)

2017-02-15

Seven new mixed oxochalcogenate compounds in the systems M{sup II}/X{sup VI}/Te{sup IV}/O/(H), (M{sup II} = Ca, Cd, Sr; X{sup VI} = S, Se) were obtained under hydrothermal conditions (210 C, one week). Crystal structure determinations based on single-crystal X-ray diffraction data revealed the compositions Ca{sub 3}(SeO{sub 4})(TeO{sub 3}){sub 2}, Ca{sub 3}(SeO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 3}(SeO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 3}(H{sub 2}O)(SO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 4}(SO{sub 4})(TeO{sub 3}){sub 3}, Cd{sub 5}(SO{sub 4}){sub 2}(TeO{sub 3}){sub 2}(OH){sub 2}, and Sr{sub 3}(H{sub 2}O){sub 2}(SeO{sub 4})(TeO{sub 3}){sub 2} for these phases. Peculiar features of the crystal structures of Ca{sub 3}(SeO{sub 4})(TeO{sub 3}){sub 2}, Ca{sub 3}(SeO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 3}(SeO{sub 4})(Te{sub 3}O{sub 8}), Cd{sub 3}(H{sub 2}O)(SO{sub 4})(Te{sub 3}O{sub 8}), and Sr{sub 3}(H{sub 2}O){sub 2}(SeO{sub 4})(TeO{sub 3}){sub 2} are metal-oxotellurate(IV) layers connected by bridging XO{sub 4} tetrahedra and/or by hydrogen-bonding interactions involving hydroxyl or water groups, whereas Cd{sub 4}(SO{sub 4})(TeO{sub 3}){sub 3} and Cd{sub 5}(SO{sub 4}){sub 2}(TeO{sub 3}){sub 2}(OH){sub 2} crystallize as framework structures. Common to all crystal structures is the stereoactivity of the Te{sup IV} electron lone pair for each oxotellurate(IV) unit, pointing either into the inter-layer space, or into channels and cavities in the crystal structures. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Do galaxy global relationships emerge from local ones? The SDSS IV MaNGA surface mass density-metallicity relation

Science.gov (United States)

Barrera-Ballesteros, Jorge K.; Heckman, Timothy M.; Zhu, Guangtun B.; Zakamska, Nadia L.; Sánchez, Sebastian F.; Law, David; Wake, David; Green, Jenny E.; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey; Malanushenko, Elena; Pan, Kaike; Roman Lopes, Alexandre; Lane, Richard R.

2016-12-01

We present the stellar surface mass density versus gas metallicity (Σ*-Z) relation for more than 500 000 spatially resolved star-forming resolution elements (spaxels) from a sample of 653 disc galaxies included in the SDSS IV MaNGA survey. We find a tight relation between these local properties, with higher metallicities as the surface density increases. This relation extends over three orders of magnitude in the surface mass density and a factor of 4 in metallicity. We show that this local relationship can simultaneously reproduce two well-known properties of disc galaxies: their global mass-metallicity relationship and their radial metallicity gradients. We also find that the Σ*-Z relation is largely independent of the galaxy's total stellar mass and specific star formation rate (sSFR), except at low stellar mass and high sSFR. These results suggest that in the present-day universe local properties play a key role in determining the gas-phase metallicity in typical disc galaxies.

Solubility studies of Np(IV)

International Nuclear Information System (INIS)

Zhang Yingjie; Yao Jun; Jiao Haiyang; Ren Lihong; Zhou Duo; Fan Xianhua

2001-01-01

The solubility of Np(IV) in simulated underground water and redistilled water has been measured with the variations of pH(6-12) and storage time (0-100 d) in the presence of reductant (Na 2 S 2 O 4 , metallic Fe). All experiments are performed in a low oxygen concentration glove box containing high purity Ar(99.99%), with an oxygen content of less than 5 x 10 -6 mol/mol. Experimental results show that the variation of pH in solution has little effect on the solubility of Np(IV) in the two kinds of water; the measured solubility of Np(IV) is affected by the composition of solution; with Na 2 S 2 O 4 as a reductant, the solubility of Np(IV) in simulated underground water is (9.23 +- 0.48) x 10 -10 mol/L, and that in redistilled water is (8.31 +- 0.35) x 10 -10 mol/L; with metallic Fe as a reductant, the solubility of Np(IV) in simulated underground water is (1.85 +- 0.56) x 10 -9 mol/L, and that in redistilled water is (1.48 +- 0.66) x 10 -9 mol/L

Process for Making a Noble Metal on Tin Oxide Catalyst

Science.gov (United States)

Davis, Patricia; Miller, Irvin; Upchurch, Billy

2010-01-01

To produce a noble metal-on-metal oxide catalyst on an inert, high-surface-area support material (that functions as a catalyst at approximately room temperature using chloride-free reagents), for use in a carbon dioxide laser, requires two steps: First, a commercially available, inert, high-surface-area support material (silica spheres) is coated with a thin layer of metal oxide, a monolayer equivalent. Very beneficial results have been obtained using nitric acid as an oxidizing agent because it leaves no residue. It is also helpful if the spheres are first deaerated by boiling in water to allow the entire surface to be coated. A metal, such as tin, is then dissolved in the oxidizing agent/support material mixture to yield, in the case of tin, metastannic acid. Although tin has proven especially beneficial for use in a closed-cycle CO2 laser, in general any metal with two valence states, such as most transition metals and antimony, may be used. The metastannic acid will be adsorbed onto the high-surface-area spheres, coating them. Any excess oxidizing agent is then evaporated, and the resulting metastannic acid-coated spheres are dried and calcined, whereby the metastannic acid becomes tin(IV) oxide. The second step is accomplished by preparing an aqueous mixture of the tin(IV) oxide-coated spheres, and a soluble, chloride-free salt of at least one catalyst metal. The catalyst metal may be selected from the group consisting of platinum, palladium, ruthenium, gold, and rhodium, or other platinum group metals. Extremely beneficial results have been obtained using chloride-free salts of platinum, palladium, or a combination thereof, such as tetraammineplatinum (II) hydroxide ([Pt(NH3)4] (OH)2), or tetraammine palladium nitrate ([Pd(NH3)4](NO3)2).

Theoretical assessment of the electro-optical features of the group III nitrides (B{sub 12}N{sub 12}, Al{sub 12}N{sub 12} and Ga{sub 12}N{sub 12}) and group IV carbides (C{sub 24}, Si{sub 12}C{sub 12} and Ge{sub 12}C{sub 12}) nanoclusters encapsulated with alkali metals (Li, Na and K)

Energy Technology Data Exchange (ETDEWEB)

Tahmasebi, Elham [Chemistry Department, Faculty of Science, Lorestan University, Khorram Abad, Lorestan (Iran, Islamic Republic of); Shakerzadeh, Ehsan, E-mail: e.shakerzadeh@scu.ac.ir [Chemistry Department, Faculty of Science, Shahid Chamran University, Ahvaz (Iran, Islamic Republic of); Biglari, Zeinab [Chemistry Department, Faculty of Science, Lorestan University, Khorram Abad, Lorestan (Iran, Islamic Republic of)

2016-02-15

Graphical abstract: - Highlights: • Encapsulation of Li, Na and K narrow the HOMO–LUMO gaps of the clusters. • The group III nitrides nanoclusters strongly interacted with the alkali metals. • First hyperpolarizabilities remarkably enhance for B{sub 12}N{sub 12} encapsulated with Na/K. - Abstract: Density functional theory (DFT) calculations have been carried out to study the influence of alkali metals (Li, Na and K) encapsulation within the group III nitrides (B{sub 12}N{sub 12}, Al{sub 12}N{sub 12} and Ga{sub 12}N{sub 12}) and the group IV carbides (C{sub 24}, Si{sub 12}C{sub 12}and Ge{sub 12}C{sub 12}) nanoclusters. The encapsulation of Li, Na and K atoms is found to narrow the HOMO–LUMO gaps of the considered clusters. The electronic properties of these clusters, especially the group III nitrides nanoclusters, are strongly sensitive to interaction with the alkali metals. Moreover it is observed that the encapsulation of alkali metals enhances the first hyperpolarizabilities of B{sub 12}N{sub 12} nanocluster. Surprisingly, due to the alkali metals encapsulation within B{sub 12}N{sub 12} nanocluster, the first hyperpolarizability values are remarkably increased to 8505.49 and 122,503.76 a.u. for Na@B{sub 12}N{sub 12} and K@B{sub 12}N{sub 12}, respectively. Also the TD-DFT calculations at both CAM-B3LYP/6-311+G(d) and PBE0/6-311+G(d) levels of theory are also performed to investigate the origin of first hyperpolarizabilities.

Recent strikes in South Africa’s platinum-group metal mines: effects upon world platinum-group metal supplies

Science.gov (United States)

Yager, Thomas R.; Soto-Viruet, Yadira; Barry, James J.

2012-01-01

The recent labor disputes over wages and working conditions that have affected South Africa’s three leading platinum-group metal (PGM) producers have affected an industry already plagued by market pressures and labor unrest and raised the specter of constraints in the world’s supply of these metals. Although low demand for these metals in 2011 and 2012 helped to offset production losses of recent years, and particularly those losses caused by the strikes in 2012, a prolonged resumption of strikes could cause severe shortages of iridium, platinum, rhodium, ruthenium, and, to a lesser extent, palladium.

Hot carrier dynamics in plasmonic transition metal nitrides

Science.gov (United States)

Habib, Adela; Florio, Fred; Sundararaman, Ravishankar

2018-06-01

Extraction of non-equilibrium hot carriers generated by plasmon decay in metallic nano-structures is an increasingly exciting prospect for utilizing plasmonic losses, but the search for optimum plasmonic materials with long-lived carriers is ongoing. Transition metal nitrides are an exciting class of new plasmonic materials with superior thermal and mechanical properties compared to conventional noble metals, but their suitability for plasmonic hot carrier applications remains unknown. Here, we present fully first principles calculations of the plasmonic response, hot carrier generation and subsequent thermalization of all group IV, V and VI transition metal nitrides, fully accounting for direct and phonon-assisted transitions as well as electron–electron and electron–phonon scattering. We find the largest frequency ranges for plasmonic response in ZrN, HfN and WN, between those of gold and silver, while we predict strongest absorption in the visible spectrum for the VN, NbN and TaN. Hot carrier generation is dominated by direct transitions for most of the relevant energy range in all these nitrides, while phonon-assisted processes dominate only below 1 eV plasmon energies primarily for the group IV nitrides. Finally, we predict the maximum hot carrier lifetimes to be around 10 fs for group IV and VI nitrides, a factor of 3–4 smaller than noble metals, due to strong electron–phonon scattering. However, we find longer carrier lifetimes for group V nitrides, comparable to silver for NbN and TaN, while exceeding 100 fs (twice that of silver) for VN, making them promising candidates for efficient hot carrier extraction.

Metal-doped semiconductor nanoparticles and methods of synthesis thereof

Science.gov (United States)

Ren, Zhifeng (Inventor); Chen, Gang (Inventor); Poudel, Bed (Inventor); Kumar, Shankar (Inventor); Wang, Wenzhong (Inventor); Dresselhaus, Mildred (Inventor)

2009-01-01

The present invention generally relates to binary or higher order semiconductor nanoparticles doped with a metallic element, and thermoelectric compositions incorporating such nanoparticles. In one aspect, the present invention provides a thermoelectric composition comprising a plurality of nanoparticles each of which includes an alloy matrix formed of a Group IV element and Group VI element and a metallic dopant distributed within the matrix.

Effect of HCl Concentration on the Oxidation of LIX 63 and the Subsequent Separation of Pd(II), Pt(IV), Ir(IV) and Rh(III) by Solvent Extraction

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Thi Hong; Lee, Man Seung [Mokpo National University, Jeollanamdo (Korea, Republic of)

2016-10-15

During the selective extraction of Pd(II) by LIX 63 from 6 M HCl solutions containing platinum group metals, an oxidation-reduction reaction occurs between the LIX 63 and Ir(IV). Since the reduced Ir(III) cannot be extracted by solvating and amine extractants, the oxidation-reduction reaction has a significant effect on the separation of Pt(IV), Ir(IV) and Rh(III). Therefore, the effect of HCl concentration on the reduction of Ir(IV) during the extraction with LIX 63 was investigated at 3 and 6 M HCl solutions. The extraction behavior of Iridium by Aliquat 336 from the Pd(II) free raffinate showed that the percentage of iridium extraction rapidly decreased when HCl concentration was increased from 3 to 6 M, indicating that more Ir(IV) was reduced to Ir(III). Extraction schemes for the separation of Pt(IV), iridium and Rh(III) by Aliquat 336 from 3 and 6 M HCl solutions were investigated.

Thin-layer chromatography of ternary complexes of group-IIIA metals with 2-thenoyltrifluoroacetone and 2,2'-bipyridyl on cellulose layer

Energy Technology Data Exchange (ETDEWEB)

Chao, H E; Saitoh, K; Suzuki, N [Tohoku Univ., Sendai (Japan). Faculty of Science

1980-11-11

Normal phase thin-layer chromatographic behaviour of several ternary complexes of group-IIIA metals with 2-thenoyltrifluoroacetone (TTA) and 2,2'bipyridyl (bpy) has been investigated on cellulose layer. The ternary complexes of lanthanide metals show higher mutual separability than the complexes with TTA alone. Mutual separation of TTA complexes with La(III), Ce(III), Eu(III) or Y(III), Sc(III), Th(IV), and U(VI) has been successfully achieved by two-dimensional TLC, primarily with carbon tetrachloride-benzene (75:25) containing 0.02M TTA, and secondary with carbon tetrachloride-hexane (35:65) containing both 0.02M TTA and 0.02M bpy.

Adsorption of alkali and alkaline-earth metal atoms on stanene: A first-principles study

Energy Technology Data Exchange (ETDEWEB)

Kadioglu, Yelda; Ersan, Fatih [Department of Physics, Adnan Menderes University, 09100 Aydın (Turkey); Gökoğlu, Gökhan [Department of Physics, Karabük University, 78050 Karabük (Turkey); Aktürk, Olcay Üzengi [Department of Electrical & Electronics Engineering, Adnan Menderes University, 09100 Aydın (Turkey); Nanotechnology Application and Research Center, Adnan Menderes University, 09100 Aydın (Turkey); Aktürk, Ethem, E-mail: ethem.akturk@adu.edu.tr [Department of Physics, Adnan Menderes University, 09100 Aydın (Turkey); Nanotechnology Application and Research Center, Adnan Menderes University, 09100 Aydın (Turkey)

2016-09-01

This paper presents a study on the adsorption of alkali and alkaline-earth metal atoms on single-layer stanene with different levels of coverage using first-principles plane wave calculations within spin-polarized density functional theory. The most favorable adsorption site for alkali atoms (Li, Na, K) were found to be the hollow site similar to other group IV single-layers, but the case of alkaline-earths on stanene is different from silicene and germanene. Whereas Mg and Ca are bound to stanene at hollow site, the bridge site is found to be energetically favorable for Be adatom. All adsorbed atoms are positively charged due to the charge transfer from adatom to stanene single-layer. The semimetallic bare stanene become metallic except for Be adsorption. The Beryllium adsorption give rise to non-magnetic semiconducting ground state. Our results illustrate that stanene has a reactive and functionalizable surface similar to graphene or silicene. - Highlights: • Alkali and alkaline-earth metal atoms form stronger bonds with stanene compared to other group IV monolayers. • Semi-metallic stanene becomes nonmagnetic metal for Li, Na, K, Mg, and Ca atoms adsorption. • Semi-metallic stanene becomes nonmagnetic semiconductor with 94 meV band gap for Be atom adsorption.

Hepatic imaging in stage IV-S neuroblastoma

International Nuclear Information System (INIS)

Franken, E.A. Jr.; Smith, W.L.; Iowa Univ., Iowa City; Cohen, M.D.; Kisker, C.T.; Platz, C.E.

1986-01-01

Stage IV-S neuroblastoma describes a group of infants with tumor spread limited to liver, skin, or bone marrow. Such patients, who constitute about 25% of affected infants with neuroblastoma, may expect spontaneous tumor remission. We report 18 infants with Stage IV-S neuroblastoma, 83% of whom had liver involvement. Imaging investigations included Technetium 99m sulfur colloid scan, ultrasound, and CT. Two patterns of liver metastasis were noted: ill-defined nodules or diffuse tumor throughout the liver. Distinction of normal and abnormal liver with diffuse type metastasis could be quite difficult, particularly with liver scans. We conclude that patients with Stage IV-S neuroblastoma have ultrasound or CT examination as an initial workup, with nuclear medicine scans reserved for followup studies. (orig.)

Salen- Zr(IV) complex grafted into amine-tagged MIL-101(Cr) as a robust multifunctional catalyst for biodiesel production and organic transformation reactions

Science.gov (United States)

Hassan, Hassan M. A.; Betiha, Mohamed A.; Mohamed, Shaimaa K.; El-Sharkawy, E. A.; Ahmed, Emad A.

2017-08-01

The synthesis of metal-organic frameworks (MOFs), porous coordination polymers with functional groups has received immense interest due to the functional groups can offer desirable properties and allow post-synthetic modification. Herein, for the first time, Zr(IV)-Sal Schiff base complex incorporated into amino-functionalized MIL-101(Cr) framework by salicylaldehyde condensing to amino group, and coordinating Zr(IV) ion have been successfully synthesized. The worthiness of the synthesized material as a catalyst has been examined for the esterification of oleic acid (free fatty acid) with methanol producing biodiesel (methyl oleate), Knoveonagel condensation reaction of aldehydes and Friedel-Crafts acylation of anisole. Our findings demonstrated that Salen-Zr(IV) grafted to framework of NH2-MIL-101(Cr) as a solid acid catalyst exhibited distinct catalytic performance for the production of biodiesel by esterification of oleic acid with methanol, Knoveonagel condensation and Friedel-Crafts acylation. These could be attributed to high surface area which allow high distribution of Zr(IV) species lead to a sufficient contact with the reactants species. Furthermore, the catalyst showed excellent recycling efficiency due to the strong interaction between the Zr(IV) ions and chelating groups in the NH2-MIL-101(Cr)-Sal.

Emergence of group B Streptococcus serotype IV in women of child-bearing age in Ireland.

LENUS (Irish Health Repository)

Kiely, R A

2011-02-01

This study determined the carriage rate and serotype distribution of group B Streptococcus (GBS) in women of child-bearing age in the southern region of Ireland. A total of 2000 vaginal swabs collected in two periods in 2004 and 2006 were examined and revealed a GBS carriage rate of 16·1%. Serotyping of isolates showed that serotypes Ia, II, III, IV, and V were the most prevalent. A high prevalence of serotype IV was found, increasing from 7·6% to 15·2% between 2004 and 2006. Random amplified polymorphic DNA analysis demonstrated considerable genetic heterogeneity in the serotype IV isolates. This serotype should be considered for inclusion in potential vaccines for use in Ireland.

The mechanism of diffusion and ionic transport of alkali metal ions in the particles of tin(IV) antimonate

International Nuclear Information System (INIS)

El-Naggar, I.M.; El-Absy, M.A.; Aly, S.I.; Atomic Energy Establishment, Cairo

1992-01-01

The kinetics of exchange Li + , Na + , K + and Cs + ions of tin(IV) antimonate with H + form was studied under particle-diffusion-control conditions at different temperatures. The value of activation energy, diffusion coefficient and entropy of activation increase with the ionic mobilities and radii, and decrease with the hydration energy of the alkali metal ions. On the basis of the kinetic parameters, the exchange of alkali metal ions occurs in the unhydrated form. (author). 29 refs.; 4 figs.; 2 tabs

Group IV Light Sources to Enable the Convergence of Photonics and Electronics

Directory of Open Access Journals (Sweden)

Shinichi eSaito

2014-09-01

Full Text Available Group IV lasers are expected to revolutionize chip-to-chip optical communications in terms of cost, scalability, yield, and compatibility to the existing infrastructure of silicon industries for mass production. Here, we review the current state-of-the-art developments of silicon and germanium light sources towards monolithic integration. Quantum confinement of electrons and holes in nano-structures has been the primary route for light emission from silicon, and we can use advanced silicon technologies using top-down patterning processes to fabricate these nano-structures, including fin-type vertical multiple quantum wells. Moreover, the electromagnetic environment can also be manipulated in a photonic crystal nano-cavity to enhance the efficiency of light extraction and emission by the Purcell effect. Germanium is also widely investigated as an active material in Group IV photonics, and novel epitaxial growth technologies are being developed to make a high quality germanium layer on a silicon substrate. To develop a practical germanium laser, various technologies are employed for tensile-stress engineering and high electron doping to compensate the indirect valleys in the conduction band. These challenges are aiming to contribute towards the convergence of electronics and photonics on a silicon chip.

Fatigue-induced changes in group IV muscle afferent activity: differences between high- and low-frequency electrically induced fatigues.

Science.gov (United States)

Darques, J L; Jammes, Y

1997-03-07

Recordings of group IV afferent activity of tibialis anterior muscle were performed in paralysed rabbits during runs of electrically induced fatigue produced by direct muscle stimulation at a high (100 Hz, high-frequency fatigue HFF) or a low rate (10 Hz, low-frequency fatigue LFF). In addition to analysis of afferent nerve action potentials, muscle force and compound muscle action potentials (M waves) elicited by direct muscle stimulation with single shocks were recorded. Changes in M wave configuration were used as an index of the altered propagation of membrane potentials and the associated efflux of potassium from muscle fibers. The data show that increased group IV afferent activity occurred during LFF as well as HFF trials and developed parallel with force failure. Enhanced afferent activity was significantly higher during LFF (maximal delta f(impulses) = 249 +/- 35%) than HFF (147 +/- 45%). No correlation was obtained between the responses of group IV afferents to LFF or to pressure exerted on tibialis anterior muscle. On the other hand, decreased M wave amplitude was minimal with LFF while it was pronounced with HFF. Close correlations were found between fatigue-induced activation of group IV afferents and decreases in force or M wave amplitude, but their strength was significantly higher with LFF compared to HFF. Thus, electrically induced fatigue activates group IV muscle afferents with a prominent effect of low-frequency stimulation. The mechanism of muscle afferent stimulation does not seem to be due to the sole increase in extracellular potassium concentration, but also by the efflux of muscle metabolites, present during fatiguing contractions at low rate of stimulation.

A further insight into the biosorption mechanism of Pt(IV by infrared spectrometry

Directory of Open Access Journals (Sweden)

Xu Zhenling

2009-07-01

Full Text Available Abstract Background Platinum nanomaterial is one of the significant noble metal catalysts, and the interaction of platinum with microbe is one of the key factors in influencing the size and the distribution of the platinum nanoparticles on the microbial biomass. Some properties of Pt(IV adsorption and reduction by resting cells of Bacillus megatherium D01 biomass have once been investigated, still the mechanism active in the platinum biosorption remains to be seen and requires further elucidating. Result A further insight into the biosorption mechanism of Pt(IV onto resting cells of Bacillus megatherium D02 biomass on a molecular level has been obtained. The image of scanning electron microscopy (SEM of the D02 biomass challenged with Pt(IV displayed a clear distribution of bioreduced platinum particles with sizes of nanometer scale on the biomass. The state of Pt(IV bioreduced to elemental Pt(0 examined via X-ray photoelectron spectroscopy (XPS suggested that the biomass reduces the Pt(IV to Pt(II followed by a slower reduction to Pt(0. The analysis of glucose content in the hydrolysates of D02 biomass for different time intervals using ultraviolet-visible (UV-vis spectrophotometry indicated that certain reducing sugars occur in the hydrolyzed biomass and that the hydrolysis of polysaccharides of the biomass is a rapid process. The infrared (IR spectrometry on D02 biomass and that challenged with Pt(IV, and on glucose and that reacted with Pt(IV demonstrated that the interaction of the biomass with Pt(IV seems to be through oxygenous or nitrogenous chemical functional groups on the cell wall biopolymers; that the potential binding sites for Pt species include hydroxyl of saccharides, carboxylate anion and carboxyl of amino acid residues, peptide bond, etc.; and that the free monosaccharic group bearing hemiacetalic hydroxyl from the hydrolyzed biomass behaving as an electron donor, in situ reduces the Pt(IV to Pt(0. And moreover, the binding of

The stability boundary of group-III transition metal diboride ScB 2 (0 0 0 1) surfaces

Science.gov (United States)

Zhao, Hui; Qin, Na

2012-01-01

Experimental observations and theoretical investigations exhibit that a group-IV(V) transition metal diboride (0 0 0 1) surface is terminated with a 1 × 1 TM(B) layer. As to a group-III transition metal diboride, we have investigated the stability boundary of ScB2 (0 0 0 1) surfaces using first principles total energy plane-wave pseudopotential method based on density functional theory. The Mulliken charge population analysis shows that Sc atoms in the second layer cannot provide B atoms in the first layer with sufficient electrons to form a complete graphene-like boron layer. We also found that the charge transfer between the first and the second layer for the B-terminated surface is more than that for Sc-terminated surface. It elucidates the reason that the outermost interlayer spacing contract more strongly in the B-terminated surface than in the Sc-terminated surface. The surface energies of both terminated ScB2 (0 0 0 1) surfaces as a function of the chemical potential of B are also calculated to check the relative stability of the two surface structures.

Synthesis, spectral, DFT modeling, cytotoxicity and microbial studies of novel Zr(IV), Ce(IV) and U(VI) piroxicam complexes

Science.gov (United States)

El-Shwiniy, Walaa H.; Zordok, Wael A.

2018-06-01

The Zr(IV), Ce(IV) and U(VI) piroxicam anti-inflammatory drug complexes were prepared and characterized using elemental analyses, conductance, IR, UV-Vis, magnetic moment, IHNMR and thermal analysis. The ratio of metal: Pir is found to be 1:2 in all complexes estimated by using molar ratio method. The conductance data reveal that Zr(IV) and U(VI) chelates are non-electrolytes except Ce(IV) complex is electrolyte. Infrared spectroscopic confirm that the Pir behaves as a bidentate ligand co-ordinated to the metal ions via the oxygen and nitrogen atoms of ν(Cdbnd O)carbonyl and ν(Cdbnd N)pyridyl, respectively. The kinetic parameters of thermogravimetric and its differential, such as activation energy, entropy of activation, enthalpy of activation, and Gibbs free energy evaluated using Coats-Redfern and Horowitz-Metzger equations for Pir and complexes. The geometry of the piroxicam drug in the Free State differs significantly from that in the metal complex. In the time of metal ion-drug bond formation the drug switches-on from the closed structure (equilibrium geometry) to the open one. The antimicrobial tests were assessed towards some types of bacteria and fungi. The in vitro cell cytotoxicity of the complexes in comparison with Pir against colon carcinoma (HCT-116) cell line was measured. Optimized geometrical structure of piroxicam ligand by using DFT calculations.

Synthesis, structure, and thermal properties of soluble hydrazinium germanium(IV) and tin(IV) selenide salts.

Science.gov (United States)

Mitzi, David B

2005-05-16

The crystal structures of two hydrazinium-based germanium(IV) and tin(IV) selenide salts are determined. (N(2)H(5))(4)Ge(2)Se(6) (1) [I4(1)cd, a = 12.708(1) Angstroms, c = 21.955(2) Angstroms, Z = 8] and (N(2)H(4))(3)(N(2)H(5))(4)Sn(2)Se(6) (2) [P, a = 6.6475(6) Angstroms, b = 9.5474(9) Angstroms, c = 9.8830(10) Angstroms, alpha = 94.110(2) degrees, beta = 99.429(2) degrees, gamma = 104.141(2) degrees, Z = 1] each consist of anionic dimers of edge-sharing metal selenide tetrahedra, M(2)Se(6)(4-) (M = Ge or Sn), separated by hydrazinium cations and, for 2, additional neutral hydrazine molecules. Substantial hydrogen bonding exists among the hydrazine/hydrazinium molecules as well as between the hydrazinium cations and the selenide anions. Whereas the previously reported tin(IV) sulfide system, (N(2)H(5))(4)Sn(2)S(6), decomposes cleanly to microcrystalline SnS(2) when heated to 200 degrees C in an inert atmosphere, higher temperatures (>300 degrees C) are required to dissociate selenium from 1 and 2 for the analogous preparations of single-phase metal selenides. The metal chalcogenide salts are highly soluble in hydrazine, as well as in a variety of amines and DMSO, highlighting the potential usefulness of these compounds as precursors for the solution deposition of the corresponding metal chalcogenide films.

Group 13 ligand supported heavy-metal complexes: first structural evidence for gallium-lead and gallium-mercury bonds.

Science.gov (United States)

Prabusankar, Ganesan; Gemel, Christian; Winter, Manuela; Seidel, Rüdiger W; Fischer, Roland A

2010-05-25

Heavy-metal complexes of lead and mercury stabilized by Group 13 ligands were derived from the oxidative addition of Ga(ddp) (ddp=HC(CMeNC(6)H(3)-2,6-iPr(2))(2), 2-diisopropylphenylamino-4-diisopropyl phenylimino-2-pentene) with corresponding metal precursors. The reaction of Me(3)PbCl and Ga(ddp) afforded compound [{(ddp)Ga(Cl)}PbMe(3)] (1) composed of Ga-Pb(IV) bonds. In addition, the monomeric plumbylene-type compound [{(ddp)Ga(OSO(2)CF(3))}(2)Pb(thf)] (2a) with an unsupported Ga-Pb(II)-Ga linkage was obtained by the reaction of [Pb(OSO(2)CF(3))(3)] with Ga(ddp) (2 equiv). Compound 2a falls under the rare example of a discrete plumbylene-type compound supported by a nonclassical ligand. Interesting structural changes were observed when [Pb(OSO(2)CF(3))(3)]2.H(2)O was treated with Ga(ddp) in a 1:2 ratio to yield [{(ddp)Ga(mu-OSO(2)CF(3))}(2)(OH(2))Pb] (2b) at below -10 degrees C. Compound 2b consists of a bent Ga-Pb-Ga backbone with a bridging triflate group between the Ga-Pb bond and a weakly interacting water molecule at the gallium center. Similarly, the reaction of mercury thiolate Hg(SC(6)F(5)) with Ga(ddp) (2 equiv) produced the bimetallic homoleptic compounds anti-[{(ddp)Ga(SC(6)F(5))}(2)Hg] (3a) and gauche-[{(ddp)Ga(SC(6)F(5))}(2)Hg] (3b), respectively, with a linear Ga-Hg-Ga linkage. Compounds 1-3 were structurally characterized and these are the first examples of compounds comprised of Ga-Pb(II), Ga-Pb(IV), and Ga-Hg bonds.

Special quasirandom structures for binary/ternary group IV random alloys

KAUST Repository

Chroneos, Alexander I.

2010-06-01

Simulation of defect interactions in binary/ternary group IV semiconductor alloys at the density functional theory level is difficult due to the random distribution of the constituent atoms. The special quasirandom structures approach is a computationally efficient way to describe the random nature. We systematically study the efficacy of the methodology and generate a number of special quasirandom cells for future use. In order to demonstrate the applicability of the technique, the electronic structures of E centers in Si1-xGex and Si1-x -yGexSny alloys are discussed for a range of nearest neighbor environments. © 2010 Elsevier B.V. All rights reserved.

Bioenergetics and ATP Synthesis during Exercise: Role of Group III/IV Muscle Afferents.

Science.gov (United States)

Broxterman, Ryan M; Layec, Gwenael; Hureau, Thomas J; Morgan, David E; Bledsoe, Amber D; Jessop, Jacob E; Amann, Markus; Richardson, Russell S

2017-12-01

The purpose of this study was to investigate the role of the group III/IV muscle afferents in the bioenergetics of exercising skeletal muscle beyond constraining the magnitude of metabolic perturbation. Eight healthy men performed intermittent isometric knee-extensor exercise to task failure at ~58% maximal voluntary contraction under control conditions (CTRL) and with lumbar intrathecal fentanyl to attenuate group III/IV leg muscle afferents (FENT). Intramuscular concentrations of phosphocreatine (PCr), inorganic phosphate (Pi), diprotonated phosphate (H2PO4), adenosine triphosphate (ATP), and pH were determined using phosphorous magnetic resonance spectroscopy (P-MRS). The magnitude of metabolic perturbation was significantly greater in FENT compared with CTRL for [Pi] (37.8 ± 16.8 vs 28.6 ± 8.6 mM), [H2PO4] (24.3 ± 12.2 vs 17.9 ± 7.1 mM), and [ATP] (75.8% ± 17.5% vs 81.9% ± 15.8% of baseline), whereas there was no significant difference in [PCr] (4.5 ± 2.4 vs 4.4 ± 2.3 mM) or pH (6.51 ± 0.10 vs 6.54 ± 0.14). The rate of perturbation in [PCr], [Pi], [H2PO4], and pH was significantly faster in FENT compared with CTRL. Oxidative ATP synthesis was not significantly different between conditions. However, anaerobic ATP synthesis, through augmented creatine kinase and glycolysis reactions, was significantly greater in FENT than in CTRL, resulting in a significantly greater ATP cost of contraction (0.049 ± 0.016 vs 0.038 ± 0.010 mM·min·N). Group III/IV muscle afferents not only constrain the magnitude of perturbation in intramuscular Pi, H2PO4, and ATP during small muscle mass exercise but also seem to play a role in maintaining efficient skeletal muscle contractile function in men.

Magnetism in Mn-nanowires and -clusters as δ-doped layers in group IV semiconductors (Si, Ge)

Science.gov (United States)

Simov, K. R.; Glans, P.-A.; Jenkins, C. A.; Liberati, M.; Reinke, P.

2018-01-01

Mn doping of group-IV semiconductors (Si/Ge) is achieved by embedding nanostructured Mn-layers in group-IV matrix. The Mn-nanostructures are monoatomic Mn-wires or Mn-clusters and capped with an amorphous Si or Ge layer. The precise fabrication of δ-doped Mn-layers is combined with element-specific detection of the magnetic signature with x-ray magnetic circular dichroism. The largest moment (2.5 μB/Mn) is measured for Mn-wires with ionic bonding character and a-Ge overlayer cap; a-Si capping reduces the moment due to variations of bonding in agreement with theoretical predictions. The moments in δ-doped layers dominated by clusters is quenched with an antiferromagnetic component from Mn-Mn bonding.

Extending the Use of Highly Porous and Functionalized MOFs to Th(IV) Capture.

Science.gov (United States)

Zhang, Nan; Yuan, Li-Yong; Guo, Wen-Lu; Luo, Shi-Zhong; Chai, Zhi-Fang; Shi, Wei-Qun

2017-08-02

Thorium separation has recently become a hot topic because of the potential application of thorium as a future nuclear fuel, while metal-organic framework (MOF) materials have received much attention in the separation field due to their unique properties. Herein, a highly porous and stable MOF, UiO-66, and its carboxyl derivatives (UiO-66-COOH and UiO-66-(COOH) 2 ) were synthesized and explored for the first time for Th(IV) capture from a weak acidic solution. Although the introduction of carboxyl groups into UiO-66 leads to an obvious decrease in the surface area and pore volume, the adsorbability toward Th(IV) is greatly enhanced. At pH = 3.0, the saturated sorption capacity for Th(IV) into UiO-66-(COOH) 2 reached 350 mg/g, representing one of the largest values for Th(IV) capture by solid extraction. Moreover, the functionalized MOFs show fast sorption kinetics and desirable selectivity toward Th(IV) over a range of competing metal ions. A possible mechanism for the selective recognition of Th(IV) by these MOFs was explored on the basis of extended X-ray absorption fine structure and Fourier transform infrared analysis. It is concluded that UiO-66-COOH and UiO-66-(COOH) 2 sorb Th(IV) through the coordination of carboxyl anions in the pores of the MOFs, whereas in the case of UiO-66, both the precipitation and the exchange with the organic solvent contribute to the Th(IV) uptake. This study contributes to the assessment of the feasibility of MOFs applied in actinides separation and better understanding of actinides sorption behavior in this kind of hybrid porous solid materials.

Bifactor model of WISC-IV: Applicability and measurement invariance in low and normal IQ groups.

Science.gov (United States)

Gomez, Rapson; Vance, Alasdair; Watson, Shaun

2017-07-01

This study examined the applicability and measurement invariance of the bifactor model of the 10 Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) core subtests in groups of children and adolescents (age range from 6 to 16 years) with low (IQ ≤79; N = 229; % male = 75.9) and normal (IQ ≥80; N = 816; % male = 75.0) IQ scores. Results supported this model in both groups, and there was good support for measurement invariance for this model across these groups. For all participants together, the omega hierarchical and explained common variance (ECV) values were high for the general factor and low to negligible for the specific factors. Together, the findings favor the use of the Full Scale IQ (FSIQ) scores of the WISC-IV, but not the subscale index scores. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Recycling of platinum group metals from the automotive catalysts

International Nuclear Information System (INIS)

Benevit, Mariana; Petter, Patricia Melo Halmenschlager; Veit, Hugo Marcelo

2014-01-01

Currently it is very important to use alternative sources of raw material for obtaining metals, avoiding the traditional mining. This work aims to characterize and evaluate the recoverability of platinum group metals present in automotive catalysts. Thus, the catalysts were divided into two groups: the first was catalysts used in 1.0 cars and the second was catalyst used in 2.0 cars. DRX and FRX techniques and chemical analysis performed by ICP/OES was used to characterized these materials. The results showed that there is a significant amount of platinum group elements in catalyst waste, which can be separated and reused. In the next step, hydro and pyrometallurgical routes, for metals extraction from catalyst waste, will be studied. (author)

Influence of NO2 and metal ions on oxidation of aqueous-phase S(IV in atmospheric concentrations

Directory of Open Access Journals (Sweden)

Cláudia R. Martins

2008-06-01

Full Text Available An investigation was made of the influence of atmospheric concentrations (15 or 130 ppbv of NO2 on the aqueous-phase oxidation rate of S(IV in the presence and absence of Fe(III, Mn(II and Cr(VI metal ions under controlled experimental conditions (pH, T, concentration of reactants, etc.. The reaction rate in the presence of the NO2 flow was slower than the reaction rate using only clean air with an initial S(IV concentration of 10-4 mol/L. NO2 appears to react with S(IV, producing a kind of inhibitor that slows down the reaction. Conversely, tenfold lower concentrations of S(IV ([S(IV]º = 10-5 mol/L caused a faster reaction in the presence of NO2 than the reaction using purified air. Under these conditions, therefore, the equilibrium shifts to sulfate formation. With the addition of Fe(III, Mn(II or Cr(VI in the presence of a NO2 flow, the reaction occurred faster under all the conditions in which S(IV oxidation was investigated.A reação de oxidação de S(IV em fase aquosa foi estudada em laboratório em presença de NO2 dos íons metálicos Fe(III, Mn(II, e Cr(VI sob condições experimentais controladas (pH, T, concentração dos reagentes, etc.. Na presença de corrente de ar com NO2 (15 ou 130 ppbv a reação de oxidação de S(IV ocorreu mais lentamente do que na presença de ar purificado, para uma concentração inicial de S(IV de 10-4 mol/L. Ao contrário, para concentração inicial de S(IV dez vezes menor ([S(IV]° = 10-5 mol/L a reação ocorreu mais rapidamente na presença de NO2. A explicação está relacionada com o equilíbrio envolvendo a formação de espécies intermediárias de longa vida, que impedem o prosseguimento da reação, porém a depender das concentrações relativas de S(IV e NO2, essas espécies se decompõem deslocando o equilíbrio no sentido de formação de sulfato. A adição dos íons Fe(III, Mn(II ou Cr(VI em presença de corrente de ar com NO2 indicou atividade catalítica para esses íons, em todas

Magnetism in Mn-nanowires and -clusters as δ-doped layers in group IV semiconductors (Si, Ge

Directory of Open Access Journals (Sweden)

K. R. Simov

2018-01-01

Full Text Available Mn doping of group-IV semiconductors (Si/Ge is achieved by embedding nanostructured Mn-layers in group-IV matrix. The Mn-nanostructures are monoatomic Mn-wires or Mn-clusters and capped with an amorphous Si or Ge layer. The precise fabrication of δ-doped Mn-layers is combined with element-specific detection of the magnetic signature with x-ray magnetic circular dichroism. The largest moment (2.5 μB/Mn is measured for Mn-wires with ionic bonding character and a-Ge overlayer cap; a-Si capping reduces the moment due to variations of bonding in agreement with theoretical predictions. The moments in δ-doped layers dominated by clusters is quenched with an antiferromagnetic component from Mn–Mn bonding.

Near infrared group IV optoelectronics and novel pre-cursors for CVD epitaxy

Science.gov (United States)

Hazbun, Ramsey Michael

Near infrared and mid infrared optoelectronic devices have become increasingly important for the telecommunications, security, and medical imaging industries. The addition of nitrogen to III-V alloys has been widely studied as a method of modifying the band gap for mid infrared (IR) applications. In xGa1-xSb1-y Ny/InAs strained-layer superlattices with type-II (staggered) energy offsets on GaSb substrates, were modeled using eight-band k˙p simulations to analyze the superlattice miniband energies. Three different zero-stress strain balance conditions are reported: fixed superlattice period thickness, fixed InAs well thickness, and fixed InxGa1-xSb 1-yNy barrier thickness. Optoelectronics have traditionally been the realm of III-V semiconductors due to their direct band gap, while integrated circuit chips have been the realm of Group IV semiconductors such as silicon because of its relative abundance and ease of use. Recently the alloying of Sn with Ge and Si has been shown to allow direct band-gap light emission. This presents the exciting prospect of integrating optoelectronics into current Group IV chip fabrication facilities. However, new approaches for low temperature growth are needed to realize these new SiGeSn alloys. Silicon-germanium epitaxy via ultra-high vacuum chemical vapor deposition has the advantage of allowing low process temperatures. Deposition processes are sensitive to substrate surface preparation and the time delay between oxide removal and epitaxial growth. A new monitoring process utilizing doped substrates and defect decoration etching is demonstrated to have controllable and unique sensitivity to interfacial contaminants. Doped substrates were prepared and subjected to various loading conditions prior to the growth of typical Si/SiGe bilayers. The defect densities were correlated to the concentration of interfacial oxygen suggesting this monitoring process may be an effective complement to monitoring via secondary ion mass spectrometry

Group IV nanocrystals with ion-exchangeable surface ligands and methods of making the same

Science.gov (United States)

Wheeler, Lance M.; Nichols, Asa W.; Chernomordik, Boris D.; Anderson, Nicholas C.; Beard, Matthew C.; Neale, Nathan R.

2018-01-09

Methods are described that include reacting a starting nanocrystal that includes a starting nanocrystal core and a covalently bound surface species to create an ion-exchangeable (IE) nanocrystal that includes a surface charge and a first ion-exchangeable (IE) surface ligand ionically bound to the surface charge, where the starting nanocrystal core includes a group IV element.

Tunable magnetic states on the zigzag edges of hydrogenated and halogenated group-IV nanoribbons

Science.gov (United States)

Chuang, Feng-Chuan; Wang, Tzu-Cheng; Hsu, Chia-Hsiu; Huang, Zhi-Quan; Su, Wan-Sheng; Guo, Guang-Yu

The magnetic and electronic properties of hydrogenated and halogenated group-IV zigzag nanoribbons (ZNRs) are investigated by first-principles density functional calculations. Fascinatingly, we find that all the ZNRs have magnetic edges with a rich variety of electronic and magnetic properties tunable by selecting the parent and passivating elements as well as controlling the magnetization direction and external strain. In particular, the electric property of the edge band structure can be tuned from the conducting to insulating with a band gap up to 0.7 eV, depending on the parent and passivating elements as well as the applied strain, magnetic configuration and magnetization orientation. The last controllability would allow us to develop magnetic on-off nano-switches. Furthermore, ZNRs such as SiI, Ge, GeI and SnH, have fully spin-polarized metallic edge states and thus are promising materials for spintronics. The calculated magnetocrystalline anisotropy energy can be as large as 9 meV/edge-site, being 2000 time greater than that of bulk Ni and Fe ( 5 μeV/atom), and thus has great potential for high density magneto-electric data-storage devices. Finally, the calculated exchange coupling strength and thus magnetic transition temperature increases as the applied strain goes from -5 % to 5 %. Our findings thus show that these ZNRs would have exciting applications in next-generation electronic and spintronic nano-devices.

Generation and Characteristics of IV-VI transition Metal Nitride and Carbide Nanoparticles using a Reactive Mesoporous Carbon Nitride

KAUST Repository

Alhajri, Nawal Saad

2016-02-22

Interstitial nitrides and carbides of early transition metals in groups IV–VI exhibit platinum-like electronic structures, which make them promising candidates to replace noble metals in various catalytic reactions. Herein, we present the preparation and characterization of nano-sized transition metal nitries and carbides of groups IV–VI (Ti, V, Nb, Ta, Cr, Mo, and W) using mesoporous graphitic carbon nitride (mpg-C3N4), which not only provides confined spaces for restricting primary particle size but also acts as a chemical source of nitrogen and carbon. We studied the reactivity of the metals with the template under N2 flow at 1023 K while keeping the weight ratio of metal to template constant at unity. The produced nanoparticles were characterized by powder X-ray diffraction, CHN elemental analysis, nitrogen sorption, X-ray photoelectron spectroscopy, and transmission electron microscopy. The results show that Ti, V, Nb, Ta, and Cr form nitride phases with face centered cubic structure, whereas Mo and W forme carbides with hexagonal structures. The tendency to form nitride or carbide obeys the free formation energy of the transition metal nitrides and carbides. This method offers the potential to prepare the desired size, shape and phase of transition metal nitrides and carbides that are suitable for a specific reaction, which is the chief objective of materials chemistry.

Peruvian perovskite Between Transition-metal to PGM/PlatinumGroupMetal Catalytic Fusion

Science.gov (United States)

Maksoed, Wh-

2016-11-01

Strongly correlated electronic materials made of simple building blocks, such as a transition-metal ion in an octahedral oxygen cage forming a perovskite structure- Dagotto & Tokura for examples are the high-temperature superconductivity & the CMR/Colossal Magnetoresistance . Helium-4 denotes from LC Case,ScD: "Catalytic Fusion of Deuterium into Helium-4"- 1998 dealt with gaseous D2- "contacted with a supported metallic catalyst at superatmospheric pressure". The catalyst is a platinum-group metal, at about 0.5% - 1% by weight, on activated C. Accompanies Stephen J Geier, 2010 quotes "transition metal complexes", the Energy thus produced is enormous, and because the deuterium is very cheap in the form of heavy water (less than US 1/g), the fuel cost is very low (seas &Deuteronomy to be eternally preserves. Heartfelt Gratitudes to HE. Mr. Prof. Ir. HANDOJO.

Borides of the group 1 metals of the periodic system

International Nuclear Information System (INIS)

Samsonov, G.V.; Serebryakova, T.I.; Neronov, V.A.

1975-01-01

The borides of alkali metals (lithium, sodium, potassium) and the metals of a copper subgroup (copper, silver, gold) are described. Consideration is given to the crystalline structure and state diagrams of the metal systems within the first group of the Periodic Table with boron. Existence, formation conditions and physico-chemical properties of binary boride phases are characterized. Conclusion is made as to the absence of interaction between boron and silver. Information on the interaction between gold and boron is scanty and conflicting. Methods are described suitable for the production of the borides of the metals within the first group of the Periodic Table [ru

Selective recognition by novel calix system: ICT based chemosensor for metal ions

Energy Technology Data Exchange (ETDEWEB)

Bhatt, Keyur D.; Makwana, Bharat A.; Vyas, Disha J.; Mishra, Divya R.; Jain, Vinod K., E-mail: drvkjain@hotmail.com

2014-02-15

A new calix[4]pyrrole derivative bearing four dansyl groups through hydroxyl groups has been synthesized and duly characterized by FT-IR, NMR and ESI-MS. Tetra dansylated calix[4]pyrrole (TDCP) shows selective behavior for U(VI), Th(IV) and Fe(III) ions among all other metal ions, e.g. Li(I), Na(I), K(I), Ca(II), Ni(II), Cd(II), Cu(II), Zn(II), Pb(II), Hg(II) and Ag(I), in the absorption spectra as well as in the emission spectra. The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. The binding constants, stoichiometry and quantum yields have been determined. The mechanism of quenching by Stern–Vohmer equation has also been discussed. -- highlights: • A new selective turn-off fluorescent sensor i.e. tetra dansylated calix[4]pyrrole (TDCP) was synthesized and characterized. • The sensor shows selective behavior for U(VI), Th(IV) and Fe(III) ions among various other metal ions. • The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. • The sensor binds metal ions in 1:1 stoichiometry with good binding constant.

Selective recognition by novel calix system: ICT based chemosensor for metal ions

International Nuclear Information System (INIS)

Bhatt, Keyur D.; Makwana, Bharat A.; Vyas, Disha J.; Mishra, Divya R.; Jain, Vinod K.

2014-01-01

A new calix[4]pyrrole derivative bearing four dansyl groups through hydroxyl groups has been synthesized and duly characterized by FT-IR, NMR and ESI-MS. Tetra dansylated calix[4]pyrrole (TDCP) shows selective behavior for U(VI), Th(IV) and Fe(III) ions among all other metal ions, e.g. Li(I), Na(I), K(I), Ca(II), Ni(II), Cd(II), Cu(II), Zn(II), Pb(II), Hg(II) and Ag(I), in the absorption spectra as well as in the emission spectra. The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. The binding constants, stoichiometry and quantum yields have been determined. The mechanism of quenching by Stern–Vohmer equation has also been discussed. -- highlights: • A new selective turn-off fluorescent sensor i.e. tetra dansylated calix[4]pyrrole (TDCP) was synthesized and characterized. • The sensor shows selective behavior for U(VI), Th(IV) and Fe(III) ions among various other metal ions. • The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. • The sensor binds metal ions in 1:1 stoichiometry with good binding constant

Interaction of terbium group metal oxides with carbon

International Nuclear Information System (INIS)

Vodop'yanov, A.G.; Baranov, S.V.; Kozhevnikov, G.N.

1990-01-01

Mechanism of carbothermal reduction of terbium group metals from oxides is investigated using thermodynamic and kinetic analyses. Interaction of metal oxides with carbon covers dissociation of metal oxides and reduction by carbon monoxide, which contribution into general reduction depends on CO pressure. Temperatures of reaction beginning for batch initial components at P=1.3x10 -4 and P CO =0.1 MPa and of formation of oxycarbide melts are determined

Phosphors containing boron and metals of Group IIIA and IIIB

Science.gov (United States)

Setlur, Anant Achyut; Srivastava, Alok Mani; Comanzo, Holly Ann; Manivannan, Venkatesan

2006-10-31

A phosphor comprises: (a) at least a first metal selected from the group consisting of yttrium and elements of lanthanide series other than europium; (b) at least a second metal selected from the group consisting of aluminum, gallium, indium, and scandium; (c) boron; and (d) europium. The phosphor is used in light source that comprises a UV radiation source to convert UV radiation to visible light.

A sputnik IV saga

Science.gov (United States)

Lundquist, Charles A.

2009-12-01

The Sputnik IV launch occurred on May 15, 1960. On May 19, an attempt to deorbit a 'space cabin' failed and the cabin went into a higher orbit. The orbit of the cabin was monitored and Moonwatch volunteer satellite tracking teams were alerted to watch for the vehicle demise. On September 5, 1962, several team members from Milwaukee, Wisconsin made observations starting at 4:49 a.m. of a fireball following the predicted orbit of Sputnik IV. Requests went out to report any objects found under the fireball path. An early morning police patrol in Manitowoc had noticed a metal object on a street and had moved it to the curb. Later the officers recovered the object and had it dropped off at the Milwaukee Journal. The Moonwarch team got the object and reported the situation to Moonwatch Headquarters at the Smithsonian Astrophysical Observatory. A team member flew to Cambridge with the object. It was a solid, 9.49 kg piece of steel with a slag-like layer attached to it. Subsequent analyses showed that it contained radioactive nuclei produced by cosmic ray exposure in space. The scientists at the Observatory quickly recognized that measurements of its induced radioactivity could serve as a calibration for similar measurements of recently fallen nickel-iron meteorites. Concurrently, the Observatory directorate informed government agencies that a fragment from Sputnik IV had been recovered. Coincidently, a debate in the UN Committee on Peaceful Uses of Outer Space involved the issue of liability for damage caused by falling satellite fragments. On September 12, the Observatory delivered the bulk of the fragment to the US Delegation to the UN. Two days later, the fragment was used by US Ambassador Francis Plimpton as an exhibit that the time had come to agree on liability for damage from satellite debris. He offered the Sputnik IV fragment to USSR Ambassador P.D. Morozov, who refused the offer. On October 23, Drs. Alla Massevitch and E.K. Federov of the USSR visited the

SiP monolayers: New 2D structures of group IV-V compounds for visible-light photohydrolytic catalysts

Science.gov (United States)

Ma, Zhinan; Zhuang, Jibin; Zhang, Xu; Zhou, Zhen

2018-06-01

Because of graphene and phosphorene, two-dimensional (2D) layered materials of group IV and group V elements arouse great interest. However, group IV-V monolayers have not received due attention. In this work, three types of SiP monolayers were computationally designed to explore their electronic structure and optical properties. Computations confirm the stability of these monolayers, which are all indirect-bandgap semiconductors with bandgaps in the range 1.38-2.21 eV. The bandgaps straddle the redox potentials of water at pH = 0, indicating the potential of the monolayers for use as watersplitting photocatalysts. The computed optical properties demonstrate that certain monolayers of SiP 2D materials are absorbers of visible light and would serve as good candidates for optoelectronic devices.

Dissimilatory Fe(III) and Mn(IV) reduction.

Science.gov (United States)

Lovley, D R

1991-06-01

The oxidation of organic matter coupled to the reduction of Fe(III) or Mn(IV) is one of the most important biogeochemical reactions in aquatic sediments, soils, and groundwater. This process, which may have been the first globally significant mechanism for the oxidation of organic matter to carbon dioxide, plays an important role in the oxidation of natural and contaminant organic compounds in a variety of environments and contributes to other phenomena of widespread significance such as the release of metals and nutrients into water supplies, the magnetization of sediments, and the corrosion of metal. Until recently, much of the Fe(III) and Mn(IV) reduction in sedimentary environments was considered to be the result of nonenzymatic processes. However, microorganisms which can effectively couple the oxidation of organic compounds to the reduction of Fe(III) or Mn(IV) have recently been discovered. With Fe(III) or Mn(IV) as the sole electron acceptor, these organisms can completely oxidize fatty acids, hydrogen, or a variety of monoaromatic compounds. This metabolism provides energy to support growth. Sugars and amino acids can be completely oxidized by the cooperative activity of fermentative microorganisms and hydrogen- and fatty-acid-oxidizing Fe(III) and Mn(IV) reducers. This provides a microbial mechanism for the oxidation of the complex assemblage of sedimentary organic matter in Fe(III)- or Mn(IV)-reducing environments. The available evidence indicates that this enzymatic reduction of Fe(III) or Mn(IV) accounts for most of the oxidation of organic matter coupled to reduction of Fe(III) and Mn(IV) in sedimentary environments. Little is known about the diversity and ecology of the microorganisms responsible for Fe(III) and Mn(IV) reduction, and only preliminary studies have been conducted on the physiology and biochemistry of this process.

Development of generation IV nuclear energy systems

International Nuclear Information System (INIS)

Matsui, Kazuaki; Oka, Yoshiaki; Ogawa, Masuro; Ichimiya, Masakazu; Noda, Hiroshi

2003-01-01

The fifth 'Generation IV International Forum (GIF), Policy Group Meetings' was held at the Zen-Nikku Hotel in Tokyo, on September 19-20, 2002, under participations of Abraham, Secretary of DOE in U.S.A., Columbani, Secretary of CEA in France, Fujiie, Chairman of CAE in Japan, Kano, Parliamental Minister of MIS in Japan, and so on. Ten nations entering GIF (Argentina, Brazil, Canada, France, Japan, Korea, South Africa, Switzerland, U.K., and U.S.A.) selected six next generation nuclear energy concepts for objects of international cooperative research and development aiming at its practice by 2030. These concepts applicable to not only power generation, but also hydrogen production, sea water purification, and so on, are sodium liquid metal cooled reactor (Japan), high temperature gas cooled reactor (France), Super-critical pressure water cooled reactor (SCWR: Canada), Lead metal cooled reactor (Switzerland), Gas cooled fast reactor (U.S.A.), and molten salts reactor. On the generation IV nuclear reactor systems aiming to further upgrade their sustainability, safety, economical efficiency, and nuclear non proliferation, the 'Plans on Technical Development' (Road-map) to decide priority of their R and Ds has been cooperatively discussed under frameworks of international research cooperation by the GIF members nations. Here were shared descriptions on nuclear fuel cycle as a remise of technical evaluation and adopted concepts by Japanese participants contributing to making up the Road-map. (G.K.)

Synthesis and spectral properties of axially substituted zirconium(IV) and hafnium(IV) water soluble phthalocyanines in solutions

International Nuclear Information System (INIS)

Gerasymchuk, Y.S.; Volkov, S.V.; Chernii, V.Ya.; Tomachynski, L.A.; Radzki, St.

2004-01-01

Methods of synthesis of novel water soluble axially substituted Zr(IV) and Hf(IV) phthalocyanines with gallic, 5-sulfosalicyllic, oxalic acids, and methyl ester of gallic acid as axial ligands coordinated to the central atom metal of phthalocyanine are presented. The absorption spectra of complex solutions in various solvents were characterized. The dependence of the spectral red shift from Reichardt's empirical polarity parameter is described. The deviation from the linearity of Beer-Bouguer-Lambert law was investigated for the range of concentration 5x10 -6 to 10x10 -5 M. Fluorescent properties of axially substituted phthalocyaninato metal complexes in DMSO solutions were investigated

Current-Voltage Characteristics of the Metal / Organic Semiconductor / Metal Structures: Top and Bottom Contact Configuration Case

Directory of Open Access Journals (Sweden)

Šarūnas MEŠKINIS

2013-03-01

Full Text Available In present study five synthesized organic semiconductor compounds have been used for fabrication of the planar metal / organic semiconductor / metal structures. Both top electrode and bottom electrode configurations were used. Current-voltage (I-V characteristics of the samples were investigated. Effect of the hysteresis of the I-V characteristics was observed for all the investigated samples. However, strength of the hysteresis was dependent on the organic semiconductor used. Study of I-V characteristics of the top contact Al/AT-RB-1/Al structures revealed, that in (0 – 500 V voltages range average current of the samples measured in air is only slightly higher than current measured in nitrogen ambient. Deposition of the ultra-thin diamond like carbon interlayer resulted in both decrease of the hysteresis of I-V characteristics of top contact Al/AT-RB-1/Al samples. However, decreased current and decreased slope of the I-V characteristics of the samples with diamond like carbon interlayer was observed as well. I-V characteristic hysteresis effect was less pronounced in the case of the bottom contact metal/organic semiconductor/metal samples. I-V characteristics of the bottom contact samples were dependent on electrode metal used.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3816

A COMPARATIVE CLINICAL STUDY BETWEEN IV ESMOLOL AND IV FENTANYL ON ATTENUATION OF HAEMODYNAMIC RESPONSES TO LARYNGOSCOPY AND INTUBATION

Directory of Open Access Journals (Sweden)

Abu Lais Mustaque

2016-04-01

Full Text Available INTRODUCTION Laryngoscopy and intubation is an integral part for providing general anaesthesia to patients undergoing various types of surgery. It also plays an important role in critical care units viz. for providing mechanical ventilation. It is a very essential tool in the hands of anaesthesiologist in maintaining airway. The present study is undertaken to determine and compare the efficacy of single bolus dose of IV esmolol 1 mg/kg and IV fentanyl 2 mcg/kg in attenuating the haemodynamic responses to laryngoscopy and tracheal intubation and to ascertain the effectiveness of esmolol hydrochloride and fentanyl citrate in suppressing sympathetic responses. MATERIAL & METHODS The study was conducted under the Department of Anaesthesiology and Critical Care, Assam Medical College and Hospital, Dibrugarh, during the period July 2013 to June 2014. For this purpose, 150 patients of either sex between 20-50 years of ASA I & II physical status were selected after obtaining informed and written consent and were divided into two groups namely, Group E receiving IV esmolol (1 mg/kg and Group F receiving IV fentanyl (2 mcg/kg. RESULTS Inj. fentanyl 2 mcg/kg IV administered 5 minutes before laryngoscopy and intubation was able to prevent adverse haemodynamic changes better than Inj. esmolol 1 mg/kg IV administered 3 minutes prior to laryngoscopy and intubation during elective surgeries under general anaesthesia. CONCLUSION Hence, from the findings of this study we can conclude that IV bolus dose of fentanyl 2 mcg/kg administered 5 minutes before laryngoscopy and intubation can attenuate the sympathetic response to laryngoscopy and intubation without any side effects of the drug in healthy patients undergoing elective surgeries under general anaesthesia.

X-ray spectroscopic characterization of Co(IV) and metal–metal interactions in Co₄O₄: Electronic structure contributions to the formation of high-valent states relevant to the oxygen evolution reaction

Energy Technology Data Exchange (ETDEWEB)

Hadt, Ryan G.; Hayes, Dugan; Brodsky, Casey N.; Ullman, Andrew M.; Casa, Diego M.; Upton, Mary H.; Nocera, Daniel G; Chen, Lin X.

2016-08-12

In this paper, the formation of high-valent states is a key factor in making highly active transition metal-based catalysts of the oxygen-evolving reaction (OER). These high oxidation states will be strongly influenced by the local geometric and electronic structures of the metal ion, which is difficult to study due to spectroscopically active and complex backgrounds, short lifetimes, and limited concentrations. Here, we use a wide range of complementary X-ray spectroscopies coupled to DFT calculations to study Co₄O₄ cubanes, which provide insight into the high-valent Co(IV) centers responsible for the activity of molecular and heterogeneous OER catalysts. The combination of X-ray absorption and 1s3p resonant inelastic X-ray scattering (Kβ RIXS) allow Co(IV) to be isolated and studied against a spectroscopically active Co(III) background. Co K- and L-edge X-ray absorption data allow for a detailed characterization of the 3d-manifold of effectively localized Co(IV) centers and provide a direct handle on the ligand field environment and covalency of the t_2g-based redox active molecular orbital. Kβ RIXS is also shown to provide a powerful probe of Co(IV), and specific spectral features are sensitive to the degree of oxo-mediated metal-metal coupling across Co₄O₄. Guided by the data, calculations show electron-hole delocalization can actually oppose Co(IV) formation. Computational extension of Co₄O₄ to CoM₃O₄ structures (M = redox-inactive metal) defines electronic structure contri-butions to Co(IV) formation. Redox activity is shown to be linearly related to covalency, and M(III) oxo inductive effects on Co(IV) oxo bonding can tune the covalency of high-valent sites over a large range and thereby tune E⁰ over hundreds of mVs.

Ruthenium(ii)-polypyridyl zirconium(iv) metal-organic frameworks as a new class of sensitized solar cells.

Science.gov (United States)

Maza, W A; Haring, A J; Ahrenholtz, S R; Epley, C C; Lin, S Y; Morris, A J

2016-01-01

A series of Ru(ii)L 2 L' (L = 2,2'-bipyridyl, L' = 2,2'-bipyridine-5,5'-dicarboxylic acid), RuDCBPY, -containing zirconium(iv) coordination polymer thin films have been prepared as sensitizing materials for solar cell applications. These metal-organic framework (MOF) sensitized solar cells, MOFSCs, each are shown to generate photocurrent in response to simulated 1 sun illumination. Emission lifetime measurements indicate the excited state quenching of RuDCBPY at the MOF-TiO 2 interface is extremely efficient (>90%), presumably due to electron injection into TiO 2 . A mechanism is proposed in which RuDCBPY-centers photo-excited within the MOF-bulk undergo isotropic energy migration up to 25 nm from the point of origin. This work represents the first example in which a MOFSC is directly compared to the constituent dye adsorbed on TiO 2 (DSC). Importantly, the MOFSCs outperformed their RuDCBPY-TiO 2 DSC counterpart under the conditions used here and, thus, are solidified as promising solar cell platforms.

Generation IV concepts - Presentation at ACRS workshop 'Regulatory challenges for future nuclear power plants'

International Nuclear Information System (INIS)

Versluis, Rob M.

2001-01-01

The concept of the Near-Term Deployment Working Group was to define a technical approach for Generation IV system with enough detail to allow evaluation against the goal, bur broad enough to allow for optional features and trade. The following concepts were taken into account: water coolant (water or heavy water), gas coolant, liquid metal coolants. Concepts were grouped according to concept sets of technology base share and design approach. Water coolant concepts were grouped as follows: PWR loop reactors, integral primary system PWRs, Integral BWRs, pressure tube reactors, high conversion cores, supercritical water reactors, advanced fuel cycle concepts. Gas coolant concepts were grouped as follows: pebble bed modular reactors; prismatic modular reactors, very high temperature reactors, fast spectrum reactors, others (fluidized bed, moving ignition zone concept). Liquid metal concepts were grouped in four major categories: Medium-to-large oxide-fueled systems; Medium-sized metal-fueled systems; Medium-sized Pb/Pb-Bi systems; Small-sized Pb/Pb-Bi systems. The three supporting technology areas were examined: Fuels (oxide, metal, nitride); Coolants (Na, Pb/Pb-Bi); Fuel Cycle (advanced aqueous, pyroprocess). Non-classical concepts were also grouped as follows: Eutectic metallic fuel; Molten salt fuel; Gas core reactor; Molten salt cooled/solid fuel; Organic cooled reactor; Solid conduction/heat pipe; Fission product direct energy conversion. The Technical working Groups are analyzing the candidate concepts for performance potential relative to the goals; and technology gaps

Two-dimensional multiferroics in monolayer group IV monochalcogenides

Science.gov (United States)

Wang, Hua; Qian, Xiaofeng

2017-03-01

Low-dimensional multiferroic materials hold great promises in miniaturized device applications such as nanoscale transducers, actuators, sensors, photovoltaics, and nonvolatile memories. Here, using first-principles theory we predict that two-dimensional (2D) monolayer group IV monochalcogenides including GeS, GeSe, SnS, and SnSe are a class of 2D semiconducting multiferroics with giant strongly-coupled in-plane spontaneous ferroelectric polarization and spontaneous ferroelastic lattice strain that are thermodynamically stable at room temperature and beyond, and can be effectively modulated by elastic strain engineering. Their optical absorption spectra exhibit strong in-plane anisotropy with visible-spectrum excitonic gaps and sizable exciton binding energies, rendering the unique characteristics of low-dimensional semiconductors. More importantly, the predicted low domain wall energy and small migration barrier together with the coupled multiferroic order and anisotropic electronic structures suggest their great potentials for tunable multiferroic functional devices by manipulating external electrical, mechanical, and optical field to control the internal responses, and enable the development of four device concepts including 2D ferroelectric memory, 2D ferroelastic memory, and 2D ferroelastoelectric nonvolatile photonic memory as well as 2D ferroelectric excitonic photovoltaics.

Structural Mimics of the [Fe]-Hydrogenase: A Complete Set for Group VIII Metals.

Science.gov (United States)

Barik, Chandan Kr; Ganguly, Rakesh; Li, Yongxin; Leong, Weng Kee

2018-06-18

A set of structural mimics of the [Fe]-hydrogenase active site comprising all the group VIII metals, viz., [M(2-NHC(O)C 5 H 4 N)(CO) 2 (2-S-C 5 H 4 N)], has been synthesized. They exist as a mixture of isomers in solution, and the relative stability of the isomers depends on the nature of the metal and the substituent at the 6-position of the pyridine ligand.

Metal cluster compounds - chemistry and importance; clusters containing isolated main group element atoms, large metal cluster compounds, cluster fluxionality

International Nuclear Information System (INIS)

Walther, B.

1988-01-01

This part of the review on metal cluster compounds deals with clusters containing isolated main group element atoms, with high nuclearity clusters and metal cluster fluxionality. It will be obvious that main group element atoms strongly influence the geometry, stability and reactivity of the clusters. High nuclearity clusters are of interest in there own due to the diversity of the structures adopted, but their intermediate position between molecules and the metallic state makes them a fascinating research object too. These both sites of the metal cluster chemistry as well as the frequently observed ligand and core fluxionality are related to the cluster metal and surface analogy. (author)

First principles calculation of material properties of group IV elements and III-V compounds

Science.gov (United States)

Malone, Brad Dean

This thesis presents first principles calculations on the properties of group IV elements and group III-V compounds. It includes investigations into what structure a material is likely to form in, and given that structure, what are its electronic, optical, and lattice dynamical properties as well as what are the properties of defects that might be introduced into the sample. The thesis is divided as follows: • Chapter 1 contains some of the conceptual foundations used in the present work. These involve the major approximations which allow us to approach the problem of systems with huge numbers of interacting electrons and atomic cores. • Then, in Chapter 2, we discuss one of the major limitations to the DFT formalism introduced in Chapter 1, namely its inability to predict the quasiparticle spectra of materials and in particular the band gap of a semiconductor. We introduce a Green's function approach to the electron self-energy Sigma known as the GW approximation and use it to compute the quasiparticle band structures of a number of group IV and III-V semiconductors. • In Chapter 3 we present a first-principles study of a number of high-pressure metastable phases of Si with tetrahedral bonding. The phases studied include all experimentally determined phases that result from decompression from the metallic beta-Sn phase, specifically the BC8 (Si-III), hexagonal diamond (Si-IV), and R8 (Si-XII). In addition to these, we also study the hypothetical ST12 structure found upon decompression from beta-Sn in germanium. • Our attention is then turned to the first principles calculations of optical properties in Chapter 4. The Bethe-Salpeter equation is then solved to obtain the optical spectrum of this material including electron-hole interactions. The calculated optical spectrum is compared with experimental data for other forms of silicon commonly used in photovoltaic devices, namely the cubic, polycrystalline, and amorphous forms. • In Chapter 5 we present

Monolithic nanoscale photonics-electronics integration in silicon and other group IV elements

CERN Document Server

Radamson, Henry

2014-01-01

Silicon technology is evolving rapidly, particularly in board-to-board or chip-to chip applications. Increasingly, the electronic parts of silicon technology will carry out the data processing, while the photonic parts take care of the data communication. For the first time, this book describes the merging of photonics and electronics in silicon and other group IV elements. It presents the challenges, the limitations, and the upcoming possibilities of these developments. The book describes the evolution of CMOS integrated electronics, status and development, and the fundamentals of silicon p

Organic / IV, III-V Semiconductor Hybrid Solar Cells

Directory of Open Access Journals (Sweden)

Pang-Leen Ong

2010-03-01

Full Text Available We present a review of the emerging class of hybrid solar cells based on organic-semiconductor (Group IV, III-V, nanocomposites, which states separately from dye synthesized, polymer-metal oxides and organic-inorganic (Group II-VI nanocomposite photovoltaics. The structure of such hybrid cell comprises of an organic active material (p-type deposited by coating, printing or spraying technique on the surface of bulk or nanostructured semiconductor (n-type forming a heterojunction between the two materials. Organic components include various photosensitive monomers (e.g., phtalocyanines or porphyrines, conjugated polymers, and carbon nanotubes. Mechanisms of the charge separation at the interface and their transport are discussed. Also, perspectives on the future development of such hybrid cells and comparative analysis with other classes of photovoltaics of third generation are presented.

Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

International Nuclear Information System (INIS)

Barrera-Ballesteros, J. K.; Heckman, T.; Sánchez, S. F.; Blanc, G. A.

2017-01-01

We present the integrated stellar mass–metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R eff ) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

Separate Ways: The Mass-Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

Science.gov (United States)

Barrera-Ballesteros, J. K.; Sánchez, S. F.; Heckman, T.; Blanc, G. A.; The MaNGA Team

2017-07-01

We present the integrated stellar mass-metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R eff) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

Energy Technology Data Exchange (ETDEWEB)

Barrera-Ballesteros, J. K.; Heckman, T. [Department of Physics and Astronomy, Johns Hopkins University, Bloomberg Center, 3400 N. Charles St., Baltimore, MD 21218 (United States); Sánchez, S. F. [Instituto de Astronomía, Universidad Nacional Autónoma de México, A.P. 70-264, 04510 México, D.F., México (Mexico); Blanc, G. A., E-mail: jbarrer3@jhu.edu [Observatories of the Carnegie Institution for Science, 813 Santa Barbara St, Pasadena, CA 91101 (United States); Collaboration: MaNGA Team

2017-07-20

We present the integrated stellar mass–metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R {sub eff}) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

Thermal decomposition and spectroscopic investigation of a new aqueous glycolato(-peroxo) Ti(IV) solution-gel precursor

International Nuclear Information System (INIS)

De Dobbelaere, Christopher; Mullens, Jules; Hardy, An; Van Bael, Marlies K.

2011-01-01

Highlights: → A totally water based glycolato-Ti(IV) precursor is presented and characterized. → The precursors' thermal decomposition profile depends on the ligand to metal ratio. → Titanium is coordinated in an unidentate fashion by the glycolate anion. → Smooth and uniform TiO 2 films can be prepared from the precursor solution. - Abstract: A new aqueous solution-gel precursor based on water soluble glycolato(-peroxo)-Ti(IV) complexes is developed for the preparation of TiO 2 films. With regard to the decomposition of complexes towards oxide formation, it is important to gain insight in the chemical transformations inside the precursor during thermal treatment. Therefore, the thermo-oxidative decomposition pathway of a gel obtained by slow evaporation of the precursor solution is described based on hyphenated thermogravimetric analysis with Fourier transform infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). Pure glycolic acid is used as a reference system for this study. By varying the molar glycolic acid to Ti(IV) ratio, the thermal decomposition of the gel can be drastically shortened and the profile's course changed. Gel structure and chemical changes in the gel upon heating are also studied by means of off-line FTIR. A unidentate coordination of the titanium(IV) ion by the carboxylate group of the glycolato ligands and the involvement of the hydroxyl group is confirmed. Phase formation at certain points in the thermal decomposition is studied by X-ray diffraction and Raman spectroscopy. Finally, it is proven that the new precursor is a valuable candidate for the deposition of low carbon containing solution-gel films which can ultimately be converted into smooth and uniform TiO 2 films.

Crystal structures of lazulite-type oxidephosphates TiIIITiIV3O3(PO4)3 and MIII4TiIV27O24(PO4)24 (MIII=Ti, Cr, Fe)

International Nuclear Information System (INIS)

Schoeneborn, M.; Glaum, R.; Reinauer, F.

2008-01-01

Single crystals of the oxidephosphates Ti III Ti IV 3 O 3 (PO 4 ) 3 (black), Cr III 4 Ti IV 27 O 24 (PO 4 ) 24 (red-brown, transparent), and Fe III 4 Ti IV 27 O 24 (PO 4 ) 24 (brown) with edge-lengths up to 0.3 mm were grown by chemical vapour transport. The crystal structures of these orthorhombic members (space group F2dd ) of the lazulite/lipscombite structure family were refined from single-crystal data [Ti III Ti IV 3 O 3 (PO 4 ) 3 : Z=24, a=7.3261(9) A, b=22.166(5) A, c=39.239(8) A, R 1 =0.029, wR 2 =0.084, 6055 independent reflections, 301 variables; Cr III 4 Ti IV 27 O 24 (PO 4 ) 24 : Z=1, a=7.419(3) A, b=21.640(5) A, c=13.057(4) A, R 1 =0.037, wR 2 =0.097, 1524 independent reflections, 111 variables; Fe III 4 Ti IV 27 O 24 (PO 4 ) 24 : Z=1, a=7.4001(9) A, b=21.7503(2) A, c=12.775(3) A, R 1 =0.049, wR 2 =0.140, 1240 independent reflections, 112 variables). For Ti III Ti IV O 3 (PO 4 ) 3 a well-ordered structure built from dimers [Ti III,IV 2 O 9 ] and [Ti IV,IV 2 O 9 ] and phosphate tetrahedra is found. The metal sites in the crystal structures of Cr 4 Ti 27 O 24 (PO 4 ) 24 and Fe 4 Ti 27 O 24 (PO 4 ) 24 , consisting of dimers [M III Ti IV O 9 ] and [Ti IV,IV 2 O 9 ], monomeric [Ti IV O 6 ] octahedra, and phosphate tetrahedra, are heavily disordered. Site disorder, leading to partial occupancy of all octahedral voids of the parent lipscombite/lazulite structure, as well as splitting of the metal positions is observed. According to Guinier photographs Ti III 4 Ti IV 27 O 24 (PO 4 ) 24 (a=7.418(2) A, b=21.933(6) A, c=12.948(7) A) is isotypic to the oxidephosphates M III 4 Ti IV 27 O 24 (PO 4 ) 24 (M III : Cr, Fe). The UV/vis spectrum of Cr 4 Ti 27 O 24 (PO 4 ) 24 reveals a rather small ligand-field splitting Δ o =14,370 cm -1 and a very low nephelauxetic ratio β=0.72 for the chromophores [Cr III O 6 ] within the dimers [Cr III Ti IV O 9 ]. - Graphical abstract: Single crystals of the oxidephosphates Ti III Ti IV 3 O 3 (PO 4 ) 3 (black), Cr III 4 Ti IV 27 O

Effect of Cerium(IV)-Surfactant Reaction in Foam Decontamination

Energy Technology Data Exchange (ETDEWEB)

Yang, Han Beom; Jung, Chong-Hun; Yoon, In-Ho; Kim, Chorong; Choi, Wang-Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

Using foams allows the decommissioning of complex shaped facilities. The decontamination foam comprises at least one surfactant to generate the foam and one or more chemical reactants to achieve the dissolution of the contaminants at the solid surface. In order to improve the efficiency of decontamination foam, the present study attempts to find the optimum condition of chemical reagents to the foaming solution. The corrosion rate of radioactive nuclides contaminated stainless steel metal is very important factor for the foam decontamination process. The goal of this study is to develop the decontamination process for contaminated stainless steel in medium of nitric acid. Stainless steel needs a strong oxidizing agent such as Ce(IV) ion and the effects of cerium(IV). Surfactant interaction involved in foam decontamination and finally the improvement brought by formulation science. The formulation of foams loaded with strong oxidizing reagents such as Ce(IV) is an important factor. The enhanced decontamination properties of nitric acid with Ce(IV) additive on stainless steel is well known in liquid mediums. stainless steel metal is an important aspect in the foam decontamination process.

Effect of Cerium(IV)-Surfactant Reaction in Foam Decontamination

International Nuclear Information System (INIS)

Yang, Han Beom; Jung, Chong-Hun; Yoon, In-Ho; Kim, Chorong; Choi, Wang-Kyu

2015-01-01

Using foams allows the decommissioning of complex shaped facilities. The decontamination foam comprises at least one surfactant to generate the foam and one or more chemical reactants to achieve the dissolution of the contaminants at the solid surface. In order to improve the efficiency of decontamination foam, the present study attempts to find the optimum condition of chemical reagents to the foaming solution. The corrosion rate of radioactive nuclides contaminated stainless steel metal is very important factor for the foam decontamination process. The goal of this study is to develop the decontamination process for contaminated stainless steel in medium of nitric acid. Stainless steel needs a strong oxidizing agent such as Ce(IV) ion and the effects of cerium(IV). Surfactant interaction involved in foam decontamination and finally the improvement brought by formulation science. The formulation of foams loaded with strong oxidizing reagents such as Ce(IV) is an important factor. The enhanced decontamination properties of nitric acid with Ce(IV) additive on stainless steel is well known in liquid mediums. stainless steel metal is an important aspect in the foam decontamination process

Solid state structure of thorium(IV) complexes with common aminopoly-carboxylate ligands

International Nuclear Information System (INIS)

Thuery, Pierre

2011-01-01

The crystal structures of the complexes formed by reaction of thorium(IV) nitrate with iminodiacetic acid (H 2 IDA), nitrilotriacetic acid (H 3 NTA), and ethylenediaminetetraacetic acid (H 4 EDTA) under hydrothermal conditions are reported. In [Th(HIDA) 2 (C 2 O 4 )].H 2 O (1), the metal atom is chelated by two carboxylate groups from two HIDA - anions and by two oxalate ligands formed in situ; two additional oxygen atoms from two more HIDA - anions complete the ten-coordinate environment of bi-capped square anti-prismatic geometry. The uncoordinated nitrogen atom is protonated and involved in hydrogen bonding. Two different ligands are present in [Th(NTA)(H 2 NTA)(H 2 O)].H 2 O (2), one of them being a O 3 ,N-chelating tri-anion which acts also as a bridge toward two neighboring metal ions, and the other being a bis-monodentate bridging species with an uncoordinated carboxylic arm and a central ammonium group. An aqua ligand completes the nine-coordinated, capped square anti-prismatic metal environment. The EDTA 4- anion in [Th(EDTA)(H 2 O)].2H 2 O (3) is chelating through one oxygen atom from each carboxylate group and the two nitrogen atoms, as in a previously reported molecular complex. Two carboxylate groups are bridging, which, with the addition of an aqua ligand, gives a capped square anti-prismatic coordination polyhedron. Aminopoly-carboxylate ligands have been much investigated in relation with actinide decorporation and nuclear wastes management studies, and the present results add to the structural information available on their complexes with thorium(IV), which has mainly been obtained up to now by extended X-ray absorption fine structure (EXAFS) spectroscopy. In particular, the bridging (non-chelating) coordination mode of H 2 NTA - is a novel feature in this context. All three complexes crystallize as two-dimensional assemblies and are thus novel examples of thorium-organic coordination polymers. (author)

Defect-Tolerant Monolayer Transition Metal Dichalcogenides

DEFF Research Database (Denmark)

Pandey, Mohnish; Rasmussen, Filip Anselm; Kuhar, Korina

2016-01-01

Localized electronic states formed inside the band gap of a semiconductor due to crystal defects can be detrimental to the material's optoelectronic properties. Semiconductors with a lower tendency to form defect induced deep gap states are termed defect-tolerant. Here we provide a systematic first...... the gap. These ideas are made quantitative by introducing a descriptor that measures the degree of similarity of the conduction and valence band manifolds. Finally, the study is generalized to nonpolar nanoribbons of the TMDs where we find that only the defect sensitive materials form edge states within......-principles investigation of defect tolerance in 29 monolayer transition metal dichalcogenides (TMDs) of interest for nanoscale optoelectronics. We find that the TMDs based on group VI and X metals form deep gap states upon creation of a chalcogen (S, Se, Te) vacancy, while the TMDs based on group IV metals form only...

NMR spectroscopic characterization and DFT calculations of zirconium(IV)-3,3'-Br2-BINOLate and related complexes used in an enantioselective Friedel-Crafts alkylation of indoles with α,β-unsaturated ketones.

Science.gov (United States)

Blay, Gonzalo; Cano, Joan; Cardona, Luz; Fernández, Isabel; Muñoz, M Carmen; Pedro, José R; Vila, Carlos

2012-12-07

Experimental and theoretical studies on the structure of several complexes based on (R)-3,3'-Br(2)-BINOL ligand and group (IV) metals used as catalysts in an enantioselective Friedel-Crafts alkylation of indoles with α,β-unsaturated ketones have been carried out. NMR spectroscopic studies of these catalysts have been performed, which suggested that at room temperature the catalysts would form a monomeric structure in the case of Ti(IV) and a dimeric structure in the cases of Zr(IV) and Hf(IV). Density functional theory (DFT) calculations clearly corroborate the conclusions of these experimental spectroscopic studies. The dimeric structure with a doubly bridged motif [Zr(IV)(2)(μ-(R)-3,3'-Br(2)-BINOL)(2)] where each binaphthol ligand acts as bridge between the metal centers (Novak's model) is more stable than the dimeric structure with a doubly bridged motif [Zr(IV)(2)(μ-O(t)Bu)(2)] where the tert-butoxide groups act as bridging ligands (Kobayashi's model). The scope of the Friedel-Crafts alkylation with regard to the indole structure has been studied. Finally a plausible mechanism for the Friedel-Crafts reaction and a stereomodel for the mode of action of the catalyst that explain the observed stereochemistry of the reaction products have been proposed.

Polyvalent type IV sensitizations to multiple fragrances and a skin protection cream in a metal worker.

Science.gov (United States)

Tanko, Zita; Shab, Arna; Diepgen, Thomas Ludwig; Weisshaar, Elke

2009-06-01

Fragrances are very common in everyday products. A metalworker with chronic hand eczema and previously diagnosed type IV sensitizations to epoxy resin, balsam of Peru, fragrance mix and fragrance mix II was diagnosed with additional type IV sensitizations to geraniol, hydroxycitronellal, lilial, tree moss, oak moss absolute, citral, citronellol, farnesol, Lyral, fragrance mix II and fragrance mix (with sorbitan sesquioleate). In addition, a type IV sensitization to the skin protection cream containing geraniol and citronellol used at the workplace was detected, and deemed occupationally relevant in this case. The patient could have had contact to fragrances through private use of cosmetics and detergents. On the other hand, the fragrance-containing skin protection cream supports occupational exposure. This case report demonstrates that fragrance contact allergy has to be searched for and clarified individually, which requires a thorough history and a detailed analysis of the work place.

Direct synthesis of some significant metal alkoxides

International Nuclear Information System (INIS)

Emilio, Gule Buyu

1998-11-01

Investigations were carried out with an attempt to study direct synthesis of metal alkoxides from elemental metals and appropriate alcohols. These were done by reacting representative metals of group I, II, III 7 IV (which are Na, Mg, Al and Sn respectively) directly with dry ethanol and dry isopropanol. The products were then analysed by infrared spectrophotometer to meter to identify metal alkoxides formed. Ethanol was found to have more acidic character in reactions with these metals than isopropanol, thus its reactions with the metals were faster. Reduction in the acidic character of isopropanol, a secondary alcohol, could be due to the existence off more alkyl groups in the molecule which displays +1 inductive effect. For the same alcohol the metals reactions were found to decrease with increase in electronegativity of the metals. Sodium being the least electronegative metal reacted fasted while tin the more electronegative metal reacted slowest. Mg, Al and Sn required a catalyst,, mercury (II) chloride and heat in order to initiate and drive the reactions completion. The alkoxides formed were found to be soluble to a certain extent in the tow alcohols and the order of solubility is such that Sn≥ Al ≥ Mg ≥ Na.(Author)

Tailoring of transition metal alkoxides via complexation for the synthesis of hybrid organic-inorganic sols and gels

International Nuclear Information System (INIS)

Sanchez, C.; In, M.; Toledano, P.; Griesmar, P.

1992-01-01

This paper reports that the chemical control of hydrolysis-condensation reactions of transition metal alkoxides can be performed through the modification of the transition metal coordination sphere by using strong complexing ligands (SCL). Complexing organic groups can be bonded to the transition metal oxide network in two different ways, as network modifiers or network formers. Different illustrations of the role of complexing ligands on Ti(IV) and Zr(IV) alkoxides are presented. As a network modifier, SCL act as termination agents for condensation reactions allowing a control of particle growth. The complexing ligands being located at the periphery of the oxo core open many opportunities for colloid surface protection. SCL carrying organofunctional groups which exhibit non linear optical (NLO) properties have also been used as probes to study sol-gel transformations. SCL functionalized with organic polymerizable functions act as network formers

Thermal decomposition and spectroscopic investigation of a new aqueous glycolato(-peroxo) Ti(IV) solution-gel precursor

Energy Technology Data Exchange (ETDEWEB)

De Dobbelaere, Christopher, E-mail: christopher.dedobbelaere@uhasselt.be [Hasselt University, Institute for Materials Research, Inorganic and Physical Chemistry, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Mullens, Jules, E-mail: jules.mullens@uhasselt.be [Hasselt University, Institute for Materials Research, Inorganic and Physical Chemistry, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Hardy, An, E-mail: an.hardy@uhasselt.be [Hasselt University, Institute for Materials Research, Inorganic and Physical Chemistry, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw, Division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Van Bael, Marlies K., E-mail: marlies.vanbael@uhasselt.be [Hasselt University, Institute for Materials Research, Inorganic and Physical Chemistry, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw, Division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium)

2011-06-10

Highlights: {yields} A totally water based glycolato-Ti(IV) precursor is presented and characterized. {yields} The precursors' thermal decomposition profile depends on the ligand to metal ratio. {yields} Titanium is coordinated in an unidentate fashion by the glycolate anion. {yields} Smooth and uniform TiO{sub 2} films can be prepared from the precursor solution. - Abstract: A new aqueous solution-gel precursor based on water soluble glycolato(-peroxo)-Ti(IV) complexes is developed for the preparation of TiO{sub 2} films. With regard to the decomposition of complexes towards oxide formation, it is important to gain insight in the chemical transformations inside the precursor during thermal treatment. Therefore, the thermo-oxidative decomposition pathway of a gel obtained by slow evaporation of the precursor solution is described based on hyphenated thermogravimetric analysis with Fourier transform infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). Pure glycolic acid is used as a reference system for this study. By varying the molar glycolic acid to Ti(IV) ratio, the thermal decomposition of the gel can be drastically shortened and the profile's course changed. Gel structure and chemical changes in the gel upon heating are also studied by means of off-line FTIR. A unidentate coordination of the titanium(IV) ion by the carboxylate group of the glycolato ligands and the involvement of the hydroxyl group is confirmed. Phase formation at certain points in the thermal decomposition is studied by X-ray diffraction and Raman spectroscopy. Finally, it is proven that the new precursor is a valuable candidate for the deposition of low carbon containing solution-gel films which can ultimately be converted into smooth and uniform TiO{sub 2} films.

Astragaloside IV liposomes ameliorates adriamycin-induced ...

African Journals Online (AJOL)

Methods: The rats were given a single tail intravenous injection of adriamycin (6 mg/kg) within 1 week, and then divided into four groups including normal, model, benazepril and astragaloside IV liposomes group. They were all orally administered dosage of benazepril and astragaloside IV liposomes once daily for 8 weeks.

Synthesis, structures, and luminescent properties of sodium rare-earth metal(III) chloride oxotellurates(IV), Na{sub 2}Ln{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4} (Ln = Sm, Eu, Gd, Tb, Dy, and Ho)

Energy Technology Data Exchange (ETDEWEB)

Charkin, Dmitri O.; Dorofeev, Sergey G.; Berdonosov, Peter S.; Dolgikh, Valery A. [Department of Chemistry, Lomonosov Moscow State University (Russian Federation); Zitzer, Sabine; Greiner, Stefan; Schleid, Thomas [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Olenev, Andrei V. [Department of Chemistry, Lomonosov Moscow State University (Russian Federation); Sine Theta Ltd., Moscow (Russian Federation)

2017-11-17

Six sodium rare-earth metal(III) chloride oxotellurates(IV), Na{sub 2}Ln{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4}, isostructural to Na{sub 2}Y{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4}, were synthesized by flux techniques and characterized by single-crystal XRD. The compounds crystallize in the monoclinic space group C2/c with lattice constants a = 23.967(1), b = 5.6342(3), c = 16.952(1) Aa, β = 134.456(5) for Ln = Sm, a = 23.932(2), b = 5.6044(5), c = 17.134(1) Aa, β = 135.151(6) for Ln = Eu, a = 23.928(1), b = 5.5928(1), c = 17.1133(8) Aa, β = 135.366(3) for Ln = Gd, a = 23.907(1), b = 5.569(3), c = 16.745(1) Aa, β = 134.205(3) for Ln = Tb, a = 23.870(1), b = 5.547(3), c = 16.665(1) Aa, β = 134.102(3) for Ln = Dy, and a = 23.814(1), b = 5.526(3), c = 16.626(1) Aa, β = 134.016(3) for Ln = Ho and Z = 4. Their crystal structure can be considered as a framework built of intergrowing Ln-O and Na-(O,Cl) slabs with channel walls decorated by tellurium atoms of [TeO{sub 3}]{sup 2-} groups. The luminescent properties of the new compounds due to the Ln{sup 3+} cations are described and discussed. We also discuss the crystal chemistry of various alkali-metal rare-earth metal(III) halide oxochalcogenates(IV). (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Improved recovery of trace amounts of gold (III), palladium (II) and platinum (IV) from large amounts of associated base metals using anion-exchange resins

Energy Technology Data Exchange (ETDEWEB)

Matsubara, I. [Lab. of Chemistry, Tokyo Women' s Medical Univ. (Japan); Takeda, Y.; Ishida, K. [Lab. of Chemistry, Nippon Medical School, Kawasaki-shi, Kanagawa-ken (Japan)

2000-02-01

The adsorption and desorption behaviors of gold (III), palladium (II) and platinum (IV) were surveyed in column chromatographic systems consisting of one of the conventional anion-exchange resins of large ion-exchange capacity and dilute thiourea solutions. The noble metals were strongly adsorbed on the anion-exchange resins from dilute hydrochloric acid, while most base metals did not show any marked adsorbability. These facts made it possible to separate the noble metals from a large quantity of base metals such as Ag (I), Al (III), Co (II), Cu (II), Fe (III), Mn (II), Ni (II), Pb (II), and Zn (II). Although it used to be very difficult to desorb the noble metals from the resins used, the difficulty was easily overcome by use of dilute thiourea solutions as an eluant. In the present study, as little as 1.00 {mu}g of the respective noble metals was quantitatively separated and recovered from as much as ca. 10 mg of a number of metals on a small column by elution with a small amount of dilute thiourea solution. The present systems should be applicable to the separation, concentration and recovery of traces of the noble metals from a number of base metals coexisting in a more extended range of amounts and ratios. (orig.)

A COMPARATIVE STUDY OF EFFICACY OF HYOSCINE BROMIDE (IV VERSUS TRAMADOL (IM VERSUS PARACETAMOL (IV ON CERVICAL DILATATION IN ACTIVE LABOUR

Directory of Open Access Journals (Sweden)

Sampathukumari S

2016-09-01

Full Text Available Labour is a natural process, which involves a series of regular and progressive uterine contractions causing effacement and dilatation of cervix leading to birth of the baby. In order to minimise the perinatal morbidity and mortality caused by the prolonged labour, several drugs have been tried to hasten the process of cervical dilatation and this study in one such exercise. AIM OF THE STUDY 1 To compare the efficacy of Hyoscine Bromide (IV vs. Tramadol (IM vs. Paracetamol (IV on cervical dilatation in active labour. 2 To compare the duration of active phase of labour. 150 full-term women with gestational age 37-42 weeks, primi and multi singleton pregnancy with cephalic presentation in active labour were included in the study. Cases were divided into 3 groups - Group A: 50 cases of labour accelerated by Hyoscine Bromide 20 mg (IV, Group B: 50 cases of labour accelerated by Tramadol 50 mg (IM and Group C: 50 cases of labour accelerated by Paracetamol 500 mg (IV. Mean duration of active phase of 1st stage of labour was 3 hrs. 8 mins. (primi and 2 hrs. 3 mins. (multi in Hyoscine Bromide group and 4 hrs. 8 mins. (primi and 3 hrs. 5 mins. (multi in Tramadol group and 4 hrs. 2 mins. (primi and 2 hrs. 5 mins. (multi in Paracetamol group. Mean rate of cervical dilatation was 1.5 cm/hr (primi and 2.6 cm/hr (multi in Hyoscine Bromide group, 1.2 cm/hr (primi and 1.6 cm/hr (multi in Tramadol group and 1.3 cm/hr (primi and 1.6 cm/hr (multi in the Paracetamol group. The difference between the groups A and B and A and C is significant (p=0.0001 and thus it is concluded that Hyoscine Bromide hastened the rate of cervical dilatation and reduced the duration of active phase of 1 st stage of labour. Divide the abstract into materials and methods, results and conclusion.

Half-metallicity and electronic structures for carbon-doped group III-nitrides: Calculated with a modified Becke-Johnson potential

Science.gov (United States)

Fan, Shuai-wei; Wang, Ri-gao; Xu, Pemg

2016-09-01

The electronic structures and magnetism for carbon-doped group III-nitrides are investigated by utilizing the first principle method with the modified Becke-Johnson potential. Calculations show that carbon substituting cations (anions) would induce the group III-nitrides to be paramagnetic metals (half-metallic ferromagnets). Single carbon substituting nitrogen could produce 1.00μB magnetic moment. Electronic structures indicate that the carriers-mediated double-exchange interaction plays a crucial role in forming the ferromagnetism. Based on the mean-field theory, the Curie temperature for carbon-doped group III-nitrides would be above the room temperature. Negative chemical pair interactions imply that carbon dopants tend to form clustering distribution in group III-nitrides. The nitrogen vacancy would make the carbon-doped group III-nitrides lose the half-metallic ferromagnetism.

Late transition metal m-or chemistry and D6 metal complex photoeliminations

Energy Technology Data Exchange (ETDEWEB)

Sharp, Paul [Univ. of Missouri, Columbia, MO (United States)

2015-07-31

With the goal of understanding and controlling photoreductive elimination reactions from d6 transition metal complexes as part of a solar energy storage cycle we have investigated the photochemistry of Pt(IV) bromo, chloro, hydroxo, and hydroperoxo complexes. Photoreductive elimination reactions occur for all of these complexes and appear to involve initial Pt-Br, Pt-Cl, or Pt-O bond fission. In the case of Pt-OH bond fission, the subsequent chemistry can be controlled through hydrogen bonding to the hydroxo group.

Computations of nuclear response functions with MACK-IV

International Nuclear Information System (INIS)

Abdou, M.A.; Gohar, Y.

1978-01-01

The MACK computer program calculates energy pointwise and multigroup nuclear response functions from basic nuclear data in ENDF/B format. The new version of the program, MACK-IV, incorporates major developments and improvements aimed at maximizing the utilization of available nuclear data and ensuring energy conservation in nuclear heating calculations. A new library, MACKLIB-IV, of nuclear response functions was generated in the CTR energy group structure of 171 neutron groups and 36 gamma groups. The library was prepared using MACK-IV and ENDF/B-IV and is suitable for fusion, fusion-fission hybrids, and fission applications

Computations of nuclear response functions with MACK-IV

Energy Technology Data Exchange (ETDEWEB)

Abdou, M A; Gohar, Y

1978-01-01

The MACK computer program calculates energy pointwise and multigroup nuclear response functions from basic nuclear data in ENDF/B format. The new version of the program, MACK-IV, incorporates major developments and improvements aimed at maximizing the utilization of available nuclear data and ensuring energy conservation in nuclear heating calculations. A new library, MACKLIB-IV, of nuclear response functions was generated in the CTR energy group structure of 171 neutron groups and 36 gamma groups. The library was prepared using MACK-IV and ENDF/B-IV and is suitable for fusion, fusion-fission hybrids, and fission applications.

Apparent formation constants of Pu(IV) and Th(IV) with humic acids determined by solvent extraction method

Energy Technology Data Exchange (ETDEWEB)

Sasaki, T.; Aoyama, S.; Yoshida, H.; Kobayashi, T.; Takagi, I. [Tokyo Univ. (Japan). Dept. of Nuclear Engineering; Kulyako, Y.; Samsonov, M.; Miyasoedov, B. [Russian Academy of Sciences, Moscow (Russian Federation). V. I. Vernadsky Institute of Geochemistry and Analytical Chemistry (GEOKHI); Moriyama, H. [Kyoto Univ. (Japan). Research Reactor Inst.

2012-07-01

Apparent formation constants of Pu(IV) and Th(IV) with two kinds of humic acids were determined in 0.1 M NaClO{sub 4} at 25 C using a solvent extraction method with thenoyltrifluoroacetone in xylene. The acid dissociation constants of humic acids were also measured by potentiometric titration and used as the degree of dissociation for calculating the formation constants. The effect of solution conditions, such as the pH, the initial metal and humic acid concentrations, and the ionic strength, on the formation constants was examined. The obtained data were compared with the ones in the literature. (orig.)

Carbide-forming groups IVB-VIB metals: a new territory in the periodic table for CVD growth of graphene.

Science.gov (United States)

Zou, Zhiyu; Fu, Lei; Song, Xiuju; Zhang, Yanfeng; Liu, Zhongfan

2014-07-09

Early transition metals, especially groups IVB-VIB metals, can form stable carbides, which are known to exhibit excellent "noble-metal-like" catalytic activities. We demonstrate herein the applications of groups IVB-VIB metals in graphene growth using atmospheric pressure chemical vapor deposition technique. Similar to the extensively studied Cu, Ni, and noble metals, these transition-metal foils facilitate the catalytic growth of single- to few-layer graphene. The most attractive advantage over the existing catalysts is their perfect control of layer thickness and uniformity with highly flexible experimental conditions by in situ converting the dissolved carbons into stable carbides to fully suppress the upward segregation/precipitation effect. The growth performance of graphene on these transition metals can be well explained by the periodic physicochemical properties of elements. Our work has disclosed a new territory of catalysts in the periodic table for graphene growth and is expected to trigger more interest in graphene research.

Fe concentration dependence of tunneling magnetoresistance in magnetic tunnel junctions using group-IV ferromagnetic semiconductor GeFe

Directory of Open Access Journals (Sweden)

Kosuke Takiguchi

2017-10-01

Full Text Available Group-IV-based ferromagnetic semiconductor Ge1−xFex (GeFe is one of the most promising materials for spin injection/detection in Si and Ge. In this paper, we demonstrate a systematic study of tunneling magnetoresistance (TMR in magnetic tunnel junctions (MTJs composed of Fe/MgO/Ge1−xFex with various Fe concentrations (x = 0.065, 0.105, 0.140, and 0.175. With increasing x, the TMR ratio increases up to 1.5% when x≤ 0.105, and it decreases when x> 0.105. This is the first observation of the TMR ratio over 1% in MTJs containing a group-IV ferromagnetic semiconductor. With increasing x, while the Curie temperature of GeFe increases, the MgO surface becomes rougher, which is thought to be the cause of the upper limit of the TMR ratio. The quality of the MgO layer on GeFe is an important factor for further improvement of TMR in Fe/MgO/GeFe MTJs.

Synthesis and Molecular Structure of a Novel Compound Containing a Carbonate-Bridged Hexacalcium Cluster Cation Assembled on a Trimeric Trititanium(IV)-Substituted Wells-Dawson Polyoxometalate.

Science.gov (United States)

Hoshino, Takahiro; Isobe, Rina; Kaneko, Takuya; Matsuki, Yusuke; Nomiya, Kenji

2017-08-21

A novel compound containing a hexacalcium cluster cation, one carbonate anion, and one calcium cation assembled on a trimeric trititanium(IV)-substituted Wells-Dawson polyoxometalate (POM), [{Ca 6 (CO 3 )(μ 3 -OH)(OH 2 ) 18 }(P 2 W 15 Ti 3 O 61 ) 3 Ca(OH 2 ) 3 ] 19- (Ca 7 Ti 9 Trimer), was obtained as the Na 7 Ca 6 salt (NaCa-Ca 7 Ti 9 Trimer) by the reaction of calcium chloride with the monomeric trititanium(IV)-substituted Wells-Dawson POM species "[P 2 W 15 Ti 3 O 59 (OH) 3 ] 9- " (Ti 3 Monomer). Ti 3 Monomer was generated in situ under basic conditions from the separately prepared tetrameric species with bridging Ti(OH 2 ) 3 groups and an encapsulated Cl - ion, [{P 2 W 15 Ti 3 O 59 (OH) 3 } 4 {μ 3 -Ti(H 2 O) 3 } 4 Cl] 21- (Ti 16 Tetramer). The Na 7 Ca 6 salt of Ca 7 Ti 9 Trimer was characterized by complete elemental analysis, thermogravimetric (TG) and differential thermal analyses (DTA), FTIR, single-crystal X-ray structure analysis, and solution 183 W and 31 P NMR spectroscopy. X-ray crystallography revealed that the [Ca 6 (CO 3 )(μ 3 -OH)(OH 2 ) 18 ] 9+ cluster cation was composed of six calcium cations linked by one μ 6 -carbonato anion and one μ 3 -OH - anion. The cluster cation was assembled, together with one calcium ion, on a trimeric species composed of three tri-Ti(IV)-substituted Wells-Dawson subunits linked by Ti-O-Ti bonds. Ca 7 Ti 9 Trimer is an unprecedented POM species containing an alkaline-earth-metal cluster cation and is the first example of alkaline-earth-metal ions clustered around a titanium(IV)-substituted POM.

Soft Magnetic Properties of Nanocrystalline Fe-M-(B and/or O)(M=Group IV A, V A Elements) Alloy Films

OpenAIRE

Hayakawa, Y.; Makino, A.; Inoue, A.; Masumoto, T.

1996-01-01

In Fe-M-(B and/or O)(M=group IV A, V A elements) alloy films, nanocrystalline bcc phase are formed by annealing the amorphous single phase for Fe-M-B films, whereas the bcc nanocrystals are already formed in an as-deposited state for Fe-M-O or Fe-M-B-O) films. Among Fe-M-B films with various M elements, Fe-(Zr, Hf, Nb, Ta)-B alloy films exhibit high saturation magnetization (Is) above 1.4 T and high relative permeability (|μ|) above 1000 at 1MHz. The highest |μ| of 3460 at 1MHz is obtained fo...

catena-Poly[[trimethyltin(IV]-μ-1,2,3-benzotriazol-1-ido-κ2N1:N3

Directory of Open Access Journals (Sweden)

Yuanyuan Li

2012-02-01

Full Text Available In the title coordination polymer, [Sn(CH33(C6H4N3]n, the SnIV atom is five-coordinated in a distorted trigonal–bipyramidal geometry with the methyl groups in equatorial positions and two N atoms of two symmetry-related benzotriazolide anions in axial positions. The anion bridges adjacent metal atoms, forming zigzag polymeric chains parallel to [011] and [0-11].

Group IV Materials for High Performance Methane Sensing in Novel Slot Optical Waveguides at 2.883 μm and 3.39 μm

Directory of Open Access Journals (Sweden)

Vittorio M. N. PASSARO

2012-03-01

Full Text Available In this paper a detailed investigation of novel photonic sensors based on slot waveguides has been carried out. Appropriate alloys of group IV materials, such as germanium (Ge, silicon (Si, carbon (C and tin (Sn, are applied in silicon-on-insulator (SOI technology for homogeneous optical sensing at 2.883 µm and 3.39 μm. Electronic and optical properties of group IV alloys have been investigated. In addition, we have designed novel group IV vertical slot waveguides in order to achieve ultra-high sensitivities, as well as good fabrication tolerances. All these features have been compared with well-known SOI slot waveguides for optical label-free homogeneous sensing at 1.55 µm. In conclusion, theoretical investigation of ring resonators based on these novel slot waveguides has revealed very good results in terms of ultra high sensing performance of methane gas, i.e., limit of detection ~ 3.6×10-5 RIU and wavelength sensitivity > 2×103 nm/RIU.

Synthesis of graphite intercalation compound of group VI metals and uranium hexafluorides

International Nuclear Information System (INIS)

Fukui, Toshihiro; Hagiwara, Rika; Ema, Keiko; Ito, Yasuhiko

1993-01-01

Systematic investigations were made on the synthesis of graphite intercalation compounds of group VI transition metals (W and Mo) and uranium hexafluorides. The reactions were performed by interacting liquid or gaseous metal hexafluorides with or without elemental fluorine at ambient temperature. The degree of intercalation of these metal fluorides depends on the formation enthalpy of fluorometallate anion from the original metal hexafluoride, as has been found for other intercalation reactions of metal fluorides. (author)

Validity of the WISC-IV Spanish for a clinically referred sample of Hispanic children.

Science.gov (United States)

San Miguel Montes, Liza E; Allen, Daniel N; Puente, Antonio E; Neblina, Cris

2010-06-01

The Wechsler Intelligence Scale for Children (WISC) is the most commonly used intelligence test for children. Five years ago, a Spanish version of the WISC-IV was published (WISC-IV Spanish; Wechsler, 2005), but a limited amount of published information is available regarding its utility when assessing clinical samples. The current study included 107 children who were Spanish speaking and of Puerto Rican descent that had been administered the WISC-IV Spanish. They were subdivided into a clinical sample of 35 children with diagnoses of various forms of brain dysfunction (primarily learning disability, attention-deficit/hyperactivity disorder, and epilepsy) and a comparison group made up of 72 normal children who were part of the WISC-IV Spanish version standardization sample. Comparisons between these groups and the standardization sample were performed for the WISC-IV Spanish index and subtest scores. Results indicated that the clinical sample performed worse than the comparison samples on the Working Memory and Processing Speed Indexes, although findings varied to some extent depending on whether the clinical group was compared with the normal comparison group or the standardization sample. These findings provide support for the criterion validity of the WISC-IV Spanish when it is used to assess a clinically referred sample with brain dysfunction.

Adriamycin continuous i.v. infusion for the treatment of childhood hepatic malignancies, toxicity and efficacy: a pilot study childrens cancer study group

International Nuclear Information System (INIS)

Ortega, J.A.; Feusner, J.; Reaman, G.; Woods, W.

1986-01-01

In an effort to increase the number of patients with hepatoblastoma and hepatocellular carcinoma receiving the benefits of complete surgical excision, a pilot study was undertaken at a few Childrens Cancer Study Group institutions. For this purpose, repeated courses of adriamycin administered as a continuous I.V. infusion either singly or in combination with c-platinum and radiation therapy treatment was selected. The patient population consisted of a total of eleven children with primary hepatic malignancies: six children had hepatoblastoma; all six were under two years of age at diagnosis. Five patients with hepatocellular carcinoma were entered to the study. Of the eleven patients, four had previously received adriamycin as an I.V. bolus. A table summarizes the patient's characteristics, the adriamycin dose they received and their responses to therapy

MACKLIB-IV: a library of nuclear response functions generated with the MACK-IV computer program from ENDF/B-IV

International Nuclear Information System (INIS)

Gohar, Y.; Abdou, M.A.

1978-03-01

MACKLIB-IV employs the CTR energy group structure of 171 neutron groups and 36 gamma groups. A retrieval computer program is included with the library to permit collapsing into any other energy group structure. The library is in the new format of the ''MACK-Activity Table'' which uses a fixed position for each specific response function. This permits the user when employing the library with present transport codes to obtain directly the nuclear responses (e.g. the total nuclear heating) summed for all isotopes and integrated over any geometrical volume. The response functions included in the library are neutron kerma factor, gamma kerma factor, gas production and tritium-breeding functions, and all important reaction cross sections. Pertinent information about the library and a graphical display of six response functions for all materials in the library are given

Progress in vacuum metal extraction, refining and consolidation

International Nuclear Information System (INIS)

Sundaram, C.V.; Mukherjee, T.K.; Sharma, B.P.

1973-01-01

The unique achievements in the process metallurgy of rare metals in the past quarter century should largely be attributed to advances in vacuum technology. New standards for high purity, increasing demand for pure metals and alloys for established applications, and steady improvement in sophistication and capacity of vacuum furnaces have provided the stimulus for developing and expanding vacuum metal extraction processes, and also exploring totally new processes. The paper discusses the thermochemistry of vacuum metallurgy, carbothermic and metallothermic reduction reactions, consolidation and refining by vacuum arc melting, electron beam melting and high temperature high vacuum sintering, and ultrapurification, with special reference to the reactive and refractory metals of Group IV to VI. (author)

Thermodynamics of the complex formation between thorium(IV) and some polydentate ligands in aqueous solution

International Nuclear Information System (INIS)

Di Bernado, P.; Cassol, A.; Tomat, G.; Bismondo, A.; Magon, L.

1983-01-01

The changes in free energy, enthalpy, and entropy for the formation of thorium(IV)-oxydiacetate, -iminodiacetate, -thiodiacetate, and -succinate complexes have been determined by potentiometric and calorimetric titrations at 25 deg C in aqueous 1 mol dm - 3 sodium perchlorate. All the ligands form 1:1 chelate complexes with the thorium(IV) ion the stability of which is dependent on both the chelate ring dimensions and the nature of the donor group in the chain. The order of the relative stabilities (iminodiacetate > oxydiacetate > thiodiacetate > succinate) is mainly dependent on the reaction enthalpies, since the δS values are close to each other. In the thorium(IV)-oxydiacetate system the maximum number of three ligands for every metal ion was reached. Because of precipitation of solid compounds in the other systems, it was only possible to define complexes with a lower number of co-ordinated ligands: two for succinate and thiodiacetate, and one for iminodiacetate. Owing to the lower stability of the chelate ring of thiodiacetate and succinate complexes and the high basicity of the amino-group of iminodiacetate, these ligands form also unchelated protonated complexes. (author)

Features of proteolytic properties of tetraphenylporphyrin complex with lanthanide group metals

Science.gov (United States)

Tobolkina, Elena A.; Skripnikova, Tatiana A.; Starikova, Anna A.; Shumilova, Galina I.; Pendin, Andrey A.

2018-01-01

Demetallation of metalloporphyrin molecules is one of the essential degradation reactions in photosynthesis. The effect of metalloporphyrin nature on removal of central metals from tetraphenylporphyrin complexes based on lanthanide group metals (Dy, Er, Lu, Ho) has been studied. pH values, at which the metal ions leave the metalloporphyrin complex were established using two-phase spectrophotometric titration with potentiometric pH-control. The pH values decrease with the increase of atomic numbers of lanthanide groups, as well as with increase of 4f-electrons. The reaction of an extra ligand exchange for the hydroxide ion was studied. For Dy-, Er- and Ho-tetraphenylporphyrin complexes one particle of extra ligand coordinates with one porphyrin complex. A complex with dimeric particles can be formed for the system of Lu-tetraphenylporphyrin. Constants of the ion exchange reactions were calculated.

The 10/66 Dementia Research Group's fully operationalised DSM-IV dementia computerized diagnostic algorithm, compared with the 10/66 dementia algorithm and a clinician diagnosis: a population validation study

Directory of Open Access Journals (Sweden)

Krishnamoorthy ES

2008-06-01

Full Text Available Abstract Background The criterion for dementia implicit in DSM-IV is widely used in research but not fully operationalised. The 10/66 Dementia Research Group sought to do this using assessments from their one phase dementia diagnostic research interview, and to validate the resulting algorithm in a population-based study in Cuba. Methods The criterion was operationalised as a computerised algorithm, applying clinical principles, based upon the 10/66 cognitive tests, clinical interview and informant reports; the Community Screening Instrument for Dementia, the CERAD 10 word list learning and animal naming tests, the Geriatric Mental State, and the History and Aetiology Schedule – Dementia Diagnosis and Subtype. This was validated in Cuba against a local clinician DSM-IV diagnosis and the 10/66 dementia diagnosis (originally calibrated probabilistically against clinician DSM-IV diagnoses in the 10/66 pilot study. Results The DSM-IV sub-criteria were plausibly distributed among clinically diagnosed dementia cases and controls. The clinician diagnoses agreed better with 10/66 dementia diagnosis than with the more conservative computerized DSM-IV algorithm. The DSM-IV algorithm was particularly likely to miss less severe dementia cases. Those with a 10/66 dementia diagnosis who did not meet the DSM-IV criterion were less cognitively and functionally impaired compared with the DSMIV confirmed cases, but still grossly impaired compared with those free of dementia. Conclusion The DSM-IV criterion, strictly applied, defines a narrow category of unambiguous dementia characterized by marked impairment. It may be specific but incompletely sensitive to clinically relevant cases. The 10/66 dementia diagnosis defines a broader category that may be more sensitive, identifying genuine cases beyond those defined by our DSM-IV algorithm, with relevance to the estimation of the population burden of this disorder.

Metal fuel development and verification for prototype generation- IV Sodium- Cooled Fast Reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, Chan Bock; Cheon, Jin Sik; Kim, Sung Ho; Park, Jeong Yong; Joo, Hyung Kook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

Metal fuel is being developed for the prototype generation-IV sodium-cooled fast reactor (PGSFR) to be built by 2028. U-Zr fuel is a driver for the initial core of the PGSFR, and U -transuranics (TRU)-Zr fuel will gradually replace U-Zr fuel through its qualification in the PGSFR. Based on the vast worldwide experiences of U-Zr fuel, work on U-Zr fuel is focused on fuel design, fabrication of fuel components, and fuel verification tests. U-TRU-Zr fuel uses TRU recovered through pyroelectrochemical processing of spent PWR (pressurized water reactor) fuels, which contains highly radioactive minor actinides and chemically active lanthanide or rare earth elements as carryover impurities. An advanced fuel slug casting system, which can prevent vaporization of volatile elements through a control of the atmospheric pressure of the casting chamber and also deal with chemically active lanthanide elements using protective coatings in the casting crucible, was developed. Fuel cladding of the ferritic-martensitic steel FC92, which has higher mechanical strength at a high temperature than conventional HT9 cladding, was developed and fabricated, and is being irradiated in the fast reactor.

Metal Fuel Development and Verification for Prototype Generation IV Sodium-Cooled Fast Reactor

Directory of Open Access Journals (Sweden)

Chan Bock Lee

2016-10-01

Full Text Available Metal fuel is being developed for the prototype generation-IV sodium-cooled fast reactor (PGSFR to be built by 2028. U–Zr fuel is a driver for the initial core of the PGSFR, and U–transuranics (TRU–Zr fuel will gradually replace U–Zr fuel through its qualification in the PGSFR. Based on the vast worldwide experiences of U–Zr fuel, work on U–Zr fuel is focused on fuel design, fabrication of fuel components, and fuel verification tests. U–TRU–Zr fuel uses TRU recovered through pyroelectrochemical processing of spent PWR (pressurized water reactor fuels, which contains highly radioactive minor actinides and chemically active lanthanide or rare earth elements as carryover impurities. An advanced fuel slug casting system, which can prevent vaporization of volatile elements through a control of the atmospheric pressure of the casting chamber and also deal with chemically active lanthanide elements using protective coatings in the casting crucible, was developed. Fuel cladding of the ferritic–martensitic steel FC92, which has higher mechanical strength at a high temperature than conventional HT9 cladding, was developed and fabricated, and is being irradiated in the fast reactor.

Sulfide precipitation method of separating uranium from Group II and Group III metal ions

International Nuclear Information System (INIS)

Sundar, P.S.

1977-01-01

Uranium is separated from analytical Group II and Group III metal ions in an aqueous liquor containing uranyl ions. The liquor is extracted with a non-interfering, water-immiscible, organic solvent containing a reagent which will react with the uranyl ions to form a complex soluble in the solvent. If the liquor is acidic, the solvent is washed with water. Then to the solvent is added an aqueous solution containing about 0.5 to 1.0 mole per liter of (NH 4 ) 2 CO 3 or NH 4 HCO 3 ions and sufficient sulfide ions to precipitate the metal ions as sulfides. The solvent and the aqueous solution are separated and the sulfides filtered from the aqueous solution. The ammonium-uranyl-tricarbonate in the aqueous solution can then be precipitated by increasing the concentration of (NH 4 ) 2 CO 3 or NH 4 HCO 3 ions to about 1.5 to 2.5 moles per liter. The precipitate is filtered and calcined to obtain U 3 O 8 or UO 2 . 21 claims, 1 figure

DSM-IV: a nosology sold before its time?

Science.gov (United States)

Zimmerman, M; Jampala, V C; Sierles, F S; Taylor, M A

1991-04-01

The purpose of this study was to determine whether American psychiatrists believe that DSM-IV is being published too soon after DSM-III-R. The authors conducted a mail survey of the attitudes of practicing psychiatrists (N = 454), residency program directors (N = 128), residents (N = 1,331), and researchers (N = 196) toward the scheduled publication of DSM-IV in the early 1990s. They found that the majority of all four groups believed that DSM-IV is being published prematurely. In contrast to respondents who believed that the timing of DSM-IV is appropriate, those who indicated that it is being published too soon had more recently completed their residency training and also believed that DSM-III-R was published prematurely. There was no association between the psychiatrists' responses and their theoretical orientation, Board certification status, ownership of the DSM manuals, the length of time they had used DSM-III, and the diagnostic manual (DSM-III or DSM-III-R) they were currently using. The belief that DSM-IV is being published too soon could contribute to underuse of DSM-IV by substantial numbers of psychiatrists. Thus, to foster compliance with it, APA must preserve in its efforts to demonstrate that the advantages of publishing it in 1993 outweigh the disadvantages of adopting yet another manual.

Synthesis, spectroscopic and biological activities studies of acyclic and macrocyclic mono and binuclear metal complexes containing a hard-soft Schiff base.

Science.gov (United States)

Abou-Hussein, Azza A A; Linert, Wolfgang

2012-09-01

Mono- and bi-nuclear acyclic and macrocyclic complexes with hard-soft Schiff base, H(2)L, ligand derived from the reaction of 4,6-diacetylresorcinol and thiocabohydrazide, in the molar ratio 1:2 have been prepared. The H(2)L ligand reacts with Co(II), Ni(II), Cu(II), Zn(II), Mn(II) and UO(2)(VI) nitrates, VO(IV) sulfate and Ru(III) chloride to get acyclic binuclear complexes except for VO(IV) and Ru(III) which gave acyclic mono-nuclear complexes. Reaction of the acyclic mono-nuclear VO(IV) and Ru(III) complexes with 4,6-diacetylresorcinol afforded the corresponding macrocyclic mono-nuclear VO(IV) and Ru(IIII) complexes. Template reactions of the 4,6-diacetylresorcinol and thiocarbohydrazide with either VO(IV) or Ru(III) salts afforded the macrocyclic binuclear VO(IV) and Ru(III) complexes. The Schiff base, H(2)L, ligand acts as dibasic with two NSO-tridentate sites and can coordinate with two metal ions to form binuclear complexes after the deprotonation of the hydrogen atoms of the phenolic groups in all the complexes, except in the case of the acyclic mononuclear Ru(III) and VO(IV) complexes, where the Schiff base behaves as neutral tetradentate chelate with N(2)S(2) donor atoms. The ligands and the metal complexes were characterized by elemental analysis, IR, UV-vis (1)H-NMR, thermal gravimetric analysis (TGA) and ESR, as well as the measurements of conductivity and magnetic moments at room temperature. Electronic spectra and magnetic moments of the complexes indicate the geometries of the metal centers are either tetrahedral, square planar or octahedral. Kinetic and thermodynamic parameters were calculated using Coats-Redfern equation, for the different thermal decomposition steps of the complexes. The ligands and the metal complexes were screened for their antimicrobial activity against Staphylococcus aureus as Gram-positive bacteria, and Pseudomonas fluorescens as Gram-negative bacteria in addition to Fusarium oxysporum fungus. Most of the complexes exhibit

Extreme conditions synthesis, processing and characterization of metal-nitrides and alloys of mechanical and optoelectronic importance

International Nuclear Information System (INIS)

Serghiou, G; McGaff, A J; Russell, N; Morniroli, J P; Frost, D J; Odling, N; Boehler, R; Troadec, D; Lathe, C

2010-01-01

High density nitrides and group IV alloys are of growing importance for both ceramic and optoelectronic applications. We present here new data and processes in our ongoing preparation of alkaline earth and transition metal nitrides as well as group IV alloys, here, up to 25 GPa and 2300 K. We employ large volume and laser-heated diamond anvil cell techniques for synthesis, processing tools including focused ion beam, and synchrotron X-ray diffraction, transmission electron microscopy and scanning electron microscopy for characterization.

A study of new rare-earth metal group-13 chalcohalides. Structures, chemistry, and optical properties

International Nuclear Information System (INIS)

Dorhout, P.K.; Van Calcar, P.M.

1998-01-01

Full text: Several new quaternary compounds from the rare-earth metal group-13 chalcohalide family have been prepared from alkaline earth halide flux reactions of binary and elemental starting materials. One compound, for example, Ca 2 La 6G a 2 S 1 4 , crystallizes as needles in an hexagonal cell while another, more disordered structure, La 11 Ga 19 Cl 6 S 42 , crystallizes as monoclinic plates. The former is a condensed structure with channels that contain the alkaline earth element while the latter forms a layered structure containing rare-earth halide clusters within interlayer galleries. These compounds are new members of a family of rare-earth metal main-group chalcogenides which show promise as electroluminescent materials. Structural and spectroscopic studies of these and related compounds will be discussed

Protecting group and switchable pore-discriminating adsorption properties of a hydrophilic-hydrophobic metal-organic framework.

Science.gov (United States)

Mohideen, M Infas H; Xiao, Bo; Wheatley, Paul S; McKinlay, Alistair C; Li, Yang; Slawin, Alexandra M Z; Aldous, David W; Cessford, Naomi F; Düren, Tina; Zhao, Xuebo; Gill, Rachel; Thomas, K Mark; Griffin, John M; Ashbrook, Sharon E; Morris, Russell E

2011-04-01

Formed by linking metals or metal clusters through organic linkers, metal-organic frameworks are a class of solids with structural and chemical properties that mark them out as candidates for many emerging gas storage, separation, catalysis and biomedical applications. Important features of these materials include their high porosity and their flexibility in response to chemical or physical stimuli. Here, a copper-based metal-organic framework has been prepared in which the starting linker (benzene-1,3,5-tricarboxylic acid) undergoes selective monoesterification during synthesis to produce a solid with two different channel systems, lined by hydrophilic and hydrophobic surfaces, respectively. The material reacts differently to gases or vapours of dissimilar chemistry, some stimulating subtle framework flexibility or showing kinetic adsorption effects. Adsorption can be switched between the two channels by judicious choice of the conditions. The monoesterified linker is recoverable in quantitative yield, demonstrating possible uses of metal-organic frameworks in molecular synthetic chemistry as 'protecting groups' to accomplish selective transformations that are difficult using standard chemistry techniques.

Peroxo complexes of molybdenum(VI), tungsten(VI), uranium(VI), zirconium(IV) and thorium(IV) ions containing tridentate Schiff bases derived from salicylaldehyde and amino acids

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Khan, A.R.

1997-01-01

The synthesis of peroxo complexes of molybdenum(VI), tungsten(VI), uranium(VI), zirconium(IV), thorium(IV) and their possible oxygen transfer reactions is presented. An attempt has also been made to study the size of the metal ions and the electronic effect derived from the tridentate Schiff bases on the v 1 (O-O) mode of the complexes in their IR spectra

Diverse anisotropy of phonon transport in two-dimensional group IV-VI compounds: A comparative study

Science.gov (United States)

Qin, Guangzhao; Qin, Zhenzhen; Fang, Wu-Zhang; Zhang, Li-Chuan; Yue, Sheng-Ying; Yan, Qing-Bo; Hu, Ming; Su, Gang

2016-05-01

New classes of two-dimensional (2D) materials beyond graphene, including layered and non-layered, and their heterostructures, are currently attracting increasing interest due to their promising applications in nanoelectronics, optoelectronics and clean energy, where thermal transport is a fundamental physical parameter. In this paper, we systematically investigated the phonon transport properties of the 2D orthorhombic group IV-VI compounds of GeS, GeSe, SnS and SnSe by solving the Boltzmann transport equation (BTE) based on first-principles calculations. Despite their similar puckered (hinge-like) structure along the armchair direction as phosphorene, the four monolayer compounds possess diverse anisotropic properties in many aspects, such as phonon group velocity, Young's modulus and lattice thermal conductivity (κ), etc. Especially, the κ along the zigzag and armchair directions of monolayer GeS shows the strongest anisotropy while monolayer SnS and SnSe show almost isotropy in phonon transport. The origin of the diverse anisotropy is fully studied and the underlying mechanism is discussed in details. With limited size, the κ could be effectively lowered, and the anisotropy could be effectively modulated by nanostructuring, which would extend the applications to nanoscale thermoelectrics and thermal management. Our study offers fundamental understanding of the anisotropic phonon transport properties of 2D materials, and would be of significance for further study, modulation and applications in emerging technologies.

DSM-IV-defined anxiety disorder symptoms in a middle-childhood-aged group of Malaysian children using the Spence Children's Anxiety Scale

OpenAIRE

Atefeh Ahmadi; Mohamed Sharif Mustaffa; Amirmudin Udin; AliAkbar Haghdoost

2016-01-01

Introduction Pediatric anxiety disorders are the most common mental health disorders in the middle-childhood age group. The purpose of this study is to assess anxiety disorder symptoms, as defined by the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), in a large community sample of low socioeconomic level rural children and to investigate some of the psychometric properties (internal consistency, construct and convergent validity and items rated as often or always...

Metal oxides modified NiO catalysts for oxidative dehydrogenation of ethane to ethylene

KAUST Repository

Zhu, Haibo; Dong, Hailin; Laveille, Paco; Saih, Youssef; Caps, Valerie; Basset, Jean-Marie

2014-01-01

in contrast to pure NiO. The introduction of group IV, V and VI transition metals into NiO decreases the catalytic activity in ethane ODH. However, the ethylene selectivity is enhanced with the highest level for the Ni-W-O and Ni-Ti-O catalysts. As a result

Analytical applications of resins containing amide and polyamine functional groups

International Nuclear Information System (INIS)

Orf, G.M.

1977-01-01

Resins are prepared by chemically bonding N,N-dialkylamides and polyamine functional groups to Amberlite XAD-4. These resins are applied to the concentration of metal ions from dilute aqueous solution and the rapid separation of metal ions by high-speed liquid chromatography with continuous on-line detection of the eluent stream. A dibutyl amide resin is used for the separation of uranium(VI), thorium(IV), and zirconium(IV) from each other and several other metal ions. Uranium(VI) and thorium(IV) are determined in the presence of large excesses of foreign metal ions and anions. A practical application of the amide resin is studied by determining uranium in low grade uranium ores. The amide resin is also used for the selective concentration of gold(III) from seawater. A triethylenetetramine resin is used for the separation of copper(II) from equal molar amounts and large excesses of nickel(II), cobalt(II), zinc(II), cadmium(II), iron(III) and aluminum(III). Copper(II), nickel(II), zinc(II), cobalt(II) and cadmium(II) are determined in the presence of large excesses of calcium(II) and magnesium(II). The resin was found to be selective for silver(I) and mercury(II) at low pH values and a rapid separation of equal molar amounts of copper(II) and silver(I) was performed. The resin was also found to have an affinity for anionic metal complexes such as iron(III)-tartrate when the resin is in the hydrogen form. A study of the retention of the anions chromium(III)-tartrate and dichromate at various pH values was performed to better understand the anion exchange properties of the resin. Triethylenetetramine resins were also prepared from polystyrene gel to make a resin with higher capacities for copper

Study of the electronic properties of organic molecules within a metal-molecule-metal junction

International Nuclear Information System (INIS)

Lambert, Mathieu

2003-01-01

This ph-D thesis is about electronic transport through organic molecules inserted in a metal molecule-metal junction. We describe first a simple process to prepare sub-3 nm gaps by controllable breakage (under an electrical stress) of gold wires lithographed on a SiO 2 Si substrate at low temperature (4.2 K). We show that the involved mechanism is thermally assisted electromigration. We observe that current-voltage (I-V) characteristics of resulting electrodes are stable up to ∼5 V. which gives access to the well-known Fowler-Nordheim regime in the I-V, allowing an accurate characterisation of the gap size. The average gap is found lo be between 1.5 nm in width and 2.5 eV in height. Molecules and nanoparticles have then been inserted in the junction in the case of nanoparticles for example. The resulting IV clearly shows the suppression of electrical current at low bias known as Coulomb blockade. Characteristic of single-electron tunnelling through nanometer-sized structures, finally we fabricated a single-electron tunneling device based on Au nanoparticles connected to the electrodes via terthiophene (T3) molecule. We use the silicon substrate, separated from the planar structure by a silicon oxide of 200 nm, as an electrostatic gate and observed clear current modulation with possible signature of the transport properties of the terthiophene molecules. (author) [fr

Oxygen Atom Transfer Using an Iron(IV)-Oxo Embedded in a Tetracyclic N-Heterocyclic Carbene System: How Does the Reactivity Compare to Cytochrome P450 Compound I?

Science.gov (United States)

Cantú Reinhard, Fabián G; de Visser, Sam P

2017-02-24

N-Heterocyclic carbenes (NHC) are commonly featured as ligands in transition metal catalysis. Recently, a cyclic system containing four NHC groups with a central iron atom was synthesized and its iron(IV)-oxo species, [Fe IV (O)(cNHC 4 )] 2+ , was characterized. This tetracyclic NHC ligand system may give the iron(IV)-oxo species unique catalytic properties as compared to traditional non-heme and heme iron ligand systems. Therefore, we performed a computational study on the structure and reactivity of the [Fe IV (O)(cNHC 4 )] 2+ complex in substrate hydroxylation and epoxidation reactions. The reactivity patterns are compared with cytochrome P450 Compound I and non-heme iron(IV)-oxo models and it is shown that the [Fe IV (O)(cNHC 4 )] 2+ system is an effective oxidant with oxidative power analogous to P450 Compound I. Unfortunately, in polar solvents, a solvent molecule will bind to the sixth ligand position and decrease the catalytic activity of the oxidant. A molecular orbital and valence bond analysis provides insight into the origin of the reactivity differences and makes predictions of how to further exploit these systems in chemical catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A simple Cr(VI)–S(IV)–O{sub 2} system for rapid and simultaneous reduction of Cr(VI) and oxidative degradation of organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Yuan, Yanan; Yang, Shaojie [Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, 430079 (China); Zhou, Danna, E-mail: zdncug@163.com [Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Wu, Feng [Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, 430079 (China)

2016-04-15

Highlights: • Rapid and simultaneous reduction of Cr(VI) and degradation of organic pollutants occur. • Oxysulfur radicals generated in Cr(VI)–S(IV)–O{sub 2} system oxidize the organic pollutants. • Acidic pH facilitates the reactions from both directions of reduction and oxidation. • Degradation potential of aromatic amines depends on the substituted groups. • Cr(VI)–S(IV)–O{sub 2} system is promising for “waste control by waste”. - Abstract: Hexavalent chromium (Cr(VI)), a heavy-metal contaminant, can be easily reduced to less toxic trivalent chromium (Cr(III)) by sulfite ions (S(IV)). However, S(IV) has not drawn as much attention as the ferrous ion has. We report herein a novel Cr(VI)–S(IV)–O{sub 2} system containing sulfite ions that rapidly and simultaneously reduces Cr(VI) and oxidize organic pollutants in the presence of oxygen in aqueous solutions. This Cr(VI)–S(IV)-O{sub 2} system contains the initiator Cr(VI), the reductant S(IV), and the oxidant O{sub 2}, which produce oxysulfur radicals (mainly SO{sub 4}·{sup −} and SO{sub 5}·{sup −}) and hydroxyl radicals (OH·). The Cr(VI)/S(IV) molar ratio, pH, and oxygen content play important roles in the entire reaction system. Acidic conditions (pH 3.0) facilitated degradation of organic compounds and reduction of Cr(VI) as well. In addition, experiments of rapid degradation of several kinds of organic pollutants such as azo dye (acid orange 7, AO7), aniline, phenol, bisphenol A etc were also conducted. Preliminary results show that the removal rates of the analogs of phenols or aromatic amines in this Cr(VI)–S(IV)–O{sub 2} system have a relationship with the electronic parameters (Hammett constant, σ) of the substituted groups. Thus, the Cr(VI)–S(IV)–O{sub 2} system, provides an excellent strategy of “waste control by waste” for removing multiple industrial contaminants.

Analytical applications of resins containing amide and polyamine functional groups

International Nuclear Information System (INIS)

Orf, G.M.

1977-12-01

A dibutyl amide resin is used for the separation of uranium(VI), thorium(IV), and zirconium(IV) from each other and several other metal ions. Uranium(VI) and thorium(IV) are determined in the presence of large excesses of foreign metal ions and anions. A practical application of the amide resin is studied by determining uranium in low grade uranium ores. The amide resin is also used for the selective concentration of gold(III) from sea water

Analytical applications of resins containing amide and polyamine functional groups

Energy Technology Data Exchange (ETDEWEB)

Orf, Gene Michael [Iowa State Univ., Ames, IA (United States)

1977-12-01

A dibutyl amide resin is used for the separation of uranium(VI), thorium(IV), and zirconium(IV) from each other and several other metal ions. Uranium(VI) and thorium(IV) are determined in the presence of large excesses of foreign metal ions and anions. A practical application of the amide resin is studied by determining uranium in low grade uranium ores. The amide resin is also used for the selective concentration of gold(III) from sea water.

Surface layers in the 4A group metals with implanted silicon ions

International Nuclear Information System (INIS)

Kovneristyj, Yu.K.; Vavilova, V.V.; Krasnopevtsev, V.V.; Galkin, L.N.; Kudyshev, A.N.; Klechkovskaya, V.V.

1987-01-01

A study was made on the change of structure and phase composition of fine near the surface layers of 4A group metals (Hf, Zr, Ti) during ion Si implantation and successive thermal annealing at elevated temperatures. Implantation of Si + ions with 30 or 16 keV energy in Ti, Zr and Hf at room temperature results to amorphization of metal surface layer. The surface hafnium and titanium layer with implanted Si atoms due to interaction with residual atmosphere of oxygen turns during annealing at 870 K to amorphous solid solution of HfO 2m or TiO 2 with Si, preventing further metal oxidation; layers of amorphous alloy are characterized by thermal stability up to 1270 K. Oxidation of the surface amorphous layer in residual oxygen atmosphere and its crystallization in ZrO 2 take place in result of Zr annealing with implanted Si ions at temperature not exceeding 870 K. Similar phenomena are observed in the case of hafnium with implanted oxygen ions or small dose of silicon ions. Thermal stability of amorphous layers produced during ion implantation of Si in Ti, Zr and Hf corresponds to scale resistance of monolithic alloys in Ti-Si, Zr-Si and Hf-Si systems

Sorption of Uranium(VI and Thorium(IV by Jordanian Bentonite

Directory of Open Access Journals (Sweden)

Fawwaz I. Khalili

2013-01-01

Full Text Available Purification of raw bentonite was done to remove quartz. This includes mixing the raw bentonite with water and then centrifuge it at 750 rpm; this process is repeated until white purified bentonite is obtained. XRD, XRF, FTIR, and SEM techniques will be used for the characterization of purified bentonite. The sorption behavior of purified Jordanian bentonite towards and Th4+ metal ions in aqueous solutions was studied by batch experiment as a function of pH, contact time, temperature, and column techniques at 25.0∘C and . The highest rate of metal ions uptake was observed after 18 h of shaking, and the uptake has increased with increasing pH and reached a maximum at . Bentonite has shown high metal ion uptake capacity toward uranium(VI than thorium(IV. Sorption data were evaluated according to the pseudo- second-order reaction kinetic. Sorption isotherms were studied at temperatures 25.0∘C, 35.0∘C, and 45.0∘C. The Langmuir, Freundlich, and Dubinin-Radushkevich (D-R sorption models equations were applied and the proper constants were derived. It was found that the sorption process is enthalpy driven for uranium(VI and thorium(IV. Recovery of uranium(VI and thorium(IV ions after sorption was carried out by treatment of the loaded bentonite with different concentrations of HNO3 1.0 M, 0.5 M, 0.1 M, and 0.01 M. The best percent recovery for uranium(VI and thorium(IV was obtained when 1.0 M HNO3 was used.

Far IR spectra of Th(IV) halide complexes of some heterocyclic bases

International Nuclear Information System (INIS)

Srivastava, A.K.; Agarwal, R.K.; Srivastava, M.; Kapoor, V.; Srivastava, T.N.

1981-01-01

The synthesis and IR spectra of Th(IV) perchlorato, nitrato and thiocyanato complexes of some heterocyclic bases have been reported. Halogens are common ligands in coordination chemistry forming coordinate bonds with metals readily. Metal halogen (M-X) stretching bands show a strong absorption in the far-IR region. Very little information is available on Th-X stretching frequencies. In the present communication, adducts of Th(IV) halide with certain nitrogen heterocyclic bases such as pyridine, α-picoline, 2-amino pyridine, 2:4-lutidine, 2:6-lutidine, quinoline, 2,2'-bipyridine and 1,10-phenanthroline were synthesised and characterised. Experimental details are given. Results are presented and discussed. (author)

Fundamental insights into conformational stability and orbital interactions of antioxidant (+)-catechin species and complexation of (+)-catechin with zinc(II) and oxovanadium(IV)

Science.gov (United States)

Yasarawan, Nuttawisit; Thipyapong, Khajadpai; Sirichai, Somsak; Ruangpornvisuti, Vithaya

2013-09-01

Conformational stability of (+)-catechin species in water has been examined with density functional theory, associated with the polarizable continuum model (PCM) of solvation. Factors such as electron delocalization, lone-pair electron donation and intramolecular hydrogen bonding substantially contribute to the conformational stabilization. Upon deprotonation, the HOMO and LUMO energies for (+)-catechin are both elevated; the energy gaps for the deprotonated species are narrower than the energy gap for the neutral species. The preferential deprotonation occurs at the C3'-, C5-, C7- and C4'-OH groups successively. The pKa value at 9.3 predicted for the most acidic OH group agrees well with previous experimental data; however the values are overestimated for the less acidic OH groups due to limitations of the PCM for charged solutes and/or complex nature of true deprotonation pathways. Formation of hydrogen radicals should be promoted at high pH values following the bond dissociation enthalpies. Complexation of (+)-catechin with either zinc(II) or oxovanadium(IV) is favored at the 1:1 metal-to-ligand (M:L) mole ratio, with the oxovanadium(IV) complex showing higher reaction preference. At M:L = 1:2, formation of two isomeric complexes are plausible for each type of metal ion. Effects of stoichiometry and isomerism on the computational spectral features of the possibly formed metal complexes have been described.

IGORR-IV: Proceedings of the fourth meeting of the International Group On Research Reactors

International Nuclear Information System (INIS)

Rosenbalm, K.F.

1995-01-01

The fourth meeting of the International Group on Research Reactors (IGORR-IV) was attended by was good 55 registered participants from 28 organizations in 13 countries, which compares well with the previous meetings. Twenty-nine papers were presented in five sessions over the two-day meeting. Session subjects were: Operating Research Reactors and Facility Upgrades; Research Reactors in Desin and Construction; Research, Development, and Analysis Results of Thermal Hydraulic Calculations, U 3 Si 2 Fuel Performance and Faibrication; Structural Materials Performance; Neutronics; Severe Accident analysis. Written versions of the papers or hard copies of the viewgraphs used are published in these Proceedings

chemical studies and sorption behavior of some hazardous metal ions on polyacrylamide stannic (IV) molybdophosphate as 'organic - inorganic' composite cation - exchanger

International Nuclear Information System (INIS)

Abdel-Galil, E.A.M.

2010-01-01

compsite materials formed by the combination of multivalent metal acid salts and organic polymers provide a new class of (organic-inorganic) hypride ion exchangers with better mechanical and granulometric properties, good ion-exchange capacity, higher chemical and radiation stabilites, reproducibility and selectivity for heavy metals. this material was characterized using X-ray (XRD and XRF), IR, TGA-DTA and total elemental analysis studies. on the basis of distribution studies, the material has been found to be highly selective for pb(II). thermodynamic parameters (i.e δG 0 , δ S 0 and δH 0 ) have also been calculated for the adsorption of Pb 2+ , Cs + , Fe 3+ , Cd 2+ , Cu +2 , Zn 2+ , Co 2+ and Eu 3+ ions on polyacrylamide Sn(IV) molybdophosphate showing that the overall adsorption process is spontaneous endothermic. the mechanism of diffusion of Fe 3+ , Co 2+ , Cu +2 , Zn 2+ , Cd 2+ , Cs + , Pb 2+ and Eu 3+ in the H-form of polyacrylamide Sn(IV) molybdophosphate composite as cation exchanger was studied as a function of particle size, concentration of the exchanging ions, reaction temperature, dring temperature and pH. the exchange rate was controlled by particle diffusion mechanism as a limited batch techneque and is confirmed from straight lines of B versus 1/r 2 polts. the values of diffusion coefficients, activation energy and entropy of activation were calculated and their significance was discussed. the data obtained have been comared with that reported for other organic and inorganic exchangers.

Assessment of Group Preferences and Group Uncertainty for Decision Making

Science.gov (United States)

1976-06-01

the individ- uals. decision making , group judgments should be preferred to individual judgments if obtaining group judgments costs more. -26- -YI IV... decision making group . IV. A. 3. Aggregation using conjugate distribution. Arvther procedure for combining indivi(jai probability judgments into a group...statisticized group group decision making group judgment subjective probability Delphi method expected utility nominal group 20. ABSTRACT (Continue on

Occurrences of flares with type II and IV radio events in interacting sunspot groups in the course of revolutions

International Nuclear Information System (INIS)

Klimes, J.; Krivsky, L.

1984-01-01

Using data from 11-year solar cycle No. 20, it was found that flares with type II radio bursts are more than twice as frequent and flares with type IV bursts nearly twice as frequent in sunspot groups which developed close to each other or which merged in the course of revolutions than in isolated sunspot groups. With both types the occurrence of these flares is concentrated in the revolution of the so-called sunspot group interaction (their approximation, merging). (author)

Chemical nature of implant-derived titanium(IV) ions in synovial fluid

International Nuclear Information System (INIS)

Silwood, Christopher J.L.; Grootveld, Martin

2005-01-01

Previous investigations have indicated a deleterious leakage of Ti(III) and/or Ti(IV) species from Ti-Al-V alloy joint prostheses into adjacent tissue, synovium or synovial fluid (SF) in vivo. In view of the importance of the particular chemical nature of such complexes in determining their biological activity, we have employed high field proton ( 1 H) NMR spectroscopy to 'speciate' Ti(IV) in inflammatory SF. Treatment of osteoarthritic SF samples with increasing concentrations of Ti(IV) (0.10-1.03 mM [TiO(C 2 O 4 ) 2 ] 2- ) gave rise to a specific broadening of the citrate proton resonances, indicating that this bioavailable oxygen-donor ligand plays an important role in complexing implant-derived Ti(IV). 1 H NMR analysis of Ti(IV)-loaded SF samples subsequently treated with a large excess of ascorbate (0.05 M) showed that this added Ti(IV) chelator was only poorly effective in removing this metal ion from Ti(IV)-citrate/Ti(IV)-oxycitrate complexes. The results obtained here provide evidence for complexation of the low-molecular-mass (non-protein-bound) fraction of implant-derived Ti(IV) by citrate in vivo

Functionalization of group IV semiconductors; Funktionalisierung von Gruppe IV-Halbleitern

Energy Technology Data Exchange (ETDEWEB)

Hoeb, Marco Andreas

2011-01-15

The present work is focused on the structural and electronic properties of thermally and photochemically grafted alkene molecules. The semiconductor substrates used in this work are the group IV-semiconductors silicon, diamond, and silicon carbide. On silicon, functionalization via the commonly known hydrosilylation reaction was performed. During thermal treatment in vacuum-distilled 1-octadecene, the alkene molecules covalently added to the substrate via Si-C bond formation, resulting in self-assembled organic monolayers. The reaction resulted in smooth and homogeneous alkyl-terminated surfaces. Static water contact angles were determined to be 113 . Photoelectron spectroscopy was performed and showed no evidence of surface oxidation. The high packing of the organic layers is indicated by the asymmetric methylene vibrational mode, which has been redshifted by -4 cm{sup -1} with respect to the liquid alkene mode position. The average molecular tilt-angle of the alkyl-molecules, relative to the surface normal, has been identified to be 34 . The transport properties have been determined to be dominated by tunneling processes. On diamond, first results on the thermal functionalization of hydrogen- and oxygen-terminated surfaces are demonstrated. Thermal functionalization with octadecene showed high selectivity, while hydrogenated diamond surfaces were found to be inert to the thermally induced reaction with alkenes. In contrast, alkene molecules were successfully grafted to oxygen-terminated sites via covalent C-O-C bonds. Reaction temperatures as high as 160 C were necessary to initiate the functionalization process.Wetting experiments on the alkyl-modified surfaces revealed contact angle values of 103 . The high quality of the monolayers on oxygenated surfaces was confirmed by IR-spectroscopy. In addition, polarized IR-measurements indicated a tilt angle of 23 . On silicon carbide, thermal and UV-induced alkoxylation were studied. Hydrofluoric acid treatment

Solid-to-solid oxidation of a vanadium(IV) to a vanadium(V) compound: chemisty of a sulfur-containing siderophore.

Science.gov (United States)

Chatterjee, Pabitra B; Crans, Debbie C

2012-09-03

Visible light facilitates a solid-to-solid photochemical aerobic oxidation of a hunter-green microcrystalline oxidovanadium(IV) compound (1) to form a black powder of cis-dioxidovanadium(V) (2) at ambient temperature. The siderophore ligand pyridine-2,6-bis(thiocarboxylic acid), H(2)L, is secreted by a microorganism from the Pseudomonas genus. This irreversible transformation of a metal monooxo to a metal dioxo complex in the solid state in the absence of solvent is unprecedented. It serves as a proof-of-concept reaction for green chemistry occurring in solid matrixes.

Bioaccumulation of platinum group metals in dolphins, Stenella sp ...

African Journals Online (AJOL)

Platinum group metals (PGMs) concentrations were measured in the tissues= of dolphins (Stenella sp.) caught along the Ghanaian coastline. Tissues from specimens caught by fishermen from Dixcove, western Ghana, were analysed in 2006 for palladium (Pd), platinum (Pt) and rhodium (Rh) using the Neutron Activation ...

A DEEPER LOOK AT LEO IV: STAR FORMATION HISTORY AND EXTENDED STRUCTURE

International Nuclear Information System (INIS)

Sand, David J.; Seth, Anil; Olszewski, Edward W.; Zaritsky, Dennis; Willman, Beth; Kallivayalil, Nitya

2010-01-01

We present MMT/Megacam imaging of the Leo IV dwarf galaxy in order to investigate its structure and star formation history, and to search for signs of association with the recently discovered Leo V satellite. Based on parameterized fits, we find that Leo IV is round, with ε h ≅ 130 pc. Additionally, we perform a thorough search for extended structures in the plane of the sky and along the line of sight. We derive our surface brightness detection limit by implanting fake structures into our catalog with stellar populations identical to that of Leo IV. We show that we are sensitive to stream-like structures with surface brightness μ r ∼ -2 , and at this limit we find no stellar bridge between Leo IV (out to a radius of ∼0.5 kpc) and the recently discovered, nearby satellite Leo V. Using the color-magnitude fitting package StarFISH, we determine that Leo IV is consistent with a single age (∼14 Gyr), single metallicity ([Fe/H] ∼ -2.3) stellar population, although we cannot rule out a significant spread in these values. We derive a luminosity of M V = -5.5 ± 0.3. Studying both the spatial distribution and frequency of Leo IV's 'blue plume' stars reveals evidence for a young (∼2 Gyr) stellar population which makes up ∼2% of its stellar mass. This sprinkling of star formation, only detectable in this deep study, highlights the need for further imaging of the new Milky Way satellites along with theoretical work on the expected, detailed properties of these possible 'reionization fossils'.

Topological characterisation and identification of critical domains within glucosyltransferase IV (GtrIV of Shigella flexneri

Directory of Open Access Journals (Sweden)

Nair Anesh

2011-12-01

Full Text Available Abstract Background The three bacteriophage genes gtrA, gtrB and gtr(type are responsible for O-antigen glucosylation in Shigella flexneri. Both gtrA and gtrB have been demonstrated to be highly conserved and interchangeable among serotypes while gtr(type was found to be specific to each serotype, leading to the hypothesis that the Gtr(type proteins are responsible for attaching glucosyl groups to the O-antigen in a site- and serotype- specific manner. Based on the confirmed topologies of GtrI, GtrII and GtrV, such interaction and attachment of the glucosyl groups to the O-antigen has been postulated to occur in the periplasm. Results In this study, the topology of GtrIV was experimentally determined by creating different fusions between GtrIV and a dual-reporter protein, PhoA/LacZ. This study shows that GtrIV consists of 8 transmembrane helices, 2 large periplasmic loops, 2 small cytoplasmic N- and C- terminal ends and a re-entrant loop that occurs between transmembrane helices III and IV. Though this topology differs from that of GtrI, GtrII, GtrV and GtrX, it is very similar to that of GtrIc. Furthermore, both the N-terminal periplasmic and the C-terminal periplasmic loops are important for GtrIV function as shown via a series of loop deletion experiments and the creation of chimeric proteins between GtrIV and its closest structural homologue, GtrIc. Conclusion The current study provides the basis for elucidating the structure and mechanism of action of this important O-antigen modifying glucosyltransferase.

Abdominal 64-MDCT for suspected appendicitis: the use of oral and IV contrast material versus IV contrast material only.

Science.gov (United States)

Anderson, Stephan W; Soto, Jorge A; Lucey, Brian C; Ozonoff, Al; Jordan, Jacqueline D; Ratevosian, Jirair; Ulrich, Andrew S; Rathlev, Niels K; Mitchell, Patricia M; Rebholz, Casey; Feldman, James A; Rhea, James T

2009-11-01

The objective of our study was to compare the diagnostic accuracy of IV contrast-enhanced 64-MDCT with and without the use of oral contrast material in diagnosing appendicitis in patients with abdominal pain. We conducted a randomized trial of a convenience sample of adult patients presenting to an urban academic emergency department with acute nontraumatic abdominal pain and clinical suspicion of appendicitis, diverticulitis, or small-bowel obstruction. Patients were enrolled between 8 am and 11 pm when research assistants were present. Consenting subjects were randomized into one of two groups: Group 1 subjects underwent 64-MDCT performed with oral and IV contrast media and group 2 subjects underwent 64-MDCT performed solely with IV contrast material. Three expert radiologists independently reviewed the CT examinations, evaluating for the presence of appendicitis. Each radiologist interpreted 202 examinations, ensuring that each examination was interpreted by two radiologists. Individual reader performance and a combined interpretation performance of the two readers assigned to each case were calculated. In cases of disagreement, the third reader was asked to deliver a tiebreaker interpretation to be used to calculate the combined reader performance. Final outcome was based on operative, clinical, and follow-up data. We compared radiologic diagnoses with clinical outcomes to calculate the diagnostic accuracy of CT in both groups. Of the 303 patients enrolled, 151 patients (50%) were randomized to group 1 and the remaining 152 (50%) were randomized to group 2. The combined reader performance for the diagnosis of appendicitis in group 1 was a sensitivity of 100% (95% CI, 76.8-100%) and specificity of 97.1% (95% CI, 92.7-99.2%). The performance in group 2 was a sensitivity of 100% (73.5-100%) and specificity of 97.1% (92.9-99.2%). Patients presenting with nontraumatic abdominal pain imaged using 64-MDCT with isotropic reformations had similar characteristics for the

Ultraviolet spectroscopy and metal ions detection

International Nuclear Information System (INIS)

Chaudry, M.A.

1995-01-01

The spectrochemical analysis is based on the interaction of radiation with the chemical species and depends on their nature, having pi, sigma or electrons, or d and f electrons, UV. Visible spectrophotometry has been used extensively in the detection and determination of both organics and inorganics. In UV detection the sensitivity is proportional to the bath length and the excitation coefficient of the given sample. It may be insensitive to many species unless these are converted to UV, absorbing derivatives. The technique has been applied for the monitoring of the effluents from HPLC, as chlorides or other complexes of various elements in this article the utility of HCl as reagent for the spectrophotometric determination of the metal ions like Al(III), As(III,IV), Ba(II), Cd(II), Ca(II) Ce(III), Cs(i), Cr(III,VI), Co(II), Cu(II), Dy(III), Eu(III), Gd(III), Au(III), Hf(IV), Ho(III), In(III), Fe(III), La(III), Pb(II), Lu (III), Mg(II), Mn(II), Hg(II), Mo(VI), Ni(II), Pd(II), Pt(IV), K(I), Pr(III), Re(VII), Ru(IV), Sm(III), Sc(III), Ag(I), Sr(II) Te(III), Th(IV), Sn(II,IV), Ti(III,IV), W(VI), U(VI), V(IV,V), Yb(III), Zn(II) AND Zr(IV) Ions i.e. for meta ions from d of the most of these metal ions has been found sufficient permit their detection in HPLC. Their molar absorptive have also been reported. Reference has also been provided to post column derivatization of some metal ions from d and f block elements for their detection in HPLC. (author) 12 figs.; 6 tabs.; 27 refs

Cycloadditions to Epoxides Catalyzed by GroupIII-V Transition-Metal Complexes

KAUST Repository

D'Elia, Valerio

2015-05-25

Complexes of groupIII-V transition metals are gaining increasing importance as Lewis acid catalysts for the cycloaddition of dipolarophiles to epoxides. This review examines the latest reports, including homogeneous and heterogeneous applications. The pivotal step for the cycloaddition reactions is the ring opening of the epoxide following activation by the Lewis acid. Two modes of cleavage (C-C versus C-O) have been identified depending primarily on the substitution pattern of the epoxide, with lesser influence observed from the Lewis acid employed. The widely studied cycloaddition of CO2 to epoxides to afford cyclic carbonates (C-O bond cleavage) has been scrutinized in terms of catalytic efficiency and reaction mechanism, showing that unsophisticated complexes of groupIII-V transition metals are excellent molecular catalysts. These metals have been incorporated, as well, in highly performing, recyclable heterogeneous catalysts. Cycloadditions to epoxides with other dipolarophiles (alkynes, imines, indoles) have been conducted with scandium triflate with remarkable performances (C-C bond cleavage). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cycloadditions to Epoxides Catalyzed by GroupIII-V Transition-Metal Complexes

KAUST Repository

D'Elia, Valerio; Pelletier, Jeremie; Basset, Jean-Marie

2015-01-01

Complexes of groupIII-V transition metals are gaining increasing importance as Lewis acid catalysts for the cycloaddition of dipolarophiles to epoxides. This review examines the latest reports, including homogeneous and heterogeneous applications. The pivotal step for the cycloaddition reactions is the ring opening of the epoxide following activation by the Lewis acid. Two modes of cleavage (C-C versus C-O) have been identified depending primarily on the substitution pattern of the epoxide, with lesser influence observed from the Lewis acid employed. The widely studied cycloaddition of CO2 to epoxides to afford cyclic carbonates (C-O bond cleavage) has been scrutinized in terms of catalytic efficiency and reaction mechanism, showing that unsophisticated complexes of groupIII-V transition metals are excellent molecular catalysts. These metals have been incorporated, as well, in highly performing, recyclable heterogeneous catalysts. Cycloadditions to epoxides with other dipolarophiles (alkynes, imines, indoles) have been conducted with scandium triflate with remarkable performances (C-C bond cleavage). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SDSS-IV MaNGA: What Shapes the Distribution of Metals in Galaxies? Exploring the Roles of the Local Gas Fraction and Escape Velocity

Science.gov (United States)

Barrera-Ballesteros, J. K.; Heckman, T.; Sánchez, S. F.; Zakamska, N. L.; Cleary, J.; Zhu, G.; Brinkmann, J.; Drory, N.; THE MaNGA TEAM

2018-01-01

We determine the local metallicity of the ionized gas for more than 9.2 × 105 star-forming regions (spaxels) located in 1023 nearby galaxies included in the Sloan Digital Sky Survey-IV MaNGA integral field spectroscopy unit survey. We use the dust extinction derived from the Balmer decrement and the stellar template fitting in each spaxel to estimate the local gas and stellar mass densities, respectively. We also use the measured rotation curves to determine the local escape velocity (V esc). We then analyze the relationships between the local metallicity and both the local gas fraction (μ) and V esc. We find that metallicity decreases with both increasing μ and decreasing V esc. By examining the residuals in these relations we show that the gas fraction plays a more primary role in the local chemical enrichment than does V esc. We show that the gas-regulator model of chemical evolution provides a reasonable explanation of the metallicity on local scales. The best-fit parameters for this model are consistent with the metal loss caused by momentum-driven galactic outflows. We also argue that both the gas fraction and the local escape velocity are connected to the local stellar surface density, which in turn is a tracer of the epoch at which the dominant local stellar population formed.

Fluorescent Hydrogel Generated Conveniently from a Perylene Tetracarboxylate Derivative of Titanium(IV) Alkoxide.

Science.gov (United States)

Zou, Dan-Hong; Wang, Peng; Luo, Wen; Hou, Jin-Le; Zhu, Qin-Yu; Dai, Jie

2018-02-05

Organic gelators and metal-coordination frameworks based on perylene derivatives as functional materials have attracted great attention because of their intense fluorescence emission as well as unique electronic and photonic properties. We report here the structures and properties of a luminescent titanium(IV) coordination compound of a perylene tetracarboxylate (PTC) derivative, [Ti 2 (O i Pr) 6 (L 1 )(phen) 2 ] (1), along with its two naphthalene analogues, [Ti 2 (O i Pr) 6 (L 2 )(phen) 2 ] (2) and [Ti 2 (O i Pr) 6 (L 2 )(bpy) 2 ] (3), where L 1 = 3,9-dicarboxylate-(4,10-diisopropanolcarboxylate)perylene, phen = 1,10-phenanthroline, L 2 = 1,5-dicarboxylate-(2,6-diisopropanolcarboxylate)naphthalene, and bpy = 2,2'-bipyridine. Compound 1 is a rare early-transition-metal PTC coordination compound that can be simply prepared in one pot as crystals by a low-heat synthesis. Unlike those of paramagnetic late-transition-metal PTC compounds, compound 1 showed intense fluorescence emission. More remarkably, the crystals of 1 can be turned immediately to a fluorescent hydrogel just through a simple procedure, putting the crystals in water and then treating with ultrasound. No acid catalyst or pH adjustment is needed. Hydrolysis of the titanium isopropanol group in water and π-π interaction of the perylene and phen play important roles in the gelation process. The film prepared from the gel can be used as a visual fluorescence sensor for aromatic amines and phenols, which are hazards for the human and environment.

Sorption of Pu(IV) from nitric acid by bifunctional anion-exchange resins

International Nuclear Information System (INIS)

Bartsch, R.A.; Zhang, Z.Y.; Elshani, S.; Zhao, W.; Jarvinen, G.D.; Barr, M.E.; Marsh, S.F.; Chamberlin, R.M.

1999-01-01

Anion exchange is attractive for separating plutonium because the Pu(IV) nitrate complex is very strongly sorbed and few other metal ions form competing anionic nitrate complexes. The major disadvantage of this process has been the unusually slow rate at which the Pu(IV) nitrate complex is sorbed by the resin. The paper summarizes the concept of bifunctional anion-exchange resins, proposed mechanism for Pu(IV) sorption, synthesis of the alkylating agent, calculation of K d values from Pu(IV) sorption results, and conclusions from the study of Pu(IV) sorption from 7M nitric acid by macroporous anion-exchange resins including level of crosslinking, level of alkylation, length of spacer, and bifunctional vs. monofunctional anion-exchange resins

IGORR-IV: Proceedings of the fourth meeting of the International Group On Research Reactors

Energy Technology Data Exchange (ETDEWEB)

Rosenbalm, K F [comp.

1995-07-01

The fourth meeting of the International Group on Research Reactors (IGORR-IV) was attended by was good 55 registered participants from 28 organizations in 13 countries, which compares well with the previous meetings. Twenty-nine papers were presented in five sessions over the two-day meeting. Session subjects were: Operating Research Reactors and Facility Upgrades; Research Reactors in Desin and Construction; Research, Development, and Analysis Results of Thermal Hydraulic Calculations, U{sub 3}Si{sub 2} Fuel Performance and Faibrication; Structural Materials Performance; Neutronics; Severe Accident analysis. Written versions of the papers or hard copies of the viewgraphs used are published in these Proceedings.

Current-voltage characteristics of the semiconductor nanowires under the metal-semiconductor-metal structure

Science.gov (United States)

Wen, Jing; Zhang, Xitian; Gao, Hong; Wang, Mingjiao

2013-12-01

We present a method to calculate the I-V characteristics of semiconductor nanowires under the metal-semiconductor-metal (MSM) structure. The carrier concentration as an important parameter is introduced into the expression of the current. The subband structure of the nanowire has been considered for associating it with the position of the Fermi level and circumventing the uncertainties of the contact areas in the contacts. The tunneling and thermionic emission currents in the two Schottky barriers at the two metal-semiconductor contacts are discussed. We find that the two barriers have different influences on the I-V characteristics of the MSM structure, one of which under the forward bias plays the role of threshold voltage if its barrier height is large and the applied voltage is small, and the other under the reverse bias controls the shapes of I-V curves. Our calculations show that the shapes of the I-V curves for the MSM structure are mainly determined by the barrier heights of the contacts and the carrier concentration. The nearly identical I-V characteristics can be obtained by using different values of the barrier heights and carrier concentration, which means that the contact type conversion can be ascribed not only to the changes of the barrier heights but also that of the carrier concentration. We also discuss the mechanisms of the ohmic-Schottky conversions and clarify the ambiguity in the literature. The possibility about the variation of the carrier concentration under the applied fields has been confirmed by experimental results.

Efficacy of IV Buscopan as a muscle relaxant in CT colonography

International Nuclear Information System (INIS)

Bruzzi, John F.; Brennan, Darren D.; Fenlon, Helen M.; Moss, Alan C.; MacMathuna, Padraic

2003-01-01

The aim of this study was to examine the efficacy of IV Buscopan as a muscle relaxant in CT colonography in terms of colonic distension and polyp detection, and to determine its particular efficacy in patients with diverticular disease. Seventy-three consecutive patients were randomised to receive IV Buscopan or no muscle relaxant prior to CT colonography. CT colonography was performed using a Siemens Somatom 4-detector multislice CT scanner. The following parameters were recorded: degree of colonic distension using a 4-point scale; diagnostic adequacy of colonic distension; presence or absence of diverticular disease; and presence of colonic polyps. Accuracy of polyp detection was assessed using subsequent conventional colonoscopy as a gold standard. There was no significant difference between the two groups in the number of segments that were deemed to be optimally or adequately distended (p=0.37). Although IV Buscopan did improve distension of certain segments, this effect was not sufficient to improve the number of diagnostically adequate studies in the Buscopan group (p=0.14). In patients with diverticular disease, IV Buscopan did not have any significant effect on segments affected by diverticulosis but was associated with an improvement in distension of more proximal segments. There was no significant difference between the two groups in terms of polyp detection (p=0.34). The addition of prone scanning to supine scanning was found to be the most useful technique for maximising colonic distension. Intravenous Buscopan at CT colonography does not improve the overall adequacy of colonic distension nor the accuracy of polyp detection. In patients with sigmoid diverticular disease IV Buscopan improves distension of more proximal colonic segments and may be useful in selected cases, but our results do not support its routine use for CT colonography. (orig.)

Photoacidic and Photobasic Behavior of Transition Metal Compounds with Carboxylic Acid Group(s)

Energy Technology Data Exchange (ETDEWEB)

O’Donnell, Ryan M. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Sampaio, Renato N. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Li, Guocan [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Johansson, Patrik G. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Ward, Cassandra L. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Meyer, Gerald J. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States

2016-03-10

Excited state proton transfer studies of six Ru polypyridyl compounds with carboxylic acid/carboxylate group(s) revealed that some were photoacids and some were photobases. The compounds [Ru^II(btfmb)₂(LL)]²⁺, [Ru^II(dtb)2(LL)]2+, and [RuII(bpy)2(LL)]2+, where bpy is 2,2'-bipyridine, btfmb is 4,4'-(CF₃)₂-bpy, and dtb is 4,4'-((CH₃)₃C)₂-bpy, and LL is either dcb = 4,4'-(CO₂H)₂-bpy or mcb = 4-(CO₂H),4'-(CO2Et)-2,2'-bpy, were synthesized and characterized. The compounds exhibited intense metal-to-ligand charge-transfer (MLCT) absorption bands in the visible region and room temperature photoluminescence (PL) with long τ > 100 ns excited state lifetimes. The mcb compounds had very similar ground state pKa’s of 2.31 ± 0.07, and their characterization enabled accurate determination of the two pK_a values for the commonly utilized dcb ligand, pK_a1 = 2.1 ± 0.1 and pKa2 = 3.0 ± 0.2. Compounds with the btfmb ligand were photoacidic, and the other compounds were photobasic. Transient absorption spectra indicated that btfmb compounds displayed a [Ru^III(btfmb–)L₂]^2+* localized excited state and a [Ru^III(dcb–)L₂]^2+* formulation for all the other excited states. Time dependent PL spectral shifts provided the first kinetic data for excited state proton transfer in a transition metal compound. PL titrations, thermochemical cycles, and kinetic analysis (for the mcb compounds) provided self-consistent pK_a* values. The ability to make a single ionizable group photobasic or photoacidic through ligand design was unprecedented and was understood based on the orientation of the lowest-lying MLCT excited state dipole relative to the ligand that contained the carboxylic acid group(s).

Electric properties and fabrication of IMI-O LB films containing the imidazole group

CERN Document Server

Yoo, S Y; Kwon, Y S; Park, J C

1999-01-01

We fabricated an IMI-O polymer containing an imidazole group that could form a complex structure between the monolayer and the metal ions at the air-water interface. Also, the monolayer behavior at the air-water interface and the electrical properties of metal-complexed Langmuir-Blodgett (LB) films were investigated by using Brewster angle microscopy (BAM) and current-voltage(I-V) measurements. The difference in the BAM images between the pure water and the aqueous metal ions is attributed to the interactions of the copolymers with the metal ions at the interface and the consequent change of the monolayer organization. In the I-V characteristics, the current for LB films with different metal ion depended on the quantity of the metal-ion complexed with the LB film due to the interaction between the metal ion and the IMI-O polymer.

Synthesis of Hydrophilic Sulfur-Containing Adsorbents for Noble Metals Having Thiocarbonyl Group Based on a Methacrylate Bearing Dithiocarbonate Moieties

Directory of Open Access Journals (Sweden)

Haruki Kinemuchi

2018-01-01

Full Text Available Novel hydrophilic sulfur-containing adsorbents for noble metals were prepared by the radical terpolymerization of a methacrylate bearing dithiocarbonate moieties (DTCMMA, hydrophilic monomers, and a cross-linker. The resulting adsorbents efficiently and selectively adsorbed noble metals (Au, Ag, and Pd from various multielement aqueous solutions at room temperature owing to the thiocarbonyl group having high affinity toward noble metals. The metal adsorption by the adsorbents was proceeded by simple mixing followed by filtration. The noble metal selectivity of the adsorbent obtained from DTCMMA and N-isopropylacrylamide was higher than that of the adsorbent obtained from DTCMMA and N,N-dimethylacrylamide due to the lower nonspecific adsorption.

Investigations of radiochemical methods for the platinum group metals for NAA

International Nuclear Information System (INIS)

Tredoux, M.

A radiochemical procedure for the determination of the platinum group metals and gold is outlined in this report. The sample is irradiated, treated with acids and passed through anion-exchange columns before being determined by gamma spectrometry

Preparation and Spectral Properties of Mixed-Ligand Complexes of VO(IV, Ni(II, Zn(II, Pd(II, Cd(II and Pb(II with Dimethylglyoxime and N-acetylglycine

Directory of Open Access Journals (Sweden)

Shayma A. Shaker

2010-01-01

Full Text Available A number of mixed-ligand complexes of the general formula [M(D(G] where D=dimethylglyoximato monoanion, G=N-acetylglycinato and M=VO(IV, Ni(II, Zn(II, Pd(II, Cd(II and Pb(II were prepared. Each complex was characterized by elemental analysis, determination of metal, infrared spectra, electronic spectra, (1H and 13C NMR spectra, conductivity and magnetic moments. All these complexes were not soluble in some of the organic solvent but highly soluble in dimethylformamide. The conductivity data showed the non-electrolytic nature of the complexes. The electronic spectra exhibited absorption bands in the visible region caused by the d-d electronic transition such as VO(IV, Ni(II and Pd(II. The IR and (1H, 13C NMR spectra which have indicate that the dimethylglyoxime was coordinated with the metal ions through the N and O atoms of the oxime group and N-acetylglycine was coordinated with metal ions through the N atom and terminal carboxyl oxygen atom.

A cerium(IV)-carbon multiple bond

Energy Technology Data Exchange (ETDEWEB)

Gregson, Matthew; Lu, Erli; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [Nottingham Univ. (United Kingdom). School of Chemistry

2013-12-02

Straightforward access to a cerium(IV)-carbene complex was provided by one-electron oxidation of an anionic ''ate'' cerium(III)-carbene precursor, thereby avoiding decomposition reactions that plague oxidations of neutral cerium(III) compounds. The cerium(IV)-carbene complex is the first lanthanide(IV)-element multiple bond and involves a twofold bonding interaction of two electron pairs between cerium and carbon. [German] Auf direktem Wege zu einem Cer(IV)-Carbenkomplex gelangt man durch die Einelektronenoxidation einer anionischen Carben-Cerat(III)-Vorstufe. So werden Zersetzungsprozesse vermieden, die die Oxidation neutraler Cer(III)-Verbindungen erschweren. Der Cer(IV)-Carbenkomplex enthaelt die erste Lanthanoid(IV)-Element-Mehrfachbindung; dabei binden Cer und Kohlenstoff ueber zwei Elektronenpaare.

Group 4 Metal Complexes of Chelating Cyclopentadienyl-ketimide Ligands

Czech Academy of Sciences Publication Activity Database

Večeřa, M.; Varga, Vojtěch; Císařová, I.; Pinkas, Jiří; Kucharczyk, P.; Sedlařík, V.; Lamač, Martin

2016-01-01

Roč. 35, č. 5 (2016), s. 785-798 ISSN 0276-7333 R&D Projects: GA ČR(CZ) GA14-08531S; GA MŠk(CZ) LO1504 Institutional support: RVO:61388955 Keywords : group 4 metal complexes * cyclopentadienyl-ketimide ligands * metallocenes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.862, year: 2016

Spectroscopy and electrochemistry of U(IV/III) in basic AlCl3-EMIC

International Nuclear Information System (INIS)

Anderson, C.J.; Deakin, M.R.; Choppin, G.R.; Heerman, L.; D'Olieslager, W.; Pruett, D.J.

1990-01-01

The electrochemistry of U(IV) has been investigated in the solvent AlCl 3 -1-ethyl-3-methyl imidazolium chloride (EMIC), a room temperature ionic liquid. In basic solutions ( 3 ) the reduction of U(IV) to U(III) on glassy carbon electrodes is reversible. Spectroscopic data as well as measurements of the formal potential for U(IV)/U(III) as a function of the basic melt composition indicate that U(IV) and U(III) are both hexachloro anions. Diffusion coefficients for these species have been measured by two methods. The values are comparable to those of transition metal hexachloro complexes in the same solvent, supporting the assignment of UCl 6 2- and UCl 6 3-

Surface Engineering of PAMAM-SDB Chelating Resin with Diglycolamic Acid (DGA) Functional Group for Efficient Sorption of U(VI) and Th(IV) from Aqueous Medium

Energy Technology Data Exchange (ETDEWEB)

Ilaiyaraja, P.; Venkatraman, B., E-mail: chemila07@gmail.com [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Deb, A.K. Singha [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India); Ponraju, D. [Safety Engineering Division, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Ali, Sk. Musharaf [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

2017-04-15

Highlights: • A new DGA-PAMAM-SDB chelating resin has been synthesized for actinide sorption. • Maximum sorption capacities of resin are 682 and 544.2 mg g{sup −1}for U(VI) and Th(IV). • DGA-PAMAM-SDB chelating resin could be regenerated and reused. • DFT calculation of actinides interaction with resin corroborates the experimental. • Resin is effective for sorption of actinides from both aqueous and HNO{sub 3} medium. - Abstract: A novel chelating resin obtained via growth of PAMAM dendron on surface of styrene divinyl benzene resin beads, followed by diglycolamic acid functionalization of the dendrimer terminal. Batch experiments were conducted to study the effects of pH, nitric acid concentration, amount of adsorbent, shaking time, initial metal ion concentration and temperature on U(VI) and Th(IV) adsorption efficiency. Diglycolamic acid terminated PAMAM dendrimer functionalized styrene divinylbenzene chelating resin (DGA-PAMAM-SDB) is found to be an efficient candidate for the removal of U(VI) and Th(IV) ions from aqueous (pH > 4) and nitric acid media (> 3 M). The sorption equilibrium could be reached within 60 min, and the experimental data fits with pseudo-second-order model. Langmuir sorption isotherm model correlates well with sorption equilibrium data. The maximum U(VI) and Th(IV) sorption capacity onto DGA-PAMAMG{sub 5}-SDB was estimated to be about 682 and 544.2 mg g{sup −1} respectively at 25 °C. The interaction of actinides and chelating resin is reversible and hence, the resin can be regenerated and reused. DFT calculation on the interaction of U(VI) and Th(IV) ions with chelating resin validates the experimental findings.

Europium-activated phosphors containing oxides of rare-earth and group-IIIB metals and method of making the same

Science.gov (United States)

Comanzo, Holly Ann; Setlur, Anant Achyut; Srivastava, Alok Mani; Manivannan, Venkatesan

2004-07-13

Europium-activated phosphors comprise oxides of at least a rare-earth metal selected from the group consisting of gadolinium, yttrium, lanthanum, and combinations thereof and at least a Group-IIIB metal selected from the group consisting of aluminum, gallium, indium, and combinations thereof. A method for making such phosphors comprises adding at least a halide of at least one of the selected Group-IIIB metals in a starting mixture. The method further comprises firing the starting mixture in an oxygen-containing atmosphere. The phosphors produced by such a method exhibit improved absorption in the UV wavelength range and improved quantum efficiency.

Preparation of some complexes of Th(IV) and U(IV) with tetradentate Schiff bases. The crystal structure of bis(N,N'-ethylenebis(3-methoxysalicylaldiminato)) thorium(IV) monopyridine

Energy Technology Data Exchange (ETDEWEB)

Hill, R J; Rickard, C E.F.; White, H E [Auckland Univ. (New Zealand). Dept. of Chemistry

1981-01-01

Complexes of Th(IV) and U(IV) with tetradentate Schiff bases derived from substituted salicylaldehydes have been prepared and characterised. The structure of bis(N,N'-ethylenebis(3-methoxysalicylaldiminato)) Th(IV) monopyridine has been determined by X-ray crystallographic methods. The crystals are triclinic, a = 13.468, b = 9.932, c = 16.552 A, ..cap alpha.. = 91.74, ..beta.. = 94.69, ..gamma.. = 93.03/sup 0/, space group P/sub 1//sup -/. The molecules are eight coordinate with a slightly distorted dodecahedral geometry with the imine nitrogen atoms in the dodecahedral A sites. The pyridine molecule is uncoordinated and functions in a space-filling role.

Improvement of Steam Generator Reliability for GEN-IV SFR

Energy Technology Data Exchange (ETDEWEB)

Kim, Seong O; Kim Se Yun; Kim, Seok Hoon; Eoh, Jae Hyuk; Lee, Hyeong Yeon; Choi, Byung Seon

2005-11-15

The R and D items performed in this study were selected from the R and D task of ' Reliability improvement of Steam Generator' of GEN-IV SFR Component Design and BOP. Since this project deals with one of the most important issues for a GEN-IV SFR system, it needs to enhance the domestic technical backgrounds associated with the corresponding R and D items even for a very short period by 2005. This study provides the R and D results for i) Development of assessment methodology for dissimilar metal weld and ii) Development of multi-dimensional simulation methodology for a SWR event in a SFR steam generator.

Improvement of Steam Generator Reliability for GEN-IV SFR

International Nuclear Information System (INIS)

Kim, Seong O; Kim Se Yun; Kim, Seok Hoon; Eoh, Jae Hyuk; Lee, Hyeong Yeon; Choi, Byung Seon

2005-11-01

The R and D items performed in this study were selected from the R and D task of ' Reliability improvement of Steam Generator' of GEN-IV SFR Component Design and BOP. Since this project deals with one of the most important issues for a GEN-IV SFR system, it needs to enhance the domestic technical backgrounds associated with the corresponding R and D items even for a very short period by 2005. This study provides the R and D results for i) Development of assessment methodology for dissimilar metal weld and ii) Development of multi-dimensional simulation methodology for a SWR event in a SFR steam generator

Synthesis and crystal structure of Fe[(Te1.5Se0.5)O5]Cl, the first iron compound with selenate(IV) and tellurate(IV) groups

Science.gov (United States)

Akhrorov, Akhmad Yu; Kuznetsova, Elena S.; Aksenov, Sergey M.; Berdonosov, Peter S.; Kuznetsov, Alexey N.; Dolgikh, Valery A.

2017-12-01

During the search for selenium analogues of FeTe2O5Cl, the new iron (III) tellurate(IV) selenate(IV) chloride with the composition Fe[(Te1.5Se0.5)O5]Cl was synthesized by chemical vapor transport (CVT) reaction and characterized by TGA-, EDX-,SCXRD-analysis, as well as IR and Raman spectroscopy. It was found that Fe[(Te1.5Se0.5)O5]Cl crystallizes in the monoclinic space group P21/c with unitcell parameters a = 5.183(3) Å, b = 15.521(9) Å, c = 7.128(5) Å and β = 107.16(1)°. The crystal structure of Fe[(Te1.5Se0.5)O5]Cl represents a new structure type and contains electroneutral heteropolyhedral layers formed by dimers of the [FeO5Cl]8- octahedra, linked via common O-O edges, and mixed [Te3SeO10]4- tetramers. Adjacent layers are stacked along the b axis and linked by weak residual bonds. The new compound is stable up to 420 °C. DFT calculations predict Fe[(Te1.5Se0.5)O5]Cl to be a wide-gap semiconductor with the band gap of ca. 2.7 eV.

Studies on Th(IV) and Zr(IV) complexes of oxygen donor ligands

International Nuclear Information System (INIS)

Agarwal, R.K.; Srivastava, M.; Srivastava, A.K.

1981-01-01

In recent years a large number of complexes of amine N-oxides with a wide variety of metal salts have been isolated and characterized. Less attention has been paid to the aromatic amine N-oxides complexes with Th(IV) thiocyanate. In the present communication studies are reported on Th(IV) thiocyanate complexes of pyridine N-oxide (PyO), quinoline N-oxide (QO), isoquinoline N-oxide (IsqO), 2-picoline N-oxide (2-picO), 3-picoline N-oxide (3-picO) and 4-picoline N-oxide (4-picO) and comparisons are made with the existing complexes of 2,6-lutidine N-oxide (LNO), 2, 2'bipyridine N-N'-dioxide (BipyO 2 ), mono N-oxides of 2,2'-bipyridine (BipyNO) and 1,10-phenanthroline (PhenNO) and 1, 10-phenanthroline N-N'-dioxide (PhenO 2 ). The analytical data correspond to the composition Th(NCS) 4 .4L. The molar conductance of all the complexes in nitrobenzene in the range 2.5 to 4.5 Ω -1 cm 2 mol -1 indicate them to be non-electrolytes. The results of IR spectroscopy and thermogravimetry are given and discussed. (author)

Crystalline cerium(IV) phosphates

International Nuclear Information System (INIS)

Herman, R.G.; Clearfield, A.

1976-01-01

The ion exchange behaviour of seven crystalline cerium(IV) phosphates towards some of the alkali metal cations is described. Only two of the compounds (A and C) possess ion exchange properties in acidic solutions. Four others show some ion exchange characteristics in basic media with some of the alkali cations. Compound G does not behave as an ion exchanger in solutions of pH + , but show very little Na + uptake. Compound E undergoes ion exchange with Na + and Cs + , but not with Li+. Both Li + and Na + are sorbed by compounds A and C. The results are indicative of structures which show steric exclusion phenomena. (author)

Caracterización de escorias metalúrgicas procedentes de yacimientos arqueológicos de Navarra (Siglos II a.C.- IV d.C.

Directory of Open Access Journals (Sweden)

Ros-Latienda, L.

2013-12-01

Full Text Available The Archaeology Section of the Government of Navarre put forward a proposal to undertake research in the characterization of a set of pieces from 2nd century B.C. to 4th century A.D. retrieved from excavations in different archaeological sites in this province, to obtain data related to the manufacturing process of the investigated artefacts and to compare the level of technical skills in different times and places, so as to achieve a better understanding of technological abilities and material culture. The finds discussed in this paper are of interest from an archaeometallurgical point of view, and they consist mainly of metallurgical slags, remains of manufactured pieces, and minerals residues used to obtain various metals. In addition to carrying out their chemical analyses by inductively coupled plasma (ICP, the study of six samples was performed by optical and scanning electron microscopy and energy-dispersive X-ray microanalysis (EDX which revealed the composition of large areas of the slags, and the study was finally completed by the determination of the phases present by X rays diffraction.Desde la Sección de Arqueología del Gobierno de Navarra llegó la propuesta de caracterizar una serie de piezas comprendidas entre el siglo II a.C. y el siglo IV d.C. procedentes de yacimientos arqueológicos de esta provincia con objeto de obtener datos relacionados con la tecnología que las produjo y poder comparar el grado de desarrollo técnico de diferentes épocas y lugares. Interesaba el estudio de estas piezas desde el punto de vista metalúrgico, habiendo entre ellas mayoritariamente escorias metalúrgicas, restos de piezas fabricadas y restos minerales utilizados en la obtención de diversos metales. Además de proceder a su análisis químico mediante técnica de plasma acoplado inductivamente (ICP, se estudiaron seis muestras mediante microscopía óptica, electrónica de barrido y microanálisis por energía dispersiva de rayos X (EDAX

Simulation of I-V and C-V curves of metal/GaN/AlGaN/GaN heterostructures with trap-assisted tunnelling

International Nuclear Information System (INIS)

Racko, J.; Benko, P.; Grmanova, A.; Harmatha, L.; Breza, J.; Granzner, R.; Schwierz, F.

2013-01-01

The described trap-assisted tunnelling (TAT) model of the metal/GaN/Al_xGaN_1_-_x/GaN structure allows analyzing the effect of deep traps upon I-V and C-V characteristics. The negative charge with magnitude proportional to the molar concentration of aluminium gives rise to a barrier at the first heterojunction, which is higher than the Schottky barrier at the metal/GaN interface. On increasing the reverse bias Va the barrier at the first heterojunction is getting lower. The drop of this barrier causes an exponential increase of the reverse current. The current saturates, when the first heterojunction barrier is lower than the Schottky barrier. The effect of TAT can be observed also on varying the parameters of the band of traps. The shape of the simulated C-V curve is affected by changes in the charge on the second heterojunction. In principle it reflects the decrease of electron concentration in the quantum well on increasing the reverse bias V_a. The space charge region becomes wider and the electron concentration at the second heterojunction falls below the concentration of ionized deep trapping centres, which manifests itself as a noticeable drop in the capacitance of the metal/GaN/Al_xGaN_1_-_x/GaN structure. (authors)

Ab initio I-V characteristics of short C-20 chains

DEFF Research Database (Denmark)

Roland, C.; Larade, B.; Taylor, Jeremy Philip

2002-01-01

We have calculated the I-V characteristics of short chains of C-20 molecular cages between Al and Au leads with an ab initio formalism. The results indicate that a linear chain of such molecules acts primarily as metallic nanowires. The transmission, however, depends sensitively both...

A fresnoite-structure-related mixed valent titanium(III/IV) chlorosilicate, Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl: A flux crystal growth route to Ti(III) containing oxides

Energy Technology Data Exchange (ETDEWEB)

Abeysinghe, Dileka; Smith, Mark D.; Loye, Hans-Conrad zur, E-mail: zurloye@mailbox.sc.edu

2017-06-15

Single crystals of mixed valent barium titanium(III/IV) chlorosilicate, Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09}, were grown in a high temperature molten chloride flux involving an in situ reduction step. The fresnoite structure related Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09} crystallizes in the tetragonal space group P4/mbm with lattice parameters of a=8.6717(2) Å, c=18.6492(5) Å. The title compound exhibits a 3D structure consisting of 2D layers of fused Ti{sub 2}O{sub 9} and Si{sub 4}O{sub 12} groups and 2D layers of fused Ti{sub 2}O{sub 9}Cl{sub 2} and Si{sub 2}O{sub 7} groups that are linked via barium atoms. The in situ reduction of Ti(IV) to Ti(III) is achieved via the addition of metallic Mg to the flux to function as the reducing agent. The temperature dependence of the magnetic susceptibility shows simple paramagnetism above 100 K. There is a discontinuity in the susceptibility data below 100 K, which might be due to a structural change that takes place resulting in charge ordering. - Graphical abstract: The fresnoite structure related novel reduced barium titanium chlorosilicate, Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09}, were synthesized via flux method. An in situ reduction of Ti(IV) to Ti(III) achieved using Mg metal. The 3D structure consists 2D layers of fused Ti{sub 2}O{sub 9} and Si{sub 4}O{sub 12} and 2D layers of fused Ti{sub 2}O{sub 9}Cl{sub 2} and Si{sub 2}O{sub 7} connected via barium atoms. Compound shows simple paramagnetism above 100 K. - Highlights: • The fresnoite related Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09} were grown via molten flux method. • The in situ reduction of Ti(IV) to Ti(III) is achieved using metallic Mg. • 2D layers of Ti{sub 2}O{sub 9} and Si{sub 4}O{sub 12} and Ti{sub 2}O{sub 9}Cl{sub 2} and Si{sub 2}O{sub 7} connect via Ba atoms. • The magnetic susceptibility shows simple paramagnetism above 100 K.

Melt cationic and anionic composition effect on titanium group metal corrosion in halogenides of alkali earths

International Nuclear Information System (INIS)

Tkhaj, V.; Kovalik, O.Yu.; Dikunov, Yu.G.; P'yankova, S.P.

1997-01-01

A study was made on interaction of titanium group metals with melts of chlorides and chloride-fluorides of alkaline earth metals and magnesium. It was revealed that the rate of metal corrosion increased from BaCl 2 2 2 2 in chloride series. It is explained by amplification of oxidation activity of salt cation in the series: Ba 2+ 2+ 2+ 2+ . It was also determined that corrosion rate of titanium exceeded the one of zirconium and hafnium, became reducing power of titanium was the highest in the given group

Sorption of uranium by clinoptilolite modified by a some metals hydroxides

International Nuclear Information System (INIS)

Plotnikov, V.I.; Medvedeva, Z.V.; Zhabykbaev, G.T.

2005-01-01

In the present report the sorption character of uranium (IV) in the static conditions on the thin layer sorbents with application of the clinoptilolite of the Chankan deposit of the Republic of Kazakhstan is shown. A wide circle of metal hydroxides - in both the individual form and in the their mixture - is used. It is shown that the most sorptive capacity against the uranium (IV) has the modified clinoptilolite of MnO 2

Chelation and stabilization of berkelium in oxidation state +IV

Science.gov (United States)

Deblonde, Gauthier J.-P.; Sturzbecher-Hoehne, Manuel; Rupert, Peter B.; An, Dahlia D.; Illy, Marie-Claire; Ralston, Corie Y.; Brabec, Jiri; de Jong, Wibe A.; Strong, Roland K.; Abergel, Rebecca J.

2017-09-01

Berkelium (Bk) has been predicted to be the only transplutonium element able to exhibit both +III and +IV oxidation states in solution, but evidence of a stable oxidized Bk chelate has so far remained elusive. Here we describe the stabilization of the heaviest 4+ ion of the periodic table, under mild aqueous conditions, using a siderophore derivative. The resulting Bk(IV) complex exhibits luminescence via sensitization through an intramolecular antenna effect. This neutral Bk(IV) coordination compound is not sequestered by the protein siderocalin—a mammalian metal transporter—in contrast to the negatively charged species obtained with neighbouring trivalent actinides americium, curium and californium (Cf). The corresponding Cf(III)-ligand-protein ternary adduct was characterized by X-ray diffraction analysis. Combined with theoretical predictions, these data add significant insight to the field of transplutonium chemistry, and may lead to innovative Bk separation and purification processes.

Leachables from saline-containing IV bags can alter therapeutic protein properties.

Science.gov (United States)

Chang, Judy Y; Xiao, Nina J; Zhu, Min; Zhang, Jennifer; Hoff, Ed; Russell, Stephen J; Katta, Viswanatham; Shire, Steven J

2010-11-01

To investigate the cause of the observed instability of dulanermin in 100 ml polyolefin (PO) infusion bags containing saline. Diluted dulanermin in IV bags was collected and frozen prior to analysis by size exclusion chromatography. The UV absorption profiles of the IV bag solutions were characterized by using spectrophotometry. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) measured the metal content. Leachables from IV bags were identified by LC-UV-high resolution MS/MS analysis. An elevated loss of dulanermin monomers was observed only in 100 ml PO bags. These IV bag solutions have a compound that contains zinc and has absorbance at 320 nm. This compound was identified to be 2-Mercaptobenzothiazole, and its zinc salt and was found to come from the stopper used in the 100 ml PO bags. The manufacturer has subsequently corrected this problem by using non-latex components in the 100 ml PO IV bag. End-users need to be aware that IV bags made from a particular polymer by the same manufacturer may contain components or use a manufacturing process that results in a different product. Analysis of samples after freezing and thawing proved to be useful in identifying potential incompatibility of dulanermin in the IV bags.

The crystal structures of some alkyldiaminium perchlorates, permanganates and hexachlouranates (IV)

International Nuclear Information System (INIS)

Marais, M.A.

1984-12-01

The diquaternary nitrogen cations N,N,N,N 1 ,N 1 ,N 1 -hexaalkyl-1,2-ethane-diaminium and N,N,N,N 1 ,N 1 ,N 1 -hexaalkyl-1,6-hexanediaminium (alkyl = n-octyl for example) are important potential solvent extractants for the extraction of transition metals (Co, Cu) and uranium from HCl medium. Since the alkyldiaminium skeleton constitutes the active centre in solution, the conformations of the cations in association with typical metallate counter-ions were of interest. The crystal structures of the hexachloro-uranate (IV) and permanganate salts of the hexamethyl ethanediaminium ion, as well as the hexachlorouranate (IV) and perchlorate salts of the hexamethyl hexanediaminium ion were therefore determined by X-ray crystallography. No evidence of any deformation of the cation skeleton from their previously well-established conformations were, however, found. The structures can all be understood as typical ionic salts in which the packing and structural features are dominated by the relatively large cations. In the permanganate salt of the N,N,N,N 1 ,N 1 ,N 1 -1,2-ethanediaminium cation the bridging methylene groups display an unusual type of positional disorder, for which there is only one precedent (also discovered in this laboratory). The values of the Mn-O and U-Cl bond lengths in the permanganate and hexachlorouranate ions were determined with a precision comparable to that of the most accurate values obtained so far in other salts. These distances are also in excellent agreement with previous values, and provide further confirmation for two bond lengths for which very few estimates were previously available

A novel technique for the treatment of stages III to IV hemorrhoids

Science.gov (United States)

Lin, Guoqiang; Ge, Qiongxiang; He, Xiaokang; Qi, Haixin; Xu, Li

2017-01-01

Abstract To compare the efficacy of homemade anal cushion suspension clamp combined with harmonic scalpel (ACS) and Milligan–Morgan hemorrhoidectomy combined with electric knife (MMH) in the treatment of stages III to IV hemorrhoids. We conducted a retrospective study of 99 patients with stages III to IV hemorrhoids hospitalized from January to December in 2013. Among them, 51 patients were treated with ACS, while 48 patients received MMH. Data from clinical recording and follow-up included operative time, intraoperative blood loss, hospitalization information, postoperative pain, and postoperative complications. Operative time, intraoperative blood loss and hospitalization time in ACS group were significantly less than those in MMH group (P hemorrhoids. PMID:28658138

Site Environmental Report for Calendar Year 2009. DOE Operations at The Boeing Company Santa Susana Field Laboratory, Area IV

Energy Technology Data Exchange (ETDEWEB)

Liu, Ning [The Boeing Company, Canoga Park, CA (United States); Rutherford, Phil [The Boeing Company, Canoga Park, CA (United States); Amar, Ravnesh [The Boeing Company, Canoga Park, CA (United States)

2010-09-01

This Annual Site Environmental Report (ASER) for 2009 describes the environmental conditions related to work performed for the Department of Energy (DOE) at Area IV of Boeing’s Santa Susana Field Laboratory (SSFL). The Energy Technology Engineering Center (ETEC), a government-owned, company-operated test facility, was located in Area IV. The operations in Area IV included development, fabrication, and disassembly of nuclear reactors, reactor fuel, and other radioactive materials. Other activities in the area involved the operation of large-scale liquid metal facilities that were used for testing non-nuclear liquid metal fast breeder reactor components. All nuclear work was terminated in 1988, and all subsequent radiological work has been directed toward decontamination and decommissioning (D&D) of the former nuclear facilities and their associated sites. Liquid metal research and development ended in 2002. Since May 2007, the D&D operations in Area IV have been suspended by the DOE, but the environmental monitoring and characterization programs have continued. Results of the radiological monitoring program for the calendar year 2009 continue to indicate that there are no significant releases of radioactive material from Area IV of SSFL. All potential exposure pathways are sampled and/or monitored, including air, soil, surface water, groundwater, direct radiation, transfer of property (land, structures, waste), and recycling.

Site Environmental Report for Calendar Year 2010. DOE Operations at The Boeing Company Santa Susana Field Laboratory, Area IV

Energy Technology Data Exchange (ETDEWEB)

Liu, Ning [The Boeing Company, Canoga Park, CA (United States); Rutherford, Phil [The Boeing Company, Canoga Park, CA (United States); Amar, Ravnesh [The Boeing Company, Canoga Park, CA (United States)

2011-09-01

This Annual Site Environmental Report (ASER) for 2010 describes the environmental conditions related to work performed for the Department of Energy (DOE) at Area IV of Boeing’s Santa Susana Field Laboratory (SSFL). The Energy Technology Engineering Center (ETEC), a government-owned, company-operated test facility, was located in Area IV. The operations in Area IV included development, fabrication, and disassembly of nuclear reactors, reactor fuel, and other radioactive materials. Other activities in the area involved the operation of large-scale liquid metal facilities that were used for testing non-nuclear liquid metal fast breeder reactor components. All nuclear work was terminated in 1988, and all subsequent radiological work has been directed toward decontamination and decommissioning (D&D) of the former nuclear facilities and their associated sites. Liquid metal research and development ended in 2002. Since May 2007, the D&D operations in Area IV have been suspended by the DOE, but the environmental monitoring and characterization programs have continued. Results of the radiological monitoring program for the calendar year 2010 continue to indicate that there are no significant releases of radioactive material from Area IV of SSFL. All potential exposure pathways are sampled and/or monitored, including air, soil, surface water, groundwater, direct radiation, transfer of property (land, structures, waste), and recycling.

Thermodynamics of carbon deoxidation and aluminium deoxidation of refractory metals

International Nuclear Information System (INIS)

Garg, S.P.; Sundaram, C.V.

1975-01-01

Carbon has been used for removing the last traces of oxygen from many refractory metals by evaporation of CO at high temperature and vacuum. Similar purification can also be achieved employing aluminium deoxidation by evaporation of Al 2 Osub(g). In the present paper a theoretical thermodynamic approach has been attempted to evaluate the deoxidation tendencies of refractory metals of groups IV to VI by these two processes. Expressions have been theoretically derived, relating the concentration product of carbon and oxygen in the metal (which is a measure of the carbon deoxidation tendency of the metal) with temperature and pressure, for various M-C-O systems. Similarly the relative vapour pressure values of Alsub(2)Osub(g),Alsub(g)andMO(g) (suboxide of the metal) over various M-Al-O systems have been calculated as a function of aluminium and oxygen contents of the metal. From these analyses, it has been shown that a substantial amount of oxygen can be removed from M-Al-O alloys by aluminium deoxidation. The estimated values are compared with the reported values based on experiment. (author)

Bowel perforation in type IV vascular Ehlers-Danlos syndrome. A systematic review.

Science.gov (United States)

El Masri, H; Loong, T-H; Meurette, G; Podevin, J; Zinzindohoue, F; Lehur, P-A

2018-05-01

Spontaneous gastrointestinal (GI) perforation is a well-known complication occurring in patients suffering from Type IV vascular Ehlers-Danlos syndrome (EDS IV). The aim of the present study was to review the current literature on spontaneous GI perforation in EDS IV and illustrate the surgical management and outcome when possible. A systematic review of all the published data on EDS IV patients with spontaneous GI perforation between January 2000 and December 2015 was conducted using three major databases PUBMED, EMBASE, and Cochrane Central Register of Controlled Trails. References of the selected articles were screened to avoid missing main articles. Twenty-seven published case reports and four retrospective studies, including 31 and 527 cases, respectively, matched the search criteria. A case from our institution was added. Mean age was 26 years (range 6-64 years). The most frequent site of perforation was the colon, particularly the sigmoid, followed by small bowel, upper rectum, and finally stomach. The majority of cases were initially managed with Hartmann's procedure. In recurrent perforations, total colectomy was performed. The reperforation rate was considerably higher in the "partial colectomy with anastomosis" group than in the Hartmann group. Colonic perforation is the most common spontaneous GI perforation in EDS IV patients. An unexpected fragility of the tissues should raise the possibility of a connective tissue disorder and prompt further investigation with eventual management of these high-risk patients with a multidisciplinary team approach in dedicated centres. In the emergency setting, a Hartmann procedure should be performed.

Controlling Thermodynamic Properties of Ferromagnetic Group-IV Graphene-Like Nanosheets by Dilute Charged Impurity

Science.gov (United States)

Yarmohammadi, Mohsen; Mirabbaszadeh, Kavoos

2017-05-01

Using the Kane-Mele Hamiltonian, Dirac theory and self-consistent Born approximation, we investigate the effect of dilute charged impurity on the electronic heat capacity and magnetic susceptibility of two-dimensional ferromagnetic honeycomb structure of group-IV elements including silicene, germanene and stanene within the Green’s function approach. We also find these quantities in the presence of applied external electric field. Our results show that the silicene (stanene) has the maximum (minimum) heat capacity and magnetic susceptibility at uniform electric fields. From the behavior of theses quantities, the band gap has been changed with impurity concentration, impurity scattering strength and electric field. The analysis on the impurity-dependent magnetic susceptibility curves shows a phase transition from ferromagnetic to paramagnetic and antiferromagnetic phases. Interestingly, electronic heat capacity increases (decreases) with impurity concentration in silicene (germanene and stanene) structure.

Modulation of individual steps in group I intron catalysis by a peripheral metal ion.

Science.gov (United States)

Forconi, Marcello; Piccirilli, Joseph A; Herschlag, Daniel

2007-10-01

Enzymes are complex macromolecules that catalyze chemical reactions at their active sites. Important information about catalytic interactions is commonly gathered by perturbation or mutation of active site residues that directly contact substrates. However, active sites are engaged in intricate networks of interactions within the overall structure of the macromolecule, and there is a growing body of evidence about the importance of peripheral interactions in the precise structural organization of the active site. Here, we use functional studies, in conjunction with published structural information, to determine the effect of perturbation of a peripheral metal ion binding site on catalysis in a well-characterized catalytic RNA, the Tetrahymena thermophila group I ribozyme. We perturbed the metal ion binding site by site-specifically introducing a phosphorothioate substitution in the ribozyme's backbone, replacing the native ligands (the pro-R (P) oxygen atoms at positions 307 and 308) with sulfur atoms. Our data reveal that these perturbations affect several reaction steps, including the chemical step, despite the absence of direct contacts of this metal ion with the atoms involved in the chemical transformation. As structural probing with hydroxyl radicals did not reveal significant change in the three-dimensional structure upon phosphorothioate substitution, the effects are likely transmitted through local, rather subtle conformational rearrangements. Addition of Cd(2+), a thiophilic metal ion, rescues some reaction steps but has deleterious effects on other steps. These results suggest that native interactions in the active site may have been aligned by the naturally occurring peripheral residues and interactions to optimize the overall catalytic cycle.

Electron transport characteristics of silicon nanowires by metal-assisted chemical etching

Energy Technology Data Exchange (ETDEWEB)

Qi, Yangyang; Wang, Zhen; Zhang, Mingliang; Wang, Xiaodong, E-mail: xdwang@semi.ac.cn; Ji, An; Yang, Fuhua [Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 (China)

2014-03-15

The electron transport characteristics of silicon nanowires (SiNWs) fabricated by metal-assisted chemical etching with different doping concentrations were studied. By increasing the doping concentration of the starting Si wafer, the resulting SiNWs were prone to have a rough surface, which had important effects on the contact and the electron transport. A metal-semiconductor-metal model and a thermionic field emission theory were used to analyse the current-voltage (I-V) characteristics. Asymmetric, rectifying and symmetric I-V curves were obtained. The diversity of the I-V curves originated from the different barrier heights at the two sides of the SiNWs. For heavily doped SiNWs, the critical voltage was one order of magnitude larger than that of the lightly doped, and the resistance obtained by differentiating the I-V curves at large bias was also higher. These were attributed to the lower electron tunnelling possibility and higher contact barrier, due to the rough surface and the reduced doping concentration during the etching process.

Electron transport characteristics of silicon nanowires by metal-assisted chemical etching

Science.gov (United States)

Qi, Yangyang; Wang, Zhen; Zhang, Mingliang; Wang, Xiaodong; Ji, An; Yang, Fuhua

2014-03-01

The electron transport characteristics of silicon nanowires (SiNWs) fabricated by metal-assisted chemical etching with different doping concentrations were studied. By increasing the doping concentration of the starting Si wafer, the resulting SiNWs were prone to have a rough surface, which had important effects on the contact and the electron transport. A metal-semiconductor-metal model and a thermionic field emission theory were used to analyse the current-voltage (I-V) characteristics. Asymmetric, rectifying and symmetric I-V curves were obtained. The diversity of the I-V curves originated from the different barrier heights at the two sides of the SiNWs. For heavily doped SiNWs, the critical voltage was one order of magnitude larger than that of the lightly doped, and the resistance obtained by differentiating the I-V curves at large bias was also higher. These were attributed to the lower electron tunnelling possibility and higher contact barrier, due to the rough surface and the reduced doping concentration during the etching process.

Bondonic effects in group-IV honeycomb nanoribbons with Stone-Wales topological defects.

Science.gov (United States)

Putz, Mihai V; Ori, Ottorino

2014-04-03

This work advances the modeling of bondonic effects on graphenic and honeycomb structures, with an original two-fold generalization: (i) by employing the fourth order path integral bondonic formalism in considering the high order derivatives of the Wiener topological potential of those 1D systems; and (ii) by modeling a class of honeycomb defective structures starting from graphene, the carbon-based reference case, and then generalizing the treatment to Si (silicene), Ge (germanene), Sn (stannene) by using the fermionic two-degenerate statistical states function in terms of electronegativity. The honeycomb nanostructures present η-sized Stone-Wales topological defects, the isomeric dislocation dipoles originally called by authors Stone-Wales wave or SWw. For these defective nanoribbons the bondonic formalism foresees a specific phase-transition whose critical behavior shows typical bondonic fast critical time and bonding energies. The quantum transition of the ideal-to-defect structural transformations is fully described by computing the caloric capacities for nanostructures triggered by η-sized topological isomerisations. Present model may be easily applied to hetero-combinations of Group-IV elements like C-Si, C-Ge, C-Sn, Si-Ge, Si-Sn, Ge-Sn.

Bondonic Effects in Group-IV Honeycomb Nanoribbons with Stone-Wales Topological Defects

Directory of Open Access Journals (Sweden)

Mihai V. Putz

2014-04-01

Full Text Available This work advances the modeling of bondonic effects on graphenic and honeycomb structures, with an original two-fold generalization: (i by employing the fourth order path integral bondonic formalism in considering the high order derivatives of the Wiener topological potential of those 1D systems; and (ii by modeling a class of honeycomb defective structures starting from graphene, the carbon-based reference case, and then generalizing the treatment to Si (silicene, Ge (germanene, Sn (stannene by using the fermionic two-degenerate statistical states function in terms of electronegativity. The honeycomb nanostructures present η-sized Stone-Wales topological defects, the isomeric dislocation dipoles originally called by authors Stone-Wales wave or SWw. For these defective nanoribbons the bondonic formalism foresees a specific phase-transition whose critical behavior shows typical bondonic fast critical time and bonding energies. The quantum transition of the ideal-to-defect structural transformations is fully described by computing the caloric capacities for nanostructures triggered by η-sized topological isomerisations. Present model may be easily applied to hetero-combinations of Group-IV elements like C-Si, C-Ge, C-Sn, Si-Ge, Si-Sn, Ge-Sn.

[New classification of Crowe type IV developmental dysplasia of the hip].

Science.gov (United States)

Ma, Hai-yang; Zhou, Yong-gang; Zheng, Chong; Cao, Wen-zhe; Wang Sen; Wu, Wen-ming; Piao, Shang; Du, Yin-qiao

2016-02-01

To compare differences between Crowe IV developmental dysplasia of the hip (DDH) with secondary acetabulum and Crowe IV DDH without secondary acetabulum,and determine whether it is necessary to divide Crowe IV DDH into two subtypes. From June 2007 to May 2015,145 hips of 112 Crowe N patients who underwent total hip arthroplasty (THA) using S-ROM stem were divided into two groups: secondary acetabulum formaton group (group A) and no secondary acetabulum formaton group (group B). In group A,there were 12 females, 96 males,with an average age of (39.38 ± 11.19) years old. In group B, there were 2 females, 35 males, with an average age of (38.19 ± 10.92) years old. All the patients were evaluated by using Harris Hip Score. Radiographic evaluations were made preoperatively and during follow up. The differences between two groups were compared on dislocation height, canal flare index (CFI), subtrochanteric shortening osteotomy (SSTO) usage, pre- and post-operation Harris scores, complications. The dislocation height for group A was (4.74 ± 1.57) cm, while the dislocation height for group B was (3.12 ± 1.15) cm. Significantly difference was detected between two groups. The CFI for group A was 2.69 ± 0.68, while the CFI for group B was 3.42 ± 0.79, and the significantly difference was detected between two groups. Harris scores were totally improved from 58.18 ± 15.67 preoperatively to 91.20 ± 3.79 post-operatively and the difference was significant. Pre-operative Harris scores was 58.1 ± 15.3 in group A, 58.3 ± 16.9 in group B. Post-operative Harris scores was 91.0 ± 4.1 in group A, 91.0 ± 5.1 in group B. No significant difference was found on Harris scores between A and B preoperatively and post-operatively. Complications of 4 cases peri-prosthesis fracture, 4 cases dislocation and 4 cases nerve injury occur in group A; While only one case dislocation and one case nerve injury occur in group B. No statistical significance was detected. Crowe IV DDH with

Workshop Report on Additive Manufacturing for Large-Scale Metal Components - Development and Deployment of Metal Big-Area-Additive-Manufacturing (Large-Scale Metals AM) System

Energy Technology Data Exchange (ETDEWEB)

Babu, Sudarsanam Suresh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility; Love, Lonnie J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility; Peter, William H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility; Dehoff, Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility

2016-05-01

Additive manufacturing (AM) is considered an emerging technology that is expected to transform the way industry can make low-volume, high value complex structures. This disruptive technology promises to replace legacy manufacturing methods for the fabrication of existing components in addition to bringing new innovation for new components with increased functional and mechanical properties. This report outlines the outcome of a workshop on large-scale metal additive manufacturing held at Oak Ridge National Laboratory (ORNL) on March 11, 2016. The charter for the workshop was outlined by the Department of Energy (DOE) Advanced Manufacturing Office program manager. The status and impact of the Big Area Additive Manufacturing (BAAM) for polymer matrix composites was presented as the background motivation for the workshop. Following, the extension of underlying technology to low-cost metals was proposed with the following goals: (i) High deposition rates (approaching 100 lbs/h); (ii) Low cost (<$10/lbs) for steel, iron, aluminum, nickel, as well as, higher cost titanium, (iii) large components (major axis greater than 6 ft) and (iv) compliance of property requirements. The above concept was discussed in depth by representatives from different industrial sectors including welding, metal fabrication machinery, energy, construction, aerospace and heavy manufacturing. In addition, DOE’s newly launched High Performance Computing for Manufacturing (HPC4MFG) program was reviewed. This program will apply thermo-mechanical models to elucidate deeper understanding of the interactions between design, process, and materials during additive manufacturing. Following these presentations, all the attendees took part in a brainstorming session where everyone identified the top 10 challenges in large-scale metal AM from their own perspective. The feedback was analyzed and grouped in different categories including, (i) CAD to PART software, (ii) selection of energy source, (iii

Removal of platinum group metals contained in molten glass using copper

International Nuclear Information System (INIS)

Uruga, Kazuyoshi; Sawada, Kayo; Arita, Yuji; Enokida, Youichi; Yamamoto, Ichiro

2007-01-01

Removal of platinum group metals (PGMs) such as Pd, Ru, and RuO 2 from molten glass by using various amounts of liquid Cu was done as a basic study on a new vitrification process for a high-level radio-active waste. We prepared two types of borosilicate glasses containing PGMs and Cu, respectively. These glasses were mixed together and heated at 1,473 K for 4h in Ar atmosphere. More than 95% of Pd were removed as a spherical metal button composed of Pd-Cu alloy when Cu was added in an amount 0.5 times the weight of Pd. Nearly 95% of Ru was also removed as a spherical button with 2.5-5 times as much Cu addition as Ru in weight. Ruthenium oxide was reduced to metallic Ru by a reaction with Cu in the molten glass. The removal fraction was increased by increasing the amount of Cu and reached 63% when Cu addition was 7.5 times as much as RuO 2 in weight. By addition of Si as a reducing agent, nearly 90% of Pd and Ru were removed with Cu and Si metal composites even under O 2 :Ar=20:80 (v/v) condition. (author)

The International (Ludwig) Breast Cancer Study Group Trials I-IV: 15 years follow-up.

Science.gov (United States)

Castiglione-Gertsch, M; Johnsen, C; Goldhirsch, A; Gelber, R D; Rudenstam, C M; Collins, J; Lindtner, J; Hacking, A; Cortes-Funes, H; Forbes, J

1994-10-01

Adjuvant systemic therapy prolongs disease-free and overall survival in both pre- and postmenopausal patients. Available data shown benefit from multi-agent chemotherapy, prolonged tamoxifen treatment, and ovarian ablation, and that the combination of chemo- and endocrine therapy might be advantageous. In 1978 the International (Ludwig) Breast Cancer Study Group (IBCSG) initiated four complementary randomized controlled clinical trials to evaluate the roles of chemo-endocrine combinations or endocrine therapy alone in specific populations defined by risk (for pre- and perimenopausal patients) or by age (for postmenopausal patients). The results at 10 and 13 years' median follow-up for these trials are summarized in this report and are compared to those of the Overview meta-analysis with regard to chemo-endocrine or endocrine therapy combinations. Furthermore, types of first relapses by sites and second malignant diseases are reported. 1601 evaluable patients with node positive disease were included into the studies I-IV. In Trial I (491 premenopausal patients with 1-3 positive axillary nodes) we studied the addition of low-dose continuous prednisone (p) to a cyclophosphamide-methotrexate-fluorouracil (CMF) combination. In Trial II 327 premenopausal patients with four or more positive axillary nodes were randomized to one year CMFp or to a surgical oophorectomy followed by CMFp. In Trial III (463 postmenopausal patients 65 years old or younger), combined chemoendocrine therapy (one year of CMFp plus tamoxifen (T)) was compared to endocrine therapy (1 year of p + T) or to surgery alone. In Trial IV 320 postmenopausal patients 66 to 80 years old were treated either by surgery alone or by surgery followed by 1 year prednisone and tamoxifen. In Trial I the addition of prednisone allowed a higher dose of cytotoxics to be administered compared with CMF alone. Despite this increased dose intensity, 13-year disease-free survival (DFS) and overall survival (OS) were similar

Understanding hydrogen sorption in a metal-organic framework with open-metal sites and amide functional groups

KAUST Repository

Pham, Tony T.

2013-05-09

Grand canonical Monte Carlo (GCMC) studies of the mechanism of hydrogen sorption in an rht-MOF known as Cu-TPBTM are presented. The MOF is a decorated/substituted isostructural analogue to the unembellished rht-MOF, PCN-61, that was studied previously [ Forrest, K. A.J. Phys. Chem. C 2012, 116, 15538-15549. ]. The simulations were performed using three different hydrogen potentials of increasing complexity. Simulated hydrogen sorption isotherms and calculated isosteric heat of adsorption, Qst, values were in excellent agreement with the reported experimental data for only a polarizable model in one of four experimentally observed crystal structure configurations. The study demonstrates the ability of modeling to distinguish the differential sorption of distinct strucures; one configuration is found to be dominant due to favorable interactions with substrates. In addition, it was discovered that the presence of polar amide groups had a significant effect on the electrostatics of the Cu2+ ions and directs the low-pressure physisorption of hydrogen in the MOF. This is in contrast to what was observed in PCN-61, where an exterior copper ion had a higher relative charge and was the favored loading site. This tunability of the electrostatics of the copper ions via chemical substitution on the MOF framework can be explained by the presence of the negatively charged oxygen atom of the amide group that causes the interior Cu2+ ion to exhibit a higher positive charge through an inductive effect. Further, control simulations, taking advantage of the flexibility afforded by theoretical modeling, include artificially modified charges for both Cu2+ ions chosen equal to or with a higher charge on the exterior Cu2+ ion. This choice resulted in distinctly different hydrogen sorption characteristics in Cu-TPBTM with no direct sorption on the open-metal sites. Thus, this study demonstrates both the tunable nature of MOF platforms and the possibility for rational design of sorption

Oxidation of Group 8 transition-Metal Hydrides and Ionic Hydrogenation of Ketones and Aldehydes

Energy Technology Data Exchange (ETDEWEB)

Smith, Kjell-Tore

1996-08-01

Transition-metal hydrides have received considerable attention during the last decades because of their unusual reactivity and their potential as homogeneous catalysts for hydrogenation and other reactions of organic substrates. An important class of catalytic processes where transition-metal hydrides are involved is the homogeneous hydrogenation of alkenes, alkynes, ketones, aldehydes, arenes and nitro compounds. This thesis studies the oxidation of Group 8 transition-metal hydrides and the ionic hydrogenation of ketones and aldehydes.

Synthesis and evaluation of artificial antigens for astragaloside IV

Directory of Open Access Journals (Sweden)

Sheng-lan Yu

Full Text Available The objective of this study was to produce artificial antigens for astragaloside IV that could be used to prepare antibodies against astragaloside IV screened in Radix astragali (Astragalus membranaceus (Fisch Bunge, Fabaceae and its preparations, using an indirect ELISA. Astragaloside IV was coupled to carrier proteins, bovine serum albumin and ovalbumin using the sodium periodate method and was then evaluated using SDS-PAGE, MALDI-TOF MS and animal immunizations. The coupling ratio of astragaloside IV to bovine serum albumin ratio was determined to be thirteen, and the indirect ELISA demonstrated that three groups of mice immunized with astragaloside IV-bovine serum albumin produced anti-astragaloside IV- bovine serum albumin-specific antibody, with a minimum serum titer of 1:9600. A method for synthesizing highly immunogenic astragaloside IV artificial antigens was successfully developed thus indicating its feasibility in the establishment of a fast immunoassay for astragaloside IV content determination in Radix astragali and its products.

A Clostridium Group IV Species Dominates and Suppresses a Mixed Culture Fermentation by Tolerance to Medium Chain Fatty Acids Products

Science.gov (United States)

Andersen, Stephen J.; De Groof, Vicky; Khor, Way Cern; Roume, Hugo; Props, Ruben; Coma, Marta; Rabaey, Korneel

2017-01-01

A microbial community is engaged in a complex economy of cooperation and competition for carbon and energy. In engineered systems such as anaerobic digestion and fermentation, these relationships are exploited for conversion of a broad range of substrates into products, such as biogas, ethanol, and carboxylic acids. Medium chain fatty acids (MCFAs), for example, hexanoic acid, are valuable, energy dense microbial fermentation products, however, MCFA tend to exhibit microbial toxicity to a broad range of microorganisms at low concentrations. Here, we operated continuous mixed population MCFA fermentations on biorefinery thin stillage to investigate the community response associated with the production and toxicity of MCFA. In this study, an uncultured species from the Clostridium group IV (related to Clostridium sp. BS-1) became enriched in two independent reactors that produced hexanoic acid (up to 8.1 g L−1), octanoic acid (up to 3.2 g L−1), and trace concentrations of decanoic acid. Decanoic acid is reported here for the first time as a possible product of a Clostridium group IV species. Other significant species in the community, Lactobacillus spp. and Acetobacterium sp., generate intermediates in MCFA production, and their collapse in relative abundance resulted in an overall production decrease. A strong correlation was present between the community composition and both the hexanoic acid concentration (p = 0.026) and total volatile fatty acid concentration (p = 0.003). MCFA suppressed species related to Clostridium sp. CPB-6 and Lactobacillus spp. to a greater extent than others. The proportion of the species related to Clostridium sp. BS-1 over Clostridium sp. CPB-6 had a strong correlation with the concentration of octanoic acid (p = 0.003). The dominance of this species and the increase in MCFA resulted in an overall toxic effect on the mixed community, most significantly on the Lactobacillus spp., which resulted in a decrease in total

The Mean Metal-line Absorption Spectrum of Damped Ly α Systems in BOSS

Energy Technology Data Exchange (ETDEWEB)

Mas-Ribas, Lluís [Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, NO-0315 Oslo (Norway); Miralda-Escudé, Jordi; Pérez-Ràfols, Ignasi; Arinyo-i-Prats, Andreu [Institut de Ciències del Cosmos, Universitat de Barcelona (UB-IEEC), Barcelona E-08028, Catalonia (Spain); Noterdaeme, Pasquier; Petitjean, Patrick [Institut d’Astrophysique de Paris, UPMC and CNRS, UMR7095 98bis Boulevard Arago, F-75014—Paris (France); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); York, Donald G. [Department of Astronomy and Astrophysics and the Enrico Fermi Institute, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Ge, Jian, E-mail: l.m.ribas@astro.uio.no [Department of Astronomy, University of Florida, Bryant Space Science Center, Gainesville, FL 32611-2055 (United States)

2017-09-01

We study the mean absorption spectrum of the Damped Ly α (DLA) population at z ∼ 2.6 by stacking normalized, rest-frame-shifted spectra of ∼27,000 DLA systems from the DR12 of the Baryon Oscillation Spectroscopic Survey (BOSS)/SDSS-III. We measure the equivalent widths of 50 individual metal absorption lines in five intervals of DLA hydrogen column density, five intervals of DLA redshift, and overall mean equivalent widths for an additional 13 absorption features from groups of strongly blended lines. The mean equivalent width of low-ionization lines increases with N {sub H} {sub i}, whereas for high-ionization lines the increase is much weaker. The mean metal line equivalent widths decrease by a factor ∼1.1–1.5 from z ∼ 2.1 to z ∼ 3.5, with small or no differences between low- and high-ionization species. We develop a theoretical model, inspired by the presence of multiple absorption components observed in high-resolution spectra, to infer mean metal column densities from the equivalent widths of partially saturated metal lines. We apply this model to 14 low-ionization species and to Al iii, S iii, Si iii, C iv, Si iv, N v, and O vi. We use an approximate derivation for separating the equivalent width contributions of several lines to blended absorption features, and infer mean equivalent widths and column densities from lines of the additional species N i, Zn ii, C ii*, Fe iii, and S iv. Several of these mean column densities of metal lines in DLAs are obtained for the first time; their values generally agree with measurements of individual DLAs from high-resolution, high signal-to-noise ratio spectra when they are available.

Medical students benefit from the use of ultrasound when learning peripheral IV techniques.

Science.gov (United States)

Osborn, Scott R; Borhart, Joelle; Antonis, Michael S

2012-03-06

Recent studies support high success rates after a short learning period of ultrasound IV technique, and increased patient and provider satisfaction when using ultrasound as an adjunct to peripheral IV placement. No study to date has addressed the efficacy for instructing ultrasound-naive providers. We studied the introduction of ultrasound to the teaching technique of peripheral IV insertion on first- and second-year medical students. This was a prospective, randomized, and controlled trial. A total of 69 medical students were randomly assigned to the control group with a classic, landmark-based approach (n = 36) or the real-time ultrasound-guided group (n = 33). Both groups observed a 20-min tutorial on IV placement using both techniques and then attempted vein cannulation. Students were given a survey to report their results and observations by a 10-cm visual analog scale. The survey response rate was 100%. In the two groups, 73.9% stated that they attempted an IV previously, and 63.7% of students had used an ultrasound machine prior to the study. None had used ultrasound for IV access prior to our session. The average number of attempts at cannulation was 1.42 in either group. There was no difference between the control and ultrasound groups in terms of number of attempts (p = 0.31). In both groups, 66.7% of learners were able to cannulate in one attempt, 21.7% in two attempts, and 11.6% in three attempts. The study group commented that they felt they gained more knowledge from the experience (p students feel they learn more when using ultrasound after a 20-min tutorial to place IVs and cannulation of the vein feels easier. Success rates are comparable between the traditional and ultrasound teaching approaches.

A prognostic scoring model for survival after locoregional therapy in de novo stage IV breast cancer.

Science.gov (United States)

Kommalapati, Anuhya; Tella, Sri Harsha; Goyal, Gaurav; Ganti, Apar Kishor; Krishnamurthy, Jairam; Tandra, Pavan Kumar

2018-05-02

The role of locoregional treatment (LRT) remains controversial in de novo stage IV breast cancer (BC). We sought to analyze the role of LRT and prognostic factors of overall survival (OS) in de novo stage IV BC patients treated with LRT utilizing the National Cancer Data Base (NCDB). The objective of the current study is to create and internally validate a prognostic scoring model to predict the long-term OS for de novo stage IV BC patients treated with LRT. We included de novo stage IV BC patients reported to NCDB between 2004 and 2015. Patients were divided into LRT and no-LRT subsets. We randomized LRT subset to training and validation cohorts. In the training cohort, a seventeen-point prognostic scoring system was developed based on the hazard ratios calculated using Cox-proportional method. We stratified both training and validation cohorts into two "groups" [group 1 (0-7 points) and group 2 (7-17 points)]. Kaplan-Meier method and log-rank test were used to compare OS between the two groups. Our prognostic score was validated internally by comparing the OS between the respective groups in both the training and validation cohorts. Among 67,978 patients, LRT subset (21,200) had better median OS as compared to that of no-LRT (45 vs. 24 months; p < 0.0001). The group 1 and group 2 in the training cohort showed a significant difference in the 3-year OS (p < 0.0001) (68 vs. 26%). On internal validation, comparable OS was seen between the respective groups in each cohort (p = 0.77). Our prognostic scoring system will help oncologists to predict the prognosis in de novo stage IV BC patients treated with LRT. Although firm treatment-related conclusions cannot be made due to the retrospective nature of the study, LRT appears to be associated with a better OS in specific subgroups.

Thermodynamic data for predicting concentrations of Th(IV), U(IV), Np(IV), and Pu(IV) in geologic environments

Energy Technology Data Exchange (ETDEWEB)

Rai, Dhanpat; Roa, Linfeng; Weger, H.T.; Felmy, A.R. [Battelle, Pacific Northwest National Laboratory (PNNL) (United States); Choppin, G.R. [Florida State University (United States); Yui, Mikazu [Waste Isolation Research Division, Tokai Works, Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

1999-01-01

This report provides thermodynamic data for predicting concentrations of Th(IV), U(IV), Np(IV), and Pu(IV) in geologic environments, and contributes to an integration of the JNC chemical thermodynamic database, JNC-TDB (previously PNC-TDB), for the performance analysis of geological isolation system for high-level radioactive wastes. Thermodynamic data for the formation of complexes or compounds with hydroxide, chloride, fluoride, carbonate, nitrate, sulfate and phosphate are discussed in this report. Where data for specific actinide(IV) species was lacking, the data were selected based on chemical analogy to other tetravalent actinides. In this study, the Pitzer ion-interaction model is used to extrapolate thermodynamic constants to zero ionic strength at 25degC. (author)

Slow and stopped light in active gain composite materials of metal nanoparticles. Ultralarge group index-bandwidth product predicted

Energy Technology Data Exchange (ETDEWEB)

Kim, Kwang-Hyon; Choe, Song-Hyok [Institute of Lasers, State Academy of Sciences, Unjong District, Pyongyang (Korea, Democratic People' s Republic of)

2017-08-15

Chip-compatible slow light devices with large group index-bandwidth products and low losses are of great interest in the community of modern photonics. In this work, active gain materials containing metal nanoparticles are proposed as the slow and stopped light materials. Gain-assisted high field enhancement in metal nanoparticles and the resultant strong dispersion lead to such phenomena. From the Maxwell-Garnett model, it is revealed that the metal nanocomposite exhibits the infinitely large group index when the gain of the host medium and the filling factor of metal nanoparticles satisfy a critical condition. For the gain of the host above the critical value, one can observe slowing down effect with amplification of light pulses. Significantly large group index-bandwidth products, which vary from a few to several thousand or even infinity depending on the gain value of the host medium, have been numerically predicted in active silica glasses containing spheroidal metal nanoparticles, as examples. The proposed scheme inherently provides the widely varying operating spectral range by changing the aspect ratio of metal nanoparticles and chip-compatibility with low cost. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Site Environmental Report for Calendar Year 2011. DOE Operations at The Boeing Company Santa Susana Field Laboratory, Area IV

Energy Technology Data Exchange (ETDEWEB)

Liu, Ning [The Boeing Company, Canoga Park, CA (United States); Rutherford, Phil [The Boeing Company, Canoga Park, CA (United States); Dassler, David [The Boeing Company, Canoga Park, CA (United States)

2012-09-01

This Annual Site Environmental Report (ASER) for 2011 describes the environmental conditions related to work performed for the Department of Energy (DOE) at Area IV of Boeing’s Santa Susana Field Laboratory (SSFL). The Energy Technology Engineering Center (ETEC), a government-owned, company-operated test facility, was located in Area IV. The operations in Area IV included development, fabrication, operation and disassembly of nuclear reactors, reactor fuel, and other radioactive materials. Other activities in the area involved the operation of large-scale liquid metal facilities that were used for testing non-nuclear liquid metal fast breeder reactor components. All nuclear work was terminated in 1988, and all subsequent radiological work has been directed toward environmental restoration and decontamination and decommissioning (D&D) of the former nuclear facilities and their associated sites. Liquid metal research and development ended in 2002. Since May 2007, the D&D operations in Area IV have been suspended by the DOE, but the environmental monitoring and characterization programs have continued. Results of the radiological monitoring program for the calendar year 2011 continue to indicate that there are no significant releases of radioactive material from Area IV of SSFL. All potential exposure pathways are sampled and/or monitored, including air, soil, surface water, groundwater, direct radiation, transfer of property (land, structures, waste), and recycling.

Site Environmental Report For Calendar Year 2012. DOE Operations at The Boeing Company Santa Susana Field Laboratory, Area IV

Energy Technology Data Exchange (ETDEWEB)

Liu, Ning [The Boeing Company, Canoga Park, CA (United States); Rutherford, Phil [The Boeing Company, Canoga Park, CA (United States); Dassler, David [The Boeing Company, Canoga Park, CA (United States)

2013-09-01

This Annual Site Environmental Report (ASER) for 2012 describes the environmental conditions related to work performed for the Department of Energy (DOE) at Area IV of Boeing’s Santa Susana Field Laboratory (SSFL). The Energy Technology Engineering Center (ETEC), a government-owned, company-operated test facility, was located in Area IV. The operations in Area IV included development, fabrication, operation and disassembly of nuclear reactors, reactor fuel, and other radioactive materials. Other activities in the area involved the operation of large-scale liquid metal facilities that were used for testing non-nuclear liquid metal fast breeder reactor components. All nuclear work was terminated in 1988, and all subsequent radiological work has been directed toward environmental restoration and decontamination and decommissioning (D&D) of the former nuclear facilities and their associated sites. Liquid metal research and development ended in 2002. Since May 2007, the D&D operations in Area IV have been suspended by the DOE, but the environmental monitoring and characterization programs have continued. Results of the radiological monitoring program for the calendar year 2012 continue to indicate that there are no significant releases of radioactive material from Area IV of SSFL. All potential exposure pathways are sampled and/or monitored, including air, soil, surface water, groundwater, direct radiation, transfer of property (land, structures, waste), and recycling.

Hydrogen storage material and related processes

Science.gov (United States)

Soloveichik, Grigorii Lev [Latham, NY; Andrus, Matthew John [Cape Canaveral, FL

2012-06-05

Disclosed herein is a composition comprising a complex hydride and a borohydride catalyst wherein the borohydride catalyst comprises a BH.sub.4 group, and a group IV metal, a group V metal, or a combination of a group IV and a group V metal. Also disclosed herein are methods of making the composition.

Level II Probabilistic Safety Analysis Methodology for the Application to GEN-IV Sodium-cooled Fast Reactor

International Nuclear Information System (INIS)

Park, S. Y.; Kim, T. W.; Han, S. H.; Jeong, H. Y.

2010-03-01

The Korea Atomic Energy Research Institute (KAERI) has been developing liquid metal reactor (LMR) design technologies under a National Nuclear R and D Program. Nevertheless, there is no experience of the probabilistic safety assessment (PSA) domestically for a fast reactor with the metal fuel. Therefore, the objective of this study is to establish the methodologies of risk assessment for the reference design of GEN-IV sodium fast reactor (SFR). An applicability of the PSA methodology of U. S. NRC and PRISM plant to the domestic GEN-IV SFR has been studied. The study contains a plant damage state analysis, a containment event tree analysis, and a source-term release category binning process

Purification, crystallization and preliminary crystallographic analysis of a thermostable endonuclease IV from Thermotoga maritima

International Nuclear Information System (INIS)

Hughes, Ronny C.; Tomanicek, Stephen J.; Ng, Joseph D.; Coates, Leighton

2009-01-01

The overexpression, purification and crystallization of endonuclease IV from T. maritima are reported. The crystals belonged to the hexagonal space group P6 1 and diffracted to 2.36 Å resolution. The DNA-repair enzyme endonuclease IV from the thermophilic bacterium Thermotoga maritima MSB8 (reference sequence NC-000853) has been expressed in Escherichia coli and crystallized for X-ray analysis. T. maritima endonuclease IV is a 287-amino-acid protein with 32% sequence identity to E. coli endonuclease IV. The protein was purified to homogeneity and was crystallized using the sitting-drop vapor-diffusion method. The protein crystallized in space group P6 1 , with one biological molecule in the asymmetric unit, corresponding to a Matthews coefficient of 2.39 Å 3 Da −1 and 47% solvent content. The unit-cell parameters of the crystals were a = b = 123.2, c = 35.6 Å. Microseeding and further optimization yielded crystals with an X-ray diffraction limit of 2.36 Å. A single 70° data set was collected and processed, resulting in an overall R merge and a completeness of 9.5% and 99.3%, respectively

Real life experimental determination of platinum group metals content in automotive catalytic converters

Science.gov (United States)

Yakoumis, I.; Moschovi, A. M.; Giannopoulou, I.; Panias, D.

2018-03-01

The real life experimental protocol for the preparation of spent automobile catalyst samples for elemental analysis is thoroughly described in the following study. Collection, sorting and dismantling, homogenization and sample preparation for X-Ray fluorescence spectroscopy and Atomic Adsorption Spectroscopy combined with Inductive coupled plasma mass spectrometry are discussed in detail for both ceramic and metallic spent catalysts. The concentrations of Platinum Group Metals (PGMs) in spent catalytic converters are presented based on typical consignments of recycled converters (more than 45,000 pieces) from the Greek Market. The conclusions clearly denoted commercial metallic catalytic foil contains higher PGMs loading than ceramic honeycombs. On the other hand, the total PGMs loading in spent ceramic catalytic converters has been found higher than the corresponding value for the metallic ones.

Comparison of Effectiveness of Betamethasone gel Applied to the Tracheal Tube and IV Dexamethasone on Postoperative Sore Throat: A Randomized Controlled Trial.

Science.gov (United States)

Tabari, Masumeh; Soltani, Ghasem; Zirak, Nahid; Alipour, Moammad; Khazaeni, Kamran

2013-09-01

Postoperative sore throat is a common complaint in patients with endotracheal intubation and has potentially dangerous complications. This randomized controlled trial study investigated the incidence of postoperative sore throat after general anesthesia when betamethasone gel is applied to a tracheal tube compared with when IV dexamethasone is prescribed. Two hundred and twenty five American Society of Anesthesiologist (ASA)-class I and II patients undergoing elective abdominal surgery with tracheal intubation were randomly divided into three groups: betamethasone gel, intravenous (IV) dexamethasone, and control groups. In the post-anesthesia care unit, a blinded anesthesiologist interviewed all patients regarding postoperative sore throat at 1,6, and 24 hours after surgery. The incidence of sore throat was significantly lower in the betamethasone gel group compared with the IV dexamethasone and control groups, 1, 6, and 24 hours after surgery. In the first day after surgery 10.7% of the betamethasone group had sore throat whereas 26.7% of the IV dexamethasone group and 30.7% of the control group had sore throat. Bucking before extubation was observed in 14(18.4%), 8(10.4%), and 9(12.2%) patients, in the IV dexamethasone, betamethasone gel, and control group, respectively. We concluded that wide spread application of betamethasone gel over tracheal tubes effectively mitigates postoperative sore throat, compared with IV dexamethasone application.

Comparison of Effectiveness of Betamethasone gel Applied to the Tracheal Tube and IV Dexamethasone on Postoperative sore Throat: A Randomized Controlled Trial

Directory of Open Access Journals (Sweden)

Masoomeh Tabari

2013-10-01

Full Text Available Introduction: Postoperative sore throat is a common complaint in patients with endotracheal intubation and has potentially dangerous complications. This randomized controlled trial study investigated the incidence of postoperative sore throat after general anesthesia when betamethasone gel is applied to a tracheal tube compared with when IV dexamethasone is prescribed.   Materials and Methods: Two hundred and twenty five American Society of Anesthesiologist (ASA-class I and II patients undergoing elective abdominal surgery with tracheal intubation were randomly divided into three groups: betamethasone gel, intravenous (IV dexamethasone, and control groups. In the post-anesthesia care unit, a blinded anesthesiologist interviewed all patients regarding postoperative sore throat at 1,6, and 24 hours after surgery.   Results: The incidence of sore throat was significantly lower in the betamethasone gel group compared with the IV dexamethasone and control groups, 1, 6, and 24 hours after surgery. In the first day after surgery 10.7% of the betamethasone group had sore throat whereas 26.7% of the IV dexamethasone group and 30.7% of the control group had sore throat. Bucking before extubation was observed in 14(18.4%, 8(10.4%, and 9(12.2% patients, in the IV dexamethasone, betamethasone gel, and control group, respectively.   Conclusion:  We concluded that wide spread application of betamethasone gel over tracheal tubes effectively mitigates postoperative sore throat, compared with IV dexamethasone application.

Extraction behaviour and mechanism of Pt(iv) and Pd(ii) by liquid-liquid extraction with an ionic liquid [HBBIm]Br.

Science.gov (United States)

Liu, Wenhui; Wang, Qi; Zheng, Yan; Wang, Shubin; Yan, Yan; Yang, Yanzhao

2017-06-06

In this study, a method of one-step separation and recycling of high purity Pd(ii) and Pt(iv) using an ionic liquid, 1-butyl-3-benzimidazolium bromate ([HBBIm]Br), was investigated. The effects of [HBBIm]Br concentration, initial metal concentration, and loading capacity of [HBBIm]Br were examined in detail. It was observed that [HBBIm]Br was a very effective extractant for selectively extracting Pd(ii) and precipitating Pt(iv). Through selectively extracting Pd(ii) and precipitating Pt(iv), each metal with high purity was separately obtained from mixed Pd(ii) and Pt(iv) multi-metal solution. The method of one-step separation of Pd(ii) and Pt(iv) is simple and convenient. The anion exchange mechanism between [HBBIm]Br and Pt(iv) was proven through Job's method and FTIR and 1 H NMR spectroscopies. The coordination mechanism between [HBBIm]Br and Pd(ii) was demonstrated via single X-ray diffraction and was found to be robust and distinct, as supported by the ab initio quantum-chemical studies. The crystals of the [PdBr 2 ·2BBIm] complex were formed first. Moreover, the influence of the concentrations of hydrochloric acid, sodium chloride, and sodium nitrate on the precipitation of Pt(iv) and extraction of Pd(ii) was studied herein. It was found that only the concentration of H + could inhibit the separation of Pt(iv) because H + could attract the anion PtCl 6 2- ; thus, the exchange (anion exchange mechanism) between the anions PtCl 6 2- and Br - was prevented. However, both the concentration of H + and Cl - can obviously inhibit the extraction of Pd(ii) because H + and Cl - are the reaction products and increasing their concentration can inhibit the progress of the reaction (coordination mechanism).

Modifications of chemical functional groups of Pandanus amaryllifolius Roxb and its effect towards biosorption of heavy metals

Energy Technology Data Exchange (ETDEWEB)

Abdullah, Mohd Zamri, E-mail: zamriab@petronas.com.my; Ismail, Siti Salwa [Chemical Engineering Department, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia)

2015-07-22

The utilization of non-living biomass as an alternative biosorbent for heavy metal removal has gain a tremendous consideration through the years. Pandanus amaryllifolius Roxb or pandan leaves, which is widely used as food additives in the South East Asia region, has been selected for its viability in the said effort due to the presence of chemical functional groups on its cellular network that enables the sorption to occur. In order to elucidate the possible mechanisms participated during the heavy metal removal process, the biosorbent undergone a series of modification techniques to alter the chemical functional groups present on its constituent. From the outcome of the chemically-modified biosorbent being subjected to the contact with metal cations, nitrogen- and oxygen-containing groups present on the biosorbent are believed to be responsible for the metal uptake to occur through complexation mechanism. Modifying amine groups causes 14% reduction of Cu(II) uptake, whereas removing protein element increases the uptake to 26% as compared to the unmodified biosorbent. Also, scanning electron micrographs further suggested that the adsorption mechanism could perform in parallel, as attributed to the evidence of porous structure throughout the biosorbent fibrous nature.

Modifications of chemical functional groups of Pandanus amaryllifolius Roxb and its effect towards biosorption of heavy metals

International Nuclear Information System (INIS)

Abdullah, Mohd Zamri; Ismail, Siti Salwa

2015-01-01

The utilization of non-living biomass as an alternative biosorbent for heavy metal removal has gain a tremendous consideration through the years. Pandanus amaryllifolius Roxb or pandan leaves, which is widely used as food additives in the South East Asia region, has been selected for its viability in the said effort due to the presence of chemical functional groups on its cellular network that enables the sorption to occur. In order to elucidate the possible mechanisms participated during the heavy metal removal process, the biosorbent undergone a series of modification techniques to alter the chemical functional groups present on its constituent. From the outcome of the chemically-modified biosorbent being subjected to the contact with metal cations, nitrogen- and oxygen-containing groups present on the biosorbent are believed to be responsible for the metal uptake to occur through complexation mechanism. Modifying amine groups causes 14% reduction of Cu(II) uptake, whereas removing protein element increases the uptake to 26% as compared to the unmodified biosorbent. Also, scanning electron micrographs further suggested that the adsorption mechanism could perform in parallel, as attributed to the evidence of porous structure throughout the biosorbent fibrous nature

Pretreatment Hepatoprotective Effect of the Marine Fungus Derived from Sponge on Hepatic Toxicity Induced by Heavy Metals in Rats

Directory of Open Access Journals (Sweden)

Nehad M. Abdel-Monem

2013-01-01

Full Text Available The aim of this study was to evaluate the pretreatment hepatoprotective effect of the extract of marine-derived fungus Trichurus spiralis Hasselbr (TS isolated from Hippospongia communis sponge on hepatotoxicity. Twenty-eight male Sprague-Dawley rats were divided into four groups (n=7. Group I served as −ve control, group II served as the induced group receiving subcutaneously for seven days 0.25 mg heavy metal mixtures, group III received (i.p. TS extract of dose 40 mg for seven days, and group IV served as the protected group pretreated with TS extract for seven days as a protection dose, and then treated with the heavy metal-mixture. The main pathological changes within the liver after heavy-metal mixtures administrations marked hepatic damage evidenced by foci of lobular necrosis with neutrophilic infiltration, adjacent to dysplastic hepatocytes. ALT and AST measurements show a significant increase in group II by 46.20% and 45.12%, respectively. Total protein, elevated by about 38.9% in induction group compared to the −ve control group, in contrast to albumin, decreased as a consequence of metal administration with significant elevation on bilirubin level. The results prove that TS extract possesses a hepatoprotective property due to its proven antioxidant and free-radical scavenging properties.

Erosion of the 4-6- and 8 group transition metals under intense laser radiation

International Nuclear Information System (INIS)

Samsonov, G.V.; Verkhoturov, A.D.; Roshchina, A.I.; Vasil'ev, A.V.; Klimenko, V.P.

1976-01-01

The erosion resistance is studied of transition metals of Groups 4-6 and 8 at laser emission of approximately 6x1O 7 W/cm 2 . It is shown that as the emission power increases from 10 6 to 6x10 7 W/cm 2 the erosion values show an increase over tenfold without any subsequent filling of the craters. The growth of the metallic erosion is largely caused by a greater crater diameter. The erosion resistance of metals enhances in the following series: Ti-Zr-Co-Ni-Fe, Hf-V-Nb-Mo-Cr-Ta-W-Cu

Effect of Platinum Group Metal Doping in Magnesium Diboride Wires

DEFF Research Database (Denmark)

Grivel, Jean-Claude; Alexiou, Aikaterini; Namazkar, Shahla

2016-01-01

The effect of some platinum group metals(PGM = Rh, Pd, and Pt) on the microstructure and critical current density of Cu/Nb-sheathed MgB2 wires has been studied using Mg1-x PGMxB2 powders with low doping levels. It was found that Pt and Pd do not enter the MgB2 lattice and have only limited influe...

Annual Site Environmental Report, Department of Energy Operations at the Energy Technology Engineering Center – Area IV, Santa Susana Field Laboratory

Energy Technology Data Exchange (ETDEWEB)

Frazee, Brad [North Wind, Inc., Idaho Falls, ID (United States); Hay, Scott [North Wind, Inc., Idaho Falls, ID (United States); Wondolleck, John [North Wind, Inc., Idaho Falls, ID (United States); Sorrels, Earl [North Wind, Inc., Idaho Falls, ID (United States); Rutherford, Phil [North Wind, Inc., Idaho Falls, ID (United States); Dassler, David [North Wind, Inc., Idaho Falls, ID (United States); Jones, John [North Wind, Inc., Idaho Falls, ID (United States)

2015-05-01

This Annual Site Environmental Report (ASER) for 2014 describes the environmental conditions related to work performed for the DOE at Area IV of the Santa Susana Field Laboratory (SSFL). The ETEC, a government-owned, company-operated test facility, was located in Area IV. The operations in Area IV included development, fabrication, operation and disassembly of nuclear reactors, reactor fuel, and other radioactive materials. Other activities in the area involved the operation of large-scale liquid metal facilities that were used for testing non-nuclear liquid metal fast breeder reactor components. All nuclear work was terminated in 1988, and all subsequent radiological work has been directed toward environmental restoration and decontamination and decommissioning (D&D) of the former nuclear facilities and their associated sites. Liquid metal research and development ended in 2002. Since May 2007, the D&D operations in Area IV have been suspended by the DOE, but the environmental monitoring and characterization programs have continued. Results of the radiological monitoring program continue to indicate that there are no significant releases of radioactive material from Area IV of SSFL. All potential exposure pathways are sampled and/or monitored, including air, soil, surface water, groundwater, direct radiation, transfer of property (land, structures, waste), and recycling.

Helping General Physical Educators and Adapted Physical Educators Address the Office of Civil Rights Dear Colleague Guidance Letter: Part IV--Sport Groups

Science.gov (United States)

Lieberman, Lauren; Lucas, Mark; Jones, Jeffery; Humphreys, Dan; Cody, Ann; Vaughn, Bev; Storms, Tommie

2013-01-01

"Helping General Physical Educators and Adapted Physical Educators Address the Office of Civil Rights Dear Colleague Guidance Letter: Part IV--Sport Groups" provides the the following articles: (1) "Sport Programming Offered by Camp Abilities and the United States Association for Blind Athletes" (Lauren Lieberman and Mark…

Volatile hexafluoroacetylacetonates for the isolation and gas-chromatographic determination of trace metals. Pt. 1

International Nuclear Information System (INIS)

Hellmuth, K.H.; Mirzai, H.

1985-01-01

The optimization of the extraction of metal cations [Sc(III), Cr(III), Mn(II), Fe(III), Co(II), Cu(II), Zn(II), Y(III), Ag(I), Cd(II), La(IIII), Ce(III), Eu(III), Yb(III), Hg(II), Pb(II), Th(IV), U(IV, VI) and Am(III)] in the form of mixed-ligand complexes with hexafluoroacetylacetone and neutral donators with nitrogen atoms or P=O-groups is described. The thermal and gas-chromatographic characteristics of the extracted volatile compounds are reported. Optimal results were achieved using tri-n-butyl-phosphine oxide as donator. (orig.) [de

Carbonic anhydrase inhibitors. A general approach for the preparation of water-soluble sulfonamides incorporating polyamino-polycarboxylate tails and of their metal complexes possessing long-lasting, topical intraocular pressure-lowering properties.

Science.gov (United States)

Scozzafava, Andrea; Menabuoni, Luca; Mincione, Francesco; Supuran, Claudiu T

2002-03-28

Reaction of polyamino-polycarboxylic acids or their dianhydrides with aromatic/heterocyclic sulfonamides possessing a free amino/imino/hydrazino/hydroxy group afforded mono- and bis-sulfonamides containing polyamino-polycarboxylic acid moieties in their molecule. The acids/anhydrides used in synthesis included IDA, NTA, EDDA, EDTA and EDTA dianhydride, DTPA and DTPA dianhydride, EGTA and EGTA dianhydride, and EDDHA, among others. All the newly prepared derivatives showed strong affinity toward isozymes I, II, and IV of carbonic anhydrase (CA). Metal complexes of the new compounds have also been prepared. Metal ions used in such preparations included di- and trivalent main-group and transition cations, such as Zn(II), Cu(II), Al(III), etc. Some of the new sulfonamides/disulfonamides obtained in this way, as well as their metal complexes, behaved as nanomolar CA inhibitors against isozymes II and IV, being slightly less effective in inhibiting isozyme I. Some of these sulfonamides as well as their metal complexes strongly lowered intraocular pressure (IOP) when applied topically, directly into the normotensive/glaucomatous rabbit eye, as 1-2% water solutions/suspensions. The good water solubility of these sulfonamide CA inhibitors, correlated with the neutral pH of their water solutions used in the ophthalmologic applications and the long duration of action of the IOP-lowering effect, makes them interesting candidates for developing novel types of antiglaucoma drugs devoid of serious topical side effects.

Group 4 Metalloporphyrin diolato Complexes and Catalytic Application of Metalloporphyrins and Related Transition Metal Complexes

Energy Technology Data Exchange (ETDEWEB)

Du, Guodong [Iowa State Univ., Ames, IA (United States)

2003-01-01

In this work, the first examples of group 4 metalloporphyrin 1,2-diolato complexes were synthesized through a number of strategies. In general, treatment of imido metalloporphyrin complexes, (TTP)M=NR, (M = Ti, Zr, Hf), with vicinal diols led to the formation of a series of diolato complexes. Alternatively, the chelating pinacolate complexes could be prepared by metathesis of (TTP)MCl₂ (M = Ti, Hf) with disodium pinacolate. These complexes were found to undergo C-C cleavage reactions to produce organic carbonyl compounds. For titanium porphyrins, treatment of a titanium(II) alkyne adduct, (TTP)Ti(η²-PhC≡CPh), with aromatic aldehydes or aryl ketones resulted in reductive coupling of the carbonyl groups to produce the corresponding diolato complexes. Aliphatic aldehydes or ketones were not reactive towards (TTP)Ti(η²-PhC≡CPh). However, these carbonyl compounds could be incorporated into a diolato complex on reaction with a reactive precursor, (TTP)Ti[O(Ph)₂C(Ph)₂O] to provide unsymmetrical diolato complexes via cross coupling reactions. In addition, an enediolato complex (TTP)Ti(OCPhCPhO) was obtained from the reaction of (TTP)Ti(η²-PhC≡CPh) with benzoin. Titanium porphyrin diolato complexes were found to be intermediates in the (TTP)Ti=O-catalyzed cleavage reactions of vicinal diols, in which atmospheric oxygen was the oxidant. Furthermore, (TTP)Ti=O was capable of catalyzing the oxidation of benzyl alcohol and α-hydroxy ketones to benzaldehyde and α-diketones, respectively. Other high valent metalloporphyrin complexes also can catalyze the oxidative diol cleavage and the benzyl alcohol oxidation reactions with dioxygen. A comparison of Ti(IV) and Sn(IV) porphyrin chemistry was undertaken. While chelated diolato complexes were invariably obtained for titanium porphyrins on treatment with 1,2-diols, the reaction of vicinal diols with tin porphyrins gave a number of products, including mono

Electron transport characteristics of silicon nanowires by metal-assisted chemical etching

Directory of Open Access Journals (Sweden)

Yangyang Qi

2014-02-01

Full Text Available The electron transport characteristics of silicon nanowires (SiNWs fabricated by metal-assisted chemical etching with different doping concentrations were studied. By increasing the doping concentration of the starting Si wafer, the resulting SiNWs were prone to have a rough surface, which had important effects on the contact and the electron transport. A metal-semiconductor-metal model and a thermionic field emission theory were used to analyse the current-voltage (I-V characteristics. Asymmetric, rectifying and symmetric I-V curves were obtained. The diversity of the I-V curves originated from the different barrier heights at the two sides of the SiNWs. For heavily doped SiNWs, the critical voltage was one order of magnitude larger than that of the lightly doped, and the resistance obtained by differentiating the I-V curves at large bias was also higher. These were attributed to the lower electron tunnelling possibility and higher contact barrier, due to the rough surface and the reduced doping concentration during the etching process.

Stage IV work-hardening related to disorientations in dislocation structures

DEFF Research Database (Denmark)

Pantleon, W.

2004-01-01

The effect of deformation-induced disorientations on the work-hardening of metals is modelled based on dislocation dynamics. Essentially, Kocks’ dislocation model describing stage III hardening is extended to stage IV by incorporation of excess dislocations related to the disorientations....... Disorientations evolving from purely statistical reasons — leading to a square root dependence of the average disorientation angle on strain — affect the initial work-hardening rate (and the saturation stress) of stage III only slightly. On the other hand, deterministic contributions to the development...... of disorientations, as differences in the activated slip systems across boundaries, cause a linear increase of the flow stress at large strains. Such a constant work-hardening rate is characteristic for stage IV....

Intrinsic thermoelectric power of group VB metals

Directory of Open Access Journals (Sweden)

Gunadhor Singh Okram

2012-03-01

Full Text Available We have reinvestigated the thermopower of group VB metals in polycrystalline forms in the temperature range of 6-300K, taking into account the critical nature of the sample surface and heat treatment especially for niobium. Strikingly small magnitude, negative sign, phonon drag dip and superconductivity not reported previously were observed in surface-cleaned single crystalline Nb. However, while thermopower magnitudes are small, mixed signs were found in the polycrystalline V, Nb and Ta samples. These properties were therefore interpreted as their intrinsic properties and were briefly discussed taking into account of the existing theory by fitting also the data that give the Fermi energies of 10.94 eV, 5.08 eV and 1.86eV, respectively.

Oxovanadium(IV), cerium(III), thorium(IV) and dioxouranium(VI) complexes of 1-ethyl-4-hydroxy-3-(nitroacetyl)quinolin-2(1H)-one: Synthesis, spectral, thermal, fluorescence, DFT calculations, antimicrobial and antitumor studies

Science.gov (United States)

El-Shafiy, H. F.; Shebl, Magdy

2018-03-01

A new series of mononuclear oxovanadium(IV), cerium(III), thorium(IV) and dioxouranium(VI) complexes of a quinolinone ligand; 1-ethyl-4-hydroxy-3-(nitroacetyl)quinolin-2(1H)-one (H2L) have been synthesized. The metal complexes were characterized by different techniques such as elemental and thermal analyses, IR, 1H NMR, electronic, ESR, mass spectra and powder XRD, TEM in addition to magnetic susceptibility and conductivity measurements. The quinolinone ligand acts as a dibasic bidentate ligand forming mononuclear complexes, which can be formulated as: [(L)VO(H2O)2]·0.5H2O, [(L)M(NO3)x(H2O)y]·nH2O; M = Ce or Th, x = 1 or 2, y = 3 or 4 and n = 2 or 7 and [(L)UO2(H2O)x(MeOH)y]·nH2O; x = 2 or 3, y = 0 or 1 and n = 0.5 or 2.5. The photoluminescent properties of the prepared complexes were studied. The ligand and its thorium(IV) complex are characterized by an intense green emission. Kinetic parameters (Ea, A, ΔH, ΔS and ΔG) of the thermal decomposition stages have been evaluated using Coats-Redfern equations. The geometry of the ligand and its oxovanadium(IV) complex has been optimized using density functional theory (DFT). Total energy, energy of HOMO and LUMO, dipole moment and structure activity relationship were performed and confirmed practical antimicrobial and antitumor results. The antimicrobial activity of the ligand and its metal complexes was conducted against the microorganisms S. aureus, K. pnemonia, E. coli, P. vulgaris and C. albicans and the MIC values were determined. The antitumor activity of the ligand and its metal complexes was investigated against human Hepatocelluar carcinoma and human breast cancer cell lines.

Transport properties of metal-metal and metal-insulator heterostructures

Energy Technology Data Exchange (ETDEWEB)

Fadlallah Elabd, Mohamed Mostafa

2010-06-09

In this study we present results of electronic structure and transport calculations for metallic and metal-insulator interfaces, based on density functional theory and the non-equilibrium Green's function method. Starting from the electronic structure of bulk Al, Cu, Ag, and Au interfaces, we study the effects of different kinds of interface roughness on the transmission coefficient (T(E)) and the I-V characteristic. In particular, we compare prototypical interface distortions, including vacancies, metallic impurities, non-metallic impurities, interlayer, and interface alloy. We find that vacancy sites have a huge effect on transmission coefficient. The transmission coefficient of non-metallic impurity systems has the same behaviour as the transmission coefficient of vacancy system, since these systems do not contribute to the electronic states at the Fermi energy. We have also studied the transport properties of Au-MgO-Au tunnel junctions. In particular, we have investigated the influence of the thickness of the MgO interlayer, the interface termination, the interface spacing, and O vacancies. Additional interface states appear in the O-terminated configuration due to the formation of Au-O bonds. An increasing interface spacing suppresses the Au-O bonding. Enhancement of T(E) depends on the position and density of the vacancies (the number of vacancies per unit cell). (orig.)

Preparation of reactive and refractory metal powders (Paper No. 25)

International Nuclear Information System (INIS)

Sundaram, C.V.; Sharma, B.P.; Krishnan, T.S.

1979-01-01

In devising processes for the preparation of refractory and reactive metal powders, one has to reckon with many relevant factors. The choice of specific flowsheets is governed by the characteristics of the metal compounds and the reducing agents, the purity required and achievable in the as-reduced powder, the need for further refining of the metal, the possibilities of chemical/physical/mechanical comminution of the purified metal without contamination, and the end application of the powder metal. Micron size zirconium powder used as trigger material in photo-flash bulbs and detonator compositions, tantalum powder of controlled particle size and high purity for the production of electrolytic capacitors, and beryllium metal powder for the preparation of hot pressed powder metallurgy components are illustrative of the variety of reactive metal powders for industrial applications. The work carried out at the Bhabha Atomic Research Centre, Bombay, on the preparation of special metal powders, with particular emphasis on Group IV and V metals and also beryllium is presented. Reduction of metal oxides with alkaline earth metals/hydrides, reduction of metal halides with sodium/magnesium, vacuum arc and electron beam melt purification followed by comminution by hydrogen embrittlement/mechanical comminution are among the processes discussed. (auth.)

STAR FORMATION FEEDBACK AND METAL-ENRICHMENT HISTORY OF THE INTERGALACTIC MEDIUM

International Nuclear Information System (INIS)

Cen Renyue; Chisari, Nora Elisa

2011-01-01

Using the state-of-the-art cosmological hydrodynamic simulations of the standard cold dark matter model with star formation feedback strength normalized to match the observed star formation history of the universe at z= 0-6, we compute the metal-enrichment history of the intergalactic medium (IGM). Overall we show that galactic superwind (GSW) feedback from star formation can transport metals to the IGM and that the properties of simulated metal absorbers match current observations. The distance of influence of GSW from galaxies is typically limited to about ≤0.5 Mpc and within regions of overdensity δ ≥ 10. Most C IV and O VI absorbers are located within shocked regions of elevated temperature (T ≥ 2 x 10 4 K), overdensity (δ ≥ 10), and metallicity ([Z/Z sun ] = [ - 2.5, - 0.5]), enclosed by double shocks propagating outward. O VI absorbers have typically higher metallicity, lower density, and higher temperature than C IV absorbers. For O VI absorbers, collisional ionization dominates over the entire redshift range z= 0-6, whereas for C IV absorbers the transition occurs at moderate redshift z ∼ 3 from collisionally dominated to photoionization dominated. We find that the observed column density distributions for C IV and O VI in the range log N cm 2 =12-15 are reasonably reproduced by the simulations. The evolution of mass densities contained in C IV and O VI lines, Ω CIV and Ω OVI , is also in good agreement with observations, which shows a near constancy at low redshifts and an exponential drop beyond redshift z= 3-4. For both C IV and O VI, most absorbers are transient and the amount of metals probed by C IV and O VI lines of column log N cm 2 =12-15 is only ∼2% of total metal density at any epoch. While gravitational shocks from large-scale structure formation dominate the energy budget (80%-90%) for turning about 50% of the IGM to the warm-hot intergalactic medium (WHIM) by z = 0, GSW feedback shocks are energetically dominant over

Theoretical aspects of graphene-like group IV semiconductors

International Nuclear Information System (INIS)

Houssa, M.; Broek, B. van den; Scalise, E.; Ealet, B.; Pourtois, G.; Chiappe, D.; Cinquanta, E.; Grazianetti, C.; Fanciulli, M.; Molle, A.; Afanas’ev, V.V.; Stesmans, A.

2014-01-01

Silicene and germanene are the silicon and germanium counterparts of graphene, respectively. Recent experimental works have reported the growth of silicene on (1 1 1)Ag surfaces with different atomic configurations, depending on the growth temperature and surface coverage. We first theoretically study the structural and electronic properties of silicene on (1 1 1)Ag surfaces, focusing on the (4 × 4)silicene/Ag structure. Due to symmetry breaking in the silicene layer (nonequivalent number of top and bottom Si atoms), the corrugated silicene layer, with the Ag substrate removed, is predicted to be semiconducting, with a computed energy bandgap of about 0.3 eV. However, the hybridization between the Si 3p orbitals and the Ag 5s orbital in the silicene/(1 1 1)Ag slab model leads to an overall metallic system, with a distribution of local electronic density of states, which is related to the slightly disordered structure of the silicene layer on the (1 1 1)Ag surface. We next study the interaction of silicene and germanene with different hexagonal non-metallic substrates, namely ZnS and ZnSe. On reconstructed (0 0 0 1)ZnS or ZnSe surfaces, which should be more energetically stable for very thin layers, silicene and germanene are found to be semiconducting. Remarkably, the nature and magnitude of their energy bandgap can be controlled by an out-of-plane electric field, an important finding for the potential use of these materials in nanoelectronic devices.

Theoretical aspects of graphene-like group IV semiconductors

Energy Technology Data Exchange (ETDEWEB)

Houssa, M., E-mail: michel.houssa@fys.kuleuven.be [Department of Physics and Astronomy, University of Leuven, B-3001 Leuven (Belgium); Broek, B. van den; Scalise, E. [Department of Physics and Astronomy, University of Leuven, B-3001 Leuven (Belgium); Ealet, B. [Aix-Marseille University, CNRS-CINaM Laboratory, 13288 Marseille (France); Pourtois, G. [imec, Kapeldreef 75, B-3001 Leuven (Belgium); Plasmant Research Group, University of Antwerp, B-2610 Wilrijk-Antwerp (Belgium); Chiappe, D.; Cinquanta, E. [MDM Laboratory, IMM-CNR, I-20864 Agrate Brianza (Italy); Grazianetti, C.; Fanciulli, M. [MDM Laboratory, IMM-CNR, I-20864 Agrate Brianza (Italy); Universita degli Studi di Milano Bicocca, 20126 Milano (Italy); Molle, A. [MDM Laboratory, IMM-CNR, I-20864 Agrate Brianza (Italy); Afanas’ev, V.V.; Stesmans, A. [Department of Physics and Astronomy, University of Leuven, B-3001 Leuven (Belgium)

2014-02-01

Silicene and germanene are the silicon and germanium counterparts of graphene, respectively. Recent experimental works have reported the growth of silicene on (1 1 1)Ag surfaces with different atomic configurations, depending on the growth temperature and surface coverage. We first theoretically study the structural and electronic properties of silicene on (1 1 1)Ag surfaces, focusing on the (4 × 4)silicene/Ag structure. Due to symmetry breaking in the silicene layer (nonequivalent number of top and bottom Si atoms), the corrugated silicene layer, with the Ag substrate removed, is predicted to be semiconducting, with a computed energy bandgap of about 0.3 eV. However, the hybridization between the Si 3p orbitals and the Ag 5s orbital in the silicene/(1 1 1)Ag slab model leads to an overall metallic system, with a distribution of local electronic density of states, which is related to the slightly disordered structure of the silicene layer on the (1 1 1)Ag surface. We next study the interaction of silicene and germanene with different hexagonal non-metallic substrates, namely ZnS and ZnSe. On reconstructed (0 0 0 1)ZnS or ZnSe surfaces, which should be more energetically stable for very thin layers, silicene and germanene are found to be semiconducting. Remarkably, the nature and magnitude of their energy bandgap can be controlled by an out-of-plane electric field, an important finding for the potential use of these materials in nanoelectronic devices.

Synthesis and Characterization of Tin (IV Tungstate Nanoparticles – A Solid Acid Catalyst

Directory of Open Access Journals (Sweden)

Manoj Sadanandan

2012-12-01

Full Text Available Tin (IV tungstate, a tetravalent metal acid salt was synthesized in the nanoform by chemical coprecipitation method using EDTA as capping agent. The material was found to be stable in mineral acids, bases and organic solvents except  in HF and aquaregia. The material was characterized using EDS, TG/DTA, FTIR, XRD, SEM, HRTEM and BET surface area measurement. The molecular formula of the compound is 2SnO2 3WO3.5H2O determined from elemental analysis using TG/DTA. Surface morphology and particle size were obtained using SEM and HRTEM. The surface area was found to be 205-225m2/g. The Na+ exchange capacity found to be 3.8 meq/g, indicates the presence of surface hydroxyl group and hence the presence of Bronsted acid sites. The catalytic activity of the material was tested by using esterification and oxidation as model reactions. For the esterification of different alcohols, the percentage yield was found to be high for n-alcohol compared to isomeric alcohols. Oxidation of benzyl alcohol gives benzaldehyde and benzoic acid as the only products. Copyright © 2012 by BCREC UNDIP. All rights reservedReceived: 12nd June 2012, Revised: 23rd July 2012, Accepted: 29th July 2012[How to Cite: S. Manoj, R. Beena, (2012. Synthesis and Characterization of tin(IV Tungstate Nanoparticles – A Solid Acid Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (2: 105-111. doi:10.9767/bcrec.7.2.3622.105-111] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3622.105-111 ] | View in 

Gen IV Materials Handbook Implementation Plan

International Nuclear Information System (INIS)

Rittenhouse, P.; Ren, W.

2005-01-01

A Gen IV Materials Handbook is being developed to provide an authoritative single source of highly qualified structural materials information and materials properties data for use in design and analyses of all Generation IV Reactor Systems. The Handbook will be responsive to the needs expressed by all of the principal government, national laboratory, and private company stakeholders of Gen IV Reactor Systems. The Gen IV Materials Handbook Implementation Plan provided here addresses the purpose, rationale, attributes, and benefits of the Handbook and will detail its content, format, quality assurance, applicability, and access. Structural materials, both metallic and ceramic, for all Gen IV reactor types currently supported by the Department of Energy (DOE) will be included in the Gen IV Materials Handbook. However, initial emphasis will be on materials for the Very High Temperature Reactor (VHTR). Descriptive information (e.g., chemical composition and applicable technical specifications and codes) will be provided for each material along with an extensive presentation of mechanical and physical property data including consideration of temperature, irradiation, environment, etc. effects on properties. Access to the Gen IV Materials Handbook will be internet-based with appropriate levels of control. Information and data in the Handbook will be configured to allow search by material classes, specific materials, specific information or property class, specific property, data parameters, and individual data points identified with materials parameters, test conditions, and data source. Details on all of these as well as proposed applicability and consideration of data quality classes are provided in the Implementation Plan. Website development for the Handbook is divided into six phases including (1) detailed product analysis and specification, (2) simulation and design, (3) implementation and testing, (4) product release, (5) project/product evaluation, and (6) product

Crystal structure of ammonium octacyanomolybdate(IV) and rubidium octacyanomolybdate(IV)

Energy Technology Data Exchange (ETDEWEB)

Semenishin, D.I.; Glovyak, T.; Mys' kiv, M.G.

1985-11-01

The crystal structure of ammonium octacyanomolybdate(IV) and rubidium octacyanomolybdate(IV) has been determined by the single-crystal method on a Syntex P2/sub 1/ automatic diffractometer: ((NH/sub 4/)/sub 4/ Mo(CN)/sub 4/) 0.5H/sub 2/O (I) (space group Pma2, a = 15.550(3), b = 14.118(3), c = 7.438(1) A, Z = 4, R = 0.062) and Rb/sub 4/(Mo(CN)/sub 8/). 3H/sub 2/O (II) (space group P4/sub 1/2/sub 1/2, a = 9.300(10, c = 21.807(3) A, Z = 4, R = 0.065). The Mo atoms in structure I occupy two special positions (2(b) and 2(c)) and are each surrounded by eight CN ligands. The mean value of the Mo-C distances for Mo(1) is equal to 2.216 A, and the corresponding value for Mo(2) is 2.235 A. The mean Mo-N lengths are practically identical in both molybdenum anions and are equal to 3.353 A. The mean values of the C identical with N bond lengths in the Mo(1) and Mo(2) anions are 1.118 and 1.137 A, respectively. The MoCn angles vary from 175.0 to 178.4/sup 0/. The coordination sphere of the Mo(1) atom corresponds to a dodecahedron with a single twofold symmetry axis, and the coordination polyhedron of the Mo(2) atom in an antiprism of m symmetry. In structure II the Mo-C distances are within the 2.130-2.160-A range, and the Mo-N distances range from 3.290 to 3.307 A. The MoCN angles vary from 176.0 to 179.3/sup 0/, and the coordination polyhedron of (MoC/sub 8/) is a dodecahedron of 2 symmetry. The existence of two types of coordination of Mo in structure I is presently the only example among the structurally studied octahyanomolybdates(IV).

The attachment of metal-chelating groups to proteins: tagging of albumin by diazonium coupling and use of the products as radiopharmaceuticals

International Nuclear Information System (INIS)

Leung, C.S.H.; Meares, C.F.; Goodwin, D.A.

1978-01-01

The ability to attach firmly chelated metal ions or powerful chelating agents to sites on biological molecules can enhance the utility of a number of physical techniques now used in the study of biological systems. A 'bifunctional' chelating agent, containing both an EDTA group and a diazonium group, has been prepared and coupled to human serum albumin. The extent of labeling under various conditions and the amino-acid sidechains labeled have been investigated. The reaction of protein-bound chelating groups with added metal ions has been studied, with the finding that only about 40-50% of these groups are available to bind metal ions. Proteolysis of the products leads to recovery of full metal-binding capacity. Properties of the products in vivo are discussed. (author)

Highly Fluorescent Group 13 Metal Complexes with Cyclic, Aromatic Hydroxamic Acid Ligands

Energy Technology Data Exchange (ETDEWEB)

Seitz, Michael; Moore, Evan G.; Raymond, Kenneth N.

2008-02-11

The neutral complexes of two ligands based on the 1-oxo-2-hydroxy-isoquinoline (1,2-HOIQO) motif with group 13 metals (Al, Ga, In) show bright blue-violet luminescence in organic solvents. The corresponding transition can be attributed to ligand-centered singlet emission, characterized by a small Stokes shifts of only a few nm combined with lifetimes in the range between 1-3 ns. The fluorescence efficiency is high, with quantum yields of up to 37% in benzene solution. The crystal structure of one of the indium(III) complexes (trigonal space group R-3, a = b = 13.0384(15) {angstrom}, c = 32.870(8) {angstrom}, ? = {beta} = 90{sup o}, {gamma} = 120{sup o}, V = 4839.3(14) {angstrom}{sup 3}, Z = 6) shows a six-coordinate geometry around the indium center which is close to trigonal-prismatic, with a twist angle between the two trigonal faces of 20.7{sup o}. Time-dependent density functional theory (TD-DFT) calculations (Al and Ga: B3LYP/6-31G(d)); In: B3LYP/LANL2DZ of the fac and mer isomers with one of the two ligands indicate that there is no clear preference for either one of the isomeric forms of the metal complexes. In addition, the metal centers do not have a significant influence on the electronic structure, and as a consequence, on the predominant intraligand optical transitions.

To nearly come full circle: Nonoperative management of high-grade IV-V blunt splenic trauma is safe using a protocol with routine angioembolization.

Science.gov (United States)

Bhullar, Indermeet S; Tepas, Joseph J; Siragusa, Daniel; Loper, Todd; Kerwin, Andrew; Frykberg, Eric R

2017-04-01

Nonoperative management (NOM) of hemodynamically stable high-grade (IV-V) blunt splenic trauma remains controversial given the high failure rates (19%) that persist despite angioembolization (AE) protocols. The NOM protocol was modified in 2011 to include mandatory AE of all grade (IV-V) injuries without contrast blush (CB) along with selective AE of grade (I-V) with CB. The purpose of this study was to determine if this new AE (NAE) protocol significantly lowered the failure rates for grade (IV-V) injuries allowing for safe observation without surgery and if the exclusion of grade III injuries allowed for the prevention of unnecessary angiograms without affecting the overall failure rates. The records of patients with blunt splenic trauma from January 2000 to October 2014 at a Level I trauma center were retrospectively reviewed. Patients were divided into two groups and failure of NOM (FNOM) rates compared: NAE protocol (2011-2014) with mandatory AE for all grade (IV-V) injuries without CB and selective AE for grade (I-V) with CB versus old AE (OAE) protocol (2000-2010) with selective AE for grade (I-V) with CB. Seven hundred twelve patients underwent NOM with 522 (73%) in the OAE group and 190 (27%) in the NAE group. Evolving from the OAE to the NAE strategy resulted in a significantly lower FNOM rate for the overall group (grade I-V) (OAE vs. NAE, 4% to 1%, p = 0.04) and the grade (IV-V) group (OAE vs. NAE, 19% vs. 3%, p = 0.01). Angiograms were avoided in 113 grade (I-III) injuries with no CB; these patients had NOM with observation alone and none failed. A protocol using mandatory AE of all high-grade (IV-V) injuries without CB and selective AE of grade (I-V) with CB may provide for optimum salvage with safe NOM of the high-grade injuries (IV-V) and limited unnecessary angiograms. Therapeutic study, level IV.

Contribution to the study of mechanisms of oxidation of uranium (IV) in solution

International Nuclear Information System (INIS)

Michaille, Patrick

1977-01-01

In the first part, the author reports a bibliographical study which aims at briefly describing the main parameters which govern redox kinetics between metallic ions in solution: acidity, complexing reaction by anions, solvent effects. The author also highlights existing contradictions and shortcomings in the interpretation of experimental results as well as in current theories, and highlights characteristics proper to uranium (IV). The author then describes results obtained for kinetics of Ce(IV)-U(IV) systems: effects of acidity, of sulphate, search for other anionic and cationic catalysts, influence of fluoride, inhibition by DMSO). Some of these results (influence of fluoride and DMSO) are compared with those obtained with the Ce(IV)-Fe(II) system. A more detailed study of the solvent role has been performed for the U(IV)-Fe(III) system in a mixed water-ethylene glycol medium and in pure glycol. The next part addresses the modifications of flow stopped spectrophotometry to solve problems of corrosion and bad temperature regulation. The author presents analog (kinetics) and digital (complexing equilibrium) calculation methods, and the development of colour indicators of temperature [fr

Synthesis, characterization and analytical application of hybrid; Acrylamide zirconium (IV) arsenate a cation exchanger, effect of dielectric constant on distribution coefficient of metal ions

Energy Technology Data Exchange (ETDEWEB)

Nabi, Syed A. [Department of Chemistry, Aligarh Muslim University, Aligarh 202002, U.P. (India)], E-mail: sanabi@rediffmail.com; Shalla, Aabid H. [Department of Chemistry, Aligarh Muslim University, Aligarh 202002, U.P. (India)

2009-04-30

A new hybrid inorganic-organic cation exchanger acrylamide zirconium (IV) arsenate has been synthesized, characterized and its analytical application explored. The effect of experimental parameters such as mixing ratio of reagents, temperature, and pH on the properties of material has been studied. FTIR, TGA, X-ray, UV-vis spectrophotometry, SEM and elemental analysis were used to determine the physiochemical properties of this hybrid ion exchanger. The material behaves as a monofunctional acid with ion-exchange capacity of 1.65 meq/g for Na{sup +} ions. The chemical stability data reveals that the exchanger is quite stable in mineral acids, bases and fairly stable in organic solvents, while as thermal analysis shows that the material retain 84% of its ion-exchange capacity up to 600 deg. C. Adsorption behavior of metal ions in solvents with increasing dielectric constant has also been explored. The sorption studies reveal that the material is selective for Pb{sup 2+} ions. The analytical utility of the material has been explored by achieving some binary separations of metal ions on its column. Pb{sup 2+} has been selectively removed from synthetic mixtures containing Mg{sup 2+}, Ca{sup 2+}, Sr{sup 2+}, Zn{sup 2+} and Cu{sup 2+}, Al{sup 3+}, Ni{sup 2+}, Fe{sup 3+}. In order to demonstrate practical utility of the material quantitative separation of the Cu{sup 2+} and Zn{sup 2+} in brass sample has been achieved on its columns.

Resistance switch employing a simple metal nanogap junction

International Nuclear Information System (INIS)

Naitoh, Yasuhisa; Horikawa, Masayo; Abe, Hidekazu; Shimizu, Tetsuo

2006-01-01

In recent years, several researchers have reported the occurrence of reversible resistance switching effects in simple metal nanogap junctions. A large negative resistance is observed in the I-V characteristics of such a junction when high-bias voltages are applied. This phenomenon is characteristic behaviour on the nanometre scale; it only occurs for gap widths slightly under 13 nm. Furthermore, such a junction exhibits a non-volatile resistance hysteresis when the bias voltage is reduced very rapidly from a high level to around 0 V, and when the bias voltage is reduced slowly. This non-volatile resistance change occurs as a result of changes in the gap width between the metal electrodes, brought about by the applied bias voltage

New Materials for NGNP/Gen IV

International Nuclear Information System (INIS)

Swindeman, Robert W.; Marriott, Douglas L.

2009-01-01

The bounding conditions were briefly summarized for the Next Generation Nuclear Plant (NGNP) that is the leading candidate in the Department of Energy Generation IV reactor program. Metallic materials essential to the successful development and proof of concept for the NGNP were identified. The literature bearing on the materials technology for high-temperature gas-cooled reactors was reviewed with emphasis on the needs identified for the NGNP. Several materials were identified for a more thorough study of their databases and behavioral features relative to the requirements ASME Boiler and Pressure Vessel Code, Section III, Division 1, Subsection NH.

49 CFR 173.164 - Mercury (metallic and articles containing mercury).

Science.gov (United States)

2010-10-01

... ounces) of mercury per package; (iv) Tubes which are completely jacketed in sealed leakproof metal cases... 49 Transportation 2 2010-10-01 2010-10-01 false Mercury (metallic and articles containing mercury... Than Class 1 and Class 7 § 173.164 Mercury (metallic and articles containing mercury). (a) For...

Oxide nanostructures on a Nb surface and related systems: experiments and ab initio calculations

International Nuclear Information System (INIS)

Kuznetsov, Mikhail V; Razinkin, A S; Ivanovskii, Alexander L

2011-01-01

This review discusses the state of the art in two related research areas: the surfaces of niobium and of its related group IV-VI transition metals, and surface (primarily oxide) nanostructures that form on niobium (and group IV-VI d-metals) due to gas adsorption or impurity diffusion from the bulk. Experimental (X-ray photoelectron spectroscopy, photoelectron diffraction, scanning tunneling microscopy) and theoretical (ab initio simulation) results on d-metal surfaces are summarized and reviewed. (reviews of topical problems)

Platinum group metal nitrides and carbides: synthesis, properties and simulation

International Nuclear Information System (INIS)

Ivanovskii, Alexander L

2009-01-01

Experimental and theoretical data on new compounds, nitrides and carbides of the platinum group 4d and 5d metals (ruthenium, rhodium, palladium, osmium, iridium, platinum), published over the past five years are summarized. The extreme mechanical properties of platinoid nitrides and carbides, i.e., their high strength and low compressibility, are noted. The prospects of further studies and the scope of application of these compounds are discussed.

PEALD grown high-k ZrO{sub 2} thin films on SiC group IV compound semiconductor

Energy Technology Data Exchange (ETDEWEB)

Khairnar, A. G., E-mail: agkhairnar@gmail.com; Patil, V. S.; Agrawal, K. S.; Salunke, R. S.; Mahajan, A. M., E-mail: ammahajan@nmu.ac.in [North Maharashtra University, Department of Electronics, School of Physical Sciences (India)

2017-01-15

The study of ZrO{sub 2} thin films on SiC group IV compound semiconductor has been studied as a high mobility substrates. The ZrO{sub 2} thin films were deposited using the Plasma Enhanced Atomic Layer Deposition System. The thickness of the thin films were measured using ellipsometer and found to be 5.47 nm. The deposited ZrO{sub 2} thin films were post deposition annealed in rapid thermal annealing chamber at temperature of 400°Ð¡. The atomic force microscopy and X-гау photoelectron spectroscopy has been carried out to study the surface topography, roughness and chemical composition of thin film, respectively.

An innovative surgical technique for treating penile incarceration injury caused by heavy metallic ring

Directory of Open Access Journals (Sweden)

S J Baruah

2009-01-01

Full Text Available Penile incarceration injury by heavy metallic ring is a rare genital injury. A man may place metal object for erotic or autoerotic purposes, for masturbation or increasing erection, and due to psychiatric disturbances are some of the reasons for a penile incarceration injury. The incarcerating injury results in reduced blood flow distal to the injury, leading to edema, ischemia, and sometimes gangrene. These injuries are divided into five grades and their treatment options are divided into four groups. Surgical techniques are reserved for the advanced grades (Grades IV and V. We describe an innovative surgical technique, which can be adopted in Grades II and III injuries.

The Complexity of Mitochondrial Complex IV: An Update of Cytochrome c Oxidase Biogenesis in Plants

Science.gov (United States)

Mansilla, Natanael; Racca, Sofia; Gras, Diana E.; Gonzalez, Daniel H.

2018-01-01

Mitochondrial respiration is an energy producing process that involves the coordinated action of several protein complexes embedded in the inner membrane to finally produce ATP. Complex IV or Cytochrome c Oxidase (COX) is the last electron acceptor of the respiratory chain, involved in the reduction of O2 to H2O. COX is a multimeric complex formed by multiple structural subunits encoded in two different genomes, prosthetic groups (heme a and heme a3), and metallic centers (CuA and CuB). Tens of accessory proteins are required for mitochondrial RNA processing, synthesis and delivery of prosthetic groups and metallic centers, and for the final assembly of subunits to build a functional complex. In this review, we perform a comparative analysis of COX composition and biogenesis factors in yeast, mammals and plants. We also describe possible external and internal factors controlling the expression of structural proteins and assembly factors at the transcriptional and post-translational levels, and the effect of deficiencies in different steps of COX biogenesis to infer the role of COX in different aspects of plant development. We conclude that COX assembly in plants has conserved and specific features, probably due to the incorporation of a different set of subunits during evolution. PMID:29495437

Photoactivation of Diiodido-Pt(IV) Complexes Coupled to Upconverting Nanoparticles.

Science.gov (United States)

Perfahl, Stefanie; Natile, Marta M; Mohamad, Heba S; Helm, Christiane A; Schulzke, Carola; Natile, Giovanni; Bednarski, Patrick J

2016-07-05

The preparation, characterization, and surface modification of upconverting lanthanide-doped hexagonal NaGdF4 nanocrystals attached to light sensitive diiodido-Pt(IV) complexes is presented. The evaluation for photoactivation and cytotoxicity of the novel carboxylated diiodido-Pt(IV) cytotoxic prodrugs by near-infrared (NIR) light (λ = 980 nm) is also reported. We attempted two different strategies for attachment of light-sensitive diiodido-Pt(IV) complexes to Yb,Er- and Yb,Tm-doped β-NaGdF4 upconverting nanoparticles (UCNPs) in order to provide nanohybrids, which offer unique opportunities for selective drug activation within the tumor cells and subsequent spatiotemporal controlled drug release by NIR-to-visible light-upconversion: (A) covalent attachment of the Pt(IV) complex via amide bond formation and (B) carboxylate exchange of oleate on the surface of the UCNPs with diiodido-Pt(IV) carboxylato complexes. Initial feasibility studies showed that NIR applied by a 980 nm laser had only a slight effect on the stability of the various diiodido-Pt(IV) complexes, but when UCNPs were present more rapid loss of the ligand-metal-charge transfer (LMCT) bands of the diiodido-Pt(IV) complexes was observed. Furthermore, Pt released from the Pt(IV) complexes platinated calf-thymus DNA (ct-DNA) more rapidly when NIR was applied compared to dark controls. Of the two attachment strategies, method A with the covalently attached diiodido-Pt(IV) carboxylates via amide bond formation proved to be the most effective method for generating UCNPs that release Pt when irradiated with NIR; the released Pt was also able to bind irreversibly to calf thymus DNA. Nonetheless, only ca. 20% of the Pt on the surface of the UCNPs was in the Pt(IV) oxidation state, the rest was Pt(II), indicating chemical reduction of the diiodido-Pt(IV) prodrug by the UCNPs. Cytotoxicity studies with the various UCNP-Pt conjugates and constructs, tested on human leukemia HL60 cells in culture, indicated a

Plasma metabolism of apolipoprotein A-IV in humans

International Nuclear Information System (INIS)

Ghiselli, G.; Krishnan, S.; Beigel, Y.; Gotto, A.M. Jr.

1986-01-01

As assessed by molecular sieve chromatography and quantitation by a specific radioimmunoassay, apoA-IV is associated in plasma with the triglyceride-rich lipoproteins, to a high density lipoprotein (HDL) subfraction of smaller size than HDL3, and to the plasma lipoprotein-free fraction (LFF). In this study, the turnover of apoA-IV associated to the triglyceride-rich lipoproteins, HDL and LFF was investigated in vivo in normal volunteers. Human apoA-IV isolated from the thoracic duct lymph chylomicrons was radioiodinated and incubated with plasma withdrawn from normal volunteers after a fatty meal. Radioiodinated apoA-IV-labeled triglyceride-rich lipoproteins, HDL, and LFF were then isolated by chromatography on an AcA 34 column. Shortly after the injection of the radioiodinated apoA-IV-labeled triglyceride-rich lipoproteins, most of the radioactivity could be recovered in the HDL and LFF column fractions. On the other hand, when radioiodinated apoA-IV-labeled HDL or LFF were injected, the radioactivity remained with the originally injected fractions at all times. The residence time in plasma of 125 I-labeled apoA-IV, when injected in association with HDL or LFF, was 1.61 and 0.55 days, respectively. When 125 I-labeled apoA-IV was injected as a free protein, the radioactivity distributed rapidly among the three plasma pools in proportion to their mass. The overall fractional catabolic rate of apoA-IV in plasma was measured in the three normal subjects and averaged 1.56 pools per day. The mean degradation rate of apoA-IV was 8.69 mg/kg X day

A Survival Analysis of Patients with Malignant Biliary Strictures Treated by Percutaneous Metallic Stenting

International Nuclear Information System (INIS)

Brountzos, Elias N.; Ptochis, Nikolaos; Panagiotou, Irene; Malagari, Katerina; Tzavara, Chara; Kelekis, Dimitrios

2007-01-01

Background. Percutaneous metal stenting is an accepted palliative treatment for malignant biliary obstruction. Nevertheless, factors predicting survival are not known. Methods. Seventy-six patients with inoperable malignant biliary obstruction were treated with percutaneous placement of metallic stents. Twenty patients had non-hilar lesions. Fifty-six patients had hilar lesions classified as Bismuth type I (n = 15 patients), type II (n = 26), type III (n = 12), or type IV (n = 3 patients). Technical and clinical success rates, complications, and long-term outcome were recorded. Clinical success rates, patency, and survival rates were compared in patients treated with complete (n = 41) versus partial (n = 35) liver parenchyma drainage. Survival was calculated and analyzed for potential predictors such as the tumor type, the extent of the disease, the level of obstruction, and the post-intervention bilirubin levels. Results. Stenting was technically successful in all patients (unilateral drainage in 70 patients, bilateral drainage in 6 patients) with an overall significant reduction of the post-intervention bilirubin levels (p < 0.001), resulting in a clinical success rate of 97.3%. Clinical success rates were similar in patients treated with whole-liver drainage versus partial liver drainage. Minor and major complications occurred in 8% and 15% of patients, respectively. Mean overall primary stent patency was 120 days, while the restenosis rate was 12%. Mean overall secondary stent patency was 242.2 days. Patency rates were similar in patients with complete versus partial liver drainage. Mean overall survival was 142.3 days. Survival was similar in the complete and partial drainage groups. The post-intervention serum bilirubin level was an independent predictor of survival (p < 0.001). A cut-off point in post-stenting bilirubin levels of 4 mg/dl dichotomized patients with good versus poor prognosis. Patient age and Bismuth IV lesions were also independent predictors

Solventless acid-free synthesis of mesostructured titania: Nanovessels for metal complexes and metal nanoclusters

Energy Technology Data Exchange (ETDEWEB)

Dag, Oe.; Celik, Oe.; Ozin, G.A. [Department of Chemistry, Bilkent University, 06533 Ankara (Turkey); Soten, I.; Polarz, S.; Coombs, N. [Materials Chemistry Research Group, Chemistry Department, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 (Canada)

2003-01-01

A new and highly reproducible method to obtain mesostructured titania materials is introduced in this contribution. The mesostructured titania is obtained by employing self-assembled structures of non-ionic alkyl-poly(ethylene oxide) surfactants as templates. The materials are produced without additional solvents such as alcohols, or even water. Only the titanium(IV) ethoxide and the surfactant (C{sub 12}EO{sub 10}) are needed. Water, in the form of that attached to the surfactant and from the atmosphere, induces growth of titania nanoclusters in the synthesis sol. It is indicated that these nanoclusters interact with the surfactant EO-head groups to form a new titanotropic amphiphile. The new amphiphiles self-assemble into titanium nanocluster-surfactant hybrid lyotropic phases, which are transformed to the final mesostructured materials by further condensation of the titania network. The titania materials can be obtained also with noble-metal particles immobilized in the mesostructured framework. It is seen that when different metal salts are used as the metal precursors, different interactions with the titania walls are found. The materials are characterized by X-ray diffraction (XRD), polarization optical microscopy (POM), transmission electron microscopy (TEM), UV-vis spectroscopy, and micro-Raman analysis. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Mechanisms of current flow in metal-semiconductor ohmic contacts

International Nuclear Information System (INIS)

Blank, T. V.; Gol'dberg, Yu. A.

2007-01-01

Published data on the properties of metal-semiconductor ohmic contacts and mechanisms of current flow in these contacts (thermionic emission, field emission, thermal-field emission, and also current flow through metal shunts) are reviewed. Theoretical dependences of the resistance of an ohmic contact on temperature and the charge-carrier concentration in a semiconductor were compared with experimental data on ohmic contacts to II-VI semiconductors (ZnSe, ZnO), III-V semiconductors (GaN, AlN, InN, GaAs, GaP, InP), Group IV semiconductors (SiC, diamond), and alloys of these semiconductors. In ohmic contacts based on lightly doped semiconductors, the main mechanism of current flow is thermionic emission with the metal-semiconductor potential barrier height equal to 0.1-0.2 eV. In ohmic contacts based on heavily doped semiconductors, the current flow is effected owing to the field emission, while the metal-semiconductor potential barrier height is equal to 0.3-0.5 eV. In alloyed In contacts to GaP and GaN, a mechanism of current flow that is not characteristic of Schottky diodes (current flow through metal shunts formed by deposition of metal atoms onto dislocations or other imperfections in semiconductors) is observed

Synthesis, molecular structure and magnetic properties of a rhenium(IV) compound with catechol

Science.gov (United States)

Cuevas, A.; Geis, L.; Pintos, V.; Chiozzone, R.; Sanchíz, J.; Hummert, M.; Schumann, H.; Kremer, C.

2009-03-01

A novel Re(IV) complex containing catechol as ligand has been prepared and characterized. The crystal structure of (HNEt 3)(NBu 4)[ReCl 4(cat)]·H 2cat was determined. The rhenium ion presents a distorted octahedral geometry, being bonded to a bidentate catecholate group and four chloride anions. The magnetic properties of the complex were studied, a /2 D/ (the energy gap between ±3/2 and ±1/2 Kramers doublets) value of 190(10) cm -1. This is the largest /2 D/ value reported for Re(IV) up to now.

Assessment of Typical Heavy Metals in Human Hair of Different Age Groups and Foodstuffs in Beijing, China.

Science.gov (United States)

Liang, Gang; Pan, Ligang; Liu, Xinhui

2017-08-14

Human hair of different age groups and foodstuff samples were collected in Beijing, China. The concerned metals-Cd, Cr, Pb, As, and Hg-were analyzed, and the metal levels in relation to age, gender, and dietary intake were further assessed. Results showed the highest level of the metals was shown by Pb, with an average concentration of 1.557 ± 0.779 mg/kg, followed by Cr (0.782 ± 0.394), Hg (0.284 ± 0.094), As (0.127 ± 0.078), and Cd (0.071 ± 0.032), following a decreasing order of Pb > Cr > Hg > As > Cd, which were all below the upper limit of normal values in China. The heavy metal concentrations varied greatly among different age groups, and higher concentrations for Cd, Cr, Pb, and As appeared in female hair, whereas higher Hg concentration were found in male hair, suggesting that age and gender were not crucial factors for assessing metal concentrations in human hair. The ingestion of cereals and vegetables were the main route by which heavy metals in the environment create hazardous health effects for local inhabitants, but the estimated metal intakes through food consumption were all lower than the proposed limit of Provisional Tolerable Weekly Intake (PTWI), indicating that heavy metals posed no health risks for the inhabitants. Furthermore, little relationship was found between metal intakes and the corresponding metal levels in hair. Nevertheless, the results of this study can be used to analyze the internal heavy metal burden in the resident population of Beijing area and can also serve as reference for further studies.

Observation of spin-polarized electron transport in Alq3 by using a low work function metal

Science.gov (United States)

Jang, Hyuk-Jae; Pernstich, Kurt P.; Gundlach, David J.; Jurchescu, Oana D.; Richter, Curt. A.

2012-09-01

We present the observation of magnetoresistance in Co/Ca/Alq3/Ca/NiFe spin-valve devices. Thin Ca layers contacting 150 nm thick Alq3 enable the injection of spin-polarized electrons into Alq3 due to the engineering of the band alignment. The devices exhibit symmetric current-voltage (I-V) characteristics indicating identical metal contacts on Alq3, and up to 4% of positive magnetoresistance was observed at 4.5 K. In contrast, simultaneously fabricated Co/Alq3/NiFe devices displayed asymmetric I-V curves due to the different metal electrodes, and spin-valve effects were not observed.

WITNESSING GAS MIXING IN THE METAL DISTRIBUTION OF THE HICKSON COMPACT GROUP HCG 31

International Nuclear Information System (INIS)

Torres-Flores, S.; Alfaro-Cuello, M.; De Oliveira, C. Mendes; Amram, P.; Carrasco, E. R.; De Mello, D. F.

2015-01-01

We present for the first time direct evidence that in a merger of disk galaxies, the pre-existing central metallicities will mix as a result of gas being transported in the merger interface region along the line that joins the two coalescing nuclei. This is shown using detailed two-dimensional kinematics as well as metallicity measurements for the nearby ongoing merger in the center of the compact group HCG 31. We focus on the emission line gas, which is extensive in the system. The two coalescing cores display similar oxygen abundances. While in between the two nuclei, the metallicity changes smoothly from one nucleus to the other indicating a mix of metals in this region, which is confirmed by the high-resolution Hα kinematics (R = 45,900). This nearby system is especially important because it involves the merging of two fairly low-mass and clumpy galaxies (LMC-like galaxies), making it an important system for comparison with high-redshift galaxies

WITNESSING GAS MIXING IN THE METAL DISTRIBUTION OF THE HICKSON COMPACT GROUP HCG 31

Energy Technology Data Exchange (ETDEWEB)

Torres-Flores, S.; Alfaro-Cuello, M. [Departamento de Física, Universidad de La Serena, Av. Cisternas 1200, La Serena (Chile); De Oliveira, C. Mendes [Instituto de Astronomia, Geofísica e Ciências Atmosféricas da Universidade de São Paulo, Cidade Universitária, CEP:05508-900, São Paulo, SP (Brazil); Amram, P. [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388, Marseille (France); Carrasco, E. R. [Gemini Observatory/AURA, Southern Operations Center, Casilla 603, La Serena (Chile); De Mello, D. F., E-mail: storres@dfuls.cl [Catholic University of America, Washington, DC 20064 (United States)

2015-01-01

We present for the first time direct evidence that in a merger of disk galaxies, the pre-existing central metallicities will mix as a result of gas being transported in the merger interface region along the line that joins the two coalescing nuclei. This is shown using detailed two-dimensional kinematics as well as metallicity measurements for the nearby ongoing merger in the center of the compact group HCG 31. We focus on the emission line gas, which is extensive in the system. The two coalescing cores display similar oxygen abundances. While in between the two nuclei, the metallicity changes smoothly from one nucleus to the other indicating a mix of metals in this region, which is confirmed by the high-resolution Hα kinematics (R = 45,900). This nearby system is especially important because it involves the merging of two fairly low-mass and clumpy galaxies (LMC-like galaxies), making it an important system for comparison with high-redshift galaxies.

Investigation of neptunium(V) reduction to neptunium(IV) by semiconductor photocatalysis

International Nuclear Information System (INIS)

Takahashi, M.; Nakamura, T.; Ikeda, T.; Karasawa, H.

1990-01-01

Np(V) is the dominant Np oxidation state in high level liquid waste from reprocessing plants. Since low extractability of Np(V) makes its separation from other nuclei difficult, valence control is required. When a 1mM Np(V) solution of 3M nitric acid was irradiated by a Xe-lamp, using n-SiC (5g/dm 3 ) as photocatalyst and hydrazine (0.1M) as donor, 100% of the Np(V) was reduced to Np(IV) within 30 min at room temperature. Electrochemical investigations suggested that Np(V) is reduced by the atomic hydrogen adsorbed on the photocatalyst surface. According to this mechanism, platinum group metals can act as reducing catalysts for No(V) reduction due to their low hydrogen overvoltage. The proposed mechanism was experimentally confirmed using platinum black (5g/dm 3 ) as catalyst and hydroxylammonium nitrate (0.9M) as reducing agent

Synthesis and ion-exchange properties of cerium(IV) molybdate

Energy Technology Data Exchange (ETDEWEB)

Srivastava, S K; Singh, Raj Pal; Agrawal, Sushma; Kumar, Satish [Roorkee Univ. (India). Dept. of Chemistry

1977-01-01

The synthesis, ion exchange properties, and the separation of a number of cation pairs on the columns of cerium (IV) molybdate is discussed. In order to obtain the product in gel form showing a high exchange capacity and suitable for column operation, preliminary experiments were performed to determine the optimum conditions of precipitation, i.e., the concentration of ceric and molybdate solutions, mixing ratio, pH of precipitation and the order of mixing. Cerium (IV) molybdate, prepared under the optimum conditions of concentration, acidity etc., shows exchange capacity of 0.96 meg per g of exchanger. The sorption of a large number of metal ions has been investigated and the compound shows promising behaviour as cation exchanger. Numerous separations of analytical and radiochemical interest have been performed on the column of this exchanger with great efficiency.

Synthesis and ion-exchange properties of cerium(IV) molybdate

International Nuclear Information System (INIS)

Srivastava, S.K.; Raj Pal Singh; Sushma Agrawal; Satish Kumar

1977-01-01

The synthesis, ion exchange properties, and the separation of a number of cation pairs on the columns of cerium (IV) molybdate is discussed. In order to obtain the product in gel form showing a high exchange capacity and suitable for column operation, preliminary experiments were performed to determine the optimum conditions of precipitation, i.e., the concentration of ceric and molybdate solutions, mixing ratio, pH of precipitation and the order of mixing. Cerium (IV) molybdate, prepared under the optimum conditions of concentration, acidity etc., shows exchange capacity of 0.96 meg per g of exchanger. The sorption of a large number of metal ions has been investigated and the compound shows promising behaviour as cation exchanger. Numerous separations of analytical and radiochemical interest have been performed on the column of this exchanger with great efficiency. (T.G.)

Scanning probe lithography for fabrication of Ti metal nanodot arrays

International Nuclear Information System (INIS)

Jung, B.; Jo, W.; Gwon, M.J.; Lee, E.; Kim, D.-W.

2010-01-01

We report fabrication of Ti metal nanodot arrays by scanning probe microscopic indentation. A thin poly-methylmethacrylate (PMMA) layer was spin-coated on Si substrates with thickness of 70 nm. Nanometer-size pore arrays were formed by indenting the PMMA layer using a cantilever of a scanning probe microscope. Protuberances with irregular boundaries appeared during the indentation process. Control of approach and pulling-out speed during indentation was able to dispose of the protrusions. Ti metal films were deposited on the patterned PMMA layers by a radio-frequency sputtering method and subsequently lifted off to obtain metal nanodot arrays. The fabricated metal nanodot arrays have 200 nm of diameter and 500 nm of interdistance, which corresponds to a density of 4x10 8 /cm 2 . Scanning probe-based measurement of current-voltage (I-V) behaviors for a single Ti metal nanodot showed asymmetric characteristics. Applying external bias is likely to induce oxidation of Ti metal, since the conductance decreased and volume change of the dots was observed. I-V behaviors of Ti metal nanodots by conventional e-beam lithography were also characterized for comparison.

Validation of Nuclear Criticality Safety Software and 27 energy group ENDF/B-IV cross sections

International Nuclear Information System (INIS)

Lee, B.L. Jr.

1994-08-01

The validation documented in this report is based on calculations that were executed during June through August 1992, and was completed in June 1993. The statistical analyses in Appendix C and Appendix D were completed in October 1993. This validation gives Portsmouth NCS personnel a basis for performing computerized KENO V.a calculations using the Martin Marietta Nuclear Criticality Safety Software. The first portion of the document outlines basic information in regard to validation of NCSS using ENDF/B-IV 27-group cross sections on the IBM 3090 at ORNL. A basic discussion of the NCSS system is provided, some discussion on the validation database and validation in general. Then follows a detailed description of the statistical analysis which was applied. The results of this validation indicate that the NCSS software may be used with confidence for criticality calculations at the Portsmouth Gaseous Diffusion Plant. When the validation results are treated as a single group, there is 95% confidence that 99.9% of future calculations of similar critical systems will have a calculated K eff > 0.9616. Based on this result the Portsmouth Nuclear Criticality Safety Department has adopted the calculational acceptance criteria that a k eff + 2σ ≤ 0.95 is safety subcritical. The validation of NCSS on the IBM 3090 at ORNL was extended to include NCSS on the IBM 3090 at K-25

Safety assessment for Generation IV nuclear systems

International Nuclear Information System (INIS)

Leahy, T.J.

2012-01-01

The Generation IV International Forum (GIF) Risk and Safety Working Group (RSWG) was created to develop an effective approach for the safety of Generation IV advanced nuclear energy systems. Recent RSWG work has focused on the definition of an integrated safety assessment methodology (ISAM) for evaluating the safety of Generation IV systems. ISAM is an integrated 'tool-kit' consisting of 5 analytical techniques that are available and matched to appropriate stages of Generation IV system concept development: 1) qualitative safety features review - QSR, 2) phenomena identification and ranking table - PIRT, 3) objective provision tree - OPT, 4) deterministic and phenomenological analyses - DPA, and 5) probabilistic safety analysis - PSA. The integrated methodology is intended to yield safety-related insights that help actively drive the evolving design throughout the technology development cycle, potentially resulting in enhanced safety, reduced costs, and shortened development time

Site Environmental Report for Calendar Year 2013. DOE Operations at The Boeing Company, Santa Susana Field Laboratory, Area IV

Energy Technology Data Exchange (ETDEWEB)

None

2014-06-30

This Annual Site Environmental Report (ASER) for 2013 describes the environmental conditions related to work performed for the Department of Energy (DOE) at Area IV of the Santa Susana Field Laboratory (SSFL). The Energy Technology Engineering Center (ETEC), a government-owned, company-operated test facility, was located in Area IV. The operations in Area IV included development, fabrication, operation and disassembly of nuclear reactors, reactor fuel, and other radioactive materials. Other activities in the area involved the operation of large-scale liquid metal facilities that were used for testing non-nuclear liquid metal fast breeder reactor components. All nuclear work was terminated in 1988, and all subsequent radiological work has been directed toward environmental restoration and decontamination and decommissioning (D&D) of the former nuclear facilities and their associated sites. Liquid metal research and development ended in 2002. Since May 2007, the D&D operations in Area IV have been suspended by the DOE, but the environmental monitoring and characterization programs have continued. Results of the radiological monitoring program for the calendar year 2013 continue to indicate that there are no significant releases of radioactive material from Area IV of SSFL. All potential exposure pathways are sampled and/or monitored, including air, soil, surface water, groundwater, direct radiation, transfer of property (land, structures, waste), and recycling. Due to the suspension of D&D activities in Area IV, no effluents were released into the atmosphere during 2013. Therefore, the potential radiation dose to the general public through airborne release was zero. Similarly, the radiation dose to an offsite member of the public (maximally exposed individual) due to direct radiation from SSFL is indistinguishable from background. All radioactive wastes are processed for disposal at DOE disposal sites and/or other licensed sites approved by DOE for radioactive waste

The affinity plutonium(IV) for nitrogen donor ligands

International Nuclear Information System (INIS)

Jarvis, N.V.; Hancock, R.D.

1994-01-01

Established ligand design principles are used to predict the solution chemistry of Pu(IV) with nitrogen donor ligands which do not contain carboxylate donors. pK a 's of the nitrogen donors are lowered by addition of hydroxyalkyl groups causing Pu(IV) to have a greater affinity for these ligands than for hydroxide. Potentiometric studies using the ligands N,N,N'N',N''-pentakis(2-hydroxypropyl)-1,4,7-triazaheptane; N,N,N',N',N''-pentakis(2-hydroxyethyl)-1,4,7-triazaheptane; N,N,N',N',N'-tetrakis(2-hydroxyethyl)-1,2-diaminoethane; N,N,N',N'-tetrakis(2-hydroxyethyl)-trans-1,2-diaminocyclohexane; 1,4,8,11-tetrakis(2-hydroxyethyl)-1,4,8,11-tetraazacyclotetradecane and N,N-bis(2-hydroxyethyl)glycine with Pu(IV) showed that Pu(IV) has a considerable aqueous solution chemistry with these ligands. Data were processed by the ESTA library of programs and stability constants for all the systems are reported. Implications for selective ligand design for Pu(IV) are discussed. (orig.)

Uranium metalla-allenes with carbene imido R{sub 2}C=U{sup IV}=NR' units (R=Ph{sub 2}PNSiMe{sub 3}; R'=CPh{sub 3}): alkali-metal-mediated push-pull effects with an amido auxiliary

Energy Technology Data Exchange (ETDEWEB)

Lu, Erli; Tuna, Floriana; Kaltsoyannis, Nikolas; Liddle, Stephen T. [School of Chemistry, The University of Manchester (United Kingdom); Lewis, William [School of Chemistry, The University of Nottingham (United Kingdom)

2016-08-08

We report uranium(IV)-carbene-imido-amide metalla-allene complexes [U(BIPM{sup TMS})(NCPh{sub 3})(NHCPh{sub 3})(M)] (BIPM{sup TMS}=C(PPh{sub 2}NSiMe{sub 3}){sub 2}; M=Li or K) that can be described as R{sub 2}C=U=NR' push-pull metalla-allene units, as organometallic counterparts of the well-known push-pull organic allenes. The solid-state structures reveal that the R{sub 2}C=U=NR' units adopt highly unusual cis-arrangements, which are also reproduced by gas-phase theoretical studies conducted without the alkali metals to remove their potential structure-directing roles. Computational studies confirm the double-bond nature of the U=NR' and U=CR{sub 2} interactions, the latter increasingly attenuated by potassium then lithium when compared to the hypothetical alkali-metal-free anion. Combined experimental and theoretical data show that the push-pull effect induced by the alkali metal cations and amide auxiliary gives a fundamental and tunable structural influence over the C=U{sup IV}=N units. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Lowered serum dipeptidyl peptidase IV activity in patients with anorexia and bulimia nervosa.

Science.gov (United States)

van West, D; Monteleone, P; Di Lieto, A; De Meester, I; Durinx, C; Scharpe, S; Lin, A; Maj, M; Maes, M

2000-01-01

The aim of this study was to examine whether anorexia nervosa and bulimia nervosa are accompanied by lower serum activity of dipeptidyl peptidase IV (DPP IV, EC 3.4.14.5), a membrane-bound serine protease that catalyses the cleavage of dipeptides from the amino-terminus of oligo- and polypeptides. Substrates of DPP IV are, amongst others, neuroactive eptides, such as substance P, growth hormone releasing hormone, neuropeptide Y, and peptide YY. DPP IV activity was measured in the serum of 21 women with anorexia nervosa, 21 women with bulimia nervosa and 18 normal women. Serum DPP IV activity was significantly lower in patients with anorexia nervosa and bulimia nervosa than in the normal controls. In the total study group, there were significant and inverse relationships between serum DPP IV activity and the total scores on the Bulimic Investigatory Test, Edinburgh, the Eating Disorder Inventory (EDI) and the Hamilton Depression Rating Scale. In the total study group no significant correlations between DPP IV and age, body weight or body mass index could be found. It is concluded that lowered serum DPP IV activity takes part in the pathophysiology of anorexia and bulimia nervosa. It is hypothesised that a combined dysregulation of DPP IV and neuroactive peptides, which are substrates of DPP IV, e.g. neuropeptide Y and peptide YY, could be an integral component of eating disorders.

Isotopic exchange rate of sodium ions between hydrous metal oxides and aqueous solutions

International Nuclear Information System (INIS)

Inoue, Yasushi; Yamazaki, Hiromichi

1991-01-01

To elucidate the kinetics of ion-exchange reaction on hydrous metal oxide, the isotopic exchange rates of sodium ions between hydrous metal oxides such as hydrous tin (IV), niobium (V), zirconium (IV) and titanium (IV) oxides, and aqueous solutions were measured radiochemically and compared with each other. The rate of reaction cannot be understood by an unified view since the rate controlling step differs with the kind of exchangers. The rate constants relevant to each exchanger such as diffusion constants and their activation energies were also determined. (author)

Effect of functionalization of boron nitride flakes by main group metal clusters on their optoelectronic properties

Science.gov (United States)

Chakraborty, Debdutta; Chattaraj, Pratim Kumar

2017-10-01

The possibility of functionalizing boron nitride flakes (BNFs) with some selected main group metal clusters, viz. OLi4, NLi5, CLi6, BLI7 and Al12Be, has been analyzed with the aid of density functional theory (DFT) based computations. Thermochemical as well as energetic considerations suggest that all the metal clusters interact with the BNF moiety in a favorable fashion. As a result of functionalization, the static (first) hyperpolarizability (β ) values of the metal cluster supported BNF moieties increase quite significantly as compared to that in the case of pristine BNF. Time dependent DFT analysis reveals that the metal clusters can lower the transition energies associated with the dominant electronic transitions quite significantly thereby enabling the metal cluster supported BNF moieties to exhibit significant non-linear optical activity. Moreover, the studied systems demonstrate broad band absorption capability spanning the UV-visible as well as infra-red domains. Energy decomposition analysis reveals that the electrostatic interactions principally stabilize the metal cluster supported BNF moieties.

A Si IV/O IV Electron Density Diagnostic for the Analysis of IRIS Solar Spectra

Science.gov (United States)

Young, P. R.; Keenan, F. P.; Milligan, R. O.; Peter, H.

2018-04-01

Solar spectra of ultraviolet bursts and flare ribbons from the Interface Region Imaging Spectrograph (IRIS) have suggested high electron densities of > {10}12 cm‑3 at transition region temperatures of 0.1 MK, based on large intensity ratios of Si IV λ1402.77 to O IV λ1401.16. In this work, a rare observation of the weak O IV λ1343.51 line is reported from an X-class flare that peaked at 21:41 UT on 2014 October 24. This line is used to develop a theoretical prediction of the Si IV λ1402.77 to O IV λ1401.16 ratio as a function of density that is recommended to be used in the high-density regime. The method makes use of new pressure-dependent ionization fractions that take account of the suppression of dielectronic recombination at high densities. It is applied to two sequences of flare kernel observations from the October 24 flare. The first shows densities that vary between 3× {10}12 and 3× {10}13 cm‑3 over a seven-minute period, while the second location shows stable density values of around 2× {10}12 cm‑3 over a three-minute period.

Congenital bilateral neuroblastoma (stage IV-S): case report

International Nuclear Information System (INIS)

Lee, Jeong Hee; Lee, Hee Jung; Woo, Seong Ku; Lee, Sang Rak; Kim, Heung Sik

2002-01-01

Congenital neonatal neuroblastoma is not uncommon but bilateral adrenal neuroblastoma is rare, accounting for about ten percent of neuroblastomas in children. We report the US the MR findings of a stage IV-S congenital bilateral neuroblastoma occurring in a one-day-old neonate

Synthesis and characterization of tin(IV) antimonate and study of its ion-exchange equilibria

International Nuclear Information System (INIS)

Burham, N.; Abdel-Halim, S.H.; El-Shahat, M.F.

1995-01-01

Tin(IV) antimonate with different Sb/Sn molar ratios has been prepared. The characterization of the product materials was carried out using X-ray diffraction pattern, thermal analysis and infrared spectra. The saturation capacities of sodium and cesium were found to increase with Sb/Sn molar ratios. The K d values on thermal treatment of tin(IV) antimonate, as a cation exchanger, have been measured for some heavy metal ions in the temperature range of 50-400 deg C. The maximum adsorption of 10 -4 M of the metal ions studied was obtained at 400 deg C. The selectivity sequence was Eu 3+ > Co 2+ > Sr 2+ > Cs + for the sample heated up to 400 deg C. No adsorption was observed on the sample heated at 700 deg C because of the formation of SnO 2 and Sb 6 O 13 . (author) 9 refs.; 7 figs.; 5 tabs

Supramolecular assembly of group 11 phosphorescent metal complexes for chemosensors of alcohol derivatives

Science.gov (United States)

Lintang, H. O.; Ghazalli, N. F.; Yuliati, L.

2018-04-01

We report on systematic study on vapochromic sensing of ethanol by using phosphorescent trinuclear metal pyrazolate complexes with supramolecular assembly of weak intermolecular metal-metal interactions using 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligand (1) and group 11 metal ions (Cu(I), Ag(I), Au(I)). Upon excitation at 284, the resulting complexes showed emission bands with a peak centered at 616, 473 and 612 nm for 2(Cu), 2(Ag) and 2(Au), respectively. Chemosensor 2(Cu) showed positive response to ethanol vapors in 5 mins by blue-shifting its emission band from 616 to 555 nm and emitting bright orange to green. Otherwise 2(Au) gave shifting from its emission band centered at 612 to 587 nm with Δλ of 25 nm (41%) and color changes from red-orange to light green-orange while 2(Ag) showed quenching in its original emission intensity at 473 nm in 40% with color changes from dark green to less emissive. These results demonstrate that sensing capability of chemosensor 2(Cu) with suitable molecular design of ligand and metal ion in the complex is due to the formation of a weak intermolecular hydrogen bonding interaction of O atom at the methoxy of the benzyl ring with the OH of the vapors at the outside of the molecules.

Infrared multiple photon dissociation spectroscopy of group I and group II metal complexes with Boc-hydroxylamine.

Science.gov (United States)

Dain, Ryan P; Gresham, Gary; Groenewold, Gary S; Steill, Jeffrey D; Oomens, Jos; Van Stipdonk, Michael J

2013-08-30

Hydroxamates are essential growth factors for some microbes, acting primarily as siderophores that solubilize iron for transport into a cell. Here we determined the intrinsic structure of 1:1 complexes between Boc-protected hydroxylamine and group I ([M(L)](+)) and group II ([M(L-H)](+)) cations, where M and L are the cation and ligand, respectively, which are convenient models for the functional unit of hydroxamate siderphores. The relevant complex ions were generated by electrospray ionization (ESI) and isolated and stored in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. Infrared spectra of the isolated complexes were collected by monitoring (infrared) photodissociation yield as a function of photon energy. Experimental spectra were then compared to those predicted by density functional theory (DFT) calculations. The infrared multiple photon dissociation (IRMPD) spectra collected are in good agreement with those predicted to be lowest-energy by DFT. The spectra for the group I complexes contain six resolved absorptions that can be attributed to amide I and II type and hydroxylamine N-OH vibrations. Similar absorptions are observed for the group II cation complexes, with shifts of the amide I and amide II vibrations due to the change in structure with deprotonation of the hydroxylamine group. IRMPD spectroscopy unequivocally shows that the intrinsic binding mode for the group I cations involves the O atoms of the amide carbonyl and hydroxylamine groups of Boc-hydroxylamine. A similar binding mode is preferred for the group II cations, except that in this case the metal ion is coordinated by the O atom of the deprotonated hydroxylamine group. Copyright © 2013 John Wiley & Sons, Ltd.

A combined XAFS, ESI TOF-MS and LIBD study on the formation of polynuclear Zr(IV), Th(IV) and Pu(IV) species

Science.gov (United States)

Rothe, J.; Walther, C.; Brendebach, B.; Büchner, S.; Fuss, M.; Denecke, M. A.; Geckeis, H.

2009-11-01

The long term radiotoxicity of spent nuclear fuel disposed of in deep underground repositories after discharge from nuclear power reactors is determined by actinide elements, mainly plutonium. Water intrusion into the repository might cause container corrosion and leaching of the waste matrices, leading to the release of Pu and other actinides into the geological environment. Performance assessment for a future nuclear waste repository requires detailed knowledge on actinide aqueous chemistry in the aquifer surrounding the disposal site. Tetravalent actinides exhibit a strong tendency towards hydrolysis and subsequent polymerization and/or colloid formation. These species provide a potential pathway for migration of actinides away from the repository. Therefore, it is of fundamental interest to study their generation and properties in-situ. To this end, X-ray Absorption Fine Structure Spectroscopy (XAFS) at the INE-Beamline for actinide research at ANKA, Electrospray Mass-Spectrometry (ESI TOF-MS) and Laser Induced Breakdown Detection (LIBD) are combined at FZK-INE in a comprehensive attempt to characterize Zr(IV) (An(IV) analogue), Th(IV) and Pu(IV) polymerization and colloid formation.

Properties of cemented carbides alloyed by metal melt treatment

International Nuclear Information System (INIS)

Lisovsky, A.F.

2001-01-01

The paper presents the results of investigations into the influence of alloying elements introduced by metal melt treatment (MMT-process) on properties of WC-Co and WC-Ni cemented carbides. Transition metals of the IV - VIll groups (Ti, Zr, Ta, Cr, Re, Ni) and silicon were used as alloying elements. It is shown that the MMT-process allows cemented carbides to be produced whose physico-mechanical properties (bending strength, fracture toughness, total deformation, total work of deformation and fatigue fracture toughness) are superior to those of cemented carbides produced following a traditional powder metallurgy (PM) process. The main mechanism and peculiarities of the influence of alloying elements added by the MMT-process on properties of cemented carbides have been first established. The effect of alloying elements on structure and substructure of phases has been analyzed. (author)

Electron momentum spectroscopy of the group I and Il metal and oxides

International Nuclear Information System (INIS)

Ford, M.J.; Dorsett, H.E.; Sashin, V.A.; Bolorizadeh, M.A.; Mikajlo, E.A.; Soule de Bas, B.; Nixon, K.L.; Coleman, V.A.

2002-01-01

Full text: The group I and Il metals and oxides are relatively simple condensed phase systems that are easily accessible to theoretical studies. For this reason they have been the subject of a number of studies using a range of theoretical techniques. Calculated electronic band structures have traditionally been compared with optical, X-ray and photo emissions measurements. While these techniques provide excellent data for testing theoretical predictions they generally probe certain aspects of the electronic structure, such as special point energies or densities of states, or require considerable theoretical input for their interpretation. In this paper we present our electron momentum spectroscopy (EMS) measurements for the lighter group Il metals and oxides and group I oxides. EMS can measure directly the full band dispersions and intensities and provides a sensitive test of theoretical predictions. We compare our measurements with Hartree-Fock (HF) and density functional theory (DFT) calculations carried out within the linear combination of atomic orbitals approximation. As expected HF significantly overestimates the bandwidths and bandgaps. DFT gives reasonable overall agreement, albeit with slight overestimation of bandwidths for the oxides. The intensity distribution for the oxides show a systematic difference from all the calculations which cannot easily be explained by experimental effects such as multiple scattering in the target. This work was funded by the Australian Research Council and Flinders University. EA Mikajlo and K L Nixon acknowledge receipt of SENRAC and Ferry scholarships respectively

Sulphonated metal phthalocyanine complexes as redox indicators in micro titrations with cerium(IV) sulphate

Energy Technology Data Exchange (ETDEWEB)

Gowda, H S; Achar, B N [Mysore Univ. (India). Dept. of Chemistry

1980-01-01

Tetrasodium salts of copper(II) 4,4', 4'', 4'''-tetrasulphophthalocyanine 2-hydrate, nickel(II) 4,4', 4'', 4'''-tetrasulphophthalocyanine, nickel(II) 3,3', 3'', 3'''-tetrasulphophthalocyanine and cobalt(II) 4,4', 4'', 4'''-tetrasulphophthalocyanine 2-hydrate, and copper phthalocyanine trisulphonic acid are prepared in pure state. The molar absorptivity and formal redox potentials of the complexes are determined. The complexes are proposed as sensitive redox indicators in the micro determination of iron(II), arsenic(III), molybdenum(V), uranium(IV) and hydroquinone with 0.001-0.0005N cerium(IV) sulphate in sulphuric, hydrochloric and acetic acid media. They give sharp colour change from light turquoise blue to pale purple colour at the equivalence point. They have advantages over a few existing redox indicators.

Phosphorescent heterobimetallic complexes involving platinum(iv) and rhenium(vii) centers connected by an unsupported μ-oxido bridge.

Science.gov (United States)

Molaee, Hajar; Nabavizadeh, S Masoud; Jamshidi, Mahboubeh; Vilsmeier, Max; Pfitzner, Arno; Samandar Sangari, Mozhgan

2017-11-28

Heterobimetallic compounds [(C^N)LMe 2 Pt(μ-O)ReO 3 ] (C^N = ppy, L = PPh 3 , 2a; C^N = ppy, L = PMePh 2 , 2b; C^N = bhq, L = PPh 3 , 2c; C^N = bhq, L = PMePh 2 , 2d) containing a discrete unsupported Pt(iv)-O-Re(vii) bridge have been synthesized through a targeted synthesis route. The compounds have been prepared by a single-pot synthesis in which the Pt(iv) precursor [PtMe 2 I(C^N)L] complexes are allowed to react easily with AgReO 4 in which the iodide ligand of the starting Pt(iv) complex is replaced by an ReO 4 - anion. In these Pt-O-Re complexes, the Pt(iv) centers have an octahedral geometry, completed by a cyclometalated bidentate ligand (C^N), two methyl groups and a phosphine ligand, while the Re(vii) centers have a tetrahedral geometry. Elemental analysis, single crystal X-ray diffraction analysis and multinuclear NMR spectroscopy are used to establish their identities. The new complexes exhibit phosphorescence emission in the solid and solution states at 298 and 77 K, which is an uncommon property of platinum complexes with an oxidation state of +4. According to DFT calculations, we found that this emission behavior in the new complexes originates from ligand centered 3 LC (C^N) character with a slight amount of metal to ligand charge transfer ( 3 MLCT). The solid-state emission data of the corresponding cycloplatinated(iv) precursor complexes [PtMe 2 I(C^N)L], 1a-1d, pointed out that the replacement of I - by an ReO 4 - anion helps enhancing the emission efficiency besides shifting the emission wavelengths.

Chemical decontamination of metals

International Nuclear Information System (INIS)

Partridge, J.A.; Lerch, R.E.

1979-10-01

A metal decontamination process based upon removal of contamination by treatment with a cerium (IV)-nitric acid solution (or other redox agent in nitric acid) is feasible and highly promising. The technique is effective in dissolving the surface layer of stainless steel. Dissolution rates of approximately 1.5 mils/h were demonstrated with cerium (IV)-nitric acid solutions. Removal of plutonium contamination from stainless steel was demonstrated in laboratory tests, in which activity levels were reduced from greater than 5 x 10 5 counts per minute to nondetectable levels in approximately one hour at 90 0 C. Removal of paint from stainless steel surfaces was also demonstrated. Advantages of this process over other chemical solutions include: (1) The solutions are not high salt systems; therefore, there is potentially less waste generated. (2) Cerium(IV) in nitric acid is a good dissolution agent for plutonium oxide. (3) Regeneration of Ce(IV) during the decontamination is accomplished by electrolysis. (4) The process should be effective for irregularly shaped equipment. (5) It could be effective as a spray or a flow-through system. 13 figures

Estudio por GXRD de la formación de fases en metales de los grupos IV y V por implantación iónica de nitrógeno

Directory of Open Access Journals (Sweden)

García, J. A.

2004-04-01

Full Text Available High doses of nitrogen ion implantation introduce important modifications in the composition and microstructure of the most outer surface of the treated materials. Owing to this modifications, treated materials increase dramatically hardness and wear resistance. In this paper the changes in hardness and in the tribological properties of the groups IV and V are summarized. Special emphasis is given to the relationships between these improvements and the results obtained from GXRD analysis. Moreover GXRD results are showing the role of nitrogen in the improvements of hardness and the tribological properties.

La implantación iónica de altas dosis de nitrógeno produce cambios significativos en la composición y estructura de las capas más externas de los materiales tratados. Estos cambios se reflejan en la modificación de las propiedades mecánicas superficiales, pudiendo conseguirse aumentos importantes de dureza y resistencia al desgaste. En el presente trabajo se presenta un resumen de los cambios en las propiedades mecánicas superficiales producidos por la implantación iónica de nitrógeno en los distintos metales de los grupos IV (Ti, Zr, Hf y V (V, Nb, Ta, intentándose relacionar dichos cambios con las distintas fases formadas estudiadas mediante técnicas de difracción de rayos X con ángulo rasante (GXRD. La caracterización por GXRD pone de manifiesto el papel del nitrógeno como responsable de los cambios en la microdureza y de las propiedades tribológicas observadas.

Kinetic study of group IV nanoparticles ion beam synthesized in SiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Bonafos, C. E-mail: bonafos@cemes.fr; Colombeau, B.; Altibelli, A.; Carrada, M.; Ben Assayag, G.; Garrido, B.; Lopez, M.; Perez-Rodriguez, A.; Morante, J.R.; Claverie, A

2001-05-01

Most studies concerning group IV (Si, Ge) ion beam synthesized nanocrystals in SiO{sub 2} have shown that a link exists between the observed physical properties and the characteristics of the 'populations' of nanoparticles (size-distribution, density, volume fraction). The aim of this paper is to study the influence of the initial supersaturation and annealing conditions on these characteristics. For this, experimental methods have been developed, that allow accurate statistical studies. Different transmission electron microscopy (TEM) imaging conditions have been tested and the most adequate ones have been identified for each system. An original method for the measurement of the density of precipitates embedded in an amorphous matrix has been developed and tested for Ge precipitates in SiO{sub 2} and has permitted to evidence a conservative Ostwald ripening during annealing. The kinetic behavior of Si nanoparticles has also been studied by coupling TEM measurements and 'atomistic' simulations. During annealing, the growth of these nanoparticles is very slow but their size significantly increases when increasing the initial Si excess. Simulations are in perfect agreement with experiment when taking into account interaction effects between particles.

Decontamination of stainless steel using cerium(IV): Material recycle and reuse

International Nuclear Information System (INIS)

Kurath, D.E.; Bray, L.A.; Jarrett, J.H.

1997-01-01

It has been demonstrated that the Cerium(IV) process can effectively remove radioactive contamination from stainless steel. Ce(IV) is a powerful oxidizing agent that is applied in an inorganic acid solution or as an atomized spray by injection into steam directed at the contaminated surface. Ce(IV) attacks the oxide layer and underlying metal surface to remove a 0.5-μm to 3-μm layer. This process has been implemented in a number of actual operations. In one application, a Ce(IV) steam decontamination process was instrumental in renovating hot cells at the High-Level Radiochemistry Facility (325-A building) at the Hanford site. The initial dose rate of approximately 100,000 mR/h was reduced to <50 mR/h and allowed manned entry during hot cell renovation activities. These valuable facilities have been returned to full operation. In an application at the West Valley Nuclear Services Co., Inc., the surfaces of stainless steel canisters that had been filled with vitrified high-level waste have been decontaminated. In some cases the free release levels for surface contamination have been achieved. In another application, five plutonium contaminated stainless steel vessels were decontaminated during decommissioning of the Critical Mass Facility at Hanford

KENO-IV code benchmark calculation, (6)

International Nuclear Information System (INIS)

Nomura, Yasushi; Naito, Yoshitaka; Yamakawa, Yasuhiro.

1980-11-01

A series of benchmark tests has been undertaken in JAERI in order to examine the capability of JAERI's criticality safety evaluation system consisting of the Monte Carlo calculation code KENO-IV and the newly developed multigroup constants library MGCL. The present report describes the results of a benchmark test using criticality experiments about Plutonium fuel in various shape. In all, 33 cases of experiments have been calculated for Pu(NO 3 ) 4 aqueous solution, Pu metal or PuO 2 -polystyrene compact in various shape (sphere, cylinder, rectangular parallelepiped). The effective multiplication factors calculated for the 33 cases distribute widely between 0.955 and 1.045 due to wide range of system variables. (author)

Synthesis and magnetic Properties of dinuclear oxovanadium(IV) complexes bridged by tetracarboxylato groups

International Nuclear Information System (INIS)

Li, Y.-T.; Guan, H.-S.; Yan, C.-W.

2004-01-01

Three novel μ-tetracarboxylato-bridged oxovanadium(IV) complexes described by the overall formula [(VO) 2 (PMTA)L 2 ] where PMTA stands for the tetraanion of pyromellitic acid, and L denotes 2,2'-bipyridine(bpy), 4,4'-dimethyl-2,2'-bipyridine (Me 2 bpy) or 1,10-phenanthroline (phen), respectively, have been synthesized and characterized by elemental analyses, molar conductivity and room-temperature magnetic moment measurements, IR, ESR, and electronic spectral studies. It is proposed that these complexes have PMTA-bridged structures and consist of two oxovanadium(IV) ions, each in the square-pyramidal environment. The [(VO) 2 (PMTA)(bpy) 2 ] (1) and [(VO) 2 (PMTA)(phen) 2 ] (2) complexes were further characterized by variable temperature (4.2 - 300 K) magnetic susceptibility measurements and the observed data were fitted to the modified Bleaney-Bowers equation by the least-squares, giving the exchange integral J = -2.75 cm -1 for (1) and J -3.91 cm -1 for (2). This results indicates that there is a weak antiferromagnetic spin-exchange interaction between the two VO 2+ ions within each molecule. (author)

Coordination Nature of 4-Mercaptoaniline to Sn(II Ion: Formation of a One Dimensional Coordination Polymer and Its Decomposition to a Mono Nuclear Sn(IV Complex

Directory of Open Access Journals (Sweden)

Eon S. Burkett

2014-12-01

Full Text Available The coordination of the bifunctional ligand 4-mercaptoaniline with aqueo us tin(II metal ion was studied. A coordination polymer was synthesized when an aqueous solution of SnCl2 was treated with 4-MA. The crystalline material is stable under atmospheric conditions retaining its oxidation state. However, when submerged in a solution saturated with oxygen, the compound oxidizes to a mononuclear tin(IV complex. Both the compounds were characterized by single crystal X-ray diffraction studies. Although the structure of the tin(IV complex was previously reported, crystal structure of this compound was redetermined.

Pyrazolates advance cerium chemistry: a CeIII/CeIV redox equilibrium with benzoquinone.

Science.gov (United States)

Werner, Daniel; Deacon, Glen B; Junk, Peter C; Anwander, Reiner

2017-05-16

Two stable cerium(iv) 3,5-dialkylpyrazolate complexes are presented, namely dimeric [Ce(Me 2 pz) 4 ] 2 (Me 2 pz = 3,5-dimethylpyrazolate) and monomeric Ce(tBu 2 pz) 4 (tBu 2 pz = 3,5-di-tert-butylpyrazolate) along with their trivalent counterparts [Ce(Me 2 pz) 3 ] and [Ce(tBu 2 pz) 3 ] 2 . All complexes were obtained from protonolysis reactions employing the silylamide precursors Ce[N(SiHMe 2 ) 2 ] 4 and Ce[N(SiMe 3 ) 2 ] 3 . Treatment of homoleptic Ce IV and Ce III Me 2 pz complexes with 1,4-hydroquinone (H 2 hq) or 1,4-benzoquinone (bq), respectively, ultimately gave the same trimetallic Ce III species via a cerium redox equilibrium. The Ce III complex Ce 3 (Me 2 pz) 5 (pchd) 2 (L) (pchd = 1,4-bis(3,5-dimethylpyrazol-1-yl)cyclohex-2,5-diene-1,4-diolato; L = Me 2 pzH or (thf) 2 ) results from a di-1,4-pyrazolyl attack on pre-coordinated bq. The reduction of bq by [Ce(Me 2 pz) 3 (thf)] 2 , and re-oxidation by the resulting Ce IV species was supported by UV-vis spectroscopic investigations. Comparisons with the redox-innocent complexes [Ln(Me 2 pz) 3 (thf)] 2 (Ln = La and Pr) revealed far less selective reactions with bq, giving hexametallic and octametallic rare-earth metal side products containing 2-Me 2 pz substituted hq ligands.

Catalyst for the use in the hydrotreatment of a heavy hydrocarbon oil, process to its preparation and process to its use

Energy Technology Data Exchange (ETDEWEB)

Shiroto, Y; Higashi, T; Ono, T

1981-10-01

A catalyst with an improved surface activity and a maintained selectivity is used in the decomposition of asphaltenes and the removal of heavy metals from a heavy hydrocarbon oil by hydrotreatment. The catalyst carrier consists of a calcined combination of a mixture from a clay mineral with double chain structure and at least one oxide-forming substance with a metal from the groups II A, III A, IV A or IV B of the periodic system. The catalytic metal component is selected from the groups V B, VI B, VIII or I B of the periodic system.

IVS: Current Status and Future Plans

Science.gov (United States)

Behrend, D.; Nothnagel, A.; Petrachenko, W. T.; Tuccari, G.

2016-12-01

The International VLBI Service for Geodesy and Astrometry (IVS) is a globally operating service that coordinates and performs Very Long Baseline Interferometry (VLBI) activities through its constituent components. The VLBI activities are associated with the creation, provision, dissemination, and archiving of relevant VLBI data and products. The products mostly pertain to the determination of the celestial and terrestrial reference frames, the Earth orientation parameters (EOP), atmospheric parameters as well as other ancillary parameters. The IVS observational network currently consists of about 40 radio telescopes worldwide. Subsets of these telescopes (8-12 stations) participate in 24-hour observing sessions that are run several times per week and in 1-hour intensive sessions for UT1 determination every day. The current VLBI network was developed mainly in the 1970s and 1980s. A number of factors, including aging infrastructure and demanding new scientific requirements, started to challenge its future sustainability and relevance. In response, the IVS and other groups developed and started implementing the next generation VLBI system, called VGOS (VLBI Global Observing System), at existing and new sites. The VGOS network is expected to reach maturity in the early 2020s. We describe the current status, progress, and anticipated prospects of geodetic/astrometric VLBI and the IVS.

Activation of the CXCR3 chemokine receptor through anchoring of a small molecule chelator ligand between TM-III, -IV, and -VI

DEFF Research Database (Denmark)

Rosenkilde, Mette M; Andersen, Michael B; Nygaard, Rie

2006-01-01

modeling and molecular simulations combined with mutational analysis indicated that the metal ion site-anchored chelators act as agonists by establishing an aromatic-aromatic, second-site interaction with TyrVI:16 on the inner face of TM-VI. It is noteworthy that this interaction required......Seven transmembrane segment (7TM) receptors are activated through a common, still rather unclear molecular mechanism by a variety of chemical messengers ranging from monoamines to large proteins. By introducing a His residue at position III:05 in the CXCR3 receptor a metal ion site was built...... between the extracellular ends of transmembrane (TM) III and TM-IV to anchor aromatic chelators at a location corresponding to the presumed binding pocket for adrenergic receptor agonists. In this construct, free metal ions had no agonistic effect in accordance with the optimal geometry of the metal ion...

Liquid liquid extraction of Th(IV) and its complexation study by Calix(4)pyrole

International Nuclear Information System (INIS)

Rathod, N.V.; Kamble, J.H.; Malkhede, D.D.

2015-01-01

Due to increased demand for carbon-free energy, accelerated growth of nuclear power is foreseen in several countries, especially in China and India. This has made the sustainable use of fuel resources such as uranium and thorium very important. Today, uranium is the main-stay of the present generation of nuclear power plants. However, the anticipated growth in nuclear energy may require introducing thorium as a fuel in future. Meso-octamethyl calix(4)pyrole is known for anion receptor however the present study evaluate the effect of cation for complexation of thorium by liquid liquid extraction technique. Calix(4)pyrole was evaluated for extraction of Th(IV), and 97% extraction efficiency was obtained. Th(IV) was determine with arsenazo(III) at 655 nm. The effect of acid molarity of 0.1 M, 1:5 metal to ligand ratio found efficient for maximum extraction. The stoichiometry ratio 1:2 between metal to ligand is established

Expanding the Therapeutic Potential of the Iron Chelator Deferasirox in the Development of Aqueous Stable Ti(IV) Anticancer Complexes.

Science.gov (United States)

Loza-Rosas, Sergio A; Vázquez-Salgado, Alexandra M; Rivero, Kennett I; Negrón, Lenny J; Delgado, Yamixa; Benjamín-Rivera, Josué A; Vázquez-Maldonado, Angel L; Parks, Timothy B; Munet-Colón, Charlene; Tinoco, Arthur D

2017-07-17

The recent X-ray structure of titanium(IV)-bound human serum transferrin (STf) exhibiting citrate as a synergistic anion reveals a difference in Ti(IV) coordination versus iron(III), the metal endogenously delivered by the protein to cells. This finding enriches our bioinspired drug design strategy for Ti(IV)-based anticancer therapeutics, which applies a family of Fe(III) chelators termed chemical transferrin mimetic (cTfm) ligands to inhibit Fe bioavailability in cancer cells. Deferasirox, a drug used for iron overload disease, is a cTfm ligand that models STf coordination to Fe(III), favoring Fe(III) binding versus Ti(IV). This metal affinity preference drives deferasirox to facilitate the release of cytotoxic Ti(IV) intracellularly in exchange for Fe(III). An aqueous speciation study performed by potentiometric titration from pH 4 to 8 with micromolar levels of Ti(IV) deferasirox at a 1:2 ratio reveals exclusively Ti(deferasirox) 2 in solution. The predominant complex at pH 7.4, [Ti(deferasirox) 2 ] 2- , exhibits the one of the highest aqueous stabilities observed for a potent cytotoxic Ti(IV) species, demonstrating little dissociation even after 1 month in cell culture media. UV-vis and 1 H NMR studies show that the stability is unaffected by the presence of biomolecular Ti(IV) binders such as citrate, STf, and albumin, which have been shown to induce dissociation or regulate cellular uptake and can alter the activity of other antiproliferative Ti(IV) complexes. Kinetic studies on [Ti(deferasirox) 2 ] 2- transmetalation with Fe(III) show that a labile Fe(III) source is required to induce this process. The initial step of this process occurs on the time scale of minutes, and equilibrium for the complete transmetalation is reached on a time scale of hours to a day. This work reveals a mechanism to deliver Ti(IV) compounds into cells and trigger Ti(IV) release by a labile Fe(III) species. Cellular studies including other cTfm ligands confirm the Fe(III) depletion

Separation of Acetylene from Carbon Dioxide and Ethylene by a Water-Stable Microporous Metal-Organic Framework with Aligned Imidazolium Groups inside the Channels.

Science.gov (United States)

Lee, Jaechul; Chuah, Chong Yang; Kim, Jaheon; Kim, Youngsuk; Ko, Nakeun; Seo, Younggyu; Kim, Kimoon; Bae, Tae Hyun; Lee, Eunsung

2018-04-24

Separation of acetylene from carbon dioxide and ethylene is challenging in view of their similar sizes and physical properties. Metal-organic frameworks (MOFs) in general are strong candidates for these separations owing to the presence of functional pore surfaces that can selectively capture a specific target molecule. Here, we report a novel 3D microporous cationic framework named JCM-1. This structure possesses imidazolium functional groups on the pore surfaces and pyrazolate as a metal binding group, which is well known to form strong metal-to-ligand bonds. The selective sorption of acetylene over carbon dioxide and ethylene in JCM-1 was successfully demonstrated by equilibrium gas adsorption analysis as well as dynamic breakthrough measurement. Furthermore, its excellent hydrolytic stability makes the separation processes highly recyclable without a substantial loss in acetylene uptake capacity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Generation of ENDF/B-IV based 35 group neutron cross-section library and its application in criticality studies

International Nuclear Information System (INIS)

Garg, S.B.; Sinha, A.

1985-01-01

A 35 group cross-section library with P/sub 3/-anisotropic scattering matrices and resonance self-shielding factors has been generated from the basic ENDF/B-IV cross-section files for 57 elements. This library covers the neutron energy range from 0.005 ev to 15 MeV and is well suited for the neutronics and safety analysis of fission, fusion and hybrid systems. The library is contained in two well known files, namely, ISOTXS and BRKOXS. In order to test the efficacy of this library and to bring out the importance of resonance self-shielding, a few selected fast critical assemblies representing large dilute oxide and carbide fueled uranium and plutonium based systems have been analysed. These assemblies include ZPPR/sub 2/, ZPR-3-48, ZPR-3-53, ZPR-6-6A, ZPR-6-7, ZPR-9-31 and ZEBRA-2 and are amongst those recommended by the US Nuclear Data Evaluation Working Group for testing the accuracy of cross-sections. The evaluated multiplication constants of these assemblies compare favourably with those calculated by others

Ion beam synthesis and characterization of metastable group-IV alloy semiconductors

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Naoto; Hasegawa, Masataka; Hayashi, Nobuyuki; Makita, Yunosuke; Shibata, Hajime [Electrotechnical Lab., Tsukuba, Ibaraki (Japan); Katsumata, Hiroshi; Uekusa, Shin-ichiro

1997-03-01

New Group-IV metastable alloy semiconductors and their heterostructures based on combinations of C-Si-Ge-Sn are recently attracting interest because of feasible new electronic and optoelectronic application in Si-technology and here research works on synthesis and characterization of the epitaxial heterostructures of Si-C, Si-Sn on Si fabricated by ion implantation together either with ion-beam-induced epitaxial crystallization (IBIEC) or solid phase epitaxial growth (SPEG) have been investigated. Formations of layers of Si{sub 1-y}C{sub y} (y=0.014 at peak concentration) on Si(100) have been performed by high-dose implantation of 17 keV C ions and successive IBIEC with 400 keV Ar or Ge ion bombardments at 300-400degC or SPEG up to 750degC. Crystalline growth by IBIEC has shown a lower growth rate in Si{sub 1-y}C{sub y}/Si than in intrinsic Si due mainly to the strain existence, which was observed by the X-ray diffraction (XRD) measurements. Photoluminescence(PL) measurements have revealed I{sub 1} or G line emissions that are relevant to small vacancy clusters or C pair formation, respectively. The crystalline growth of Si{sub 1-z}Sn{sub z} layers by 110 keV {sup 120}Sn ion implantation (z=0.029 and z=0.058 at peak concentration) into Si(100) followed either by IBIEC or by SPEG has been also investigated. PL emission from both IBIEC-grown and SPEG-grown samples with the lower Sn concentration has shown similar peaks to those by ion-implanted and annealed Si samples with intense I{sub 1} or I{sub 1}-related (Ar) peaks. Present results suggest that IBIEC has a feature for the non-thermal equilibrium fabrication of Si-C and Si-Sn alloy semiconductors. (J.P.N.)

Electrochemical behavior of Th(IV) and its electrodeposition from ThF_4-LiCl-KCl melt

International Nuclear Information System (INIS)

Wang, Xianbin; Huang, Wei; Gong, Yu; Jiang, Feng; Zheng, Haiyang; Zhu, Tiejian; Long, Dewu; Li, Qingnuan

2016-01-01

The electrochemical behavior of Th(IV) ion on molybdenum (Mo) electrode was studied by cyclic voltammetry (CV) and square wave voltammetry (SWV) technologies at 773 K in ThF_4-LiCl-KCl melt. The reduction of Th(IV) to metal Th at −1.67 V (vs. Ag/AgCl) is a four-electron exchange process, which is quasi-reversible and diffusion-controlled. The diffusion coefficient (D) and activation energy of diffusion process for Th(IV) were determined to be 3.77 × 10"−"5 cm"2 s"−"1 and 59.2 kJ mol"−"1. The pulse potential electrolysis of ThF_4-LiCl-KCl melt revealed that 86.8% of Th(IV) can be separated from the melt based on the inductively coupled plasma atomic emission spectrometer (ICP-AES) results.

The generation IV nuclear reactor systems - Energy of future

International Nuclear Information System (INIS)

Ohai, Dumitru; Jianu, Adrian

2006-01-01

Ten nations joined within the Generation IV International Forum (GIF), agreeing on a framework for international cooperation in research. Their goal is to develop future-generation nuclear energy systems that can be licensed, constructed, and operated in an economically competitive way while addressing the issues of safety, proliferation, and other public perception concerns. The objective is for the Gen IV systems to be available for deployment by 2030. Using more than 100 nuclear experts from its 10 member nations, the GIF has developed a Gen IV Technology Roadmap to guide the research and development of the world's most advanced, efficient and safe nuclear power systems. The Gen IV Technology Roadmap calls for extensive research and development of six different potential future reactor systems. These include water-cooled, gas-cooled, liquid metal-cooled and nonclassical systems. One or more of these reactor systems will provide the best combination of safety, reliability, efficiency and proliferation resistance at a competitive cost. The main goals for the Gen IV Nuclear Energy Systems are: - Provide sustainable energy generation that meets clean air objectives and promotes long-term availability of systems and effective fuel use for worldwide energy production; - Minimize and manage their nuclear waste and noticeably reduce the long-term stewardship burden in the future, improving the protection of public health and the environment; - Increase the assurance that these reactors are very unattractive and the least desirable route for diversion or theft of weapons-usable materials, and provide increased protection against acts of terrorism; - Have a clear life-cycle cost advantage over other energy sources; - Have a level of financial risk comparable to other energy projects; - Excel in safety and reliability; - Have a low likelihood and degree of reactor core damage. (authors)

U(IV) fluorescence spectroscopy. A new speciation tool

Energy Technology Data Exchange (ETDEWEB)

Lehmann, Susanne; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Steudtner, Robin [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

2017-06-01

We combined absorption and fluorescence spectroscopy to study the speciation of U(IV) in solution in concentrations down to 10{sup -6} M uranium. With our time-resolved laser-induced fluorescence setup we could determine the fluorescence decay time of U(IV) in perchloric as well as in chloric acid with 2.6 ± 0.3 ns at room temperature and 148.4 ± 6.5 ns at liquid nitrogen temperature. For the U(IV) sulfate system, we observed a bathochromic shift and a peak shape modification in the fluorescence spectra with increasing sulfate concentration in solution. Thus, the potential of U(IV) fluorescence for speciation analysis could be proven.

Group B Strep Infection

Science.gov (United States)

... IV) to kill the germs. If you take antibiotics while you’re in labor, the chances are very good that your baby won’t get this infection. What if my baby has group B strep? If your baby gets group B strep, he or she will be treated with IV antibiotics to kill the bacteria. Your baby will stay ...

Test Review: Advanced Clinical Solutions for WAIS-IV and WMS-IV

Science.gov (United States)

Chu, Yiting; Lai, Mark H. C.; Xu, Yining; Zhou, Yuanyuan

2012-01-01

The authors review the "Advanced Clinical Solutions for WAIS-IV and WMS-IV". The "Advanced Clinical Solutions (ACS) for the Wechsler Adult Intelligence Scale-Fourth Edition" (WAIS-IV; Wechsler, 2008) and the "Wechsler Memory Scale-Fourth Edition" (WMS-IV; Wechsler, 2009) was published by Pearson in 2009. It is a…

Recycling of platinum group metals from the automotive catalysts; Reciclagem de metais do grupo da platina proveniente de catalisadores automotivos

Energy Technology Data Exchange (ETDEWEB)

Benevit, Mariana; Petter, Patricia Melo Halmenschlager; Veit, Hugo Marcelo, E-mail: patymhp@yahoo.com.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Faculdade de Engenharia. Departamento de Materiais

2014-07-01

Currently it is very important to use alternative sources of raw material for obtaining metals, avoiding the traditional mining. This work aims to characterize and evaluate the recoverability of platinum group metals present in automotive catalysts. Thus, the catalysts were divided into two groups: the first was catalysts used in 1.0 cars and the second was catalyst used in 2.0 cars. DRX and FRX techniques and chemical analysis performed by ICP/OES was used to characterized these materials. The results showed that there is a significant amount of platinum group elements in catalyst waste, which can be separated and reused. In the next step, hydro and pyrometallurgical routes, for metals extraction from catalyst waste, will be studied. (author)

Indirect complexometric determination of thorium(IV) using sodium fluoride as masking agent

International Nuclear Information System (INIS)

Sreekumar, N.V.; Nazareth, R.A.; Narayana, B.; Hegde, P.; Manjunatha, B.R.

2002-01-01

A complexometric method for the determination of thorium(IV) in presence of other metal ions based on the selective masking ability of sodium fluoride towards thorium is described. Thorium(IV) present in a given sample solution is first complexed with a known excess of EDTA and the surplus EDTA is titrated against bismuth nitrate solution at pH 2-3 using xylenol orange as indicator. A known excess of sodium fluoride (5 %) is then added and the EDTA released from the Th-EDTA complex is titrated against standard bismuth nitrate solution. Reproducible and accurate results are obtained for 5 mg to 280 mg of thorium with relative errors ±0.65 % and standard deviations /leq 0.75 mg. The interference of various ions was studied. (author)

Non-equilibrium ionization by a periodic electron beam. II. Synthetic Si IV and O IV transition region spectra

Science.gov (United States)

Dzifčáková, Elena; Dudík, Jaroslav

2018-03-01

Context. Transition region (TR) spectra typically show the Si IV 1402.8 Å line to be enhanced by a factor of 5 or more compared to the neighboring O IV 1401.2 Å, contrary to predictions of ionization equilibrium models and the Maxwellian distribution of particle energies. Non-equilibrium effects in TR spectra are therefore expected. Aims: To investigate the combination of non-equilibrium ionization and high-energy particles, we apply the model of the periodic electron beam, represented by a κ-distribution that recurs at periods of several seconds, to plasma at chromospheric temperatures of 104 K. This simple model can approximate a burst of energy release involving accelerated particles. Methods: Instantaneous time-dependent charge states of silicon and oxygen were calculated and used to synthesize the instantaneous and period-averaged spectra of Si IV and O IV. Results: The electron beam drives the plasma out of equilibrium. At electron densities of Ne = 1010 cm-3, the plasma is out of ionization equilibrium at all times in all cases we considered, while for a higher density of Ne = 1011 cm-3, ionization equilibrium can be reached toward the end of each period, depending on the conditions. In turn, the character of the period-averaged synthetic spectra also depends on the properties of the beam. While the case of κ = 2 results in spectra with strong or even dominant O IV, higher values of κ can approximate a range of observed TR spectra. Spectra similar to typically observed spectra, with the Si IV 1402.8 Å line about a factor 5 higher than O IV 1401.2 Å, are obtained for κ = 3. An even higher value of κ = 5 results in spectra that are exclusively dominated by Si IV, with negligible O IV emission. This is a possible interpretation of the TR spectra of UV (Ellerman) bursts, although an interpretation that requires a density that is 1-3 orders of magnitude lower than for equilibrium estimates. Movies associated to Fig. A.1 are available at http://https://www.aanda.org

Half-sandwich pentamethylcyclopentadienyl group 9 metal ...

Indian Academy of Sciences (India)

453 and LS-174) revealed low anti-proliferative activity. Replacement of substituted pyridine ligand in complexes such as picolinic acid exhibits better DNA binding affinity and cytotoxicity.7–10. Till now, a few reports are available for metal com-.

Preparation and Characterization of Styrene Bearing Diethanolamine Side Group, Styrene Copolymer Systems, and Their Metal Complexes

Directory of Open Access Journals (Sweden)

Aslışah Açıkses

2018-01-01

Full Text Available The two copolymer systems of styrene bearing diethanol amine side group and styrene were prepared by free radical polymerization method at 60°C in presence of 1,4-dioxane as solvent and AIBN as initiator. Their metal complexes were prepared by reaction of the copolymer used as ligand P(DEAMSt-co-StL′′ and Ni(II and Co(II metal ions, which was carried out in presence of ethanol and NaOH at 65°C for 48 h in pH = 7.5. The structures of the copolymers used as ligand and metal complexes were identified by FT-IR, 1H-NMR spectra, and elemental analysis. The properties of the copolymers used as ligand and metal complexes were characterized by SEM-EDX, AAS, DSC, TGA, and DTA techniques. Then, the electrical properties of the copolymers and metal complexes were examined as a function of the temperature and frequency, and the activation energies (Ea were estimated with conductivity measurements.

Kohn Anomaly and Phase Stability in Group VB Transition Metals

Directory of Open Access Journals (Sweden)

Alexander Landa

2018-03-01

Full Text Available In the periodic table, only a few pure metals exhibit lattice or magnetic instabilities associated with Fermi surface nesting, the classical examples being α-U and Cr. Whereas α-U displays a strong Kohn anomaly in the phonon spectrum that ultimately leads to the formation of charge density waves (CDWs, Cr is known for its nesting-induced spin density waves (SDWs. Recently, it has become clear that a pronounced Kohn anomaly and the corresponding softening in the elastic constants is also the key factor that controls structural transformations and mechanical properties in compressed group VB metals—materials with relatively high superconducting critical temperatures. This article reviews the current understanding of the structural and mechanical behavior of these metals under pressure with an introduction to the concept of the Kohn anomaly and how it is related to the important concept of Peierls instability. We review both experimental and theoretical results showing different manifestations of the Kohn anomaly in the transverse acoustic phonon mode TA (ξ00 in V, Nb, and Ta. Specifically, in V the anomaly triggers a structural transition to a rhombohedral phase, whereas in Nb and Ta it leads to an anomalous reduction in yield strength.

Cost analysis of surgically treated pressure sores stage III and IV.

Science.gov (United States)

Filius, A; Damen, T H C; Schuijer-Maaskant, K P; Polinder, S; Hovius, S E R; Walbeehm, E T

2013-11-01

Health-care costs associated with pressure sores are significant and their financial burden is likely to increase even further. The aim of this study was to analyse the direct medical costs of hospital care for surgical treatment of pressure sores stage III and IV. We performed a retrospective chart study of patients who were surgically treated for stage III and IV pressure sores between 2007 and 2010. Volumes of health-care use were obtained for all patients and direct medical costs were subsequently calculated. In addition, we evaluated the effect of location and number of pressure sores on total costs. A total of 52 cases were identified. Average direct medical costs in hospital were €20,957 for the surgical treatment of pressure sores stage III or IV; average direct medical costs for patients with one pressure sore on an extremity (group 1, n = 5) were €30,286, €10,113 for patients with one pressure sore on the trunk (group 2, n = 32) and €40,882 for patients with multiple pressure sores (group 3, n = 15). The additional costs for patients in group 1 and group 3 compared to group 2 were primarily due to longer hospitalisation. The average direct medical costs for surgical treatment of pressure sores stage III and IV were high. Large differences in costs were related to the location and number of pressure sores. Insight into the distribution of these costs allows identification of high-risk patients and enables the development of specific cost-reducing measures. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Decontamination of alpha contaminated metallic waste by cerium IV redox process

International Nuclear Information System (INIS)

Shah, J.G.; Dhami, P.S.; Gandhi, P.M.; Wattal, P.K.

2012-01-01

Decontamination of alpha contaminated metallic waste is an important aspect in the management of waste generated during dismantling and decommissioning of nuclear facilities. Present work on cerium redox process targets decontamination of alpha contaminated metallic waste till it qualifies for the non alpha waste category for disposal in near surface disposal facility. Recovery of the alpha radio nuclides and cerium from aqueous secondary waste streams was also studied deploying solvent extraction process and established. The alpha-lean secondary waste stream has been immobilised in cement based matrix for final disposal. (author)

Oxochloroalkoxide of the Cerium (IV and Titanium (IV as oxides precursor

Directory of Open Access Journals (Sweden)

Machado Luiz Carlos

2002-01-01

Full Text Available The Cerium (IV and Titanium (IV oxides mixture (CeO2-3TiO2 was prepared by thermal treatment of the oxochloroisopropoxide of Cerium (IV and Titanium (IV. The chemical route utilizing the Cerium (III chloride alcoholic complex and Titanium (IV isopropoxide is presented. The compound Ce5Ti15Cl16O30 (iOPr4(OH-Et15 was characterized by elemental analysis, FTIR and TG/DTG. The X-ray diffraction patterns of the oxides resulting from the thermal decomposition of the precursor at 1000 degreesC for 36 h indicated the formation of cubic cerianite (a = 5.417Å and tetragonal rutile (a = 4.592Å and (c = 2.962 Å, with apparent crystallite sizes around 38 and 55nm, respectively.

Chemoselective Hydrogenation with Supported Organoplatinum(IV) Catalyst on Zn(II)-Modified Silica

Energy Technology Data Exchange (ETDEWEB)

Camacho-Bunquin, Jeffrey [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, Illinois 60439, United States; Ferrandon, Magali [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, Illinois 60439, United States; Sohn, Hyuntae [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, Illinois 60439, United States; Yang, Dali [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, Illinois 60439, United States; Liu, Cong [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, Illinois 60439, United States; Ignacio-de Leon, Patricia Anne [Energy Sciences Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, Illinois 60439, United States; Perras, Frédéric A. [Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50010, United States; Pruski, Marek [Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50010, United States; Department of Chemistry, Iowa State University, 2416 Pammel Drive, Ames, Iowa 50011, United States; Stair, Peter C. [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, Illinois 60439, United States; Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States; Delferro, Massimiliano [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, Illinois 60439, United States

2018-02-22

Well-defined organoplatinum(IV) sites were grafted on a Zn(II)-modified SiO2 support via surface organometallic chemistry in toluene at room temperature. Solid-state spectroscopies including XAS, DRIFTS, DRUV-Vis, and solid-state (SS)NMR enhanced by dynamic nuclear polarization (DNP), as well as TPR-H2 and TEM techniques revealed highly dispersed (methylcyclopentadi-enyl)methylplatinum(IV) sites on the surface ((MeCp)PtMe/Zn/SiO2, 1). In addition, computational modelling suggests that the surface reaction of (MeCp)PtMe3 with Zn(II)-modified SiO2 support is thermodynamically favorable (ΔG = -12.4 kcal/mol), likely due to the increased acidity of the hydroxyl group, as confirmed by NH3-TPD and DNP-enhanced 17O{1H} SSNMR. In situ DRIFTS and XAS hydrogenation experiments reveal the formation of a surface Pt(IV)-H upon hydrogenolysis of Pt-Me groups. The heterogenized organoplatinum(IV)-H sites catalyze the selective partial hydrogenation of 1,3-butadiene to butenes (up to 95%) and the reduction of nitrobenzene derivatives to anilines (up to 100%) with excellent tolerance of reduction-sensitive func-tional groups (olefin, carbonyl, nitrile, halogens) under mild reaction conditions.

An Integrated Safety Assessment Methodology for Generation IV Nuclear Systems

International Nuclear Information System (INIS)

Leahy, Timothy J.

2010-01-01

The Generation IV International Forum (GIF) Risk and Safety Working Group (RSWG) was created to develop an effective approach for the safety of Generation IV advanced nuclear energy systems. Early work of the RSWG focused on defining a safety philosophy founded on lessons learned from current and prior generations of nuclear technologies, and on identifying technology characteristics that may help achieve Generation IV safety goals. More recent RSWG work has focused on the definition of an integrated safety assessment methodology for evaluating the safety of Generation IV systems. The methodology, tentatively called ISAM, is an integrated 'toolkit' consisting of analytical techniques that are available and matched to appropriate stages of Generation IV system concept development. The integrated methodology is intended to yield safety-related insights that help actively drive the evolving design throughout the technology development cycle, potentially resulting in enhanced safety, reduced costs, and shortened development time.

Direct Observation of a Nonheme Iron(IV)–Oxo Complex That Mediates Aromatic C–F Hydroxylation

OpenAIRE

Sahu, Sumit; Quesne, Matthew G.; Davies, Casey G.; Dürr, Maximilian; Ivanović-Burmazović, Ivana; Siegler, Maxime A.; Jameson, Guy N. L.; de Visser, Sam P.; Goldberg, David P.

2014-01-01

The synthesis of a pentadentate ligand with strategically designed fluorinated arene groups in the second coordination sphere of a nonheme iron center is reported. The oxidatively resistant fluorine substituents allow for the trapping and characterization of an FeIV(O) complex at −20 °C. Upon warming of the FeIV(O) complex, an unprecedented arene C–F hydroxylation reaction occurs. Computational studies support the finding that substrate orientation is a critical factor in the observed reactiv...

Removal of 238Pu(IV) from mice by poly-catechoylate, -hydroxamate or -hydroxypyridinonate ligands

International Nuclear Information System (INIS)

Durbin, P.W.; Jeung, N.; Rodgers, S.J.; Turowski, P.N.; Weitl, F.L.; White, D.L.; Raymond, K.N.; California Univ., Berkeley, CA

1989-01-01

Binding of actinide (IV) by plasma proteins impedes excretion. Facilitation of elimination with chelating agents is the only known way to reduce carcinogenic risk. Iron-sequestering agents produced by micro-organisms contain metal-binding groups that bind Pu(IV) at pH 7.4 (catechol, CAM, in enterobactin; hydroxamate, X, in the ferrioaxamines; hydroxypyridinone, HOPO). Our synthetic ligands contain up to four such groups linked by alkyl chains or attached to desferrioxamine (DFO) or diethylene-triamine-pentaacetic acid (DPTA). 238 Pu excretion was tested in mice given 30 μmol.kg -1 of a ligand. Ligands that removed as much or more Pu than CaNa 3 -DTPA(≥70% of injected Pu(% ID)) are, in decreasing order of effectiveness: (1) Fe(III)-3,4,3-LIHOPO, (2) DFO-HOPO, (3) 3,4,3-LIHOPO, (4) 3,4,3-LICAM(C). Orally administered ligands 1-4, (5) 3,4,3-LICAM(S) and (6) ZnNa-DTPA-DX removed as much or more Pu than CaNa 3 -DTPA (≥ 15% ID). Ligands 1-4 and 6 injected 24 h after the Pu removed ≥ 5% ID more than control excretion (equivalent to or better than CaNa 3 -DTPA). All the new ligands at a dosage of 0.3 μmol.kg -1 removed a significant amount of Pu compared with controls: CaNa 3 -DTPA was ineffective. Ligand 3 is acutely toxic at high dosage, but the others appear to be of low toxicity. The HOPO ligands and ZnNa-DTPA-DX are recommended for further study. (author)

Separation of some metal ions using coupled transport supported liquid membranes

International Nuclear Information System (INIS)

Chaudhary, M.A.

1993-01-01

Liquid membrane extraction processes has become very popular due to their superiority in many ways over other separation techniques. In coupled transport membranes the metal ions can be transported across the membrane against their concentration gradient under the influence of chemical potential difference. Liquid membranes consisting of a carrier-cum-diluent, supported in microporous polymeric hydrophobic films have been studied for transport of metal ions like U(VI), Cr(VI), Be(II), V(V), Ti(IV), Zn(II), Cd(II), Hf(IV), W(VI), and Co(II). The present paper presents basic data with respect to flux and permeabilities of these metal ions across membranes based on experimental results and theoretical equations, using different carriers and diluents and provides a brief reference to possibility of such membranes for large scale applications. (author)

Controlling applied to information processing: quality management applied to IP projects and IP services; Informationsverarbeitungs-Controlling: Qualitaetsmanagement fuer IV-Projekte und fuer IV-Service

Energy Technology Data Exchange (ETDEWEB)

Becker, B. [Vereinigung Deutscher Elektrizitaetswerke e.V. (VDEW), Frankfurt am Main (Germany); Beckers, F. [Isar-Amperwerke AG, Muenchen (Germany); Dewald, N. [Bayernwerk AG, Muenchen (Germany); Hauffe, P. [Pfalzwerke AG, Ludwigshafen am Rhein (Germany); Hein, F. [EVS AG Stuttgart (Germany); Hoederath, M. [Vereinigte Elektrizitaetswerke Westfalen AG (VEW), Dortmund (Germany); Seyen, R. [Staedtische Werke Nuernberg GmbH (Germany)

1998-01-12

The working group on information processing (IP) basics (in German: `IV-Grundlagen`) has prepared this contribution dealing with controlling applied to information processing. This new report, on the one hand, takes into consideration the role of the organizational IP unit as one offering its services to all sections of a company. On the other hand, information processing as an operational infrastructure influencing all business processes becomes increasingly important with respect to the competitiveness of the EVU. Therefore, quality management applied to IP projects and IP services must support this development. (orig./RHM) [Deutsch] Der VDEW Arbeitskreis `IV-Grundlagen` hat einen Beitrag zum Controlling fuer die Informationsverarbeitung erstellt. Hier geht zum einen die Rolle der Organisationseinheit IV als Dienstleister fuer alle Unternehmensbereiche ein. Zum anderen gewinnt die Informationsverarbeitung als betriebliche Infrastruktur fuer alle Geschaeftsprozesse zunehmende Bedeutung fuer die Wettbewerbsfaehigkeit der EVU. Das Qualitaetsmanagement fuer IV-Projekte und fuer IV-Service muss dies unterstuetzen. (orig./RHM)

Spectral Analysis, Synthesis, & Energy Distributions of Nearby E+A Galaxies Using SDSS-IV MaNGA

Science.gov (United States)

Weaver, Olivia A.; Anderson, Miguel Ricardo; Wally, Muhammad; James, Olivia; Falcone, Julia; Liu, Allen; Wallack, Nicole; Liu, Charles; SDSS Collaboration

2017-01-01

Utilizing data from the Mapping Nearby Galaxies at APO (MaNGA) Survey (MaNGA Product Launch-4, or MPL-4), of the latest generation of the Sloan Digital Sky Survey (SDSS-IV), we identified nine post-starburst (E+A) systems that lie within the Green Valley transition zone. We identify the E+A galaxies by their SDSS single fiber spectrum and u-r color, then confirmed their classification as post-starburst by coding/plotting methods and spectral synthesis codes (FIREFLY and PIPE3D), as well as with their Spectral Energy Distributions (SEDs) from 0.15 µm to 22 µm, using GALEX, SDSS, 2MASS, and WISE data. We produced maps of gaussian-fitted fluxes, equivalent widths, stellar velocities, metallicities and age. We also produced spectral line ratio diagrams to classify regions of stellar populations of the galaxies. We found that our sample of E+As retain their post-starburst properties across the entire galaxy, not just at their center. We detected matching a trend line in the ultraviolet and optical bands, consistent with the expected SEDs for an E+A galaxy, and also through the J, H and Ks bands, except for one object. We classified one of the nine galaxies as a luminous infrared galaxy, unusual for a post-starburst object. Our group seeks to further study stellar population properties, spectral energy distributions and quenching properties in E+A galaxies, and investigate their role in galaxy evolution as a whole. This work was supported by the Alfred P. Sloan Foundation via the SDSS-IV Faculty and Student Team (FAST) initiative, ARC Agreement #SSP483 to the CUNY College of Staten Island. This work was also supported by grants to The American Museum of Natural History, and the CUNY College of Staten Island through from National Science Foundation.

A structurally characterized organometallic plutonium(IV) complex

Energy Technology Data Exchange (ETDEWEB)

Apostolidis, Christos; Walter, Olaf [European Commission, Joint Research Centre, Directorate G - Nuclear Safety and Security, Karlsruhe (Germany); Vogt, Jochen; Liebing, Phil; Edelmann, Frank T. [Chemisches Institut, Otto-von-Guericke-Universitaet Magdeburg (Germany); Maron, Laurent [Laboratoire de Physique et Chimie des Nanoobjets (LPCNO), Universite de Toulouse/INSA/CNRS (UMR5215), Toulouse (France)

2017-04-24

The blood-red plutonocene complex Pu(1,3-COT'')(1,4-COT'') (4; COT''=η{sup 8}-bis(trimethylsilyl)cyclooctatetraenyl) has been synthesized by oxidation of the anionic sandwich complex Li[Pu(1,4-COT''){sub 2}] (3) with anhydrous cobalt(II) chloride. The first crystal structure determination of an organoplutonium(IV) complex revealed an asymmetric sandwich structure for 4 where one COT'' ring is 1,3-substituted while the other retains the original 1,4-substitution pattern. The electronic structure of 4 has been elucidated by a computational study, revealing a probable cause for the unexpected silyl group migration. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Development of reliable analytical method for extraction and separation of thorium(IV) by Cyanex 272 in kerosene

International Nuclear Information System (INIS)

Madane, N.S.; Mohite, B.S.

2011-01-01

A simple and selective spectrophotometric method has been developed for the extraction and separation of thorium(IV) from sodium salicylate media using Cyanex 272 in kerosene. Thorium(IV) was quantitatively extracted by 5 x 10 -4 M Cyanex 272 in kerosene from 1 x 10 -5 M sodium salicylate medium. The extracted thorium(IV) was stripped out quantitatively from the organic phase with 4.0 M hydrochloric acid and determined spectrophotometrically with arsenazo(III) at 620 nm. The effect of concentrations of sodium salicylate, extractant, diluents, metal ion and strippants has been studied. Separation of thorium(IV) from other elements was achieved from binary as well as multicomponent mixtures such as uranium(VI), strontium(II), rubidium(I), cesium(I), potassium(I), Sodium(I), lithium(I), lead(II), barium(II), beryllium(II) etc. Using this method separation and determination of thorium(IV) in geological and real samples has been carried out. The method is simple, rapid and selective with good reproducibility (approximately ±2%). (author)

Extraordinary light transmission through opaque thin metal film with subwavelength holes blocked by metal disks.

Science.gov (United States)

Li, Wen-Di; Hu, Jonathan; Chou, Stephen Y

2011-10-10

We observed that when subwavelength-sized holes in an optically opaque metal film are completely covered by opaque metal disks larger than the holes, the light transmission through the holes is not reduced, but rather enhanced. Particularly we report (i) the observation of light transmission through the holes blocked by the metal disks up to 70% larger than the unblocked holes; (ii) the observation of tuning the light transmission by varying the coupling strength between the blocking disks and the hole array, or by changing the size of the disks and holes; (iii) the observation and simulation that the metal disk blocker can improve light coupling from free space to a subwavelength hole; and (iv) the simulation that shows the light transmission through subwavelength holes can be enhanced, even though the gap between the disk and the metal film is partially connected with a metal. We believe these finding should have broad and significant impacts and applications to optical systems in many fields.

PUFF-IV, Code System to Generate Multigroup Covariance Matrices from ENDF/B-VI Uncertainty Files

International Nuclear Information System (INIS)

2007-01-01

1 - Description of program or function: The PUFF-IV code system processes ENDF/B-VI formatted nuclear cross section covariance data into multigroup covariance matrices. PUFF-IV is the newest release in this series of codes used to process ENDF uncertainty information and to generate the desired multi-group correlation matrix for the evaluation of interest. This version includes corrections and enhancements over previous versions. It is written in Fortran 90 and allows for a more modular design, thus facilitating future upgrades. PUFF-IV enhances support for resonance parameter covariance formats described in the ENDF standard and now handles almost all resonance parameter covariance information in the resolved region, with the exception of the long range covariance sub-subsections. PUFF-IV is normally used in conjunction with an AMPX master library containing group averaged cross section data. Two utility modules are included in this package to facilitate the data interface. The module SMILER allows one to use NJOY generated GENDF files containing group averaged cross section data in conjunction with PUFF-IV. The module COVCOMP allows one to compare two files written in COVERX format. 2 - Methods: Cross section and flux values on a 'super energy grid,' consisting of the union of the required energy group structure and the energy data points in the ENDF/B-V file, are interpolated from the input cross sections and fluxes. Covariance matrices are calculated for this grid and then collapsed to the required group structure. 3 - Restrictions on the complexity of the problem: PUFF-IV cannot process covariance information for energy and angular distributions of secondary particles. PUFF-IV does not process covariance information in Files 34 and 35; nor does it process covariance information in File 40. These new formats will be addressed in a future version of PUFF

Studies on coordination chemistry and bioactivity of complexes of a tridentate ONS Schiff base with some heavier transition metal ions

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Tan Mei Lin; Ali, A.M.

2003-09-01

A tridentate Schiff base, S-benzyl-β-N-(2-hydroxyphenyl)methylenedithiocarbazate, (HONSH), with a donor sequence of ONS, was synthesized from the condensation of S-benzyldithiocarbazate (SBDTC) with an equimolar amount of 2-hydroxybenzaldehyde in absolute ethanol. The reactions of HONSH with metal ions [La(III), Ce(IV) and Th(IV)] yielded complexes of compositions, [La(ONS)NO 3 .2H 2 O], [Ce(ONS)(NO 3 ) 2 ] and [Th(ONS) 2 ]. The ligands and the complexes were characterized from elemental analyses and spectroscopic measurements. The metal complexes were found to be active against colon cancer cell lines with the CD 50 values of 27.5, 28.4 and 19.3 μg/ml for the La(III), Ce(FV) and Th(IV) complexes, respectively. The La(IH) complex was found to be very active against leukemic cell lines with the CD 50 value of 6.8 μg/ml. (author)

Ionic behavior of organic-inorganic metal halide perovskite based metal-oxide-semiconductor capacitors.