Warm hydroforming of iridium + 0.3 wt % tungsten hemishells

International Nuclear Information System (INIS)

Wyder, W.C.

1976-01-01

A technique for the production of iridium alloy hemispherical shells to be used for the primary encapsulation of plutonium-238 oxide spheres is described. The encapsulated spheres, 24 per heat source, provide the thermal heat used to drive thermoelectric converters which supply power for the Department of Defense's LES 8/9 satellites. The technique used a standard production type Hydroform machine converted for hot tooling. The iridium alloy discs were canned in stainless steel waster sheets of a larger size than the iridium discs and separated from the latter by tantalum foil barrier discs. The stainless steel was electron beam welded around the edge to form an envelope. The iridium disc assembly was heated to approximately 900 0 C and the tooling to approximately 500 0 C. After forming, the iridium shell was cut to length while in the waster sheet; and the latter was removed by dissolving in hot aqua regia. After removal of the waster sheets, the hemishells were cleaned and heat treated. Production efficiency reached a level of better than 95 percent and was maintained to produce some 600-odd hemishells

Formation of nano iridium oxide: material properties and neural cell culture

International Nuclear Information System (INIS)

Lee, In-Seop; Whang, Chung-Nam; Lee, Young-Hee; Hwan Lee, Gun; Park, Bong-Joo; Park, Jong-Chul; Seo, Won-Seon; Cui Fuzhai

2005-01-01

Iridium film with the thickness of 30 and 60 nm were formed on both Si wafer and commercially pure (CP) Ti by electron beam evaporation. The thin iridium film showed the identical charge injection capability with the bulk Ir. However, the charge injection value of iridium film was decreased with continuous potential cycling when the deposited iridium became depleted due to the formation of oxide. The number of cycles at which the charge injection value decreased was 800 and 1600 cycles for the 30- and 60-nm-thick Ir film, respectively. FE-SEM observations on the cross section of Ir film clearly showed the thicker iridium oxide was formed with the more potential cycling. Ar ion beam etching to substrates before deposition certainly improved the adhesion strength of Ir film enough to resist to the strain induced by the larger volume occupation of iridium oxide. Swiss 3T3 fibroblasts culture on Ir and Ir oxide showed no cytotoxicity. Also, embryonic cortical neural cell culture on electrode indicated neurons adhered and survived by the formation of neurofilament

EKA 90. aastapäeva juubelinädalale on planeeritud mitmeid üritusi nii peamajas kui osakondades

Index Scriptorium Estoniae

2004-01-01

Kunstööstuskooli tutvustavast näitusest. 29. X audoktorite Udo Kultermanni ja Juhani Pallasmaa loengud ning ümarlaua ettekanded (osalejad loetletud), ümarlauda juhib Jüri Soolep. EKA galeriis valgusinstallatsioonide näitus "Think Lightly", osalevad Sirli Põllumäe, Riho Tiivel, Helis Podnek, Marion Uuspõld, Pent Talvet, Mehis Tiitsar, Merike Rehepapp, Veiko Vaine. Üliõpilaste loomingu väljapanekud. 30. X vilistlaspäev, pidulikul aktusel promoveeritakse audoktoriteks Juhani Pallasmaa, Udo Kultermann, Lars Olof Larsson ja Yrjö Sotamaa. Vabade kunstide osakonna rändnäitus "Ekskursioon" sisekaitseakadeemias

Iridium-192 sources production for brachytherapy use

International Nuclear Information System (INIS)

Rostelato, Maria Elisa Chuery Martins

1997-01-01

The incidence of cancer increases every year in Brazil and turns out to be one of the most important causes of mortality. Some of the patients are treated with brachytherapy, a form of lesion treatment which is based on the insertion of sources into tumors, in this particular case, activated iridium wires. During this process, the ionizing radiation efficiently destroys the malignant cells. These iridium wires have a nucleus made out of an iridium-platinum alloy 20-30/70-80 of 0,1 mm in diameter either coated by platinum or encased in a platinum tube. The technique consists in irradiating the wire in the reactor neutron flux in order to produce iridium-192. The linear activity goes from 1 mCi/cm to 4 mCi/cm and the basic characteristic, which is required, is the homogeneity of the activation along the wire. It should not present a dispersion exceeding 5% on a wire measuring 50 cm in length, 0.5 mm or 0.3 mm in diameter. Several experiments were carried out in order to define the activation parameters. Wires from different origins were analyzed. It was concluded that United States of America and France wires were found to be perfectly adequate for brachytherapy purposes and have therefore been sent to specialized hospitals and successfully applied to cancer patients. Considering that the major purpose of this work is to make this product more accessible in Brazil, at a cost reflecting the Brazilian reality, the IPEN is promoting the preparation of iridium-192 sources to be used in brachytherapy, on a national level. (author)

Synthesis of benzimidazoles via iridium-catalyzed acceptorless dehydrogenative coupling.

Science.gov (United States)

Sun, Xiang; Lv, Xiao-Hui; Ye, Lin-Miao; Hu, Yu; Chen, Yan-Yan; Zhang, Xue-Jing; Yan, Ming

2015-07-21

Iridium-catalyzed acceptorless dehydrogenative coupling of tertiary amines and arylamines has been developed. A number of benzimidazoles were prepared in good yields. An iridium-mediated C-H activation mechanism is suggested. This finding represents a novel strategy for the synthesis of benzimidazoles.

Weldability of general purpose heat source new-process iridium

International Nuclear Information System (INIS)

Kanne, W.R.

1987-01-01

Weldability tests on General Purpose Heat Source (GPHS) iridium capsules showed that a new iridium fabrication process reduced susceptibility to underbead cracking. Seventeen capsules were welded (a total of 255 welds) in four categories and the number of cracks in each weld was measured

Synthesis and characterization of low-valence actinide phosphide tellurides and ternary selenium-halide iridium complexes; Synthese und Charakterisierung niedervalenter Actinoidphosphidtelluride und ternaerer Selen-Halogenid-Komplexe des Iridiums

Energy Technology Data Exchange (ETDEWEB)

Stolze, Karoline

2016-04-07

The thesis on the synthesis and characterization of low-valence actinide phosphide tellurides and ternary selenium-halide iridium complexes includes two parts: a description of the experimental synthesis of UPTe and U2PTe2O and ThPTe and the synthesis of selenium-chloride iridium complexes and selenium-bromide iridium complexes. The characterization included X-ray diffraction and phase studies.

Laser welding parameters for manufacturing iridium-192 (Ir-192) source

International Nuclear Information System (INIS)

Anung Pujiyanto; Moch Subechi; Hotman Lubis; Diandono KY

2013-01-01

Number of cervical cancer patients in Indonesia is growing every year. One of cervical cancer treatment was fairly effective use brachytherapy treatment with radioisotope sources of iridium-192. Manufacturing of iridium sources for brachytherapy can be done by incorporating the iridium-192 into stainless steel microcapsules then welding using laser welder which the quality of the welding of iridium source (Ir-192) was determined by the welding parameters such as full power, energy frequency, average power and speed. Based on the result of leakage test using pressure -20 inch Hg and tensile test 2.5 bar showed the welding parameters III and IV did not have leakage and damaged. So that parameters III and IV are recommended to be applied to Ir-192 HDR's source. (author)

Welding of iridium heat source capsule components

International Nuclear Information System (INIS)

Mustaleski, T.M.; Yearwood, J.C.; Burgan, C.E.; Green, L.A.

1991-01-01

Interplanetary spacecraft have long used radioisotope thermoelectric generators (RTG) to produce power for instrumentation. These RTG produce electrical energy from the heat generated through the radioactive decay of plutonium-238. The plutonium is present as a ceramic pellet of plutonium oxide. The pellet is encapsulated in a containment shell of iridium. Iridium is the material of choice for these capsules because of its compatibility with the plutonium dioxide. The high-energy beam welding (electron beam and laser) processes used in the fabrication of the capsules has not been published. These welding procedures were originally developed at the Mound Laboratories and have been adapted for use at the Oak Ridge Y-12 Plant. The work involves joining of thin material in small sizes to exacting tolerances. There are four different electron beam welds on each capsule, with one procedure being used in three locations. There is also a laser weld used to seal the edges of a sintered frit assembly. An additional electron beam weld is also performed to seal each of the iridium blanks in a stainless steel waster sheet prior to forming. In the transfer of these welding procedures from one facility to another, a number of modifications were necessary. These modifications are discussed in detail, as well as the inherent problems in making welds in material which is only 0.005 in. thick. In summary, the paper discusses the welding of thin components of iridium using the high energy beam processes. While the peculiarities of iridium are pertinent to the discussion, much of the information is of general interest to the users of these processes. This is especially true of applications involving thin materials and high-precision assemblies

Iridium complexes for the application of photodynamic therapy

Directory of Open Access Journals (Sweden)

SHI Min

2015-10-01

Full Text Available Photodynamic therapy can destruct tumor cells by singlet oxygen which is generated via a photodynamic reaction of the photosensitizer under a specfic excitation wavelength.Due to the heavy atom effect of metal iridium,iridiumcomplexes are excited by suitable light and then reach their excited triple state through intersystem crossing.The excited iridium complexes transfer energy to oxygen molecules to produce singlet oxygen for photodynamic therapy.

Determination of traces of iridium with thiodibenzoylmethane by substoichiometric isotope dilution analysis

International Nuclear Information System (INIS)

Roebisch, G.; Bansse, W.; Ludwig, E.

1980-01-01

Iridium(III or IV) reacts with thiodibenzoylmethane on heating at pH 6 to form a 1:3 complex, which can be concentrated by extraction into chloroform. Based on this reaction, a reproducible, selective determination of iridium is achieved by means of substoichiometric isotope dilution analysis, based on 192 Ir. The linear range is 1-11 nmol of iridium. (Auth.)

Simultaneous iridium catalysed oxidation and enzymatic reduction employing orthogonal reagents

NARCIS (Netherlands)

Mutti, Francesco G.; Orthaber, Andreas; Schrittwieser, Joerg H.; Vries, Johannes G. de; Pietschnig, Rudolf; Kroutil, Wolfgang

2010-01-01

An iridium catalysed oxidation was coupled concurrently to an asymmetric biocatalytic reduction in one-pot; thus it was shown for the first time that iridium- and alcohol dehydrogenase-catalysed redox reactions are compatible. As a model system racemic chlorohydrins were transformed to

pH-sensor properties of electrochemically grown iridium oxide

NARCIS (Netherlands)

Olthuis, Wouter; Robben, M.A.M.; Bergveld, Piet; Bos, M.; van der Linden, W.E.

1990-01-01

The open-circuit potential of an electrochemically grown iridium oxide film is measured and shows a pH sensitivity between −60 and −80 mV/pH. This sensitivity is found to depend on the state of oxidation of the iridium oxide film; for a higher state of oxidation (or more of the oxide in the high

PENGARUH PELAYANAN, KINERJA PENGURUS KOPERASI, DAN MOTIVASI BERKOPERASI TERHADAP PARTISIPASI ANGGOTA KOPERASI PEGAWAI REPUBLIK INDONESIA (KPRI EKA KARYA KABUPATEN KENDAL

Directory of Open Access Journals (Sweden)

Tri Yuni Sulistyowati

2015-06-01

Full Text Available Tujuan penelitian ini adalah untuk mengetahui pengaruh pelayanan, kinerja pengurus koperasi, dan motivasi berkoperasi terhadap partisipasi anggota Koperasi Pegawai Republik Indonesia (KPRI Eka Karya Kabupaten Kendal. Penelitian ini merupakan penelitian kuantitatif, dengan populasi berjumlah 496 anggota dengan sampel 83 anggota. Metode pengambilan data yang digunakan adalah kuesioner dan dokumentasi. Metode analisis data menggunakan analisis deskriptif, regresi linier berganda dan uji asumsi klasik. Hasil penelitian menunjukkan bahwa secara simultan terdapat pengaruh pelayanan, kinerja pengurus koperasi, dan motivasi berkoperasi terhadap partisipasi anggota sebesar 58,2%. Secara parsial pelayanan berpengaruh sebesar 7,1%, kinerja pengurus koperasi berpengaruh sebesar 3,3% dan motivasi berkoperasi berpengaruh sebesar 27%. Dengan pelayanan, kinerja pengurus koperasi, dan motivasi berkoperasi yang baik maka akan meningkatkan partisipasi anggota. The results showed the service, the performance of cooperative management and cooperative motivation affect the participation of members simultaneously by 58.2% while the rest is influenced by other variables not examined. Furthermore, the effect of partial services to the participation of members was 7.1%, the effect of partial performance of the cooperative board member participation was 3.3% and the effect of partial motivation for the participation of members of cooperatives was 27%. Suggestions for KPRI Eka Karya Kendal is to be improving as more responsive services tehadap complaints, better hygiene as well as expanding the cooperative store stores that optimal participation of more members.

Screening the collision risk of the Iridium 33 - Cosmos 2251 Clouds

OpenAIRE

Rossi, Alessandro; Valsecchi, Giovanni Battista

2011-01-01

More than 10 years ago, in Rossi, Valsecchi and Farinella (Nature, 1999), it was shown how a near polar multi-plane constellation such as Iridium is particularly at risk of a collisional cascade if one of its satellites is first accidentally fragmented. Those results are recalled and actualized in the light of the real collision of February 2009, between Iridium 33 and Cosmos 2251. The collision risk, for the remaining Iridium satellites, arising from the two clouds of fragments generated by ...

The Iridium (tm) system: Personal communications anytime, anyplace

Science.gov (United States)

Hatlelid, John E.; Casey, Larry

1993-01-01

The Iridium system is designed to provide handheld personal communications between diverse locations around the world at any time and without prior knowledge of the location of the personal units. This paper provides an overview of the system, the services it provides, its operation, and an overview of the commercial practices and relatively high volume satellite production techniques which will make the system cost effective. A constellation of 66 satellites will provide an orbiting, spherical-shell, infrastructure for this global calling capability. The satellites act as tall cellular towers and allow convenient operation for portable handheld telephones. The system will provide a full range of services including voice, paging, data, geolocation, and fax capabilities. Motorola is a world leader in the production of high volume, high quality, reliable telecommunications hardware. One of Iridium's goals is to apply these production techniques to high reliability space hardware. Concurrent engineering, high performance work teams, advanced manufacturing technologies, and improved assembly and test methods are some of the techniques that will keep the Iridium system cost effective. Mobile, global, flexible personal communications are coming that will allow anyone to call or receive a call from/to anyplace at anytime. The Iridium system will provide communications where none exist today. This connectivity will allow increased information transfer, open new markets for various business endeavors, and in general increase productivity and development.

pH sensors based on iridium oxide

International Nuclear Information System (INIS)

Tarlov, M.J.; Kreider, K.G.; Semancik, S.; Huang, P.

1990-03-01

Results are presented on the pH-potential response of dc magnetron reactively sputtered iridium oxide films. The films exhibit a nearly Nernstian response to pH, no hysteresis effects, and minimal response to ionic interferences. Sensitivity to certain redox species is observed, however. In addition, methods are discussed for preparing model iridium oxide sensor surfaces for ultrahigh vacuum surface analytical studies. Stoichiometric IrO 2 -like surfaces are shown to be relatively inert to gas phase water. However, hydroxylation of IrO 2 -like surfaces can be induced by rf water plasma treatment. 17 refs., 5 figs

Iridium Oxide pH Sensor Based on Stainless Steel Wire for pH Mapping on Metal Surface

Science.gov (United States)

Shahrestani, S.; Ismail, M. C.; Kakooei, S.; Beheshti, M.; Zabihiazadboni, M.; Zavareh, M. A.

2018-03-01

A simple technique to fabricate the iridium oxide pH sensor is useful in several applications such as medical, food processing and engineering material where it is able to detect the changes of pH. Generally, the fabrication technique can be classified into three types: electro-deposition iridium oxide film (EIrOF), activated iridium oxide film (AIROF) and sputtering iridium oxide film (SIROF). This study focuses on fabricating electrode, calibration and test. Electro-deposition iridium oxide film is a simple and effective method of fabricating this kind of sensor via cyclic voltammetry process. The iridium oxide thick film was successfully electrodeposited on the surface of stainless steel wire with 500 cycles of sweep potential. A further analysis under FESEM shows detailed image of iridium oxide film which has cauliflower-liked microstructure. EDX analysis shows the highest element present are iridium and oxygen which concluded that the process is successful. The iridium oxide based pH sensor has shown a good performance in comparison to conventional glass pH sensor when it is being calibrated in buffer solutions with 2, 4, 7 and 9 pH values. The iridium oxide pH sensor is specifically designed to measure the pH on the surface of metal plate.

Development of iridium coated x-ray mirrors for astronomical applications

Science.gov (United States)

Döhring, Thorsten; Probst, Anne-Catherine; Emmerich, Florian; Stollenwerk, Manfred; Stehlíková, Veronika; Friedrich, Peter; Damm, Christine

2017-08-01

Future space-based X-ray observatories need to be very lightweight for launcher mass constraints. Therefore they will use a reduced mirror thickness, which results in the additional requirement of low coating stress to avoid deformation of the initial precisely shaped mirror substrates. Due to their excellent reflection properties iridium coatings are sometimes applied for grazing incidence mirrors in astronomical X-ray telescopes. At Aschaffenburg University of Applied Sciences the coating of thin iridium films by an RF-magnetron sputtering technique is under development. The work is embedded in collaborations with the Max-Planck-Institute for Extraterrestrial Physics in Germany, the Czech Technical University in Prague, the Osservatorio Astronomico di Brera in Italy, the German Leibniz Institute for Solid State and Materials Research in Dresden, and the French Institute Fresnel. Sputtering with different parameters leads to iridium films with different properties. The current work is focused on the microstructure of the iridium coatings to study the influence of the substrate and of the argon gas pressure on the thin film growing process. Correlations between coating density, surface micro-roughness, the crystalline structure of the iridium layers, and the expected reflectivity of the X-ray mirror as well as coating stress effects are presented and discussed. The final goal of the project is to integrate the produced prototype mirrors into an X-ray telescope module. On a longer timescale measurements of the mirror modules optical performance are planned at the X-ray test facility PANTER.

Prototyping iridium coated mirrors for x-ray astronomy

Science.gov (United States)

Döhring, Thorsten; Probst, Anne-Catherine; Stollenwerk, Manfred; Emmerich, Florian; Stehlíková, Veronika; Inneman, Adolf

2017-05-01

X-ray astronomy uses space-based telescopes to overcome the disturbing absorption of the Earth's atmosphere. The telescope mirrors are operating at grazing incidence angles and are coated with thin metal films of high-Z materials to get sufficient reflectivity for the high-energy radiation to be observed. In addition the optical payload needs to be light-weighted for launcher mass constrains. Within the project JEUMICO, an acronym for "Joint European Mirror Competence", the Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague started a collaboration to develop mirrors for X-ray telescopes. The X-ray telescopes currently developed within this Bavarian- Czech project are of Lobster eye type optical design. Corresponding mirror segments use substrates of flat silicon wafers which are coated with thin iridium films, as this material is promising high reflectivity in the X-ray range of interest. The deposition of the iridium films is based on a magnetron sputtering process. Sputtering with different parameters, especially by variation of the argon gas pressure, leads to iridium films with different properties. In addition to investigations of the uncoated mirror substrates the achieved surface roughness has been studied. Occasional delamination of the iridium films due to high stress levels is prevented by chromium sublayers. Thereby the sputtering parameters are optimized in the context of the expected reflectivity of the coated X-ray mirrors. In near future measurements of the assembled mirror modules optical performances are planned at an X-ray test facility.

Measurements of iridium and the meteoric impact hypothesis at cretaceous end

International Nuclear Information System (INIS)

Sircilli Neto, F.

1986-12-01

Both instrumental and radiochemical neutron activation analysis methods were developed for trace-element determination, such as iridium and gold, for application in cosmochemistry. The magnitude of the determined concentrations is in the range of parts per billion. In the instrumental method 1.5 grams of sample were submitted to irradiation by 10 13 thermal neutrons.cm -2 .s -1 during 32 hours. The gamma spectrometry is carried out with 10 to 12 hours counting time after 40 days of decay. In the radiochemical analysis a method of radiochemical separation of noble metals based on tellurium coprecipitation is implanted for iridium and gold determinations. As an application of the instrumental neutron activation analysis, preliminary iridium concentrations are measured for the first time in sedimentary rocks collected in the Brazilian territory. These techniques for determinations of iridium will be useful to check the asteroid impact hypothesis, which is supposed to be the cause of the great Cretaceous/Tertiary mass extinction, using samples collected in the South Hemisphere. (Author) [pt

Welding iridium heat-source capsules for space missions

International Nuclear Information System (INIS)

Kanne, W.R. Jr.

1982-03-01

A remote computer-controlled welding station was developed to encapsulate radioactive PuO 2 in iridium. Weld quench cracking caused an interruption in production of capsules for upcoming space missions. Hot crack sensitivity of the DOP-26 iridium alloy was associated with low melting constituents in the grain boundaries. The extent of cracking was reduced but could not be eliminated by changes to the welding operation. An ultrasonic test was developed to detect underbead cracks exceeding a threshold size. Production was continued using the ultrasonic test to reject capsules with detectable cracks

Iridium-catalyst-based autonomous bubble-propelled graphene micromotors with ultralow catalyst loading.

Science.gov (United States)

Wang, Hong; Sofer, Zdeněk; Eng, Alex Yong Sheng; Pumera, Martin

2014-11-10

A novel concept of an iridium-based bubble-propelled Janus-particle-type graphene micromotor with very high surface area and with very low catalyst loading is described. The low loading of Ir catalyst (0.54 at %) allows for fast motion of graphene microparticles with high surface area of 316.2 m(2)  g(-1). The micromotor was prepared with a simple and scalable method by thermal exfoliation of iridium-doped graphite oxide precursor composite in hydrogen atmosphere. Oxygen bubbles generated from the decomposition of hydrogen peroxide at the iridium catalytic sites provide robust propulsion thrust for the graphene micromotor. The high surface area and low iridium catalyst loading of the bubble-propelled graphene motors offer great possibilities for dramatically enhanced cargo delivery. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of iridium on the reactivity of LaFeO3 base perovskites

DEFF Research Database (Denmark)

Kindermann, L.; Das, D.; Bahadur, D.

1998-01-01

The influence of iridium on the reactivity of powder mixtures made of perovskites and 8 mol% yttria stabilized zirconia (8 YSZ) is reported. Iridium is added to the perovskites of the composition (La0.6M0.4)(z)Fe0.8TM0.2O3-delta (M = Sr, Ca; TM = Mn, Co; z = 0.90, 1.00) via the gaseous phase....... Iridium is present in the perovskite lattice as Ir4+ replacing iron as is evident from XRD and TEM/EDX results. Compatibility studies carried out at 1000 degrees C demonstrate that iridium has considerable influence on the reactivity. The results are discussed with respect to the stability...... of the perovskites, thermodynamic activities, Ir(IV)-O bonding, tolerance factor and oxygen migration....

Iridium-Catalyzed Condensation of Primary Amines To Form Secondary Amines

DEFF Research Database (Denmark)

Lorentz-Petersen, Linda Luise Reeh; Jensen, Paw; Madsen, Robert

2009-01-01

Symmetric secondary amines are readily obtained by heating a neat primary amine with 0.5 mol% of bis(dichloro[eta(5)-pentamethylcyclopentadienyl]iridium). The products are isolated by direct distillation in good yields.......Symmetric secondary amines are readily obtained by heating a neat primary amine with 0.5 mol% of bis(dichloro[eta(5)-pentamethylcyclopentadienyl]iridium). The products are isolated by direct distillation in good yields....

Balancing activity, stability and conductivity of nanoporous core-shell iridium/iridium oxide oxygen evolution catalysts

Energy Technology Data Exchange (ETDEWEB)

Kim, Yong-Tae; Lopes, Pietro Papa; Park, Shin-Ae; Lee, A-Yeong; Lim, Jinkyu; Lee, Hyunjoo; Back, Seoin; Jung, Yousung; Danilovic, Nemanja; Stamenkovic, Vojislav; Erlebacher, Jonah; Snyder, Joshua; Markovic, Nenad M.

2017-11-13

The selection of oxide materials for catalyzing the Oxygen Evolution Reaction in acid-based electrolyzers must be guided by the proper balance between activity, stability and conductivity – a challenging mission of great importance for delivering affordable and environmentally friendly hydrogen. Here we report that the highly conductive nanoporous architecture of an iridium oxide shell on a metallic iridium core, formed through the fast dealloying of osmium from an Ir25Os75 alloy, exhibits an exceptional balance between oxygen evolution activity and stability as quantified by the Activity-Stability FactorASF. Based on this metric, the nanoporous Ir/IrO2 morphology of dealloyed Ir25Os75 shows a factor of ~30 improvement ASFrelative to conventional Ir-based oxide materials and a ~8 times improvement over dealloyed Ir25Os75 nanoparticles due to optimized stability and conductivity, respectively. We propose that the Activity-Stability FactorASF is the key “metric” for determining the technological relevance of oxide-based anodic water electrolyzer catalysts.

Iridium Interfacial Stack - IrIS

Science.gov (United States)

Spry, David

2012-01-01

Iridium Interfacial Stack (IrIS) is the sputter deposition of high-purity tantalum silicide (TaSi2-400 nm)/platinum (Pt-200 nm)/iridium (Ir-200 nm)/platinum (Pt-200 nm) in an ultra-high vacuum system followed by a 600 C anneal in nitrogen for 30 minutes. IrIS simultaneously acts as both a bond metal and a diffusion barrier. This bondable metallization that also acts as a diffusion barrier can prevent oxygen from air and gold from the wire-bond from infiltrating silicon carbide (SiC) monolithically integrated circuits (ICs) operating above 500 C in air for over 1,000 hours. This TaSi2/Pt/Ir/Pt metallization is easily bonded for electrical connection to off-chip circuitry and does not require extra anneals or masking steps. There are two ways that IrIS can be used in SiC ICs for applications above 500 C: it can be put directly on a SiC ohmic contact metal, such as Ti, or be used as a bond metal residing on top of an interconnect metal. For simplicity, only the use as a bond metal is discussed. The layer thickness ratio of TaSi2 to the first Pt layer deposited thereon should be 2:1. This will allow Si from the TaSi2 to react with the Pt to form Pt2Si during the 600 C anneal carried out after all layers have been deposited. The Ir layer does not readily form a silicide at 600 C, and thereby prevents the Si from migrating into the top-most Pt layer during future anneals and high-temperature IC operation. The second (i.e., top-most) deposited Pt layer needs to be about 200 nm to enable easy wire bonding. The thickness of 200 nm for Ir was chosen for initial experiments; further optimization of the Ir layer thickness may be possible via further experimentation. Ir itself is not easily wire-bonded because of its hardness and much higher melting point than Pt. Below the iridium layer, the TaSi2 and Pt react and form desired Pt2Si during the post-deposition anneal while above the iridium layer remains pure Pt as desired to facilitate easy and strong wire-bonding to the Si

Postimpact examinations of three DOP 4 iridium shells from simulant fuel sphere assemblies

International Nuclear Information System (INIS)

Cramer, E.M.; Hecker, S.S.

1975-12-01

Three fuel sphere assemblies, with thoria in doped iridium containment shells, were examined after a simulated earth impact from an aborted orbital mission of a multihundred-watt thermoelectric heat source. The extent of deformation of each unit was measured. Damage to the containment shells was minimal in comparison to that in undoped iridium. Metallographic sections from critical areas indicated that superficial grain boundary cracking in weld zones and microscopic cracking in regions of maximum diameter had occurred in addition to local thinning and coining. The improved properties of the doped iridium are attributed to the retention of a small grain size and to an additional fracture resistance over iridium of a comparable grain size, imparted by either a change in grain boundary chemistry or the flow characteristics of the doped material

Synthesis and Luminescence Properties of Iridium(III Azide- and Triazole-Bisterpyridine Complexes

Directory of Open Access Journals (Sweden)

Timothy W. Schmidt

2013-07-01

Full Text Available We describe here the synthesis of azide-functionalised iridium(III bisterpyridines using the “chemistry on the complex” strategy. The resulting azide-complexes are then used in the copper(I-catalysed azide-alkyne Huisgen 1,3-dipolar cycloaddition “click chemistry” reaction to from the corresponding triazole-functionalised iridium(III bisterpyridines. The photophysical characteristics, including lifetimes, of these compounds were also investigated. Interestingly, oxygen appears to have very little effect on the lifetime of these complexes in aqueous solutions. Unexpectedly, sodium ascorbate acid appears to quench the luminescence of triazole-functionalised iridium(III bisterpyridines, but this effect can be reversed by the addition of copper(II sulfate, which is known to oxidize ascorbate under aerobic conditions. The results demonstrate that iridium(III bisterpyridines can be functionalized for use in “click chemistry” facilitating the use of these photophysically interesting complexes in the modification of polymers or surfaces, to highlight just two possible applications.

Dynamic High-Temperature Characterization of an Iridium Alloy in Compression at High Strain Rates

Energy Technology Data Exchange (ETDEWEB)

Song, Bo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Experimental Environment Simulation Dept.; Nelson, Kevin [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials Dept.; Lipinski, Ronald J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Nuclear Fuel Cycle Technology Dept.; Bignell, John L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Structural and Thermal Analysis Dept.; Ulrich, G. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Radioisotope Power Systems Program; George, E. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Radioisotope Power Systems Program

2014-06-01

Iridium alloys have superior strength and ductility at elevated temperatures, making them useful as structural materials for certain high-temperature applications. However, experimental data on their high-temperature high-strain-rate performance are needed for understanding high-speed impacts in severe elevated-temperature environments. Kolsky bars (also called split Hopkinson bars) have been extensively employed for high-strain-rate characterization of materials at room temperature, but it has been challenging to adapt them for the measurement of dynamic properties at high temperatures. Current high-temperature Kolsky compression bar techniques are not capable of obtaining satisfactory high-temperature high-strain-rate stress-strain response of thin iridium specimens investigated in this study. We analyzed the difficulties encountered in high-temperature Kolsky compression bar testing of thin iridium alloy specimens. Appropriate modifications were made to the current high-temperature Kolsky compression bar technique to obtain reliable compressive stress-strain response of an iridium alloy at high strain rates (300 – 10000 s^-1) and temperatures (750°C and 1030°C). Uncertainties in such high-temperature high-strain-rate experiments on thin iridium specimens were also analyzed. The compressive stress-strain response of the iridium alloy showed significant sensitivity to strain rate and temperature.

Impedance analysis of nanostructured iridium oxide electrocatalysts

International Nuclear Information System (INIS)

Sunde, Svein; Lervik, Ingrid Anne; Tsypkin, Mikhail; Owe, Lars-Erik

2010-01-01

Impedance data were collected for nanostructured iridium oxide (NIROF) at potentials below those at which the oxygen evolution reaction commences. The measurements included thin oxide films covered by a protective Nafion TM layer and thicker composite Nafion TM -oxide electrodes. The time constants for the low-frequency diffusion process were approximately the same for both types of electrodes, indicating diffusion in individual particles in the porous electrode rather than across the film. The diffusion process involves trapping of the diffusion species. The impedance data indicated that there were no significant variations in conductivity of the oxides with potential, as opposed to what appears to be the case for anodically formed iridium oxide films (AIROF). This is interpreted to reflect differences in electronic structure between NIROF and AIROF.

Enantiomeric separation of iridium (III) complexes using HPLC chiral stationary phases based on amylose derivatives

International Nuclear Information System (INIS)

Kim, Hee Eun; Seo, Na Hyeon; Hyun, Myung Ho

2016-01-01

Cyclometalated iridium (III) complexes formed with three identical cyclometalating (C-N) ligands (homoleptic) or formed with two cyclometalating (C-N) ligands and one ancillary (LX) ligand (heteroleptic) have been known as highly phosphorescent materials and, thus, they have been utilized as efficient phosphorescent dopants in organic light emitting diodes (OLEDs) 1–3 or as effective phosphorescent chemosensors. 4–7 Cylometalated iridium (III) complexes are chiral compounds consisting of lambda (Λ, left-handed) and delta (Δ, right-handed) isomers. Racemic cyclometa- lated iridium (III) complexes emit light with no net polarization, but optically active cyclometalated iridium (III) complexes emit circularly polarized light. 8,9 Circularly polarized light can be used in various fields including highly efficient three dimensional electronic devices, photo nic devices for optical data storage, biological assays, and others. 8,9 In order to obtain optically active cylometalated iridium (III) complexes and to determine the enantiomeric composition of optically active cylometalated iridium (III) complexes, liquid chromatogr aphic enantiomer separation method on chiral stationary phases (CSPs) has been used. For example, Okamoto and coworkers first reported the high performance liquid chromatographic (HPLC) direct enantiomeric separation of two homoleptic cylometalated iridium (III) complexes on immobilized amylose tris(3,5- dimethylphenylcarbamate) (Chiralpak IA), coated cellulose tris(3,5-dimethylphenylcarbamate) (Chiralc el OD), and coated cellulose tris(4-methylbenzoate) (Chiralce l OJ). 10 Supercritical fluid chromatography (SFC) was also used by Bernhard and coworkers for the enantiomeric separation of cylometalated iridium (III) complexes on coated amylose tris(3,5-dimethylphenylcarbamate) (Chiralpak AD-H). 8 However, the general use of the HPLC method for the direct enantiomeric separation of homoleptic

Enantiomeric separation of iridium (III) complexes using HPLC chiral stationary phases based on amylose derivatives

Energy Technology Data Exchange (ETDEWEB)

Kim, Hee Eun; Seo, Na Hyeon; Hyun, Myung Ho [Dept. of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan (Korea, Republic of)

2016-12-15

Cyclometalated iridium (III) complexes formed with three identical cyclometalating (C-N) ligands (homoleptic) or formed with two cyclometalating (C-N) ligands and one ancillary (LX) ligand (heteroleptic) have been known as highly phosphorescent materials and, thus, they have been utilized as efficient phosphorescent dopants in organic light emitting diodes (OLEDs) 1–3 or as effective phosphorescent chemosensors. 4–7 Cylometalated iridium (III) complexes are chiral compounds consisting of lambda (Λ, left-handed) and delta (Δ, right-handed) isomers. Racemic cyclometa- lated iridium (III) complexes emit light with no net polarization, but optically active cyclometalated iridium (III) complexes emit circularly polarized light. 8,9 Circularly polarized light can be used in various fields including highly efficient three dimensional electronic devices, photo nic devices for optical data storage, biological assays, and others. 8,9 In order to obtain optically active cylometalated iridium (III) complexes and to determine the enantiomeric composition of optically active cylometalated iridium (III) complexes, liquid chromatogr aphic enantiomer separation method on chiral stationary phases (CSPs) has been used. For example, Okamoto and coworkers first reported the high performance liquid chromatographic (HPLC) direct enantiomeric separation of two homoleptic cylometalated iridium (III) complexes on immobilized amylose tris(3,5- dimethylphenylcarbamate) (Chiralpak IA), coated cellulose tris(3,5-dimethylphenylcarbamate) (Chiralc el OD), and coated cellulose tris(4-methylbenzoate) (Chiralce l OJ). 10 Supercritical fluid chromatography (SFC) was also used by Bernhard and coworkers for the enantiomeric separation of cylometalated iridium (III) complexes on coated amylose tris(3,5-dimethylphenylcarbamate) (Chiralpak AD-H). 8 However, the general use of the HPLC method for the direct enantiomeric separation of homoleptic.

Antiferromagnetic iridium-manganese intermediate layers for perpendicular recording media (invited)

Science.gov (United States)

Srinivasan, Kumar; Piramanayagam, S. N.; Sbiaa, Rachid; Kay, Yew Seng; Tan, Hang Khume; Wong, Seng Kai

2009-04-01

Current generation of cobalt-oxide-based perpendicular magnetic recording media uses single or dual ruthenium intermediate layers in order to grow crystallographically textured, and magnetically isolated granular media. In this work, the potential advantages of an antiferromagnetic iridium-manganese intermediate layer directly under the recording layer are highlighted. Owing to its close lattice matching with hexagonal cobalt, iridium-manganese which has the L12, or AuCu3-type crystal structure, can support the heteroepitaxial growth of the cobalt-based recording layer. In one of the media schemes described here, (111) textured iridium-manganese thin film was grown on 7.5 nm thick ruthenium layer. On the iridium-manganese as segregation layer, the Co-oxide-based magnetic recording layer showed perpendicular texture with Δθ50 below 4°, coercivity of over 4000 Oe alongside magnetic exchange decoupling, average grain sizes of 6 nm with distributions under 14%, and improved thermal stability. Measurements of the anisotropy constant did not show any significant change and even an IrMn capping layer was observed to improve the thermal stability. The possible mechanisms through which the IrMn layer could affect the thermal stability are hypothesized. The initial layers of the magnetic recording layer on IrMn segregation layers also showed exchange-decoupled and segregated grains, which is unlike that observed on Ru segregation layers. In a second media scheme, (111) textured iridium-manganese thin film was grown on a crystalline soft magnetic underlayer belonging on top of amorphous soft underlayers. In this scheme, partial pinning of the soft underlayer due to exchange-bias interaction with the IrMn layer was observed. This scheme offers the possibility to reduce the intermediate layer thickness, thus improve media writability, and with further optimization, could potentially facilitate the approach toward 1 Tbits/in.2.

Nanoporous sputtered platinum-iridium-thinfilms for medical and energy applications; Nanoporoese gesputterte Platin-Iridium-Schichten fuer Anwendungen in der Medizin- und Energietechnik

Energy Technology Data Exchange (ETDEWEB)

Ganske, Gerald

2012-10-05

Sputtering makes it possible to create thinfilms of only a few atom layers and to customize them for special applications by adjusting the deposition parameters. In this work interface-layers are deposited and characterized in biological systems as stimulation electrodes for neural cells and as catalysts in hydrogen fuel cells. First of all, highly porous platinum films were created by sputtering at a pressure of 9 Pa and low power of less than 100 W. These parameters are an ideal compromise between deposition rate, porosity and disordered crystal structure of the layers. Investigations on co-sputtered platinum-iridium-films (PtIr) showed that these films form homogeneous structures and no distinction between the separate layers is possible. It was demonstrated that these films obtain the crystal structure of Pt as well as the finer cauliflower-like structure of iridium, if the atoms reach the substrate surface only with their thermal energy. Furthermore, it was shown that the film composition reflects the sputtering power of the separate targets in a linear way. The structure of the films can be predicted by means of monte-carlo-simulation, which was verified by SEM-pictures. The ratio of the sputtering power can be used to control the amount of interface elements which was confirmed by electrochemical tests. Electrode materials for the stimulation of neural cells need a large electrochemically active surface that allows for an interface between electron and ion conductivity. Test on platinum, iridium and PtIr have shown that the films sputtered at the lowest impact energy do have the largest active surface as well as the largest charge delivery capacity (CDC). Iridium films show the highest CDC (48 mC/cm{sup 2}), followed by platinum-iridium (2 mC/cm{sup 2}, 100 W power at both targets) and pure platinum (16 mC/cm{sup 2}). This can be explained by the large surface area of iridium and its electrochemical activation process. Although PtIr layers also show an

Development of an Iridium-192 seed for use in ophthalmic brachytherapy

International Nuclear Information System (INIS)

Mattos, Fabio R.; Rostelato, Maria Elisa C.M.; Zeituni, Carlos; Moura, Joao A.; Costa, Osvaldo L.; Feher, Anselmo; Moura, Eduardo S.; Souza, Carla D.; Peleias Junior, Fernando S.

2011-01-01

The Institute for Energy and Nuclear Research (IPEN), in partnership with the School or Medicine (UNIFESP), created a project that aims to develop and implement an ophthalmic therapeutic treatment for cancer with Iridium-192 seeds. The School of Medicine treats many cancer cases in the SUS (Brazilian Public Health System), and brachytherapy group of IPEN has extensive experience in prototype sources. The seed to be manufactured will perform as follows: a core of Iridium-192 is packaged inside small cylindrical seeds consist of a titanium capsule of 0.8 mm outer diameter, 0.05 mm wall thickness and 4 5 mm in length. The core is an alloy of platinum-iridium (20/80) of 3.0 mm in length and 0.3 mm in diameter. Material analysis, neutron activation and activity measurements were carried out. (author)

An iron-57 Moessbauer spectroscopic study of titania-supported iron- and iron-iridium catalysts

International Nuclear Information System (INIS)

Berry, F.J.; Jobson, S.

1992-01-01

57 Fe Moessbauer spectroscopy shows that titania-supported iron is reduced by treatment in hydrogen at significantly lower temperatures than corresponding silica- and alumina-supported catalysts. The metallic iron formed under hydrogen at 600deg C is partially converted to carbide by treatment in carbon monoxide and hydrogen. In contrast to its alumina- and silica-supported counterparts, the remainder of the titania-supported iron is unchanged by this gaseous mixture. The 57 Fe Moessbauer spectra of EXAFS show that iron and iridium in the titania-supported iron-iridium catalysts are reduced in hydrogen at even lower temperatures and, after treatment at 600deg C, are predominantly present as the iron-iridium alloy. The treatment of these reduced catalysts in carbon monoxide and hydrogen is shown by Moessbauer spectroscopy and EXAFS to induce the segregation of iron from the iron-iridium alloy and its conversion to iron oxide. (orig.)

ANALISA DAN PERANCANGAN SISTEM AKUNTANSI PENJUALAN, PEMBELIAN DAN KAS PT. BERLIAN EKA SAKTI TANGGUH, MEDAN

Directory of Open Access Journals (Sweden)

Pwee Leng

2001-01-01

Full Text Available The rise of globalization causes the influence of a company's environment to be wider and more complex. The role of handling information is very dominant in highly competitive situations, especially in the business world. Information has even been accepted as one of the business resources, where the company attempts to optimize the role of information in management decision-making, for planning, operations and even control. With the help of computer technology, the spread of information, which initially was quite limited, can now be distributed according to need. This is also the case in accounting, where accounting information, which before only had a role at the operations control level, now has a role in management control. As a result of the increasing role of information in accounting, a system is needed to organize the accounting information in order to give the company a strategic competitive advantage. Because of that, Berlian Eka Sakti Tangguh, an export-oriented company located in Medan, operating in the cooking oil industry has purposed to upgrade the present system (semi-computerized to become a computerized, on-line system in order to help the company face the ever-increasing competition in the business world. Abstract in Bahasa Indonesia : Derasnya arus globalisasi menyebabkan pengaruh lingkungan usaha di tempat perusahaan beroperasi menjadi semakin luas dan kompleks. Peran penguasaan informasi menjadi sangat dominan dalam persaingan yang ketat, tidak terkecuali dalam dunia bisnis. Bahkan informasi telah diakui sebagai salah satu sumber daya, dimana perusahaan berupaya mengoptimalkan peran informasi dalam pengambilan keputusan manajemen baik untuk perencanaan, pelaksanaan, maupun pengendalian. Dengan bantuan teknologi komputer, penyebaran informasi yang pada awalnya sangat terbatas kini telah dapat didistribusikan sesuai dengan kebutuhan. Demikian pula pada bidang akuntansi, dimana informasi akuntansi yang sebelumnya hanya berperan

A preliminary study of factors affecting the calibration stability of the iridium versus iridium-40 percent rhodium thermocouple

Science.gov (United States)

Ahmed, Shaffiq; Germain, Edward F.; Daryabeigi, Kamran; Alderfer, David W.; Wright, Robert E.

1987-01-01

An iridium versus iridium-40% rhodium thermocouple was studied. Problems associated with the use of this thermocouple for high temperature applications (up to 2000 C) were investigated. The metallurgical studies included X-ray, macroscopic, resistance, and metallographic studies. The thermocouples in the as-received condition from the manufacturer revealed large amounts of internal stress caused by cold working during manufacturing. The thermocouples also contained a large amount of inhomogeneities and segregations. No phase transformations were observed in the alloy up to 1100 C. It was found that annealing the thermocouple at 1800 C for two hours, and then at 1400 C for 2 to 3 hours yielded a fine grain structure, relieving some of the strains, and making the wire more ductile. It was also found that the above annealing procedure stabilized the thermal emf behavior of the thermocouple for application below 1800 C (an improvement from + or - 1% to + or - 0.02% within the range of the test parameters used).

Study and development of an Iridium-192 seed for use in ophthalmic cancer

International Nuclear Information System (INIS)

Mattos, Fabio Rodrigues de

2013-01-01

Even ocular tumors are not among the cases with a higher incidence, they affect the population, especially children. The Institute of Energy and Nuclear Research (IPEN-CNEN/SP) in partnership with Escola Paulista de Medicina (UNIFESP), created a project to develop and implement a alternative treatment for ophthalmic cancer that use brachytherapy iridium-192 seeds. The project arose by reason of the Escola Paulista treat many cancer cases within the Unified Health System (SUS) and the research experience of sealed radioactive sources group at IPEN. The methodology was developed from the available infrastructure and the experience of researchers. The prototype seed presents with a core (192-iridium alloy of iridium-platinum) of 3.0 mm long sealed by a capsule of titanium of 0.8 mm outside diameter, 0.05 mm wall thickness and 4,5mm long. This work aims to study and develop a seed of iridium-192 from a platinum-iridium alloy. No study on the fabrication of these seeds was found in available literature. It was created a methodology that involved: characterization of the material used in the core, creation of device for neutron activation irradiation and and seed sealing tests. As a result, proved the feasibility of the method. As a suggestion for future work, studies regarding metrology and dosimetry of these sources and improvement of the methodology should be carried out, for future implementation in national scope. (author)

Phosphorescent systems based on iridium(III) complexes

NARCIS (Netherlands)

Ulbricht, C.

2009-01-01

Phosphorescent iridium(III)-based complexes are experiencing a growing interest in a number of research fields. Aside from lighting and display technologies (i.e. OLEDs and LECs), they find use in various applications such as biolabeling, sensors, solar cells and water splitting. In particular, the

Iridium Catalysis: Reductive Conversion of Glucan to Xylan

DEFF Research Database (Denmark)

Pedersen, Martin Jæger; Madsen, Robert; Clausen, Mads Hartvig

2018-01-01

By using iridium catalysed dehydrogenative decarbonylation, we converted a partly protected cellobioside into a fully protected xylobioside. We demonstrate good yields with two different aromatic ester protecting groups. The resulting xylobioside was directly used as glycosyl donor in further...

Iridium: Global OTH data communications for high altitude scientific ballooning

Science.gov (United States)

Denney, A.

beneficial points provided by the Iridium platform include pure global accessibility (as well as polar), cost effectiveness because it is available as a COTS (Commercially Off The Shelf) technology, reliability in that the equipment must operate in extreme conditions (near space), integration and development time into current systems must be minimized. As a bonus Motorola and NAL Research Corporation are developing SBD (Short Burst Data) into the Iridium network. This may lead the way to a global IP (Internet Protocol) node based ballooning platform. The Iridium satellite data modems employ the Iridium Low-Earth Orbit (LEO) satellite network. The scope of this paper is to introduce an OTH communications alternative, albeit not necessarily a primary one, to existing ballooning platforms using COTS based emerging technologies. Design aspects, characteristics, actual flight testing statistics, principles of the Iridium modems and communication paths are described including payload and support instrumentation interfacing. Not limited to high altitude ballooning, the Iridium communications platform opens a new era in remote commanding and data retrieval.

3,9-Dithia-6-azaundecane-appended Iridium (III) Complex for the Selective Detection of Hg2+ in Aqueous Acetonitrile

International Nuclear Information System (INIS)

Ann, Jee Hye; Li, Yinan; Hyun, Myung Ho

2012-01-01

Detection of mercuric ion (Hg 2+ ) originated from natural or industrial sources is very important because it is extremely toxic even at low levels and causes serious environmental and health problems. Consequently, many efforts have been devoted to the development of sensitive chemosensors for the detection of Hg 2+ . For example, various fluorescent chemosensors based on rhodamine, nitrobenzoxadiazole, fluorescein, boradiazaindacene (BODIPY), dansyl, pyrene, or other fluorophores have been developed for the selective detection of Hg 2+ . While various fluorescent chemosensors for the selective detection of Hg 2+ have been developed, phosphorescent chemosensors for the selective detection of Hg 2+ are relatively rare. Among various phosphors, iridium (III) complexes with sulfur containing cyclometalated ligands have been used as phosphorescent chemosensors for the selective detection of Hg 2+ . Azacrown ether-appended iridium (III) complex developed in our laboratory has also been utilized as a phosphorescent chemosensor for the selective detection of Hg 2+ . As an another iridium (III) complex-based phosphorescent chemosensors for the selective detection of Hg 2+ , in this study, we wish to prepare iridium (III) complex containing two 3,9-dithia-6-azaundecane units as chelating ligands for metal ions. Some fluorophores containing 3,9-dithia-6-azaundecane unit have been successfully applied for the selective detection of Hg 2+ . In this instance, iridium (III) complex containing two 3,9-dithia-6-azaundecane units is expected to be useful as a phosphorescent chemosensor for the selective detection of Hg 2+ . Iridium (III) complex containing two 3,9-dithia-6-azaundecane units was prepared starting from 2-phenylpyridine according to the procedure shown in Scheme 1. 2-Phenylpyridine was transformed into chloride bridged dimeric iridium complex, [(ppy) 2 IrCl] 2 , via the reported procedure. By treating [(ppy) 2 IrCl] 2 with 4,4'-bis(bromomethyl)-2,2'-bipyridine, which

Network flexibility of the IRIDIUM (R) Global Mobile Satellite System

Science.gov (United States)

Hutcheson, Jonathan; Laurin, Mala

1995-01-01

The IRIDIUM system is a global personal communications system supported by a constellation of 66 low earth orbit (LEO) satellites and a collection of earth-based 'gateway' switching installations. Like traditional wireless cellular systems, coverage is achieved by a grid of cells in which bandwidth is reused for spectral efficiency. Unlike any cellular system ever built, the moving cells can be shared by multiple switching facilities. Noteworthy features of the IRIDIUM system include inter-satellite links, a GSM-based telephony architecture, and a geographically controlled system access process. These features, working in concert, permit flexible and reliable administration of the worldwide service area by gateway operators. This paper will explore this unique concept.

Diphosphinoazine Rhodium(I) and Iridium(I) Complexes

Czech Academy of Sciences Publication Activity Database

Pošta, Martin; Čermák, Jan; Vojtíšek, P.; Císařová, I.

2006-01-01

Roč. 71, č. 2 (2006), s. 197-206 ISSN 0010-0765 R&D Projects: GA ČR(CZ) GA203/01/0554; GA ČR(CZ) GA203/99/M037 Institutional research plan: CEZ:AV0Z40720504 Keywords : diphosphinoazines * rhodium complexes * iridium complexes Subject RIV: CC - Organic Chemistry Impact factor: 0.881, year: 2006

Development of Iridium Solid-state Reference Electrode for the Water Chemistry Status Measurement in Nuclear Power Plants

International Nuclear Information System (INIS)

Ku, Heekwon; Lim, Dongseok; Cho, Jaeseon

2013-01-01

The result of ECP measurement of piping material in nuclear power plant at low temperature using the developed iridium (SSRE) reference electrode is approximately -0.370V. Based on the various results of this study, the developed iridium (SSRE) reference electrode can be applied to the water chemistry environments of nuclear power plant. Various metallic materials used in a nuclear power plant have been exposed to a variety of water chemistry environments and the corrosion of metallic materials occurs due to the reactions between metal structures and water chemistry environments. Therefore, the management of the water chemistry factors is needed to prevent corrosion. The chemical factors affecting the corrosion are pH and Electrochemical Corrosion Potential (ECP). The world-wide studies suggest that ECP and pH are effective indicators for preventing the material damage from water chemistry condition. ECP and pH should be measured as the reference electrodes, and should show stable potential characteristics with fast responses. In this study, the iridium reference electrodes using a solid-state metal oxide electrode has been developed to measure effective indicators such as ECP and pH. The iridium (SSRE) reference electrode for the ECP measurement in water chemistry environment of nuclear power plants has been developed. A calibration for water chemistry measurement was performed by potential measurement of iridium (SSRE) reference electrode with Ag/AgCl (SSRE) reference electrode. The result exhibited a stable potential for 117 hours and a super-Nernst ian response with 63.12mV/p H. In this study, the iridium (SSRE) reference electrode shows super-Nernst ian characteristic and it may be caused by the property of electrolytically coated iridium oxide. Considering the long-term stability of the developed electrode, it is possible to apply as a reference electrode through calibration procedure

An Analysis of the FY-1C, Iridium 33, and Cosmos 2251 Fragments

Science.gov (United States)

Liou, J.-C.

2014-01-01

The beginning of the year 2013 marks the sixth anniversary of the destruction of the Fengyun-1C (FY-1C) weather satellite as the result of an anti-satellite test conducted by China in January 2007 and the fourth anniversary of the accidental collision between Cosmos 2251 and the operational Iridium 33 in February 2009. These two events represent the worst satellite breakups in history. A total of 5579 fragments have been cataloged by the U.S. Space Surveillance Network (SSN), and almost 5000 of them were still in orbit in January 2013. In addition to these cataloged objects, hundreds of thousands (or more) of fragments down to the millimeter size regime were also generated during the breakups. These fragments are too small to be tracked by the SSN, but are large enough to be a safety concern for human space activities and robotic missions in low Earth orbit (LEO, the region below 2000 km altitude). Like their cataloged siblings, many of them remain in orbit today. These two breakup events dramatically changed the landscape of the orbital debris environment in LEO. The spatial density of the cataloged population in January 2013 is shown as the top blue curve. The combined FY-1C, Iridium 33, and Cosmos 2251 fragments (black curve) account for about 50 percent of the cataloged population below an altitude of 1000 km. They are also responsible for the concentrations at 770 km and 850 km, altitudes at which the collisions occurred. The effects of the FY-1C, Iridium 33, and Cosmos 2251 fragments will continue to be felt for decades to come. For example, approximately half of the generated FY-1C fragments will remain in orbit 20 years from now. In general, the Iridium 33 and Cosmos 2251 fragments will decay faster than the FY-1C fragments because of their lower altitudes. Of the Iridium 33 and Cosmos 2251 fragments, the former have much shorter orbital lifetimes than the latter, because lightweight composite materials were heavily used in the construction of the Iridium

Single orientation graphene synthesized on iridium thin films grown by molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Dangwal Pandey, A., E-mail: arti.pandey@desy.de; Grånäs, E.; Shayduk, R.; Noei, H.; Vonk, V. [Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg (Germany); Krausert, K.; Franz, D.; Müller, P.; Keller, T. F.; Stierle, A., E-mail: andreas.stierle@desy.de [Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg (Germany); Fachbereich Physik, Universität Hamburg, D-22607 Hamburg (Germany)

2016-08-21

Heteroepitaxial iridium thin films were deposited on (0001) sapphire substrates by means of molecular beam epitaxy, and subsequently, one monolayer of graphene was synthesized by chemical vapor deposition. The influence of the growth parameters on the quality of the Ir films, as well as of graphene, was investigated systematically by means of low energy electron diffraction, x-ray reflectivity, x-ray diffraction, Auger electron spectroscopy, scanning electron microscopy, and atomic force microscopy. Our study reveals (111) oriented iridium films with high crystalline quality and extremely low surface roughness, on which the formation of large-area epitaxial graphene is achieved. The presence of defects, like dislocations, twins, and 30° rotated domains in the iridium films is also discussed. The coverage of graphene was found to be influenced by the presence of 30° rotated domains in the Ir films. Low iridium deposition rates suppress these rotated domains and an almost complete coverage of graphene was obtained. This synthesis route yields inexpensive, air-stable, and large-area graphene with a well-defined orientation, making it accessible to a wider community of researchers for numerous experiments or applications, including those which use destructive analysis techniques or irreversible processes. Moreover, this approach can be used to tune the structural quality of graphene, allowing a systematic study of the influence of defects in various processes like intercalation below graphene.

Iridium Sulfide and Ir Promoted Mo Based Catalysts.

Czech Academy of Sciences Publication Activity Database

Vít, Zdeněk

2007-01-01

Roč. 322, - (2007), s. 142-151 ISSN 0926-860X R&D Projects: GA ČR(CZ) GA104/06/0870 Institutional research plan: CEZ:AV0Z40720504 Keywords : iridium sulfide * IrMo catalyst * hydrodesulfurization Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.166, year: 2007

Synthesis of Fluoroalkoxy Substituted Arylboronic Esters by Iridium-Catalyzed Aromatic C–H Borylation

KAUST Repository

Batool, Farhat

2015-08-17

The preparation of fluoroalkoxy arylboronic esters by iridium-catalyzed aromatic C–H borylation is described. The fluoroalkoxy groups employed include trifluoromethoxy, difluoromethoxy, 1,1,2,2-tetrafluoroethoxy, and 2,2-difluoro-1,3-benzodioxole. The borylation reactions were carried out neat without the use of a glovebox or Schlenk line. The regioselectivities available through the iridium-catalyzed C–H borylation are complementary to those obtained by the electrophilic aromatic substitution reactions of fluoroalkoxy arenes. Fluoroalkoxy arylboronic esters can serve as versatile building blocks.

Synthesis of Fluoroalkoxy Substituted Arylboronic Esters by Iridium-Catalyzed Aromatic C–H Borylation

KAUST Repository

Batool, Farhat; Parveen, Shehla; Emwas, Abdul-Hamid M.; Sioud, Salim; Gao, Xin; Munawar, Munawar A.; Chotana, Ghayoor A.

2015-01-01

The preparation of fluoroalkoxy arylboronic esters by iridium-catalyzed aromatic C–H borylation is described. The fluoroalkoxy groups employed include trifluoromethoxy, difluoromethoxy, 1,1,2,2-tetrafluoroethoxy, and 2,2-difluoro-1,3-benzodioxole. The borylation reactions were carried out neat without the use of a glovebox or Schlenk line. The regioselectivities available through the iridium-catalyzed C–H borylation are complementary to those obtained by the electrophilic aromatic substitution reactions of fluoroalkoxy arenes. Fluoroalkoxy arylboronic esters can serve as versatile building blocks.

Production of iridium-alloy clad vent sets for the Cassini mission to Saturn

International Nuclear Information System (INIS)

Helle, K.J.; Moore, J.P.

1995-01-01

Martin Marietta Energy Systems, Inc., has successfully produced the iridium-alloy clad vent sets required for encapsulation of plutonia for the National Aeronautics and Space Administration Cassini mission to Saturn. Numerous improvements were made to the manufacturing process in various areas including dye-penetrant examination of cups, foil part stamping, chemical analysis, tungsten fixturing for laser welding, and enhanced inspections at high magnification. In addition, systems were initiated to ensure process control, and a detailed quality and technical surveillance program was prepared and followed to detect any incipient production problem early in the process so that corrective action could be taken immediately. The quality of the resulting iridium components has been high, and production yields have been above 90%. During the course of the production campaign for the Cassini mission, worker efficiencies lowered production costs, and further cost reductions are possible if operations are consolidated into a single area and bare-forming of the iridium alloys cups can be qualified for flight-quality clad vent sets

Development and characterisation of iridium-192 seeds for brachytherapy treatment of ocular tumors

International Nuclear Information System (INIS)

Peleias Jr, F.S.; Zeituni, C.A.; Souza, C.D.; Rostelato, M.E.CM.; Mattos, F.R.; Banega, M.A.G.; Rodrigues, B.T.; Tiezzi, R.; Oliveira, T.B.; Feher, A.; Moura, J.A.; Costa, O.L.

2014-01-01

Even ocular tumors are not amongst the cases with a high incidence, they affect the population, particularly children. The Institute of Energy and Nuclear Research (IPEN-CNEN/SP) in partnership with Escola Paulista de Medicina (UNIFESP), created a project to develop an alternative treatment for ophthalmic cancer that uses iridium-192 seeds in brachytherapy. This work aims to study and develop a seed of iridium-192 from a platinum-iridium alloy The prototype seed has a 3.0 mm long core sealed by a titanium capsule of 0.8 mm of outer diameter, 0.05 mm of wall thickness and 4.5 mm long. We developed a methodology that covered: characterisation of the material used in the core, creation of a device for neutron activation of the cores and leakage tests. The results show that this methodology is feasible. As a suggestion for future work, studies regarding metrology and dosimetry of these sources should be carried out. (authors)

Experimental and Theoretical Mechanistic Investigation of the Iridium-Catalyzed Dehydrogenative Decarbonylation of Primary Alcohols

DEFF Research Database (Denmark)

Olsen, Esben Paul Krogh; Singh, Thishana; Harris, Pernille

2015-01-01

The mechanism for the iridium-BINAP catalyzed dehydrogenative decarbonylation of primary alcohols with the liberation of molecular hydrogen and carbon monoxide was studied experimentally and computationally. The reaction takes place by tandem catalysis through two catalytic cycles involving...... cycles. One carbon monoxide ligand was shown to remain coordinated to iridium throughout the reaction, and release of carbon monoxide was suggested to occur from a dicarbonyl complex. IrH2Cl(CO)(rac-BINAP) was also synthesized and detected in the dehydrogenation of benzyl alcohol. In the same experiment......, IrHCl2(CO)(rac-BINAP) was detected from the release of HCl in the dehydrogenation and subsequent reaction with IrCl(CO)(rac-BINAP). This indicated a substitution of chloride with the alcohol to form a square planar iridium alkoxo complex that could undergo a beta-hydride elimination. A KIE of 1...

Preparation and determination of kerma for Iridium 192 sources of low dose rate for brachytherapy

International Nuclear Information System (INIS)

Tendilla, J.I.; Tovar M, V.; Mitsoura, E.; Aguilar H, F.; Alanis M, J.

2000-01-01

The practice of Brachytherapy with Iridium-192 sources of low dose rate (0.4 - 0.8 Gy/h) is a technique used in the treatment of diverse illnesses. in this work the preparation, quality control and calibration are presented in terms of kerma in air of Iridium-192 using as target these recycled Iridium-Platinum wires. The targets were obtained as decayed sources of different radio therapeutical centers in the country and they were characterized by Scanning electron microscopy in order to determine their chemical composition. Subsequently it was developed an experimental design to establish the effect of neutron flux, geometrical array and irradiation time over the activity and percentage of the sources homogeneity. The homogeneity was determined by auto radiography and by Gamma spectroscopy. Once the optimal irradiation conditions were established, it is determined the apparent activity and kerma in air using a well type ionization chamber with traceability to a primary laboratory. Iridium-192 sources were obtained with an average homogeneity 96 %, apparent activity 282.129 ± 0.531 M Bq and kerma in air 0.03200 ± 0.00006 m Gy m/h A. (Author)

Synthesis and electrophosphorescence of iridium complexes containing benzothiazole-based ligands.

Science.gov (United States)

Liu, Di; Ren, Huicai; Deng, Lijun; Zhang, Ting

2013-06-12

Four heteroleptic bis-cyclometalated iridium(III) complexes containing 2-aryl-benzothiazole ligands, in which the aryl is dibenzofuran-2-yl [Ir(O-bt)2(acac)], dibenzothiophene-2-yl [Ir(S-bt)2(acac)], dibenzothiophene-S,S-dioxide-2-yl [Ir(SO2-bt)2(acac)] and 4-(diphenylphosphoryl)phenyl [Ir(PO-bt)2(acac)], have been synthesized and characterized for use in organic light-emitting diodes (OLEDs). These complexes emit bright yellow (551 nm) to orange-red (598 nm) phosphorescence at room temperature, the peak wavelengths of which can be finely tuned depending upon the electronic properties of the aryl group in the 2-position of benzothiazole. The strong electron-withdrawing aryls such as dibenzothiophene-S,S-dioxide2-yl and 4-(diphenylphosphoryl)phenyl caused bathochromatic shift of the iridium complex phosphorescence. These iridium complexes were used as doped emitters to fabricate yellow to orange-red OLEDs and good performance was obtained. In particular, a maximum luminance efficiency of 58.4 cd A(-1) (corresponding to 30.6 lm W(-1) and 19%) with CIE coordinates of (0.45, 0.52) was achieved for Ir(O-bt)2(acac)-based yellow device. Furthermore, the yellow emitting Ir(S-bt)2(acac) was used to fabricate two-element white OLED that exhibited a high efficiency of 32.4 cd A(-1) with CIE coordinates of (0.28, 0.44).

Interstitial curietherapy with iridium 192 applied to small cancers of the rectum

International Nuclear Information System (INIS)

Papillon, J.; Montbarbon, J.F.; Gerard, J.P.

1975-01-01

Intracavity irradiation aimed at curing cancers of the rectum mainly calls on contact radiotherapy but also on interstitial curietherapy. Iridium curietherapy has replaced radium-therapy owing to the better homogeneousness of its action and precise method of assay. It uses a 2 pronged fork containing 2 iridium wires which can be very simply placed in position. It is applied on the one hand to the base of the ulcerated tumour, after abrasion by contactotherapy and on the other hand as a method of prophylactic irradiation after exeresis of a malignant or degenerated polyp where the scar is badly adapted to contactotherapy [fr

Electrogenerated chemiluminescence of a cationic cyclometalated iridium complex–Nafion modified electrode in neutral aqueous solution

International Nuclear Information System (INIS)

Dong, YongPing; Ni, ZiYue; Zhang, Jing; Tong, BiHai; Chu, XiangFeng

2013-01-01

Electrogenerated chemiluminescence (ECL) of a cationic cyclometalated iridium complex, [(pqcm) 2 Ir(bpy)](PF 6 ) (1, pqcmH=2-phenyl-quinoline-4-carboxylic acid methyl ester, bpy=2,2′-bipyridine), was investigated at a bare glassy carbon electrode in CH 3 CN solution and 4 ECL peaks were observed. Then, the ECL of the iridium complex was studied in neutral phosphate buffer solution (PBS) by immobilizing it on a glassy carbon electrode. Two closely located ECL peaks were obtained at 1.07 and 1.40 V when the potential was scanned from −3.00 V to 2.20 V, while only one broad ECL peak located around −2.0 V was obtained when the potential was scanned from 2.20 V to −3.00 V. In the presence of oxalate, one ECL peak located around 1.22 V could be obtained except the broad ECL peak located at −2.00 V. The ECL peak at positive potential range was enhanced more than one magnitude in the presence of Nafion and was nearly 5-times higher than that of Ru(bpy) 3 2+ –Nafion modified electrode, suggesting that the synthesized iridium complex has great application potential in ECL detection. The ECL spectra of iridium complex were identical to its photoluminescence spectrum, indicating the same metal-to-ligand charge transfer (MLCT) excited states. The mechanisms of ECL were proposed based on the experimental results. The present ECL sensor gave a linear response for the oxalate concentration from 1.0×10 −6 to 1.0×10 −4 mol L −1 with a detection limit (S/N=3) of 9.1×10 −7 mol L −1 . -- Graphical abstract: Electrochemiluminescence (ECL) of immobilized novel cationic cyclometalated iridium complex in neutral phosphate buffer solution is reported for the first time. The intensity of iridium complex ECL is 5-times higher than that of Ru(bpy) 3 2+ ECL. Highlights: ► Cationic cyclometalated iridium complex was modified on a bare electrode. ► Electrochemiluminescence (ECL) of the modified electrode was studied. ► The ECL intensity is higher than that of Ru

A projector of iridium 192 wires: motivations and preliminary studies

International Nuclear Information System (INIS)

Cosset, J.M.; Gerbaulet, A.; Chassagne, D.

1979-01-01

Though the majority of procedures involved in curietherapy with Iridium 192 wires cause very few problems concerning radiation protection, this is not true in all cases: in elderly of debilitated patients, young children, or when using special techniques (curietherapy for prostate of bladder cancers for example). In these cases, the need for frequent treatment exposes the therapists to increased doses. The projector of Iridium 192 wires was conceived in order to reduce this irradiated hazard. A simple manipulation places the radioactive wires in a lead container during treatment, and then replaces them in the right position after therapy. This apparatus appears to offer the possibility of: an almost total protection of the therapists, and thus an opportunity for enlarging the indications for curietherapy; an improved quality of treatment to the patient during the application [fr

Asymmetric Hydrogenation of Quinoxalines Catalyzed by Iridium/PipPhos

NARCIS (Netherlands)

Mrsic, Natasa; Jerphagnon, Thomas; Minnaard, Adriaan J.; Feringa, Ben L.; de Vries, Johannes G.

2009-01-01

A catalyst made in situ from the (cyclooctadiene)iridium chloride dimer, [Ir(COD)Cl](2), and the monodentate phosphoramidite ligand (S)-PipPhos was used in the enantioselective hydrogenation of 2- and 2,6-substituted quinoxalines. In the presence of piperidine hydrochloride as additive full

3,9-Dithia-6-azaundecane-appended Iridium (III) Complex for the Selective Detection of Hg{sup 2+} in Aqueous Acetonitrile

Energy Technology Data Exchange (ETDEWEB)

Ann, Jee Hye; Li, Yinan; Hyun, Myung Ho [Pusan National Univ., Busan (Korea, Republic of)

2012-10-15

Detection of mercuric ion (Hg{sup 2+}) originated from natural or industrial sources is very important because it is extremely toxic even at low levels and causes serious environmental and health problems. Consequently, many efforts have been devoted to the development of sensitive chemosensors for the detection of Hg{sup 2+}. For example, various fluorescent chemosensors based on rhodamine, nitrobenzoxadiazole, fluorescein, boradiazaindacene (BODIPY), dansyl, pyrene, or other fluorophores have been developed for the selective detection of Hg{sup 2+}. While various fluorescent chemosensors for the selective detection of Hg{sup 2+} have been developed, phosphorescent chemosensors for the selective detection of Hg{sup 2+} are relatively rare. Among various phosphors, iridium (III) complexes with sulfur containing cyclometalated ligands have been used as phosphorescent chemosensors for the selective detection of Hg{sup 2+}. Azacrown ether-appended iridium (III) complex developed in our laboratory has also been utilized as a phosphorescent chemosensor for the selective detection of Hg{sup 2+}. As an another iridium (III) complex-based phosphorescent chemosensors for the selective detection of Hg{sup 2+}, in this study, we wish to prepare iridium (III) complex containing two 3,9-dithia-6-azaundecane units as chelating ligands for metal ions. Some fluorophores containing 3,9-dithia-6-azaundecane unit have been successfully applied for the selective detection of Hg{sup 2+}. In this instance, iridium (III) complex containing two 3,9-dithia-6-azaundecane units is expected to be useful as a phosphorescent chemosensor for the selective detection of Hg{sup 2+}. Iridium (III) complex containing two 3,9-dithia-6-azaundecane units was prepared starting from 2-phenylpyridine according to the procedure shown in Scheme 1. 2-Phenylpyridine was transformed into chloride bridged dimeric iridium complex, [(ppy){sub 2}IrCl]{sub 2}, via the reported procedure. By treating [(ppy){sub 2}Ir

Assessment of radiation exposure of personnel during clinical application of radioactive iridium

Energy Technology Data Exchange (ETDEWEB)

Dworakowski, M; Krystman-Mazgajska, E; Wysopolski, J [Instytut Onkologii, Warsaw (Poland); Centralne Lab. Ochrony Radiologicznej, Warsaw (Poland))

1975-01-01

The authors describe the results of measurements of doses and the evaluation of radiation exposure of the personnel of the Department of General Oncology working with application of radioactive iridium for interstitial and superficial treatment of neoplasma. The doses were measured by the photographic method simultaneously at six sites of the body: on the forehead, left side of the chest, 4th fingers of both hands, and on the left and right sides of the trunk at the level of gonads. The authors believe that introduction of iridium in place of radium will improve the conditions of work from the standpoint of protection against radioactivity.

Enantioselective synthesis of almorexant via iridium-catalysed intramolecular allylic amidation

NARCIS (Netherlands)

Fananas Mastral, Martin; Teichert, Johannes F.; Fernandez-Salas, Jose Antonio; Heijnen, Dorus; Feringa, Ben L.

2013-01-01

An enantioselective synthesis of almorexant, a potent antagonist of human orexin receptors, is presented. The chiral tetrahydroisoquinoline core structure was prepared via iridium-catalysed asymmetric intramolecular allylic amidation. Further key catalytic steps of the synthesis include an oxidative

Surface studies of iridium-alloy grain boundaries associated with weld cracking

International Nuclear Information System (INIS)

Mosley, W.C.

1982-01-01

Plutonium-238 oxide fuel pellets for the General Purpose Heat Source (GPHS) Radioisotopic Thermoelectric Generators to be used on the NASA Galileo Mission to Jupiter and the International Solar Polar Mission are produced and encapsulated in iridium alloy at the Savannah River Plant (SRP). Underbead cracks occasionally occur in the girth weld on the iridium-alloy-clad vent sets in the region where the gas tungsten arc is quenched. Grain-boundary structures and compositions were characterized by scanning electron microscopy/x-ray energy spectroscopy, electron microprobe analysis and scanning Auger microprobe analysis to determine the cause of weld quench area cracking. Results suggest that weld quench area cracking may be caused by gas porosity or liquation in the grain boundaries

Determination of iridium in the Bering Sea and Arctic Ocean seawaters by anion exchange preconcentration-neutron activation analysis

International Nuclear Information System (INIS)

Li Shihong; Mao Xueying; Chai Zhifang

2004-01-01

Anion exchange method is investigated to separate and enrich iridium in seawater by radiotracer 192 Ir. The adsorption of Ir in the resin increases with the decreasing acidity in the 0.05-1.2 mol/L HCl media, The recovery of iridium in pH=1.5 seawater reaches 89% by a single anion-exchange column. The polyethylene container of acidity of pH=1.5 are suitable for storing trace Ir in seawater. An anion exchange preconcentration-neutron activation analysis procedure is developed to determine iridium in seawaters sampled from the Bering Sea and Arctic Ocean at different depth. The reagent blank value of the whole procedures is (0.18-0.20) x 10 -12 g Ir. The iridium concentrations in the Bering Sea and Arctic Ocean seawater samples are (0.85-3.58) x 10 -12 g/L (0-3504 m) and (1.26-1.97) x 10 -12 g/L (25-1900 m), respectively

Iridium/Bipyridine-Catalyzed ortho-Selective C-H Borylation of Phenol and Aniline Derivatives.

Science.gov (United States)

Li, Hong-Liang; Kanai, Motomu; Kuninobu, Yoichiro

2017-11-03

An iridium-catalyzed ortho-selective C-H borylation of phenol and aniline derivatives has been successfully developed. Iridium/bipyridine-catalyzed C-H borylation generally occurred at the meta- and para-positions of aromatic substrates. Introduction of an electron-withdrawing substituent on the bipyridine-type ligand and a methylthiomethyl group on the hydroxy and amino groups of the phenol and aniline substrates, however, dramatically altered the regioselectivity, affording exclusively ortho-borylated products. The reaction proceeded in good to excellent yields with good functional group tolerance. C-H borylation was applied to the synthesis of a calcium receptor modulator.

Triazole-pyridine ligands: a novel approach to chromophoric iridium arrays

NARCIS (Netherlands)

Juríček, M.; Felici, M.; Contreras-Carballada, P.; Lauko, J.; Bou, S.R.; Kouwer, P.H.J.; Brouwer, A.M.; Rowan, A.E.

2011-01-01

We describe a novel modular approach to a series of luminescent iridium complexes bearing triazole-pyridine-derived ligands that were conveniently prepared by using "click" chemistry. One, two or three triazole-pyridine units were effectively built into the heteroaromatic macromolecule using

Neutron activation determination of iridium, gold, platinum, and silver in geologic samples

International Nuclear Information System (INIS)

Millard, H.T.

1986-01-01

Low-level methods for the determination of iridium and other noble metals have been important in recent years due to interest in locating abundance anomalies associated with the Cretaceous/Tertiary (K/T) boundary. Typical iridium anomalies are in the range of 1 to 100 ppb. Thus methods with detection limits near 0.1 ppb should be adequate to detect K/T boundary anomalies. Radiochemical neutron activation analysis methods continue to be required although instrumental neutron activation analysis techniques employing elaborate gamma-counters are under development. In the procedure employed in this study samples irradiated in the epithermal neutron facility of the U.S. Geological Survey TRIGA Reactor are treated with a mini-fire assay technique. The iridium, gold, and silver are collected in a 1-gram metallic lead button. Primary contaminants at this stage are arsenic and antimony. These can be removed by heating the button with a mixture of sodium peroxide and sodium hydroxide. The resulting 0.2-gram lead bead is counted in a Compton suppression spectrometer. Carrier yields are determined by reirradiation of the lead beads. This procedure has been applied to the U.S.G.S. Standard Rock PCC-1. and samples from K/T boundary sites in the Western Interior of North America. (author)

Iridium catalyzed growth of vertically aligned CNTs by APCVD

International Nuclear Information System (INIS)

Sahoo, R.K.; Jacob, C.

2014-01-01

Highlights: • Growth of uniform-diameter vertically-aligned multi-walled CNTs by APCVD. • Use of high melting point low carbon solubility iridium nanoparticles as catalyst. • Optimization of growth time for uniform sized, uniformly aligned CNTs. • Growth model for the various features in the vertically aligned CNTs is proposed. - Abstract: Vertically aligned carbon nanotubes (VA-CNTs) have been synthesized using high temperature catalyst nanoparticles of iridium. The catalyst layer was prepared by DC sputtering. Particle density, circularity and average particle size of the catalyst were analyzed using field emission scanning electron microscopy. The alignment, morphology and the length of the as-grown CNTs were analyzed using field-emission scanning electron microscopy. High resolution transmission electron microscopy was carried out to observe the layers of graphitic stacking which form the carbon nanotubes. Micro Raman measurement was used for the analysis of the graphitic crystallinity of the as-grown carbon nano structures. Effects of growth time variation on growth morphology and alignment have been studied. The alignment has been explained on the basis of the crowding effect of the neighboring nanoparticles

Iridium catalyzed growth of vertically aligned CNTs by APCVD

Energy Technology Data Exchange (ETDEWEB)

Sahoo, R.K.; Jacob, C., E-mail: cxj14_holiday@yahoo.com

2014-07-01

Highlights: • Growth of uniform-diameter vertically-aligned multi-walled CNTs by APCVD. • Use of high melting point low carbon solubility iridium nanoparticles as catalyst. • Optimization of growth time for uniform sized, uniformly aligned CNTs. • Growth model for the various features in the vertically aligned CNTs is proposed. - Abstract: Vertically aligned carbon nanotubes (VA-CNTs) have been synthesized using high temperature catalyst nanoparticles of iridium. The catalyst layer was prepared by DC sputtering. Particle density, circularity and average particle size of the catalyst were analyzed using field emission scanning electron microscopy. The alignment, morphology and the length of the as-grown CNTs were analyzed using field-emission scanning electron microscopy. High resolution transmission electron microscopy was carried out to observe the layers of graphitic stacking which form the carbon nanotubes. Micro Raman measurement was used for the analysis of the graphitic crystallinity of the as-grown carbon nano structures. Effects of growth time variation on growth morphology and alignment have been studied. The alignment has been explained on the basis of the crowding effect of the neighboring nanoparticles.

Phosphorescent Organic Light-Emitting Devices: Working Principle and Iridium Based Emitter Materials

Directory of Open Access Journals (Sweden)

Emil J. W. List

2008-08-01

Full Text Available Even though organic light-emitting device (OLED technology has evolved to a point where it is now an important competitor to liquid crystal displays (LCDs, further scientific efforts devoted to the design, engineering and fabrication of OLEDs are required for complete commercialization of this technology. Along these lines, the present work reviews the essentials of OLED technology putting special focus on the general working principle of single and multilayer OLEDs, fluorescent and phosphorescent emitter materials as well as transfer processes in host materials doped with phosphorescent dyes. Moreover, as a prototypical example of phosphorescent emitter materials, a brief discussion of homo- and heteroleptic iridium(III complexes is enclosed concentrating on their synthesis, photophysical properties and approaches for realizing iridium based phosphorescent polymers.

Extrahepatic bile duct carcinoma treated by intraluminal irradiation with iridium-192 wire

International Nuclear Information System (INIS)

Ikeda, Hiro; Kuroda, Tomosumi; Uchida, Hideo

1980-01-01

A 57-year-old male with obstructive jaundice was diagnosed extrahepatic bile duct carcinoma at bifurcation by percutaneous transhepatic cholangiography (PTC). He was treated 3,300 rad of external irradiation and then intraluminal irradiation using the Iridium-192 wire by two times with the aid of PTC internal drainage, each was given by the dose of 1,600 rad at 5 mm inside the tumor from the PTC-tube. He had been well for about 1 year and then died because of ascites and cachexia. Autopsy revealed only microscopic tumor cells remaining around the common duct below the cystic junction. It was confirmed that intraluminal irradiation using the Iridium-192 wire was potentially curable and easily applicable to the bile duct carcinoma. (author)

High temperature reactive ion etching of iridium thin films with aluminum mask in CF4/O2/Ar plasma

Directory of Open Access Journals (Sweden)

Chia-Pin Yeh

2016-08-01

Full Text Available Reactive ion etching (RIE technology for iridium with CF4/O2/Ar gas mixtures and aluminum mask at high temperatures up to 350 °C was developed. The influence of various process parameters such as gas mixing ratio and substrate temperature on the etch rate was studied in order to find optimal process conditions. The surface of the samples after etching was found to be clean under SEM inspection. It was also shown that the etch rate of iridium could be enhanced at higher process temperature and, at the same time, very high etching selectivity between aluminum etching mask and iridium could be achieved.

Nuclear resonance scattering study of iridates, iridium and antimony based pyrochlores

International Nuclear Information System (INIS)

Alexeev, P.

2017-04-01

This thesis shows the first synchrotron-based Moessbauer spectroscopy studies on iridium containing compounds and first vibrational spectroscopy on Sb containing compounds carried out at the P01 beamline of PETRA III. In this context, two types of X-ray monochromators have been developed: a monochromator for 73 keV photons with medium energy resolution, and a high-resolution backscattering monochromator based on a sapphire crystal. The monochromator for 73 keV X-rays is the key instrument for hyperfine spectroscopy on Iridium compounds, while the sapphire backscattering monochromator is purposed to vibrational spectroscopy on any Moessbauer resonances with the transition energies in the 20-50 keV range. Additionally, the signal detection for nuclear resonance scattering experiments at the beamline was significantly improved during this work, inspired by the high energies and low lifetimes of the employed resonances. The first synchrotron-based hyperfine spectroscopy on Iridium-containing compounds was demonstrated by NRS on 73 keV resonance in "1"9"3Ir. The results can be interpreted by dynamical theory of nuclear resonance scattering. In this work, special emphasis is set onto the electronic and magnetic properties of Ir nuclei in IrO_2 and in Ruddlesden-Popper (RP) phases of strontium iridates Sr_n_+_1Ir_nO_3_n_+_1 (n=0,1). These systems are well-suited for studies with X-ray scattering techniques, since the scattered signal contains vast information about the widely tunable crystallographic and electronic structure of these systems; furthermore, studies with X-rays are less limited by absorption from iridium as it is the case for neutron scattering experiments. The hyperfine parameters in IrO_2, SrIrO_3 and Sr_2IrO_4 have been measured via Nuclear Forward Scattering for the first time. Using the dynamical theory of NRS, the temperature and magnetic field dependence of the electric field gradient and magnetic hyperfine field on Ir nucleus have been determined for

Nuclear resonance scattering study of iridates, iridium and antimony based pyrochlores

Energy Technology Data Exchange (ETDEWEB)

Alexeev, P.

2017-04-15

This thesis shows the first synchrotron-based Moessbauer spectroscopy studies on iridium containing compounds and first vibrational spectroscopy on Sb containing compounds carried out at the P01 beamline of PETRA III. In this context, two types of X-ray monochromators have been developed: a monochromator for 73 keV photons with medium energy resolution, and a high-resolution backscattering monochromator based on a sapphire crystal. The monochromator for 73 keV X-rays is the key instrument for hyperfine spectroscopy on Iridium compounds, while the sapphire backscattering monochromator is purposed to vibrational spectroscopy on any Moessbauer resonances with the transition energies in the 20-50 keV range. Additionally, the signal detection for nuclear resonance scattering experiments at the beamline was significantly improved during this work, inspired by the high energies and low lifetimes of the employed resonances. The first synchrotron-based hyperfine spectroscopy on Iridium-containing compounds was demonstrated by NRS on 73 keV resonance in {sup 193}Ir. The results can be interpreted by dynamical theory of nuclear resonance scattering. In this work, special emphasis is set onto the electronic and magnetic properties of Ir nuclei in IrO{sub 2} and in Ruddlesden-Popper (RP) phases of strontium iridates Sr{sub n+1}Ir{sub n}O{sub 3n+1} (n=0,1). These systems are well-suited for studies with X-ray scattering techniques, since the scattered signal contains vast information about the widely tunable crystallographic and electronic structure of these systems; furthermore, studies with X-rays are less limited by absorption from iridium as it is the case for neutron scattering experiments. The hyperfine parameters in IrO{sub 2}, SrIrO{sub 3} and Sr{sub 2}IrO{sub 4} have been measured via Nuclear Forward Scattering for the first time. Using the dynamical theory of NRS, the temperature and magnetic field dependence of the electric field gradient and magnetic hyperfine field

Determination of surface coverage of catalysts : temperature programmed experiments on platinum and iridium sponge catalysts after low temperature ammonia oxidation

NARCIS (Netherlands)

van den Broek, A.C.M.; Grondelle, van J.; Santen, van R.A.

1999-01-01

The activity of iridium and platinum sponge catalysts was studied in the low temperature gas phase oxidation of ammonia with oxygen. Under the reaction conditions used, iridium was found to be more active and more selective to nitrogen than platinum. Furthermore it was established from activity

Low-Stress Iridium Coatings for Thin-Shell X-Ray Telescopes, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — We propose to develop and commercialize a new type of low-stress iridium (Ir) X-ray mirror coating technology that can be used for the construction of...

Intercalating cobalt between graphene and iridium (111): Spatially dependent kinetics from the edges

Science.gov (United States)

Vlaic, Sergio; Rougemaille, Nicolas; Kimouche, Amina; Burgos, Benito Santos; Locatelli, Andrea; Coraux, Johann

2017-10-01

Using low-energy electron microscopy, we image in real time the intercalation of a cobalt monolayer between graphene and the (111) surface of iridium. Our measurements reveal that the edges of a graphene flake represent an energy barrier to intercalation. Based on a simple description of the growth kinetics, we estimate this energy barrier and find small, but substantial, local variations. These local variations suggest a possible influence of the graphene orientation with respect to its substrate and of the graphene edge termination on the energy value of the barrier height. Besides, our measurements show that intercalated cobalt is energetically more favorable than cobalt on bare iridium, indicating a surfactant role of graphene.

The effect of surface depletion on the work function of arc-melted dilute solution tungsten-iridium alloys

International Nuclear Information System (INIS)

D'Cruz, L.A.; Bosch, D.R.; Jacobson, D.L.

1991-01-01

The requirements of thermionic electrode materials have emphasized the need for substantial improvements in microstructural stability, strength, and creep resistance at service temperature in excess of 2,500K. The present work extends an earlier study of the effective work function trends of a series of dilute solution tungsten, iridium alloys with iridium contents of 1, 3, and 5 wt%. Since the lifetime of candidate electrode materials is an important consideration, the present work attempts to evaluate the repeatability of the work function trends in these alloys. The effective work function was obtained from measurements of the current emitted from the electrode surface under UHV conditions in the temperature range of 1,800-2,500K using a Vacuum Emission Vehicle (VEV). The data generated in this work have been compared with data obtained in earlier studies performed on these alloys. It was found that the magnitude of the effective work function of these alloys was affected by changes in the subsurface iridium concentration. Furthermore, these alloys exhibited a dependence of the work function on temperature, after prolonged exposure to elevated temperatures. Such a temperature dependence can be explained by diffusion-controlled changes in the coverage of an iridium monolayer on the surface. It is proposed that the significant difference in effective work function trends obtained after prolonged exposure to elevated temperatures is a direct consequence of changes in the coverage of an iridium-rich monolayer on the electrode surface. The constitution of such a surface layer, however, would be governed by composition changes in the subsurface regions of the electrode caused thermally-activated transport processes

Dose determination in breast tumor in brachytherapy using Iridium-192

International Nuclear Information System (INIS)

Okuno, S.F.

1984-01-01

Thermoluminescent dosimetry studies in vivo and in vitro aiming to determing radiation dose in the breast tumor, in brachytherapy using Iridium-192 was done. The correlation between radiation doses in tumor and external surface of the breast was investigated for correcting the time interval of radiation source implantation. (author) [pt

Study of neutron deficient iridium isotopes by using laser spectroscopy; Etude des noyaux d'iridium deficients en neutrons par spectroscopie laser

Energy Technology Data Exchange (ETDEWEB)

Verney, D

2000-12-19

Resonance ionization spectroscopy was performed on neutron deficient iridium isotopes {sup 182-189}Ir, {sup 186}Ir{sup m} and stable isotopes {sup 191,193}Ir. Hyperfine spectra were recorded from the optical transition at 351,7 nm between the 5d{sup 7}6s{sup 2} {sup 4}F{sub 9/2} ground state and the 5d{sup 7}6s6p {sup 6}F{sub 11/2} excited state. Radioactive iridium isotopes were obtained from {beta}{sup +}/EC decay of radioactive mercury nuclei deposited on a graphite substrate. The radioactive mercury nuclei were produced at the ISOLDE facility at CERN through spallation reactions, by bombarding a molten lead target with the 1 GeV proton beam delivered by the PS-Booster. Magnetic dipole moments and spectroscopic quadrupole moments were extracted from the hyperfine spectra. The mean square charge radius variations, as deduced from the measured isotopic shift, show a sharp change between {sup 187}Ir and {sup 186}Ir{sup g}, accompanied by a sudden increase in deformation: from {beta}2 {approx} 0,16 to {beta}2 > 0, 2. These results were analysed in the framework of an axial rotor plus one or two quasiparticles. The wave functions of the osmium and platinum cores which are used in order to describe the iridium nuclei were calculated from the HF+BCS method with the Skyrme SIII effective interaction. The cores were constrained to take the deformation parameters extracted from the isotopic shift measurements. One shows then that this sudden deformation change corresponds also to a change in the proton state that describes the odd nuclei ground state or that participates in the coupling with the neutron in odd-odd nuclei. This state is identified with the {pi}3/2{sup +}[402] orbital for the smaller deformations nuclei and with the {pi}1/2{sup -}[541] orbital stemming from the h{sub 9/2} subshell for bigger deformations nuclei. (author)

Development of U.S. Government General Technical Requirements for UAS Flight Safety Systems Utilizing the Iridium Satellite Constellation

Science.gov (United States)

Murray, Jennifer; Birr, Richard

2010-01-01

This slide presentation reviews the development of technical requirements for Unmanned Aircraft Systems (UAS) utilization of the Iridium Satellite Constellation to provide flight safety. The Federal Aviation Authority (FAA) required an over-the-horizon communication standard to guarantee flight safety before permitting widespread UAS flights in the National Air Space (NAS). This is important to ensure reliable control of UASs during loss-link and over-the-horizon scenarios. The core requirement was to utilize a satellite system to send GPS tracking data and other telemetry from a flight vehicle down to the ground. Iridium was chosen as the system because it is one of the only true satellite systems that has world wide coverage, and the service has a highly reliable link margin. The Iridium system, the flight modems, and the test flight are described.

Dosimetry of wires and single ribbons of Iridium 192

International Nuclear Information System (INIS)

Mazzucco, L.D.

1998-01-01

The objective of this work is in order to present in table formats the dosimetry of wires and single ribbons of Iridium with lengths 1-12 cm for each one linear source along the bisector which is perpendicular at tissue sources (water) computed for linear activity 1 mCi/cm in the case of wires, and 1 mCi/seed for ribbons. The above tables are of direct use, adaptable at particular cases so they facilitate logarithmic graphics of doses in function of the distance for interpolation and use in the treatments planning. It was shown that for two sources with identical linear activity and total length, one of the equidistant seeds at 1 cm (ribbon) and one wire on the other hand, the differences in dose rates in near positions can be about the 15% so corroborating that it is not possible to use wire tables for seeds neither vice versa. Moreover it was elaborated tables of practical direct use for dose rate in water at c Gy/hr for wires and Ribbons 1-12 cm length and from 0.5-10 cm of distance in the perpendicular bisector at the Iridium implant. (Author)

Problems associated with iridium-192 wire implants

International Nuclear Information System (INIS)

Arnott, S.J.; Law, J.; Ash, D.; Flynn, A.; Paine, C.H.; Durrant, K.R.; Barber, C.D.; Dixon-Brown, A.

1985-01-01

Three incidents are reported, from different radiotherapy centres, in which an implanted iridium-192 wire remained in the tissues of a patient after withdrawal of the plastic tubing in which it was contained. In each case the instrument used to cut the wire had probably formed a hook on the end of the wire which caused it to catch in the tissues. Detailed recommendations are made for avoiding such incidents in the future, the most important of which is that the patient should be effectively monitored after the supposed removal of all radioactive sources. (author)

The asymmetric rotator model applied to odd-mass iridium isotopes

International Nuclear Information System (INIS)

Piepenbring, R.

1980-04-01

The method of inversion of the eigenvalue problem previously developed for nuclei with axial symmetry is extended to asymmetric equilibrium shapes. This new approach of the asymmetric rotator model is applied to the odd-mass iridium isotopes. A satisfactory and coherent description of the observed energy spectra is obtained, especially for the lighter isotopes

Synthesis, structure, redox and spectra of green iridium complexes ...

Indian Academy of Sciences (India)

Reactions of IrCl3 ⋅ H2O with the ligands, 2-[(phenylamino)phenylazo]pyridine (HL1a) and 2-[(-tolylamino)phenylazo]pyridine (HL1b) produce [Ir(L1)2]Cl (L1 = L1a, [1]Cl and L1 = L1b, [2]Cl) along with many unidentified products. The iridium complexes have been characterized by various techniques such as X-ray ...

Development of accurate mass spectrometric routine and reference methods for the determination of trace amounts of iridium and rhodium in photographic emulsionsf

NARCIS (Netherlands)

Krystek, Petra; Heumann, Klaus G.

1999-01-01

For the determination of trace amounts of iridium and rhodium in photographic emulsions different sample treatment procedures were coupled with inductively coupled plasma mass spectrometry (ICP-MS) and, for iridium, also with negative thermal ionisation isotope dilution mass spectrometry (NTI-IDMS)

Oxygen Sensing by the Hybrid Langmuir-Blodgett Films of Iridium(III Complexes and Synthetic Saponite on the Basis of Energy Transfer

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Hisako Sato

2017-09-01

Full Text Available An ultra-thin hybrid film of amphiphilic iridium(III complexes and synthetic saponite was manipulated by means of the modified Langmuir-Blodgett method. In the film deposited onto a quartz substrate, the external mixed molecular layer of amphiphilic iridium(III complexes was reinforced by the inner layer of exfoliated synthetic saponite. As components of the molecular layer, two iridium(III complexes were used: [Ir(dfppy2(dc9bpy]+ (dfppyH = 2-(4′,6′-difluorophenyl pyridine; dc9bpy = 4,4′-dinonyl-2,2′-bipyridine (denoted as DFPPY and [Ir(piq2(dc9bpy]+ (piqH = 1-phenyisoquinoline denoted as PIQ. The emission spectra from the films changed from blue to red maxima with the decrease of a ratio of DFPPY/PIQ due to the energy transfer from excited DFPPY to PIQ. The intensity of red decreased with the increase of oxygen pressure through the quenching of excited iridium(III complexes, promising a possibility as an oxygen-sensing film.

Iridium anomaly in the cretaceous-paleogene boundary at Højerup (Stevns Klint, Denmark and Woodside Creek (New Zealand: The question of an enormous proportion of extraterrestrial component

Directory of Open Access Journals (Sweden)

Premović Pavle I.

2012-01-01

Full Text Available The Cretaceous-Paleogene boundary clays at Højerup and Woodside Creek show anomalous enrichments of iridium compared with the marine sedimentary rocks. For the average iridium content of 465 ppb in CI chondrite the estimate of the carbonaceous chondritic proportions in the decarbonated iridium-rich boundary layers, based on the integrated iridium fluencies, is about 26% at Højerup and 65% at Woodside Creek. These proportions are most likely too high due to a significant Ir influx from the nearby marine or continental site to these sections.

A colorimetric and luminescent dual-modal assay for Cu(II ion detection using an iridium(III complex.

Directory of Open Access Journals (Sweden)

Dik-Lung Ma

Full Text Available A novel iridium(III complex-based chemosensor bearing the 5,6-bis(salicylideneimino-1,10-phenanthroline ligand receptor was developed, which exhibited a highly sensitive and selective color change from colorless to yellow and a visible turn-off luminescence response upon the addition of Cu(II ions. The interactions of this iridium(III complex with Cu2+ ions and thirteen other cations have been investigated by UV-Vis absorption titration, emission titration, and 1H NMR titration.

Mechanistic investigation of the iridium-catalysed alkylation of amines with alcohols

DEFF Research Database (Denmark)

Fristrup, Peter; Tursky, Matyas; Madsen, Robert

2012-01-01

where the intermediate aldehyde stays coordinated to the iridium catalyst and reacts with the amine to give a hemiaminal which is also bound to the catalyst. Dehydration to the imine and reduction to the product amine also takes place without breaking the coordination to the catalyst. The fact...

Iridium-coated micropore x-ray optics using dry etching of a silicon wafer and atomic layer deposition.

Science.gov (United States)

Ogawa, Tomohiro; Ezoe, Yuichiro; Moriyama, Teppei; Mitsuishi, Ikuyuki; Kakiuchi, Takuya; Ohashi, Takaya; Mitsuda, Kazuhisa; Putkonen, Matti

2013-08-20

To enhance x-ray reflectivity of silicon micropore optics using dry etching of silicon (111) wafers, iridium coating is tested by use of atomic layer deposition. An iridium layer is successfully formed on sidewalls of tiny micropores with a pore width of 20 μm and depth of 300 μm. The film thickness is ∼20  nm. An enhanced x-ray reflectivity compared to that of silicon is confirmed at Ti Kα 4.51 keV, for what we believe to be the first time, with this type of optics. Some discrepancies from a theoretical reflectivity curve of iridium-coated silicon are noticed at small incident angles <1.3°. When a geometrical shadowing effect due to occultation by a ridge existing on the sidewalls is taken into account, the observed reflectivity becomes well represented by the modified theoretical curve. An estimated surface micro roughness of ∼1  nm rms is consistent with atomic force microscope measurements of the sidewalls.

(4-Chloroacetanilido-κ2N,Obis[2-(pyridin-2-ylphenyl-κ2C1,N]iridium(III

Directory of Open Access Journals (Sweden)

Lijun Sun

2013-02-01

Full Text Available In the neutral mononuclear iridium(III title compound, [Ir(C8H7ClNO(C11H8N2], the IrIII atom adopts an octahedral geometry, and is coordinated by two 2-phenylpyridyl ligands and one anionic 4-chloroacetanilide ligand. The 2-phenylpyridyl ligands are arranged in a cis-C,C′ and cis-N,N′ fashion. Each 2-phenylpyridyl ligand forms a five-membered ring with the IrIII atom. The 2-phenylpyridyl planes are perpendicular to each other [dihedral angle = 89.9 (1°]. The Ir—C and Ir—N bond lengths are comparable to those reported for related iridium(III 2-phenylpyridyl complexes. The remaining two coordination sites are occupied by the amidate N and O atoms, which form a four-membered ring with the iridium atom (Ir—N—C—O. The amidate plane is nearly perpendicular to both 2-phenylpyridyl ligands [dihedral angles = 87.8 (2 and 88.3 (2°].

Synthesis and Electroluminescent Property of New Orange Iridium Compounds for Flexible White Organic Light Emitting Diodes.

Science.gov (United States)

Lee, Ho Won; Jeong, Hyunjin; Kim, Young Kwan; Ha, Yunkyoung

2015-10-01

Recently, white organic light-emitting diodes (OLEDs) have aroused considerable attention because they have the potential of next-generation flexible displays and white illuminated applications. White OLED applications are particularly heading to the industry but they have still many problems both materials and manufacturing. Therefore, we proposed that the new iridium compounds of orange emitters could be demonstrated and also applied to flexible white OLEDs for verification of potential. First, we demonstrated the chemical properties of new orange iridium compounds. Secondly, conventional two kinds of white phosphorescent OLEDs were fabricated by following devices; indium-tin oxide coated glass substrate/4,4'-bis[N-(napthyl)-N-phenylamino]biphenyl/N,N'-dicarbazolyl-3,5-benzene doped with blue and new iridium compounds for orange emitting 8 wt%/1,3,5-tris[N-phenylbenzimidazole-2-yl]benzene/lithium quinolate/aluminum. In addition, we fabricated white OLEDs using these emitters to verify the potential on flexible substrate. Therefore, this work could be proposed that white light applications can be applied and could be extended to additional research on flexible applications.

Electro-catalytic oxidation of ethanol on platinum-iridium mixtures supported on glassy carbon

International Nuclear Information System (INIS)

Rodriguez, Henry; Hoyos Bibian

2004-01-01

Electro-catalytic oxidation of ethanol on platinum-iridium mixtures supported on glassy carbon was studied, in acid media at different temperatures and concentrations. During the maturation time of deposited iridium, the surface is covered by an irreversible oxide formation, which affects the behavior of the catalytic mixture. The Pt 7 0 Ir 3 0 and Pt 9 0 Ir 1 0 mixtures seem to be a little more active than the Pt/C electrode at potentials below 800 mV (vs. HRE). In all electrodes appears two reactions: partial ethanol oxidation to produce acetaldehyde (main path of reaction at low temperatures and high electrode coverage with ethanol adsorption residues) and the total oxidation to carbon dioxide which is considerable at potential above 800 mV and it is increased with increasing temperature

Synthesis and structural studies of Cp{sup *} rhodium and Cp{sup *} iridium complexes of picolinic hydrazine ligand

Energy Technology Data Exchange (ETDEWEB)

Palepu, Narasinga Rao; Kollipara, Mohan Rao [Centre for Advanced Studies in Chemistry, North-Eastern Hill University, Shillong (India); Kaminsky Werner [Dept. of Chemistry, University of Washington, Seattle (United States)

2017-01-15

A series of Cp{sup *}Rh and Cp{sup *}Ir complexes of picolinic hydrazine ligand are synthesized and characterized. Picolinic hydrazine has yielded only dinuclear complexes in the case of rhodium metal whereas both mono and dinuclear complexes with iridium metal. Iridium complexes are formed as quaternary salts by the migration of the N–H proton onto the adjacent amine group of the hydrazine after binding to the metal. Picolinic hydrazine acts as nitrogen and oxygen donor ligand in the form of bi and tetradentate bonding modes.

Grain Growth and Precipitation Behavior of Iridium Alloy DOP-26 During Long Term Aging

Energy Technology Data Exchange (ETDEWEB)

Pierce, Dean T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Muralidharan, Govindarajan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fox, Ethan E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cox, Victoria A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Geer, Tom [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-05-01

The influence of long term aging on grain growth and precipitate sizes and spatial distribution in iridium alloy DOP-26 was studied. Samples of DOP-26 were fabricated using the new process, recrystallized for 1 hour (h) at 1375 C, then aged at either 1300, 1400, or 1500 C for times ranging from 50 to 10,000 h. Grain size measurements (vertical and horizontal mean linear intercept and horizontal and vertical projection) and analyses of iridium-thorium precipitates (size and spacing) were made on the longitudinal, transverse, and rolling surfaces of the as-recrystallized and aged specimens from which the two-dimensional spatial distribution and mean sizes of the precipitates were obtained. The results obtained from this study are intended to provide input to grain growth models.

Interaction of an iridium-clad RTG heat source unit with a simulated terrestrial environment

International Nuclear Information System (INIS)

Patterson, J.H.; Herrera, B.; Nelson, G.B.; Matlack, G.M.; Waterbury, G.R.

1976-02-01

An iridium-clad, 100-W 238 PuO 2 sphere, a prototype for the multihundred-watt radioisotope thermoelectric generator, was exposed for 1 y to a simulated temperate humid climate in an environmental test chamber containing sandy soil. The hot sphere sank into the soil after the first rain, then gradually acquired a hard crust around it as a result of the rainwater reacting with the hot soil during successive rains. Time and temperature profiles of the sphere were recorded during the weekly rains, and the air and rainwater that percolated through the soil were monitored for plutonium. No plutonium was released from the sphere. Aside from the crust formation, very little reaction occurred between the hot iridium shell and the soil

Efficiency Control in Iridium Complex-Based Phosphorescent Light-Emitting Diodes

Directory of Open Access Journals (Sweden)

Boucar Diouf

2012-01-01

Full Text Available Key factors to control the efficiency in iridium doped red and green phosphorescent light emitting diodes (PhOLEDs are discussed in this review: exciton confinement, charge trapping, dopant concentration and dopant molecular structure. They are not independent from each other but we attempt to present each of them in a situation where its specific effects are predominant. A good efficiency in PhOLEDs requires the triplet energy of host molecules to be sufficiently high to confine the triplet excitons within the emitting layer (EML. Furthermore, triplet excitons must be retained within the EML and should not drift into the nonradiative levels of the electron or hole transport layer (resp., ETL or HTL; this is achieved by carefully choosing the EML’s adjacent layers. We prove how reducing charge trapping results in higher efficiency in PhOLEDs. We show that there is an ideal concentration for a maximum efficiency of PhOLEDs. Finally, we present the effects of molecular structure on the efficiency of PhOLEDs using red iridium complex dopant with different modifications on the ligand to tune its highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO energies.

Influence of the profile of Iridium-192 wire in measurements of quality control for use in brachytherapy

International Nuclear Information System (INIS)

Costa, Osvaldo L.; Zeituni, Carlos A.; Rostelato, Maria Elisa C.M.; Moura, Joao A.; Feher, Anselmo; Moura, Eduardo S.; Souza, Carla D.; Somessari, Samir L.; Peleias Junior, Fernando S.; Mattos, Fabio R.

2013-01-01

Brachytherapy is a method used in the treatment of cancerous tumors, by ionizing radiation produced by sources, introduced into the tumor area, this method seeks a more direct to the tumor, thereby maximizing the radiation dose to diseased tissue, while minimizing the dose to healthy tissues. One of the radionuclides used in brachytherapy is iridium-192. The Radiation Technology Center (CTR), of the Nuclear and Energy Research Institute (IPEN), has produced commercially, since 1998, iridium-192 wires used in low dose rate (LDR) brachytherapy. To produce this radionuclides, firstly an iridium-platinum wire is irradiated in the nuclear reactor IEA-R1 for 30 hours, with a neutron flux of 5x 10 13 n cm -2 s -1 , the wire is left to decay by 30 days to remove the main contaminants, and then goes through a quality control, before being sent to the hospital. In this quality control is checked the radiation homogeneity along each centimeter of the wire. To implement this procedure, is used a device, consisting of an ionization chamber, surrounded by a lead shield, with a samol 1 cm wide slit, linked to the ionization chamber is a voltage source, and a Keithley 617 electrometer, 2 minutes is the range used to measure the charge by the electrometer. The iridium wire is considered in accordance, when there is no variation higher than 5%, between the average measures and the maximum and minimum values. However, due to design features of the measurement system, the wire may appear to the detector through the slit in larger sizes than the ideal, improperly influencing the final quality control. This paper calculates the difference in size of these variations in profile, and their influence on the final count, it compares the actual values obtained, and describes the improvements, made in quality control procedures, that provided more accurate measurement data, analyzes the results, and suggests changes in devices, aimed at further improving the quality control of iridium-192

Transformation of a Cp*-iridium(III) precatalyst for water oxidation when exposed to oxidative stress.

Science.gov (United States)

Zuccaccia, Cristiano; Bellachioma, Gianfranco; Bortolini, Olga; Bucci, Alberto; Savini, Arianna; Macchioni, Alceo

2014-03-17

The reaction of [Cp*Ir(bzpy)NO3 ] (1; bzpy=2-benzoylpyridine, Cp*=pentamethylcyclopentadienyl anion), a competent water-oxidation catalyst, with several oxidants (H2 O2 , NaIO4 , cerium ammonium nitrate (CAN)) was studied to intercept and characterize possible intermediates of the oxidative transformation. NMR spectroscopy and ESI-MS techniques provided evidence for the formation of many species that all had the intact Ir-bzpy moiety and a gradually more oxidized Cp* ligand. Initially, an oxygen atom is trapped in between two carbon atoms of Cp* and iridium, which gives an oxygen-Ir coordinated epoxide, whereas the remaining three carbon atoms of Cp* are involved in a η(3) interaction with iridium (2 a). Formal addition of H2 O to 2 a or H2 O2 to 1 leads to 2 b, in which a double MeCOH functionalization of Cp* is present with one MeCOH engaged in an interaction with iridium. The structure of 2 b was unambiguously determined in the solid state and in solution by X-ray single-crystal diffractometry and advanced NMR spectroscopic techniques, respectively. Further oxidation led to the opening of Cp* and transformation of the diol into a diketone with one carbonyl coordinated at the metal (2 c). A η(3) interaction between the three non-oxygenated carbons of "ex-Cp*" and iridium is also present in both 2 b and 2 c. Isolated 2 b and mixtures of 2 a-c species were tested in water-oxidation catalysis by using CAN as sacrificial oxidant. They showed substantially the same activity than 1 (turnover frequency values ranged from 9 to 14 min(-1) ). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Incorporation of iridium into electrodeposited rhenium–nickel alloys

International Nuclear Information System (INIS)

Cohen Sagiv, Maayan; Eliaz, Noam; Gileadi, Eliezer

2013-01-01

Rhenium (Re), a refractory metal that has gained significant recognition as a high performance engineering material, is mostly used in military, aircraft and aerospace applications, as well as for catalysis in the petrochemical industry. However, its performance at high temperature in humid air is limited by the formation of rhenium heptoxide (Re 2 O 7 ), which penetrates the grain boundaries and causes brittleness. Improvement of this is being sought through the incorporation of iridium (Ir) into Re deposits. To this end, suitable plating baths for Re–Ir–Ni coatings were developed. These alloys were deposited from different aqueous solutions on copper substrates under galvanostatic conditions, in a three-electrode cell. The plating bath consisted of iridium tri-chloride, ammonium perrhenate and nickel sulfamate as the electroactive species, and citric acid as the complexing agent. The effects of bath composition and operating conditions on the Faradaic efficiency (FE), partial current densities, as well as on the thickness of the coatings and their composition were studied. Re–Ir–Ni coatings as thick as 18 μm, with Re-content as high as 73 at.% and Ir-content as high as 29 at.%, were obtained, using different plating baths. A mechanism of the electrochemical process was suggested. It was found that both an HCP Ir 0.4 Re 0.6 phase and an HCP Ni phase with nanometric crystallites were formed, possibly together with a hexagonal nickel hydride (Ni 2 H) phase

Synthesis and optoelectronic properties of oxadiazole-functionalized iridium complexes in the poly(vinylcarbazole)-hosted devices

International Nuclear Information System (INIS)

Wu Zhonglian; Luo Cuiping; Jiang Changyun; Zhu Meixiang; Cao, Yong; Zhu Weiguo

2008-01-01

A class of oxadiazole-functionalized iridium complexes was used as phosphor emitters in poly (vinylcarbazole)-hosted devices. Efficient green electrophosphorescences were achieved in the devices with a maximum luminance efficiency of 9.3 cd/A at 10.6 mA/cm 2 and brightness of 3882 cd/m 2 at 92.1 mA/cm 2 . More importantly, the iridium complexes-doped devices exhibited a low turn-on voltage of 7.0 V and an applied voltage of 9.2 V at 500 cd/m 2 . The good optoelectronic properties of the complexes were attributed to the enhanced electron-injection and transport properties resulting from the effect of oxadiazole ligands in the complexes

16 CFR 23.7 - Misuse of the words “platinum,” “iridium,” “palladium,” “ruthenium,” “rhodium,” and “osmium.”

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Misuse of the words âplatinum,â âiridium,â... § 23.7 Misuse of the words “platinum,” “iridium,” “palladium,” “ruthenium,” “rhodium,” and “osmium.” (a) It is unfair or deceptive to use the words “platinum,” “iridium,” “palladium,” “ruthenium,” “rhodium...

Regio- and Enantioselective N-Allylations of Imidazole, Benzimidazole, and Purine Heterocycles Catalyzed by Single-Component Metallacyclic Iridium Complexes

Science.gov (United States)

Stanley, Levi M.

2010-01-01

Highly regio- and enantioselective iridium-catalyzed N-allylations of benzimidazoles, imidazoles, and purines have been developed. N-Allylated benzimidazoles and imidazoles were isolated in high yields (up to 97%) with high branched-to-linear selectivity (up to 99:1) and enantioselectivity (up to 98% ee) from the reactions of benzimidazole and imidazole nucleophiles with unsymmetrical allylic carbonates in the presence of single component, ethylene-bound, metallacyclic iridium catalysts. N-Allylated purines were also obtained in high yields (up to 91%) with high N9:N7 selectivity (up to 96:4), high branched-to-linear selectivity (98:2), and high enantioselectivity (up to 98% ee) under similar conditions. The reactions encompass a range of benzimidazole, imidazole, and purine nucleophiles, as well as a variety of unsymmetrical aryl, heteroaryl, and aliphatic allylic carbonates. Competition experiments between common amine nucleophiles and the heterocyclic nitrogen nucleophiles studied in this work illustrate the effect of nucleophile pKa on the rate of iridium-catalyzed N-allylation reactions. Kinetic studies on the allylation of benzimidazole catalyzed by metallacyclic iridium-phosphoramidite complexes, in combination with studies on the deactivation of these catalysts in the presence of heterocyclic nucleophiles, provide insight into the effects of the structure of the phosphoramidite ligands on the stability of the metallacyclic catalysts. The data obtained from these studies has led to the development of N-allylations of benzimidazoles and imidazoles in the absence of an exogenous base. PMID:19480431

High-Performance Computer Modeling of the Cosmos-Iridium Collision

Energy Technology Data Exchange (ETDEWEB)

Olivier, S; Cook, K; Fasenfest, B; Jefferson, D; Jiang, M; Leek, J; Levatin, J; Nikolaev, S; Pertica, A; Phillion, D; Springer, K; De Vries, W

2009-08-28

This paper describes the application of a new, integrated modeling and simulation framework, encompassing the space situational awareness (SSA) enterprise, to the recent Cosmos-Iridium collision. This framework is based on a flexible, scalable architecture to enable efficient simulation of the current SSA enterprise, and to accommodate future advancements in SSA systems. In particular, the code is designed to take advantage of massively parallel, high-performance computer systems available, for example, at Lawrence Livermore National Laboratory. We will describe the application of this framework to the recent collision of the Cosmos and Iridium satellites, including (1) detailed hydrodynamic modeling of the satellite collision and resulting debris generation, (2) orbital propagation of the simulated debris and analysis of the increased risk to other satellites (3) calculation of the radar and optical signatures of the simulated debris and modeling of debris detection with space surveillance radar and optical systems (4) determination of simulated debris orbits from modeled space surveillance observations and analysis of the resulting orbital accuracy, (5) comparison of these modeling and simulation results with Space Surveillance Network observations. We will also discuss the use of this integrated modeling and simulation framework to analyze the risks and consequences of future satellite collisions and to assess strategies for mitigating or avoiding future incidents, including the addition of new sensor systems, used in conjunction with the Space Surveillance Network, for improving space situational awareness.

Report of Iridium/{sup 238}PuO{sub 2} Compatibility Test

Energy Technology Data Exchange (ETDEWEB)

Taylor, D.H.

2001-08-09

This study indicates that the chemical purity of the fuel used presently to fabricate fueled clad vent sets will not present any special problems to the performance of the fueled clad vent sets as intended. However, cation impurities in the fuel can have a deleterious effect on the iridium cladding and vents and should be minimized as much as practical.

Asymmetric hydrogenation of quinolines catalyzed by iridium complexes of monodentate BINOL-derived phosphoramidites

NARCIS (Netherlands)

Mrsic, Natasa; Lefort, Laurent; Boogers, Jeroen A. F.; Minnaard, Adriaan J.; Feringa, Ben L.; de Vries, Johannes G.; Mršić, Nataša

The monodentate BINOL-derived phosphoramidite PipPhos is used as ligand for the iridium-catalyzed asymmetric hydrogenation of 2- and 2,6-substituted quinolines. If tri-ortho-tolylphosphine and/or chloride salts are used as additives enantioselectivities are strongly enhanced up to 89%. NMR indicates

Iridium-192 implants in the treatment of tonsillar region malignancies

International Nuclear Information System (INIS)

Puthawala, A.A.; Syed, A.M.; Gates, T.C.

1985-01-01

A total of 127 patients with histologically proved diagnosis of carcinoma of the tonsillar region and soft palate were treated over the past ten years utilizing interstitial iridium-192 implants. Eighty patients were treated for primary tumors and 47 patients for either recurrent or persistent tumors after definitive irradiation and/or surgery. All patients with primary tumors were treated by a combination of external megavoltage irradiation and interstitial iridium-192 implants, whereas patients with recurrent tumors were treated by interstitial implants alone. In the primary group, 95% of patients with T1 and T2 lesions and 79% with T3 and T4 lesions achieved complete local tumor control. The three-year absolute disease-free survival rate was 72%. Seventy-five percent local tumor control was obtained in patients with recurrent disease, with two-year absolute disease-free survival of 42%. Treatment-related complications such as soft-tissue necrosis or osteoradionecrosis occurred in 6% of patients in the primary group and 23% in recurrent group. This treatment regimen offers an excellent locoregional control with no significant functional or esthetic impairment. Most patients with primary lesions who fail this regimen can be salvaged by surgery or reirradiation using interstitial implants

Implantation of the maxillary antrum for delivery of iridium brachytherapy and microwave induced hyperthermia

International Nuclear Information System (INIS)

Coughlin, C.T.; Wong, T.Z.; Geurkink, N.

1985-01-01

A 63 year-old male was referred tp Dartmouth in March 1984 for a locally advanced recurrent squamous cell carcinoma of the left maxillary antrum. This had been initially diagnosed in January 1983 by a Caldwell-Luc procedure and had failed partial resection, external radiation therapy, and multiagent chemotherapy. Our initial evaluation revealed disease replacing the left maxillary antrum, extending into the pterygomaxillary fossa, the lateral aspect of the superior alveloar ridge, and into the soft palate. He was taken to the operating room and under general anesthesia was implanted the 7 catheters through this tumor volume. Two days later a therapeutic (>42 0 C for 1 hour) hyperthermia treatment was administered followed by iridium placement. A second heating was performed upon removal of the iridium and was accomplished without major side effects. Thermometry data and follow-up are presented

Separation of rhodium(III and iridium(IV chlorido species by quaternary diammonium centres hosted on silica microparticles

Directory of Open Access Journals (Sweden)

A. Majavu

2017-12-01

Full Text Available Silica gel was functionalized with six different quaternary diammonium centres derived from ethylenediamine (EDA, tetramethylenediamine (TMDA, hexamethylenediamine (HMDA, 1,8-diaminooctane (OMDA, 1,10-diaminodecane (DMDA and 1,12-diaminododecane (DDMDA to produce Si-QUAT EDA, Si-QUAT TMDA, Si-QUAT HMDA, Si-QUAT OMDA, Si-QUAT DMDA and Si-QUAT DDMDA, respectively. The synthesized silica-based resins were characterized by means of FTIR, XPS, SEM, BET surface area, thermogravimetric analysis and elemental analysis. The materials were used to investigate the adsorption and separation of [RhCl5(H2O]2− and [IrCl6]2−. Batch studies (equilibrium and kinetic studies were conducted to study the adsorption of [RhCl5(H2O]2− and [IrCl6]2− onto Si-QUAT EDA, Si-QUAT TMDA, Si-QUAT HMDA, Si-QUAT OMDA, Si-QUAT DMDA and Si-QUAT DDMDA using single metal aqueous solutions. The Freundlich isotherm confirmed multilayer adsorption and the Freundlich constant (kf displayed the following ascending order; Si-QUAT EDA, Si-QUAT TMDA, Si-QUAT HMDA, Si-QUAT OMDA and Si-QUAT DMDA, and a decrease in kf for Si-QUAT DDMDA. Kinetic studies suggest a pseudo-first order kinetic model. Column studies were also conducted for a binary mixture of these metal ion chlorido species ([RhCl5(H2O]2− and [IrCl6]2−. The iridium loading capacities increased as the carbon spacer between the diammonium centres increased in the following order; Si-QUAT EDA, Si-QUAT TMDA, Si-QUAT HMDA, Si-QUAT OMDA and Si-QUAT DMDA (4.56 mg/g, 6.88 mg/g, 14.63 mg/g, 19.01 mg/g and 29.35 mg/g, respectively. It was observed that the iridium loading capacity of Si-QUAT DDMDA decreased to 8.90 mg/g. This paper presents iridium-specific materials that could be applied in solutions of secondary PGMs sources containing rhodium and iridium as well as in feed solutions from ore processing. Keywords: Silica gel, Quaternary diammonium centres, Rhodium, Iridium, Separation

Iridium-Knife: Another knife in radiation oncology.

Science.gov (United States)

Milickovic, Natasa; Tselis, Nikolaos; Karagiannis, Efstratios; Ferentinos, Konstantinos; Zamboglou, Nikolaos

Intratarget dose escalation with superior conformity is a defining feature of three-dimensional (3D) iridium-192 ( 192 Ir) high-dose-rate (HDR) brachytherapy (BRT). In this study, we analyzed the dosimetric characteristics of interstitial 192 Ir HDR BRT for intrathoracic and cerebral malignancies. We examined the dose gradient sharpness of HDR BRT compared with that of linear accelerator-based stereotactic radiosurgery and stereotactic body radiation therapy, usually called X-Knife, to demonstrate that it may as well be called a Knife. Treatment plans for 10 patients with recurrent glioblastoma multiforme or intrathoracic malignancies, five of each entity, treated with X-Knife (stereotactic radiosurgery for glioblastoma multiforme and stereotactic body radiation therapy for intrathoracic malignancies) were replanned for simulated HDR BRT. For 3D BRT planning, we used identical structure sets and dose prescription as for the X-Knife planning. The indices for qualitative treatment plan analysis encompassed planning target volume coverage, conformity, dose falloff gradient, and the maximum dose-volume limits to different organs at risk. Volume coverage in HDR plans was comparable to that calculated for X-Knife plans with no statistically significant difference in terms of conformity. The dose falloff gradient-sharpness-of the HDR plans was considerably steeper compared with the X-Knife plans. Both 3D 192 Ir HDR BRT and X-Knife are effective means for intratarget dose escalation with HDR BRT achieving at least equal conformity and a steeper dose falloff at the target volume margin. In this sense, it can reasonably be argued that 3D 192 Ir HDR BRT deserves also to be called a Knife, namely Iridium-Knife. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

The determination, by atomic-absorption spectrophotometry using electrothermal atomization, of platinum, palladium, rhodium, ruthenium, and iridium

International Nuclear Information System (INIS)

Haines, J.; Robert, R.V.D.

1982-01-01

A method that involves measurement by atomic-absorption spectrophotometry using electrothermal atomization has been developed for the determination of trace quantities of platinum, palladium, rhodium, ruthenium, and iridium in mineralogical samples. The elements are separated and concentrated by fusion, nickel sulphide being used as the collector, and the analyte elements are measured in the resulting acid solution. An organic extraction procedure was found to offer no advantages over the proposed method. Mutual interferences between the five platinum-group metals examined, as well as interferences from gold, silver, and nickel were determined. The accuracy of the measurement was established by the analysis of a platinum-ore reference material. The lower limits of determination of each of the analyte elements in a sample material are as follows: platinum 1,6μg/l, palladium 0,2μg/1, rhodium 0,5μg/l, ruthenium 3μg/l, and iridium 2,5μg/l. The relative standard deviations range from 0,05 for rhodium to 0.08 for iridium. The method, which is described in detail in the Appendix, is applicable to the determination of these elements in ores, tailings, and geological materials in which the total concentration of the noble metals is less than 1g/t

Research of remote control for Chinese Antarctica Telescope based on iridium satellite communication

Science.gov (United States)

Xu, Lingzhe; Yang, Shihai

2010-07-01

Astronomers are ever dreaming of sites with best seeing on the Earth surface for celestial observation, and the Antarctica is one of a few such sites only left owing to the global air pollution. However, Antarctica region is largely unaccessible for human being due to lacking of fundamental living conditions, travel facilities and effective ways of communication. Worst of all, the popular internet source as a general way of communication scarcely exists there. Facing such a dilemma and as a solution remote control and data transmission for telescopes through iridium satellite communication has been put forward for the Chinese network Antarctic Schmidt Telescopes 3 (AST3), which is currently under all round research and development. This paper presents iridium satellite-based remote control application adapted to telescope control. The pioneer work in China involves hardware and software configuration utilizing techniques for reliable and secure communication, which is outlined in the paper too.

A label-free luminescent switch-on assay for ATP using a G-quadruplex-selective iridium(III) complex.

Science.gov (United States)

Leung, Ka-Ho; Lu, Lihua; Wang, Modi; Mak, Tsun-Yin; Chan, Daniel Shiu-Hin; Tang, Fung-Kit; Leung, Chung-Hang; Kwan, Hiu-Yee; Yu, Zhiling; Ma, Dik-Lung

2013-01-01

We report herein the G-quadruplex-selective property of a luminescent cyclometallated iridium(III) complex for the detection of adenosine-5'-triphosphate (ATP) in aqueous solution. The ATP-binding aptamer was employed as the ATP recognition unit, while the iridium(III) complex was used to monitor the formation of the G-quadruplex structure induced by ATP. The sensitivity and fold enhancement of the assay were higher than those of the previously reported assay using the organic dye crystal violet as a fluorescent probe. This label-free luminescent switch-on assay exhibits high sensitivity and selectivity towards ATP with a limit of detection of 2.5 µM.

A label-free luminescent switch-on assay for ATP using a G-quadruplex-selective iridium(III complex.

Directory of Open Access Journals (Sweden)

Ka-Ho Leung

Full Text Available We report herein the G-quadruplex-selective property of a luminescent cyclometallated iridium(III complex for the detection of adenosine-5'-triphosphate (ATP in aqueous solution. The ATP-binding aptamer was employed as the ATP recognition unit, while the iridium(III complex was used to monitor the formation of the G-quadruplex structure induced by ATP. The sensitivity and fold enhancement of the assay were higher than those of the previously reported assay using the organic dye crystal violet as a fluorescent probe. This label-free luminescent switch-on assay exhibits high sensitivity and selectivity towards ATP with a limit of detection of 2.5 µM.

Earth Radiation Imbalance from a Constellation of 66 Iridium Satellites: Technological Aspects

Science.gov (United States)

Wiscombe, W.; Chiu, C. J-Y.

2012-01-01

Iridium Communications Inc. is launching a new generation of polar orbiting communication satellites in 2015-2017. Iridium will provide a hosted payload bay on each of the 66 satellites (plus 6 in-space spares). This offers the potential for a paradigm shift in the way we measure Earth radiation imbalance from space, as well as massive cost savings. Because the constellation provides 24/7 global coverage, there is no need to account for diurnal cycle via extrapolations from uncalibrated narrowband geostationary imagers. And the spares can be rolled over to view the Sun and deep space, then transfer their calibration to the other members of the constellation during the frequent cross-overs. In part using simulations of the constellation viewing realistic Earth scenes, this presentation will address the technological aspects of such a constellation: (1) the calibration strategy; (2) the highly-accurate and stable radiometers for measuring outgoing flux; and (3) the GRACE-inspired algorithms for representing the outgoing flux field in spherical harmonics and thus achieving rv500-km spatial resolution and two-hour temporal resolution.

Iridium Coating Deposited by Double Glow Plasma Technique — Effect of Glow Plasma on Structure of Coating at Single Substrate Edge

International Nuclear Information System (INIS)

Wu Wangping; Chen Zhaofeng; Liu Yong

2012-01-01

Double glow plasma technique has a high deposition rate for preparing iridium coating. However, the glow plasma can influence the structure of the coating at the single substrate edge. In this study, the iridium coating was prepared by double glow plasma on the surface of single niobium substrate. The microstructure of iridium coating at the substrate edge was observed by scanning electron microscopy. The composition of the coating was confirmed by energy dispersive spectroscopy and X-ray diffraction. There was a boundary between the coating and the substrate edge. The covered area for the iridium coating at the substrate edge became fewer and fewer from the inner area to the outer flange-area. The bamboo sprout-like particles on the surface of the substrate edge were composed of elemental niobium. The substrate edge was composed of the Nb coating and there was a transition zone between the Ir coating and the Nb coating. The interesting phenomenon of the substrate edge could be attributed to the effects of the bias voltages and the plasma cloud in the deposition chamber. The substrate edge effect could be mitigated or eliminated by adding lots of small niobium plates around the substrate in a deposition process. (plasma technology)

Method of making a long life high current density cathode from tungsten and iridium powders using a quaternary compound as the impregnant

International Nuclear Information System (INIS)

Branovich, L.E.; Smith, B.; Freemen, G.L.; Eckart, D.W.

1990-01-01

This patent describes a method of making a long life high current density cathode. It is suitable for operation in microwave devices. It is made from tungsten and iridium powders using a quaternary compound including barium, oxygen, a metal selected from the group consisting of osmium, iridium, rhodium, and rhenium, and a metal selected from the group consisting of strontium, calcium, scandium, and titanium as the impregnant

76 FR 46313 - Notice of Issuance of Final Determination Concerning Iridium Satellite Telephones

Science.gov (United States)

2011-08-02

... modulates them into radio streams that communicate with the Iridium gateway network infrastructure using a... (DSP) cores, made in China, and two radio frequency (RF) backend chips, made in Taiwan. The bill of... marking of a cellular phone. CBP found that a digital mobile telephone was substantially transformed in...

Techniques for Achieving Zero Stress in Thin Films of Iridium, Chromium, and Nickel

Science.gov (United States)

Broadway, David M.; O'Dell, Stephen L.; Ramsey, Brian D.; Weimer, Jeffrey

2015-01-01

We examine techniques for achieving zero intrinsic stress in thin films of iridium, chromium, and nickel deposited by magnetron sputter deposition. The intrinsic stress is further correlated to the microstructural features and physical properties such as surface roughness and optical density at a scale appropriate to soft X-ray wavelengths. The examination of the stress in these materials is motivated by efforts to advance the optical performance of light-weight X-ray space telescopes into the regime of sub-arcsecond resolution through various deposition techniques that rely on control of the film stress to values within 10-100 MPa. A characteristic feature of the intrinsic stress behavior in chromium and nickel is their sensitivity to the magnitude and sign of the intrinsic stress with argon gas pressure and deposition rate, including the existence of a critical argon process pressure that results in zero film stress which scales linearly with the atomic mass of the sputtered species. While the effect of stress reversal with argon pressure has been previously reported by Hoffman and others for nickel and chromium, we report this effect for iridium. In addition to stress reversal, we identify zero stress in the optical functioning iridium layer shortly after island coalescence for low process pressures at a film thickness of approximately 35nm. The measurement of the low values of stress during deposition was achieved with the aid of a sensitive in-situ instrument capable of a minimum detectable level of stress, assuming a 35nm thick film, in the range of 0.40-6.0 MPa for oriented crystalline silicon substrate thicknesses of 70-280 microns, respectively.

Solid-state electrochromic cell with anodic iridium oxide film electrodes

International Nuclear Information System (INIS)

Dautremont-Smith, W.C.; Beni, G.; Schiavone, L.M.; Shay, J.L.

1979-01-01

A new solid-state electrochromic cell has been fabricated using an anodic iridium oxide film (AIROF) display electrode. The cell has the symmetric sandwich structure AIROFvertical-barNafionvertical-barAIROF, with the Nafion solid electrolyte opacified by an in situ precipitation technique. A symmetric square-wave voltage of 1.5 V amplitude produces clearly perceivable color changes from pale to dark blue-gray in approx. =1 sec when viewed in diffuse reflection. Good open-circuit optical memory is exhibited:

Extrahepatic bile duct carcinoma treated by intraluminal irradiation with iridium-192 wire. Report of a case

Energy Technology Data Exchange (ETDEWEB)

Ikeda, H; Kuroda, T; Uchida, H [Osaka Univ. (Japan). Faculty of Medicine

1980-08-01

A 57-year-old male with obstructive jaundice was diagnosed extrahepatic bile duct carcinoma at bifurcation by percutaneous transhepatic cholangiography (PTC). He was treated 3,300 rad of external irradiation and then intraluminal irradiation using the Iridium-192 wire by two times with the aid of PTC internal drainage, each was given by the dose of 1,600 rad at 5 mm inside the tumor from the PTC-tube. He had been well for about 1 year and then died because of ascites and cachexia. Autopsy revealed only microscopic tumor cells remaining around the common duct below the cystic junction. It was confirmed that intraluminal irradiation using the Iridium-192 wire was potentially curable and easily applicable to the bile duct carcinoma.

Microindentation hardness evaluation of iridium alloy clad vent set cups

International Nuclear Information System (INIS)

Ulrich, G.B.; DeRoos, L.F.; Stinnette, S.E.

1993-01-01

An iridium alloy, DOP-26, is used as cladding for 238 PuO 2 fuel in radioisotope heat sources for space power systems. Presently, DOP-26 iridium alloy clad vent sets (CVS) are being manufactured at the Oak Ridge Y-12 Plant for potential use in the National Aeronautics and Space Administration's Cassini mission to Saturn. Wrought/ground/stress relieved blanks are warm formed into CVS cups. These cups are then annealed to recrystallize the material for subsequent fabrication/assembly operations as well as for final use. One of the cup manufacturing certification requirements is to test for Vickers microindentation hardness. New microindentation hardness specification limits, 210 to 310 HV, have been established for a test load of 1000 grams-force (gf). The original specification limits, 250 to 350 HV, were for 200 gf testing. The primary reason for switching to a higher test load was to reduce variability in the test data. The DOP-26 alloy exhibits microindentation hardness load dependence, therefore, new limits were needed for 1000 gf testing. The new limits were established by testing material from 15 CVS cups using 200 gf and 1000 gf loads and then statistically analyzing the data. Additional work using a Knoop indenter and a 10 gf load indicated that the DOP-26 alloy grain boundaries have higher hardnesses than the grain interiors

Microindentation hardness evaluation of iridium alloy clad vent set cups

International Nuclear Information System (INIS)

Ulrich, G.B.; DeRoos, L.F.; Stinnette, S.E.

1992-01-01

An iridium alloy, DOP-26, is used as cladding for 238 PuO 2 fuel in radioisotope heat sources for space power systems. Presently, DOP-26 iridium alloy clad vent sets (CVS) are being manufactured at the Oak Ridge Y-12 Plant for potential use in the National Aeronautics and Space Administration's Cassini mission to Saturn. Wrought/ground/stress relieved blanks are warm formed into CVS cups. These cups are then annealed to recrystallize the material for subsequent fabrication/assembly operations as well as for final use. One of the cup manufacturing certification requirements is to test for Vickers microindentation hardness. New microindentation hardness specification limits, 210 to 310 HV, have been established for a test load of 1000 grams-force (gf). The original specification limits, 250 to 350 HV, were for 200 gf testing. The primary reason for switching to a higher test load was to reduce variability in the test data. The DOP-26 alloy exhibits microindentation hardness load dependence, therefore, new limits were needed for 1000 gf testing. The new limits were established by testing material from 15 CVS cups using 200 gf and 1000 gf loads and then statistically analyzing the data. Additional work using a Knoop indenter and a 10 gf load indicated that the DOP-26 alloy grain boundaries have higher hardnesses than the grain interiors

Effect of the lead screen in the radiographic image using iridium 192 as a source

International Nuclear Information System (INIS)

Garate Rojas, M.

1983-01-01

It's presented the effect of the lead screen in the image obtained on an impressionable film used in industrial gammagraphy. The source used was Iridium 192 and the tests were simulated like a real inspection. (E.G.) [pt

Reverse saturable absorption (RSA) in fluorinated iridium derivatives

Science.gov (United States)

Ferry, Michael J.; O'Donnell, Ryan M.; Bambha, Neal; Ensley, Trenton R.; Shensky, William M.; Shi, Jianmin

2017-08-01

The photophysical properties of cyclometallated iridium compounds are beneficial for nonlinear optical (NLO) applications, such as the design of reverse saturable absorption (RSA) materials. We report on the NLO characterization of a family of compounds of the form [Ir(pbt)2(LX)], where pbt is 2-phenylbenzothiazole and LX is a beta-diketonate ligand. In particular, we investigate the effects of trifluoromethylation on compound solubility and photophysics compared to the parent acetylacetonate (acac) version. The NLO properties, such as the singlet and triplet excited-state cross sections, of these compounds were measured using the Z-scan technique. The excited-state lifetimes were determined from visible transient absorption spectroscopy.

Growth and characterization of iridium dioxide nanorods

International Nuclear Information System (INIS)

Chen, R.S.; Huang, Y.S.; Liang, Y.M.; Tsai, D.S.; Tiong, K.K.

2004-01-01

Conductive iridium dioxide (IrO 2 ) nanorods have been successfully grown on the Si(1 0 0) substrates via metalorganic chemical vapor deposition (MOCVD). A wedge-shaped morphology and naturally formed sharp tips are observed for IrO 2 nanorods using field-emission scanning electron microscopy (FESEM). High-resolution transmission electron microscopy (TEM) image and electron diffraction pattern show the growth of IrO 2 nanorods preferentially along c-axis. Structure and composition of IrO 2 nanorods have also been characterized using the techniques of Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. It is noted that the IrO 2 nanorods are self-mediated instead of the conventional vapor-liquid-solid (VLS) approach or catalyst-mediated method

Colorimetric and luminescent bifunctional iridium(III) complexes for the sensitive recognition of cyanide ions

Science.gov (United States)

Chen, Xiudan; Wang, Huili; Li, Jing; Hu, Wenqin; Li, Mei-Jin

2017-02-01

Two new cyclometalated iridium(III) complexes [(ppy)2Irppz]Cl (1) and [(ppy)2Irbppz]Cl (2) (where ppy = 2-phenylpyridine, ppz = 4,7-phenanthrolino-5,6:5,6-pyrazine, bppz = 2.3-di-2-pyridylpyrazine), were designed and synthesized. The structure of [(ppy)2Irppz]Cl was determined by single crystal X-ray diffraction. Their photophysical properties were also studied. This kind of complexes could coordinate with Cu2 +, the photoluminescence (PL) of the complex was quenched, and the color changed from orange-red to green. The forming M-Cu (M: complexes 1 and 2) ensemble could be further utilized as a colorimetric and emission ;turn-on; bifunctional detection for CN-, especially for complex 1-Cu2 + showed a high sensitivity toward CN- with a limit of diction is 97 nM. Importantly, this kind of iridium(III) complexes shows a unique recognition of cyanide ions over other anions which makes it an eligible sensing probe for cyanide ions.

Phosphorescence Imaging of Living Cells with Amino Acid-Functionalized Tris(2-phenylpyridine)iridium(III) Complexes

NARCIS (Netherlands)

Steunenberg, P.; Ruggi, A.; Berg, van den N.S.; Buckle, T.; Kuil, J.; Leeuwen, van F.W.B.; Velders, A.H.

2012-01-01

A series of nine luminescent cyclometalated octahedral iridium(III) tris(2-phenylpyridine) complexes has been synthesized, functionalized with three different amino acids (glycine, alanine, and lysine), on one, two, or all three of the phenylpyridine ligands. All starting complexes and final

Sterically directed iridium-catalyzed hydrosilylation of alkenes in the presence of alkynes.

Science.gov (United States)

Muchnij, Jill A; Kwaramba, Farai B; Rahaim, Ronald J

2014-03-07

A selective iridium catalyzed hydrosilylation of alkenes in the presence of more reactive alkynes is described. By utilizing [IrCl(COD)]2 in the presence of excess COD, hydrosilylation of alkenes and alkynes with ethynylsilanes is achieved with good chemo- and regioselectivity. This approach goes against the traditional reactivity trends of platinum and rhodium catalysts and allows access to highly substituted silicon alkyne tethers.

Angular absorption of iridium - ICW12 needles: practical considerations

International Nuclear Information System (INIS)

Szymczyk, W.; Lesiak, J.

1984-01-01

An analysis was made of two potential sources of error in Ir 192 dosimetry: the effect of angular absorption and the differences in the ionization constants found in literature. Corrections for selfabsorption in the ICW12 iridium source were determined from measurements and calculations. It was found that the decrease in the dose caused by the angular absorption in the central therapeutic area of a typical implantation can exceed 5 percent. The need for employing the concept of ''constant exposure rate'' is stressed as well as that for using angular absorption in the form of absorption. 13 refs., 6 figs., 1 tab. (author)

Chlorido(η4-1,5-cyclooctadiene[(pentafluoroethyldiphenylphosphane]iridium(I

Directory of Open Access Journals (Sweden)

Russell G. Baughman

2011-01-01

Full Text Available The title structure,[IrCl(C8H12(C14H10F5P], reveals that (C2F5PPh2 (pentafluoroethyldiphenylphosphane or pfepp disrupts the iridium dimer [(codIrCl]2 (cod = cycloocta-1,5-diene by rupturing the bridging chloride ligands and binding in the open coordination site to form (codIr(pfeppCl with the IrI atom in a distorted square-planar coordination environment. The structure deviates very little from the IrI–triphenylphosphine analog, although a significantly (∼20σ shorter Ir—P bond is noted for the title compound.

Electron beam welding of iridium heat source capsules

International Nuclear Information System (INIS)

Mustaleski, T.M.; Yearwood, J.C.; Burgan, C.E.; Green, L.A.

1991-01-01

The development of the welding procedures for the production of DOP-26 iridium alloy cups for heat source encapsulation is described. All the final assembly welds were made using the electron beam welding process. The welding of the 0.13-mm weld shield required the use of computer controlled X-Y table and a run-off tab. Welding of the frit vent to the cup required that a laser weld be made to hold the frit assembly edges together for the final electron beam weld. Great care is required in tooling design and beam placement to achieve acceptable results. Unsuccessful attempts to use laser beam welding for heat shield butt weld are discussed

Sol-Gel Deposition of Iridium Oxide for Biomedical Micro-Devices

Directory of Open Access Journals (Sweden)

Cuong M. Nguyen

2015-02-01

Full Text Available Flexible iridium oxide (IrOx-based micro-electrodes were fabricated on flexible polyimide substrates using a sol-gel deposition process for utilization as integrated pseudo-reference electrodes for bio-electrochemical sensing applications. The fabrication method yields reliable miniature on-probe IrOx electrodes with long lifetime, high stability and repeatability. Such sensors can be used for long-term measurements. Various dimensions of sol-gel iridium oxide electrodes including 1 mm × 1 mm, 500 µm × 500 µm, and 100 µm × 100 µm were fabricated. Sensor longevity and pH dependence were investigated by immersing the electrodes in hydrochloric acid, fetal bovine serum (FBS, and sodium hydroxide solutions for 30 days. Less pH dependent responses, compared to IrOx electrodes fabricated by electrochemical deposition processes, were measured at 58.8 ± 0.4 mV/pH, 53.8 ± 1.3 mV/pH and 48 ± 0.6 mV/pH, respectively. The on-probe IrOx pseudo-reference electrodes were utilized for dopamine sensing. The baseline responses of the sensors were higher than the one using an external Ag/AgCl reference electrode. Using IrOx reference electrodes integrated on the same probe with working electrodes eliminated the use of cytotoxic Ag/AgCl reference electrode without loss in sensitivity. This enables employing such sensors in long-term recording of concentrations of neurotransmitters in central nervous systems of animals and humans.

Sol-Gel Deposition of Iridium Oxide for Biomedical Micro-Devices

Science.gov (United States)

Nguyen, Cuong M.; Rao, Smitha; Yang, Xuesong; Dubey, Souvik; Mays, Jeffrey; Cao, Hung; Chiao, Jung-Chih

2015-01-01

Flexible iridium oxide (IrOx)-based micro-electrodes were fabricated on flexible polyimide substrates using a sol-gel deposition process for utilization as integrated pseudo-reference electrodes for bio-electrochemical sensing applications. The fabrication method yields reliable miniature on-probe IrOx electrodes with long lifetime, high stability and repeatability. Such sensors can be used for long-term measurements. Various dimensions of sol-gel iridium oxide electrodes including 1 mm × 1 mm, 500 μm × 500 μm, and 100 μm × 100 μm were fabricated. Sensor longevity and pH dependence were investigated by immersing the electrodes in hydrochloric acid, fetal bovine serum (FBS), and sodium hydroxide solutions for 30 days. Less pH dependent responses, compared to IrOx electrodes fabricated by electrochemical deposition processes, were measured at 58.8 ± 0.4 mV/pH, 53.8 ± 1.3 mV/pH and 48 ± 0.6 mV/pH, respectively. The on-probe IrOx pseudo-reference electrodes were utilized for dopamine sensing. The baseline responses of the sensors were higher than the one using an external Ag/AgCl reference electrode. Using IrOx reference electrodes integrated on the same probe with working electrodes eliminated the use of cytotoxic Ag/AgCl reference electrode without loss in sensitivity. This enables employing such sensors in long-term recording of concentrations of neurotransmitters in central nervous systems of animals and humans. PMID:25686309

Ammonia synthesis in the presence of rhodium-ruthenium-iridium carbonyl clusters

International Nuclear Information System (INIS)

Fedoseev, I.V.; Solov'ev, N.V.

2007-01-01

Researches in the field of platinum metal coordination compounds, where nitrogen enters as a ligand in coordination sphere of metal, are discussed. Results of experiments on the ammonia synthesis during the CO+N 2 mixture passing through alkali solution containing mixture of carbonyl clusters of rhodium, ruthenium and iridium at atmospheric pressure are given. Technique of the experiment and steps of assumed reactions of nitrogen fixation by Rh, Ir and Ru carbonyl clusters are demonstrated [ru

Determination of iridium at low levels (sub ng g-1) in geological materials by neutron activation analysis

International Nuclear Information System (INIS)

Morcelli, Claudia Petronilho Ribeiro

1999-01-01

The analysis of the platinum group elements (PGE: Ru, Rh, Pd, Os, Ir and Pt) in geological materials is difficult, due to the low concentrations of these elements (ng g -1 or sub ng g -1 ) and their heterogeneous distribution in many geological matrices. The determination of PGE has attracted great interest due not only to the increasing utilization of these elements in modern industry, but also to the information that these elements can provide on mantle processes. The determination of very low amounts of iridium is particularly important on account of some anomalous concentrations of iridium in sedimentary rock samples, related to the impact of an extraterrestrial object responsible for extinctions at the Cretaceous-Tertiary (K-T) boundary. In the present paper, a radiochemical neutron activation method for the determination of iridium in geological materials is presented. The procedure consisted of thermal neutron irradiation of about 500 mg of the sample, followed by sintering with sodium peroxide, precipitation with tellurium and high resolution gamma-ray spectrometry with a hyper-pure Ge detector. The accuracy and precision of the procedure were evaluated by analysis of the certified reference material SARM-7 (South Africa Bureau of Standards) and W-1 (USGS). The detection limit for the analytical conditions employed was 0.004 ng g -1 . The procedure was applied to the reference materials TDB-1 and WGB-1 (CANMET), which present provisional values for Ir, and to the reference materials GXR-3, GXR-5 and GXR- 6 (USGS), which do not present information values for Ir. This work is a contribution to Ir values in these reference materials. As an example of application of the method to real samples, the developed procedure was employed in the determination of iridium in basalts from Parana basin, collected in Bom Guara do Sul, Santa Catarina, provided by the Geosciences Institute of the University of Campinas. (author)

Iridium-Catalyzed Asymmetric Intramolecular Allylic Amidation : Enantioselective Synthesis of Chiral Tetrahydroisoquinolines and Saturated Nitrogen Heterocycles

NARCIS (Netherlands)

Teichert, Johannes F.; Fañanás-Mastral, Martín; Feringa, Bernard

2011-01-01

For the first time iridium catalysis has been used for the synthesis of chiral tetrahydroisoquinolines with excellent yields and high enantioselectivities (see scheme; cod=1,5-cyclooctadiene, DBU=1,8-diazabicyclo[5.4.0]undec-7-ene). These products are important chiral building blocks for the

Installing an additional emission quenching pathway in the design of iridium(III)-based phosphorogenic biomaterials for bioorthogonal labelling and imaging.

Science.gov (United States)

Li, Steve Po-Yam; Yip, Alex Man-Hei; Liu, Hua-Wei; Lo, Kenneth Kam-Wing

2016-10-01

We report the synthesis, characterization, photophysical and electrochemical behaviour and biological labelling applications of new phosphorogenic bioorthogonal probes derived from iridium(III) polypyridine complexes containing a 1,2,4,5-tetrazine moiety. In contrast to common luminescent cyclometallated iridium(III) polypyridine complexes, these tetrazine complexes are almost non-emissive due to effective Förster resonance energy transfer (FRET) and/or photoinduced electron transfer (PET) from the excited iridium(III) polypyridine unit to the appended tetrazine moiety. However, they exhibited significant emission enhancement upon reacting with (1R,8S,9s)-bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN-OH) (ca. 19.5-121.9 fold) and BCN-modified bovine serum albumin (BCN-BSA) (ca. 140.8-1133.7 fold) as a result of the conversion of the tetrazine unit to a non-quenching pyridazine derivative. The complexes were applied to image azide-modified glycans in live cells using a homobifunctional crosslinker, 1,13-bis((1R,8S,9s)-bicyclo[6.1.0]non-4-yn-9-ylmethyloxycarbonylamino)-4,7,10-trioxatridecane (bis-BCN). Copyright © 2016 Elsevier Ltd. All rights reserved.

Interstitial hyperthermia and iridium-192 treatment alone vs. interstitial iridium-192 treatment/hyperthermia and low dose cisplatinum infusion in the treatment of locally advanced head and neck malignancies

International Nuclear Information System (INIS)

Schreiber, David P.; Overett, Thomas K.

1995-01-01

Purpose: To determine whether the addition of low dose platinum infusional chemotherapy adds to the effectiveness of interstitial hyperthermia/iridium-192 management of locally advanced head and neck malignancies. Methods and Materials: From 1987 to 1993, 36 patients with locally advanced head and neck malignancies were treated locally with interstitial hyperthermia and iridium-192 as part or all of their management. Twenty-two of the above-mentioned patients also received low dose infusional cisplatinum chemotherapy at 20 mg/M 2 per day during the time of the implant. No patient received greater than 100 mg/M 2 total dose. Implant times ranged from 38.5 to 134 h and total doses delivered with the radiation implants ranged from 15 to 39.9 Gy. Average implant volume was 50 cc. Twenty-three patients received external beam irradiation supplementation in a dose range from 25.2 to 64 Gy. Results: Median follow-up for the entire group was 8, months with 7 months for the chemotherapy group vs. 12 months for the no-chemotherapy group. Freedom from relapse rates for the chemotherapy group vs. the no-chemotherapy group were 70% at 41 months vs. 63% at 60 months, p not significant (p = NS). Overall survival by Life Table Analysis was 28% for the chemotherapy group at 41 months vs. 31% for the no-chemotherapy group at 60 months (p = NS). Complete response (CR) rates were 93% for the chemotherapy group vs. 86% for the no-chemotherapy group. Seven patients in the chemotherapy group had recurrent disease and four patients in the no-chemotherapy group were being treated for recurrent disease. Complication rates were similar in both groups, with two patients in the chemotherapy arm requiring hyperbaric oxygen treatments and one patient in the no-chemotherapy arm requiring hyperbaric oxygen treatments (for soft tissue necrosis). Conclusion: It appears that low dose platinum infusional chemotherapy can be added safely to patients receiving interstitial iridium-192 implants along with

Study and development of an Iridium-192 seed for use in ophthalmic cancer; Estudo e desenvolvimento de uma semente de iridio-192 para aplicacao em cancer oftalmico

Energy Technology Data Exchange (ETDEWEB)

Mattos, Fabio Rodrigues de

2013-07-01

Even ocular tumors are not among the cases with a higher incidence, they affect the population, especially children. The Institute of Energy and Nuclear Research (IPEN-CNEN/SP) in partnership with Escola Paulista de Medicina (UNIFESP), created a project to develop and implement a alternative treatment for ophthalmic cancer that use brachytherapy iridium-192 seeds. The project arose by reason of the Escola Paulista treat many cancer cases within the Unified Health System (SUS) and the research experience of sealed radioactive sources group at IPEN. The methodology was developed from the available infrastructure and the experience of researchers. The prototype seed presents with a core (192-iridium alloy of iridium-platinum) of 3.0 mm long sealed by a capsule of titanium of 0.8 mm outside diameter, 0.05 mm wall thickness and 4,5mm long. This work aims to study and develop a seed of iridium-192 from a platinum-iridium alloy. No study on the fabrication of these seeds was found in available literature. It was created a methodology that involved: characterization of the material used in the core, creation of device for neutron activation irradiation and and seed sealing tests. As a result, proved the feasibility of the method. As a suggestion for future work, studies regarding metrology and dosimetry of these sources and improvement of the methodology should be carried out, for future implementation in national scope. (author)

A pH Sensor Based on a Stainless Steel Electrode Electrodeposited with Iridium Oxide

Science.gov (United States)

Martinez, C. C. M.; Madrid, R. E.; Felice, C. J.

2009-01-01

A simple procedure to make an iridium oxide (IrO[subscript 2]) electrodeposited pH sensor, that can be used in a chemical, biomedical, or materials laboratory, is presented here. Some exercises, based on this sensor, that can be used to teach important concepts in the field of biomedical, biochemical, tissue, or materials engineering, are also…

Substrate-induced antiferromagnetism of ultrathin iron overlayers on the iridium and rhodium (001) surfaces

Czech Academy of Sciences Publication Activity Database

Máca, František; Kudrnovský, Josef; Drchal, Václav; Turek, Ilja; Bengone, O.; Redinger, J.

2009-01-01

Roč. 11, - (2009), s. 38-40 ISSN 1642-6037 R&D Projects: GA ČR GA202/07/0456; GA MŠk OC09028 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z20410507 Keywords : iridium * rhodium * iron * magnetismus in thin layers * density functional calculations Subject RIV: BM - Solid Matter Physics ; Magnetism

Efficient near-infrared emission of π-extended cyclometalated iridium complexes based on pyrene in solution-processed polymer light-emitting diode

Science.gov (United States)

Liu, Yu; Hao, Zhaoran; Meng, Fanyuan; Wang, Pu; Yang, Liang; Wang, Yafei; Pei, Yong; Su, Shijian

2018-05-01

A novel iridium complex grafting hole-transporting triphenylamine (TPA) unit onto cyclometalated ligand, namely t-BuPyrPyTPA)2Ir(acac), was successfully synthesized and characterized. The photophysical, electrochemical and DFT/TD-DFT calculation, as well as electroluminescence properties of this iridium complex were fully investigated. Meanwhile, the PLEDs employing (t-BuPyrPyTPA)2Ir(acac) as dopant presented stable NIR emission peaked at 697 nm and a shoulder at 764 nm with a highest external quantum efficiency (EQE) of 0.56% at 4 wt% dopant concentration. These results demonstrate that expanding the conjugation length of the ligand is an effective way to achieve NIR emission.

Single step radiolytic synthesis of iridium nanoparticles onto graphene oxide

International Nuclear Information System (INIS)

Rojas, J.V.; Molina Higgins, M.C.; Toro Gonzalez, M.; Castano, C.E.

2015-01-01

Graphical abstract: - Highlights: • Ir nanoparticles were synthesized through a single step gamma irradiation process. • Homogeneously distributed Ir nanoparticles on graphene oxide are ∼2.3 nm in size. • Ir−O bonds evidenced the interaction of the nanoparticles with the support. - Abstract: In this work a new approach to synthesize iridium nanoparticles on reduced graphene oxide is presented. The nanoparticles were directly deposited and grown on the surface of the carbon-based support using a single step reduction method through gamma irradiation. In this process, an aqueous isopropanol solution containing the iridium precursor, graphene oxide, and sodium dodecyl sulfate was initially prepared and sonicated thoroughly to obtain a homogeneous dispersion. The samples were irradiated with gamma rays with energies of 1.17 and 1.33 MeV emitted from the spontaneous decay of the 60 Co irradiator. The interaction of gamma rays with water in the presence of isopropanol generates highly reducing species homogeneously distributed in the solution that can reduce the Ir precursor down to a zero valence state. An absorbed dose of 60 kGy was used, which according to the yield of reducing species is sufficient to reduce the total amount of precursor present in the solution. This novel approach leads to the formation of 2.3 ± 0.5 nm Ir nanoparticles distributed along the surface of the support. The oxygenated functionalities of graphene oxide served as nucleation sites for the formation of Ir nuclei and their subsequent growth. XPS results revealed that the interaction of Ir with the support occurs through Ir−O bonds.

Structural characterization and comparison of iridium, platinum and gold/palladium ultra-thin film coatings for STM of biomolecules

Energy Technology Data Exchange (ETDEWEB)

Sebring, R.; Arendt, P.; Imai, B.; Bradbury, E.M.; Gatewood, J. [Los Alamos National Lab., NM (United States); Panitz, J. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Physics and Astronomy; Yau, P. [Univ. of California, Davis, CA (United States)

1997-10-30

Scanning tunneling microscopy (STM) is capable of atomic resolution and is ideally suited for imaging surfaces with uniform work function. A biological sample on a conducting substrate in air does not meet this criteria and requires a conductive coating for stable and reproducible STM imaging. In this paper, the authors describe the STM and transmission electron microscopy (TEM) characterization of ultra-thin ion-beam sputtered films of iridium and cathode sputtered gold/palladium and platinum films on highly ordered pyrolytic graphite (HOPG) which were developed for use as biomolecule coatings. The goals were the development of metal coatings sufficiently thin and fine grained that 15--20 {angstrom} features of biological molecules could be resolved using STM, and the development of a substrate/coating system which would allow complementary TEM information to be obtained for films and biological molecules. The authors demonstrate in this paper that ion-beam sputtered iridium on highly ordered pyrolytic graphite (HOPG) has met both these goals. The ion-beam sputtered iridium produced a very fine grained (< 10 {angstrom}) continuous film at 5--6 {angstrom} thickness suitable for stable air STM imaging. In comparison, cathode sputtered platinum produced 16 {angstrom} grains with the thinnest continuous film at 15 {angstrom} thickness, and the sputtered gold/palladium produced 25 {angstrom} grains with the thinnest continuous film at 18 {angstrom} thickness.

MEMBANGUN KEUNGGULAN KOMPETITIF CPO MELALUI SUPPLY CHAIN MANAGEMENT: STUDI KASUS DI PT. EKA DURA INDONESIA, ASTRA AGRO LESTARI, RIAU

Directory of Open Access Journals (Sweden)

Setiadi Djohar

2011-08-01

Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Todays, Supply Chain Management (SCM becomes one icon of strategic factors to achieve a competitive advantage. This is a SCM case study in agroindustry especially crude palm oil (CPO at PT. Eka Dura Indonesia (PT EDI, Astra Agro Lestari, Riau. The objectives of study is mapping of SCM problems of PT EDI, especially about value advantage and productivity advantage. Beside that, the objectives is building a SCM simulation model as strategic tool for developing strategy to achieve a competitive advantage. A system approach and modeling is used to analyze SCM problems. This study is successfully to build SCM Model that consist of SCM Strategic Model and SCM Tactic Model. SCM Model is used for simulating some scenarios about site management, supply schedulling, and tank management to CPO forecasting. From this model, the study also develops strategy chain for SCM to achieve a competitive advantage

A calorimetric particle detector using an iridium superconducting phase transition thermometer

International Nuclear Information System (INIS)

Frank, M.; Dummer, D.; Cooper, S.; Igalson, J.; Proebst, F.; Seidel, W.

1994-01-01

We report on a calorimetric particles detector consisting of an 18.3 g silicon crystal and an iridium superconducting phase transition thermometer. The cryogenic calorimeter and the associated apparatus are described in detail. The pulses from irradiation with an α-particle source have a large unexpected overshoot in addition to the component expected from a naive thermal model. The pulse height spectrum displays an energy resolution of 1 percent FWHM at 6 MeV and good linearity. The noise, electrothermal feedback, and position dependence are discussed. (orig.)

Synthesis and crystal structure of the iridium(I) carbene complex with a pair of hydrogen wing tips

Energy Technology Data Exchange (ETDEWEB)

Huang, H.-Y.; Chen, Z.-M.; Wang, Y.; Wu, E.-M.; Wang, G. [Jiangsu Institute of Nuclear Medicine, Ministry of Health, Key Laboratory of Molecular Nuclear Medicine (China); Jiang, M.-J., E-mail: jmj16888@126.com [Nanjing Medical University, Affiliated Wuxi Peoples Hospital, Wuxi Institute of Translational Medicine, Department of Clinical Laboratory Science (China)

2016-12-15

The iridium(I) cyclooctadiene complex with two (3-tert-butylimidazol-2-ylidene) ligands [(H-Im{sup t}Bu){sub 2}Ir(COD)]{sup +}PF{sub 6}{sup −} (C{sub 22}H{sub 32}PF{sub 6}IrN{sub 4}) has been prepared, and its crystal structure is determined by X-ray diffraction. Complex exhibits slightly distorted square planar configurations around the metal atom, which is coordinated by two H-Im{sup t}Bu ligands and one cyclooctadiene group. The new iridium carbene complex has a pair of hydrogen wing tips. The Ir−C{sub carbene} bond lengths are 2.066(5) and 2.052(5) Å, and the bond angle C−Ir−C between these bonds is 95.54(19)°. The dihedral angle between two imidazol-2-ylidene rings is 86.42°.

Muscle invasive bladder cancer treated by transurethral resection, followed by external beam radiation and interstitial iridium-192

NARCIS (Netherlands)

A. Wijnmaalen (Arendjan); P.A. Helle (Peter); P.C.M. Koper (Peter); P.P. Jansen (Peter); P. Hanssens (Patrick); C.G.G. Boeken Kruger (Cornelis); W.L.J. van Putten (Wim)

1997-01-01

textabstractPurpose: To evaluate the results of transurethral resection (TUR), external beam radiotherapy (EBRT), and interstitial radiation (IRT) with iridium-192, using the afterloading technique in patients with muscle invasive bladder cancer. Methods and Materials: From May 1989 until September

A highly selective and non-reaction based chemosensor for the detection of Hg2+ ions using a luminescent iridium(III complex.

Directory of Open Access Journals (Sweden)

Daniel Shiu-Hin Chan

Full Text Available We report herein a novel luminescent iridium(III complex with two hydrophobic carbon chains as a non-reaction based chemosensor for the detection of Hg(2+ ions in aqueous solution (<0.002% of organic solvent attributed to the probe solution. Upon the addition of Hg(2+ ions, the emission intensity of the complex was significantly enhanced and this change could be monitored by the naked eye under UV irradiation. The iridium(III complex shows high specificity for Hg(2+ ions over eighteen other cations. The system is capable of detecting micromolar levels of Hg(2+ ions, which is within the range of many chemical systems.

Muscle invasive bladder cancer treated by transurethral resection, followed by external beam radiation and interstitial iridium-192

International Nuclear Information System (INIS)

Wijnmaalen, Arendjan; Helle, Peter A.; Koper, Peter C.M.; Jansen, Peter P.; Hanssens, Patrick E.J.; Boeken Kruger, Cornelis G.G.; Putten, Wim L.J. van

1996-01-01

Purpose: In our center interstitial radiation has played an important role in the treatment of bladder cancer patients for over 40 years. Radium needles, that were initially used, were replaced by caesium needles in 1983, whereas the afterloading iridium wire technique was adopted in 1989. Patients with solitary tumors (T1, T2 and T3) with a surface diameter of < 5 cm are considered for interstitial radiation. In this study we report on the results of the afterloading iridium wire technique in patients with muscle invasive bladder cancer. Materials and Methods: From May 1989 to September 1993 interstitial radiation using iridium wires was part of the treatment in 46 patients with muscle invasive bladder cancer (37 T2, 9 T3). The mean age was 67 years. After transurethral resection of all visible tumor (if possible), in most cases 40 Gy (20 x 2.0 Gy, midplane dose) external beam radiation was delivered to the true pelvis, followed by 30 Gy interstitial radiation using iridium-192 wires covering the tumor area in the bladder. Results: After a median follow-up of 26 months, bladder relapses occurred in 7 patients. In 5 of them the tumor relapsed in the initial area, in 1 patient elsewhere in the bladder and in 1 patient tumor recurred in and outside the initial site. Recurrence was superficial (T1) in 4 patients. A relapse in the urethra was found once. Metastases developed in 13 patients, in 8 without bladder relapse. During the observation period 17 patients died, 13 due to bladder cancer. The actuarial bladder relapse-free survival at 4 years was 74% and 82% for T2 and T3 tumors, respectively. The actuarial distant metastases-free survival was 65% for both categories. No serious toxicity was recorded. Conclusion: In a selected group of patients with muscle invasive bladder cancer transurethral resection in combination with external beam and interstitial radiation provides an excellent opportunity to preserve the bladder with a high chance of success. Development of

Detection of triglyceride using an iridium nano-particle catalyst based amperometric biosensor.

Science.gov (United States)

Liao, Wei-Yin; Liu, Chung-Chiun; Chou, Tse-Chuan

2008-12-01

The detection and quantification of triglyceride (TG) using an iridium nano-particle modified carbon based biosensor was successfully carried out in this study. The detection procedures were based on the electrochemical detection of enzymatically produced NADH. TG was hydrolyzed by lipase and the glycerol produced was catalytically oxidized by NAD-dependent glycerol dehydrogenase producing NADH in a solution containing NAD(+). Glyceryl tributyrate, a short chain triglyceride, was chosen as the substrate for the evaluation of this TG biosensor in bovine serum and human serum. A linear response to glyceryl tributyrate in the concentration range of 0 to 10 mM and a sensitivity of 7.5 nA mM(-1) in bovine serum and 7.0 nA mM(-1) in human serum were observed experimentally. The potential interference of species such as uric acid (UA) and ascorbic acid (AA) was assessed. The incorporation of a selected surfactant and an increase in the incubation temperature appeared to enhance the performance of this biosensor. The conditions for the determination of TG levels in bovine serum using this biosensor were optimized, with sunflower seed oil being used as an analyte to simulate the detection of TG in blood. The experimental results demonstrated that this iridium nano-particle modified working electrode based biosensor provided a relatively simple means for the accurate determination of TG in serum.

New cyclometalated Iridium(III) beta-dicetone complex as phosphorescent dopant in Organic light emitting devices

Science.gov (United States)

Ivanov, P.; Petrova, P.; Stanimirov, S.; Tomova, R.

2017-01-01

A new Bis[4-(benzothiazolato-N,C2‧-2-yl)-N,N-dimethylaniline]Iridium(III) acetylacetonate (Me2N-bt) 2Ir(acac) was synthesized and identified by 1H NMR and elemental analysis. The application of the new compound as a dopant in the hole transporting layer (HTL) of Organic light emitting diode (OLED) structure: HTL/EL/ETL, where HTL was N,N’-bis(3-methylphenyl)-N,N’-diphenylbenzidine (TPD), incorporated in Poly(N-vinylcarbazole) (PVK) matrix, EL - electroluminescent layer of Bis(8-hydroxy-2-methylquinoline)-(4-phenylpheno-xy)aluminum (BAlq) and ETL - electron-transporting layer of Tris-(8-hydroxyquinoline) aluminum (Alq3) or Bis[2-(2-benzothiazoly) phenolato]zinc (Zn(btz)2). We established that the electroluminescent spectra of OLEDs at different concentrations of the dopant were basically the sum of the greenish-blue emission of BAlq and yellowish-green emission of Ir complex. It was found that with increasing of the dopant concentration the relative electroluminescent intensity of Iridium complex emission increased and this of BAlq decreased and as a result the fine tuning of OLED color was observed.

Adsorption and the initial stages of samarium condensation on iridium coated by graphite monolayer

International Nuclear Information System (INIS)

Abdullaev, R.M.; Tontegode, A.Ya.; Yusifov, F.K.

1978-01-01

Adsorption and the initial stages of vacuum samarium condensation on iridium coated by graphite monolayer (valent-saturated neutral substrate) were studied by the thermodesorption mass-spectrometry and thermoemission methods, and were compared with samarium adsorption and condensation on iridium. Desorption heat of samarium atoms with thin coating of Ir-C, equal to E approximately 1.9 eV has been determined. For desorption with Ir E is approximately 6 eV. Such a great difference in desorption heats is connected with the reduction of covalent constituent of adsorption bond in a neutral substrate. Samarium on Ir-C is found to be condensated in two states: loosely bound and tightly bound which sharply differ in properties. The tightly bound state is characterized by abnormally low vapour pressure. Possible nature of this state is discussed. Double effect on the condensation of the substrate valent saturation is noted. On the one hand, the reduction of the particle bond with the substrate decreases their concentration on the surface, preventing condensation. On the other hand, the release of the valent eloctrons of adatous brings about strong lateral interaction between them, which in its turn, promotes condensation during eased migration on the neutral substrate

Oxidation of iridium coating on rhenium coated graphite at elevated temperature in stagnated air

International Nuclear Information System (INIS)

Huang, Yongle; Bai, Shuxin; Zhang, Hong; Ye, Yicong

2015-01-01

Highlights: • Continuous and dense Ir coatings were prepared on graphite by electrodepostion. • The purification of the as-prepared Ir coating was higher than about 99.98%. • The Ir/Re/C specimen kept integrity without significant failures after oxidation. • The average oxidation rate of the Ir coating was about 0.219 mg/(cm 2 min). • Penetrating holes at gains boundaries resulted in the failure of the Ir coating. - Abstract: Continuous and dense iridium coatings were prepared on the rhenium coated graphite specimens by electrodeposition. The iridium/rhenium coated graphite (Ir/Re/C) specimens were oxidized at elevated temperatures in stagnated air for 3600 s. The purification of the as-prepared Ir coating was higher than about 99.98% with the main impurity elements Si, Al, Fe and Ru. After oxidation, the Ir/Re/C specimens kept integrity without significant failures and the average oxidation rate was about 0.219 mg/(cm 2 min). Pores were found at the grain boundaries and concentrated to penetrating holes with the growth of Ir grains, which resulted in disastrous failures of the Ir coating

Oxidation of iridium coating on rhenium coated graphite at elevated temperature in stagnated air

Energy Technology Data Exchange (ETDEWEB)

Huang, Yongle; Bai, Shuxin, E-mail: NUDT_MSE_501@163.com; Zhang, Hong; Ye, Yicong

2015-02-15

Highlights: • Continuous and dense Ir coatings were prepared on graphite by electrodepostion. • The purification of the as-prepared Ir coating was higher than about 99.98%. • The Ir/Re/C specimen kept integrity without significant failures after oxidation. • The average oxidation rate of the Ir coating was about 0.219 mg/(cm{sup 2} min). • Penetrating holes at gains boundaries resulted in the failure of the Ir coating. - Abstract: Continuous and dense iridium coatings were prepared on the rhenium coated graphite specimens by electrodeposition. The iridium/rhenium coated graphite (Ir/Re/C) specimens were oxidized at elevated temperatures in stagnated air for 3600 s. The purification of the as-prepared Ir coating was higher than about 99.98% with the main impurity elements Si, Al, Fe and Ru. After oxidation, the Ir/Re/C specimens kept integrity without significant failures and the average oxidation rate was about 0.219 mg/(cm{sup 2} min). Pores were found at the grain boundaries and concentrated to penetrating holes with the growth of Ir grains, which resulted in disastrous failures of the Ir coating.

A study on the relationship between iridium concentration in hen eggshell and iridium-enriched feed by NAA

International Nuclear Information System (INIS)

Yang Gaochuang; Mao Xueying; Wang Jinchun; Lu Yali; Ouyang Hong; Zhang Zhaohui; Chai Zhifang

2001-01-01

Four hens were fed by adding ammonium hexachloroiridate into their forage. After two weeks, Ir concentration in three fractions (eggshell, albumen, egg yolk) of their eggs were measured by instrumental neutron activation analysis (INAA). Ir was present in all the three parts of the eggs. Further, the highest concentration of Ir was found in the egg yolk fraction, about 10 times higher than that in the eggshell and albumen. Moreover, the longer the Ir-containing feed was used, the higher the Ir concentration in the egg fractions was. After 4-6 day feeding, the Ir concentration became stable. The experimental results indicated that the Ir concentration was about 2-7 x 10 -10 g/g in the eggshell fraction compared to 5.6 x 10 -7 g/g in feed. Therefore, the ratio from the feed over the eggshell via gastrointestinal pathway was estimated to be about 0.08%. The new result is useful to evaluate the iridium-enriched eggshell fossils of dinosauria and to interpret the origin of the mass extinction of dinosauria at the end of Cretaceous. (author)

Probing the mer- to fac-isomerization of tris-cyclometallated homo- and heteroleptic (C,N)3 Iridium(III) complexes

NARCIS (Netherlands)

McDonald, A.R.; Lutz, M.; von Chrzanowski, L.S.; van Klink, G.P.M.; Spek, A.L.; van Koten, G.

2008-01-01

We have developed techniques which allow for covalent tethering, via a “hetero” cyclometallating ligand, of heteroleptic tris-cyclometallated iridium(III) complexes to polymeric supports (for application in light-emitting diode technologies). This involved the selective synthesis and thorough

Mixed N-Heterocyclic Carbene-Bis(oxazolinyl)borato Rhodium and Iridium Complexes in Photochemical and Thermal Oxidative Addition Reactions

Energy Technology Data Exchange (ETDEWEB)

Xu, Songchen [Ames Laboratory; Manna, Kuntal [Ames Laboratory; Ellern, Arkady [Ames Laboratory; Sadow, Aaron D [Ames Laboratory

2014-12-08

In order to facilitate oxidative addition chemistry of fac-coordinated rhodium(I) and iridium(I) compounds, carbene–bis(oxazolinyl)phenylborate proligands have been synthesized and reacted with organometallic precursors. Two proligands, PhB(OxMe2)2(ImtBuH) (H[1]; OxMe2 = 4,4-dimethyl-2-oxazoline; ImtBuH = 1-tert-butylimidazole) and PhB(OxMe2)2(ImMesH) (H[2]; ImMesH = 1-mesitylimidazole), are deprotonated with potassium benzyl to generate K[1] and K[2], and these potassium compounds serve as reagents for the synthesis of a series of rhodium and iridium complexes. Cyclooctadiene and dicarbonyl compounds {PhB(OxMe2)2ImtBu}Rh(η4-C8H12) (3), {PhB(OxMe2)2ImMes}Rh(η4-C8H12) (4), {PhB(OxMe2)2ImMes}Rh(CO)2 (5), {PhB(OxMe2)2ImMes}Ir(η4-C8H12) (6), and {PhB(OxMe2)2ImMes}Ir(CO)2 (7) are synthesized along with ToMM(η4-C8H12) (M = Rh (8); M = Ir (9); ToM = tris(4,4-dimethyl-2-oxazolinyl)phenylborate). The spectroscopic and structural properties and reactivity of this series of compounds show electronic and steric effects of substituents on the imidazole (tert-butyl vs mesityl), effects of replacing an oxazoline in ToM with a carbene donor, and the influence of the donor ligand (CO vs C8H12). The reactions of K[2] and [M(μ-Cl)(η2-C8H14)2]2 (M = Rh, Ir) provide {κ4-PhB(OxMe2)2ImMes'CH2}Rh(μ-H)(μ-Cl)Rh(η2-C8H14)2 (10) and {PhB(OxMe2)2ImMes}IrH(η3-C8H13) (11). In the former compound, a spontaneous oxidative addition of a mesityl ortho-methyl to give a mixed-valent dirhodium species is observed, while the iridium compound forms a monometallic allyl hydride. Photochemical reactions of dicarbonyl compounds 5 and 7 result in C–H bond oxidative addition providing the compounds {κ4-PhB(OxMe2)2ImMes'CH2}RhH(CO) (12) and {PhB(OxMe2)2ImMes}IrH(Ph)CO (13). In 12, oxidative addition results in cyclometalation of the mesityl ortho-methyl similar to 10, whereas the iridium compound reacts with the benzene solvent to give a rare crystallographically characterized cis

Reversible switching of the sol- gel transition with ultrasound in rhodium(I) and iridium(I) coordination networks

NARCIS (Netherlands)

Paulusse, J.M.J.; Beek, van D.J.M.; Sijbesma, R.P.

2007-01-01

Reversible coordination networks were prepared by combining diphenylphosphinite telechelic polytetrahydrofuran (2) with [RhCl(COD)]2 or [IrCl(COD)]2 in chloroform. Both systems resulted in stable gels at concentrations above 50 and 30 g/L for the rhodium(I) and iridium(I) networks, respectively. The

Synthesis of a red electrophosphorescent heteroleptic iridium complex and its application in efficient polymer light-emitting diodes

International Nuclear Information System (INIS)

Zhang Xiuju; Xu Yunhua; Sun Yiheng; Shi Huahong; Zhu Xuhui; Cao Yong

2007-01-01

The preparation and characterization of a heteroleptic iridium complex [2-(benzo[b]thiophen-2-yl)pyridine]Ir(III)[2-(4H-1,2,4-triazol-3-yl) pyridine] [(Btp) 2 Ir(PZ)] were reported (2-(benzo[b]thiophen-2-yl)pyridine = Btp; 2-(4H-1,2,4-triazol-3-yl)pyridine = PZ). Electrophosphorescence was investigated in the device structure [indium-tin-oxide (ITO)/poly(ethlenedioxythiophene) (PEDOT)/poly(vinylcarbazole)(PVK)/Poly(9,9-dioctylfluorenyl-2,7-diyl) end capped with dimethylphenyl (PFO): (Btp) 2 Ir(PZ)/Ba/Al] by using this iridium complex as guest and PFO as host. The red electrophosphorescent devices showed a peak emission at approximately 604 nm and shoulder at 654 nm with the Commission International de'Eclairage (CIE) coordinates of (0.64, 0.35) and external quantum efficiency of 7.7% at a doping concentration of 8 wt.% without an electron-transporting material in the emitting layer

Palynological and iridium anomalies at Cretaceous-Tertiary boundary, south-central Saskatchewan

Science.gov (United States)

Nichols, D.J.; Jarzen, D.M.; Orth, C.J.; Oliver, P.Q.

1986-01-01

The Cretaceous-Tertiary boundary in south-central Saskatchewan is marked by coincident anomalies in abundance of iridium and fern spores at the extinction level of a suite of Cretaceous pollen taxa. Evidence of disruption of the terrestrial flora includes the fern-spore abundance anomaly and local extinction of as much as 30 percent of angiosperm species. The reorganized earliest Tertiary flora is made up largely of surviving species that assumed new roles of dominance. Persistence of climatically sensitive taxa across the boundary indicates that if paleoclimate was altered by the terminal Cretaceous event, it returned quickly to the pre-event condition.

UV-light promoted C-H bond activation of benzene and fluorobenzenes by an iridium(i) pincer complex.

Science.gov (United States)

Hauser, Simone A; Emerson-King, Jack; Habershon, Scott; Chaplin, Adrian B

2017-03-28

Iridium(i) carbonyl complex [Ir(2,6-(P t Bu 2 CH 2 ) 2 C 6 H 3 )(CO)] undergoes reversible C-H bond activation of benzene and a series of fluorobenzenes on UV irradiation. Exclusive ortho-selectivity is observed in reactions of fluorobenzene and 1,2-difluorobenzene.

UV-light promoted C–H bond activation of benzene and fluorobenzenes by an iridium(i) pincer complex

OpenAIRE

Hauser, Simone A.; Emerson-King, Jack; Habershon, Scott; Chaplin, Adrian B.

2017-01-01

Iridium(I) carbonyl complex [Ir(2,6-(PtBu2CH2)2C6H3)(CO)] undergoes reversible C–H bond activation of benzene and a series of fluorobenzenes on UV irradiation. Exclusive ortho-selectivity is observed in reactions of fluorobenzene and 1,2-difluorobenzene.\\ud \\ud

Grain growth behavior and high-temperature high-strain-rate tensile ductility of iridium alloy DOP-26

International Nuclear Information System (INIS)

McKamey, C.G.; Gubbi, A.N.; Lin, Y.; Cohron, J.W.; Lee, E.H.; George, E.P.

1998-04-01

This report summarizes results of studies conducted to date under the Iridium Alloy Characterization and Development subtask of the Radioisotope Power System Materials Production and Technology Program to characterize the properties of the new-process iridium-based DOP-26 alloy used for the Cassini space mission. This alloy was developed at Oak Ridge National Laboratory (ORNL) in the early 1980's and is currently used by NASA for cladding and post-impact containment of the radioactive fuel in radioisotope thermoelectric generator (RTG) heat sources which provide electric power for interplanetary spacecraft. Included within this report are data generated on grain growth in vacuum or low-pressure oxygen environments; a comparison of grain growth in vacuum of the clad vent set cup material with sheet material; effect of grain size, test temperature, and oxygen exposure on high-temperature high-strain-rate tensile ductility; and grain growth in vacuum and high-temperature high-strain-rate tensile ductility of welded DOP-26. The data for the new-process material is compared to available old-process data

Hybrid white organic light-emitting devices based on phosphorescent iridium-benzotriazole orange-red and fluorescent blue emitters

Energy Technology Data Exchange (ETDEWEB)

Xia, Zhen-Yuan, E-mail: xiazhenyuan@hotmail.com [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237 (China); Su, Jian-Hua [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237 (China); Chang, Chi-Sheng; Chen, Chin H. [Display Institute, Microelectronics and Information Systems Research Center, National Chiao Tung University, Hsinchu, Taiwan 300 (China)

2013-03-15

We demonstrate that high color purity or efficiency hybrid white organic light-emitting devices (OLEDs) can be generated by integrating a phosphorescent orange-red emitter, bis[4-(2H-benzotriazol-2-yl)-N,N-diphenyl-aniline-N{sup 1},C{sup 3}] iridium acetylacetonate, Ir(TBT){sub 2}(acac) with fluorescent blue emitters in two different emissive layers. The device based on deep blue fluorescent material diphenyl-[4-(2-[1,1 Prime ;4 Prime ,1 Double-Prime ]terphenyl-4-yl-vinyl)-phenyl]-amine BpSAB and Ir(TBT){sub 2}(acac) shows pure white color with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.33,0.30). When using sky-blue fluorescent dopant N,N Prime -(4,4 Prime -(1E,1 Prime E)-2,2 Prime -(1,4-phenylene)bis(ethene-2,1-diyl) bis(4,1-phenylene))bis(2-ethyl-6-methyl-N-phenylaniline) (BUBD-1) and orange-red phosphor with a color-tuning phosphorescent material fac-tris(2-phenylpyridine) iridium (Ir(ppy){sub 3} ), it exhibits peak luminance yield and power efficiency of 17.4 cd/A and 10.7 lm/W, respectively with yellow-white color and CIE color rendering index (CRI) value of 73. - Highlights: Black-Right-Pointing-Pointer An iridium-based orange-red phosphor Ir(TBT){sub 2}(acac) was applied in hybrid white OLEDs. Black-Right-Pointing-Pointer Duel- and tri-emitter WOLEDs were achieved with either high color purity or efficiency performance. Black-Right-Pointing-Pointer Peak luminance yield of tri-emitter WOLEDs was 17.4 cd/A with yellow-white color and color rendering index (CRI) value of 73.

Adsorption and desorption of hydrogen and carbon monoxide were studied on alumina-supported iridium catalysts

Energy Technology Data Exchange (ETDEWEB)

Etherton, B.P.

1980-01-01

The adsorption and desorption of hydrogen and carbon monoxide were studied on alumina-supported iridium catalysts which were examined by a scanning transmission electron microscope (STEM). The metal particle size and number of particles per area of catalyst increased with increasing metal loading. The particles were approx. 10 A. in diameter, cubo-octahedral shaped, and approx. 80-90% disperse. The STEM electron beam caused negligible damage to the samples. Hydrogen adsorption measurements showed that the hydrogen-iridium atom ratio was 1.2:1-1.3:1 and increased with decreasing metal loading. Temperature-programed desorption showed four types of adsorbed hydrogen desorbing at -90/sup 0/C (I), 15/sup 0/C (IV), 115/sup 0/C (II), and 245/sup 0/C (III). Types II and IV desorb from single atom sites and Types I and III from multiple atom sites. Type I is in rapid equilibrium with the gas phase. All desorption processes appear to be first order. Carbon monoxide adsorbed nondissociatively at 25/sup 0/C with approx. 0.7:1 CO/Ir atom ratio. It adsorbed primarily in linear forms at low coverage, but a bridged form appeared at high coverage.

Influence of iridium doping in MgB2 superconducting wires

DEFF Research Database (Denmark)

Grivel, Jean-Claude

2018-01-01

MgB2 wires with iridium doping were manufactured using the in-situ technique in a composite Cu-Nb sheath. Reaction was performed at 700°C, 800°C or 900°C for 1h in argon atmosphere. A maximum of about 1.5 at.% Ir replaces Mg in MgB2. The superconducting transition temperature is slightly lowered...... by Ir doping. The formation of IrMg3 and IrMg4 secondary phase particles is evidenced, especially for a nominal stoichiometry with 2.0 at.% Ir doping. The critical current density and accommodation field of the wires are strongly dependent on the Ir content and are generally weakened in the presence...

An iridium abundance anomaly at the palynological Cretaceous-Tertiary boundary in northern New Mexico

Science.gov (United States)

Orth, C.J.; Gilmore, J.S.; Knight, J.D.; Pillmore, C.L.; Tschudy, R.H.; Fassett, J.E.

1981-01-01

An iridium abundance anomaly, with concentrations up to 5000 parts per trillion over a background level of 4 to 20 parts per trillion, has been located in sedimentary rocks laid down under freshwater swamp conditions in the Raton Basin of northeastern New Mexico. The anomaly occurs at the base of a coal bed, at the same stratigraphic position at which several well-known species of Cretaceous-age pollen became extinct. Copyright ?? 1981 AAAS.

Osmium-191 → iridium-191m radionuclide generator: development and clinical application. Progress report, March 1, 1981-February 28, 1982

International Nuclear Information System (INIS)

Treves, S.; Cheng, C.

1981-01-01

A prototype osmium-191 (T 1/2 = 16 days) → iridium-191m (T 1/2 = 4.9 seconds) generator designed for first pass radionuclide angiography was developed in our laboratory (Os-191 → Ir-191m). Our generator had 14 to 20% Ir-191m yield and a 1 to 3 x 10 -3 % Os-191 breakthrough. Iridium-191m decays with emission of a 65 and a 129 keV photon in 50% and 25% abundance respectively. This radionuclide is advantageous for angiography since it provides higher photon flux and results in much lower radiation dose to the patient than Tc-99m. One objective of this research is to improve the Os-191 → Ir-191m generator for first pass radionuclide angiography at an increase in the Ir-191m yield and a decrease in the Os-191 breakthrough. In addition, we would like to develop an Os-191 → Ir-191m generator for continuous infusion which will be used for ECG gated blood pool ventriculography, venography, and arteriography. Another approach will be to develop a carrier free Os-191 → Ir-191m generator in combination with organic or inorganic exchangers. Iridium-191m from our current generator has been employed successfully in two patient studies for the quantitation left-to-right shunting and the measurement of right and left ventricular ejection fractions. These types of studies will be expanded and further evaluated

A study on the relationship between iridium concentration in hen eggs and the iridium-enriched feed stuff by INAA

International Nuclear Information System (INIS)

Yang Gaochuang; Mao Xueying; Lu Yali; Ouyang Hong; Wang Jinchun; Zhang Zhaohui; Chai Zhifang

2000-01-01

Several hens were fed by adding ammonium chloroiridate into their forage. After two weeks, the Ir concentration in three fractions (eggshell, albumen, egg yolk) of their eggs were measured by INAA. Ir was found in all of the three parts. However, the highest concentration of Ir was found in the egg yolk fraction, which was about 10 times higher than that in the eggshell and albumen. Moreover, the longer the Ir-containing feed stuff was used, the higher the Ir concentration in the egg fractions was. After 7-8 days feeding, it kept stable. On the other hand, as soon as adding the Ir-containing additives were stopped, the Ir concentration in the egg fractions fell down quickly. The experimental results indicated that the ratio from the feedstuff to the eggshell via gastrointestinal pathway to be about 0.07 percent. The new result might be beneficial to explain the iridium-enriched dinosaur eggshell fossils and to interpret the origin of the mass extinct event of dinosaur occurred at the end of Cretaceous

Highly efficient and heavily-doped organic light-emitting devices based on an orange phosphorescent iridium complex

International Nuclear Information System (INIS)

Zhou, Shunliang; Wang, Qi; Li, Ming; Lu, Zhiyun; Yu, Junsheng

2014-01-01

Heavily doped and highly efficient phosphorescent organic light-emitting devices (PhOLEDs) had been fabricated by utilizing an orange iridium complex, bis[2-(3′,5′-di-tert-butylbiphenyl-4-yl)benzothiazolato-N,C 2' ]iridium(III) (acetylacetonate) [(tbpbt) 2 Ir(acac)], as a phosphor. When the doping concentration of [(tbpbt) 2 Ir(acac)] reached as high as 15 wt%, the PhOLEDs exhibited a power efficiency, current efficiency, and external quantum efficiency of 24.5 lm/W, 32.1 cd/A, 15.7%, respectively, implying a promising quenching-resistant characteristics of this novel phosphor. Furthermore, the efficient white PhOLEDs had been obtained by employing (tbpbt) 2 Ir(acac) as a self-host orange emitter, indicating that (tbpbt) 2 Ir(acac) could serve as a promising phosphor to fabricate white organic light-emitting devices with simplified manufacturing process. - Highlights: • Efficient phosphorescent devices were fabricated. • Optimized phosphor doping ratio reached as high as 15 wt%. • The results proved a promising quench-resistant property of the phosphor. • Efficient white devices based on this phosphor as self-host layer had been realized

Highly efficient and heavily-doped organic light-emitting devices based on an orange phosphorescent iridium complex

Energy Technology Data Exchange (ETDEWEB)

Zhou, Shunliang; Wang, Qi [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu, 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu, 610064 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2014-10-15

Heavily doped and highly efficient phosphorescent organic light-emitting devices (PhOLEDs) had been fabricated by utilizing an orange iridium complex, bis[2-(3′,5′-di-tert-butylbiphenyl-4-yl)benzothiazolato-N,C{sup 2'}]iridium(III) (acetylacetonate) [(tbpbt){sub 2}Ir(acac)], as a phosphor. When the doping concentration of [(tbpbt){sub 2}Ir(acac)] reached as high as 15 wt%, the PhOLEDs exhibited a power efficiency, current efficiency, and external quantum efficiency of 24.5 lm/W, 32.1 cd/A, 15.7%, respectively, implying a promising quenching-resistant characteristics of this novel phosphor. Furthermore, the efficient white PhOLEDs had been obtained by employing (tbpbt){sub 2}Ir(acac) as a self-host orange emitter, indicating that (tbpbt){sub 2}Ir(acac) could serve as a promising phosphor to fabricate white organic light-emitting devices with simplified manufacturing process. - Highlights: • Efficient phosphorescent devices were fabricated. • Optimized phosphor doping ratio reached as high as 15 wt%. • The results proved a promising quench-resistant property of the phosphor. • Efficient white devices based on this phosphor as self-host layer had been realized.

High-efficiency and heavily doped organic light-emitting devices based on quench-resistant red iridium complex

Energy Technology Data Exchange (ETDEWEB)

Wang, Qi [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhao, Juan; Wang, Jun [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu 610064 (China)

2013-02-15

Highly efficient red phosphorescent organic light-emitting devices had been fabricated using a new iridium complex, bis[2-(9,9-dimethyl-9H-fluoren-2-yl) benzothiazolato-N,C{sup 2'}]iridium(III) (acetylacetonate) [(fbt){sub 2}Ir(acac)] as phosphor. With a high doping concentration of 15 wt%, the device exhibited a maximum luminance efficiency, power efficiency and external quantum efficiency (EQE) of 35.2 cd/A, 21.3 lm/W, 18.2%, respectively, indicating an excellent quench-resistant property of (fbt){sub 2}Ir(acac). The results are appealing towards the development of 'easy-to-make' OLEDs. It has been demonstrated that the high efficiency arises from more balanced charge carriers in the emissive layer. - Highlight: Black-Right-Pointing-Pointer We obtained efficient OLEDs based on newly synthesized quench-resistant phosphor. Black-Right-Pointing-Pointer Peak performance was obtained with 15 wt% (fbt){sub 2}Ir(acac) doped device. Black-Right-Pointing-Pointer Our devices gave one of the best performance among heavily-doped red devices. Black-Right-Pointing-Pointer Balanced carrier transport is crucial for the high performance of our devices.

Thermal hydraulic modelling of the Mo and Iridium irradiation facilities of the RA10 reactor

International Nuclear Information System (INIS)

Gramajo, M.; García, J.; Marcel, C.P.

2013-01-01

The RA-10 reactor is a multipurpose, open pool research reactor. The core consists of a rectangular array of MTR type fuel. The produced thermal power is 30 MW which is extracted by the refrigeration system via an ascendant flow through the core. The core reflector is D 2 O contained in a watertight tank. The design of the reactor includes a number of out-core facilities which are meant to be used for industrial, medical and research purposes. Among all the facilities, the most important ones are the Molybdenum and Iridium ones which we modeled in this work. During the normal operation of the reactor, the manipulation and the on-line extraction of the irradiation facilities is foreseen. Therefore the study of the head loss during the normal operation as well as during the extraction maneuvers plays a relevant role in the design and safety analysis. In this work a CFD commercial code is use dto perform the calculations needed to guarantee the design requirements.In addition, a full detailed geometric model for both, the Molybdenum and Iridium facilities,is used to perform the required simulations. The obtained results allow to evaluating the thermal-hydraulic performance of the proposed facilities designs. (author)

Synthesis and green electrophosphorescence of a novel cyclometalated iridium complex in polymer light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Wu Lilan [Department of Chemistry, National Cheng Kung University, Tainan, Taiwan 70101 (China); Tsai Sunghao [Institute of Electro-Optical Science and Engineering, National Cheng Kung University, Tainan, Taiwan 70101 (China); Guo Tzungfang [Institute of Electro-Optical Science and Engineering, National Cheng Kung University, Tainan, Taiwan 70101 (China); Yang Chenghsien [Carbon Nanocapsules Research Department, Nano-Powder and Thin Film Technology Center, ITRI South, Tainan, Taiwan 709 (China)]. E-mail: jasonyang0606@yahoo.com.tw; Sun, I-W. [Department of Chemistry, National Cheng Kung University, Tainan, Taiwan 70101 (China)]. E-mail: iwsun@mail.ncku.edu.tw

2007-10-15

Abstact: In this paper, we synthesized a new complex bis(dibenzo[f,h]quinolinato-N,C {sup 2'}) iridium(III) acetylactonate ((DBQ){sub 2}Ir(acac)) having a longer conjugate system than bis(2-phenylpyridinato-N,C {sup 2'}) iridium(III) acetylacetonate ((PPY){sub 2}Ir(acac)). Interestingly (DBQ){sub 2}Ir(acac) emits at the same wavelength as (photoluminescence of 530 nm) (PPY){sub 2}Ir(acac). A high-efficiency electrophosphorescent polymer light-emitting diodes was constructed by using (DBQ){sub 2}Ir(acac) as the dopant, and a blend of poly(vinylcarbazole) (PVK) with 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazol (PBD) as the host material. The electroluminescence efficiency of 9.5 cd/A is reported for the device doped with 3 wt% of (DBQ){sub 2}Ir(acac). In this device, the emission from the PVK or PBD host was effectively inhibited with the using (DBQ){sub 2}Ir(acac) . Emission from the dopant molecules in such devices involve localization of the injected electron and hole on the metal-organic center. This can occur by a variety of mechanisms, including Foerster and Dexter energy transfer from the host transport material to the dopant, and direct trapping of both electrons and holes on the metal-organic center.

Preparation and determination of kerma for Iridium 192 sources of low dose rate for brachytherapy; Preparacion y determinacion del kerma de fuentes de iridio-192 de baja tasa de dosis para braquiterapia

Energy Technology Data Exchange (ETDEWEB)

Tendilla, J.I.; Tovar M, V.; Mitsoura, E.; Aguilar H, F.; Alanis M, J. [Instituto Nacional de Investigaciones Nucleares, C.P. 52045-1, Salazar, Esrado de Mexico, D.F. (Mexico)

2000-07-01

The practice of Brachytherapy with Iridium-192 sources of low dose rate (0.4 - 0.8 Gy/h) is a technique used in the treatment of diverse illnesses. in this work the preparation, quality control and calibration are presented in terms of kerma in air of Iridium-192 using as target these recycled Iridium-Platinum wires. The targets were obtained as decayed sources of different radio therapeutical centers in the country and they were characterized by Scanning electron microscopy in order to determine their chemical composition. Subsequently it was developed an experimental design to establish the effect of neutron flux, geometrical array and irradiation time over the activity and percentage of the sources homogeneity. The homogeneity was determined by auto radiography and by Gamma spectroscopy. Once the optimal irradiation conditions were established, it is determined the apparent activity and kerma in air using a well type ionization chamber with traceability to a primary laboratory. Iridium-192 sources were obtained with an average homogeneity 96 %, apparent activity 282.129 {+-} 0.531 M Bq and kerma in air 0.03200 {+-} 0.00006 m Gy m/h A. (Author)

Lewis Base Activation of Silyl Acetals: Iridium-Catalyzed Reductive Horner-Wadsworth-Emmons Olefination.

Science.gov (United States)

Dakarapu, Udaya Sree; Bokka, Apparao; Asgari, Parham; Trog, Gabriela; Hua, Yuanda; Nguyen, Hiep H; Rahman, Nawal; Jeon, Junha

2015-12-04

A Lewis base promoted deprotonative pronucleophile addition to silyl acetals has been developed and applied to the iridium-catalyzed reductive Horner-Wadsworth-Emmons (HWE) olefination of esters and the chemoselective reduction of the resulting enoates. Lewis base activation of silyl acetals generates putative pentacoordinate silicate acetals, which fragment into aldehydes, silanes, and alkoxides in situ. Subsequent deprotonative metalation of phosphonate esters followed by HWE with aldehydes furnishes enoates. This operationally convenient, mechanistically unique protocol converts the traditionally challenging aryl, alkenyl, and alkynyl esters to homologated enoates at room temperature within a single vessel.

Mono and dinuclear iridium, rhodium and ruthenium complexes containing chelating carboxylato pyrazine ligands: Synthesis, molecular structure and electrochemistry

Czech Academy of Sciences Publication Activity Database

Govindaswamy, P.; Therrien, B.; Süss-Fink, G.; Štěpnička, P.; Ludvík, Jiří

2007-01-01

Roč. 692, č. 8 (2007), s. 1661-1671 ISSN 0022-328X R&D Projects: GA MŠk LC510; GA MŠk(CZ) LC06070 Institutional research plan: CEZ:AV0Z40400503 Keywords : dinuclear complexes * iridium * rhodium * ruthenium * electrochemistry Subject RIV: CG - Electrochemistry Impact factor: 2.168, year: 2007

Ligand-Centred Reactivity of Bis(picolyl)amine Iridium: Sequential Deprotonation, Oxidation and Oxygenation of a "Non-Innocent" Ligand

Czech Academy of Sciences Publication Activity Database

Tejel, C.; del Río, M. P.; Ciriano, M. A.; Reijerse, E. J.; Hartl, F.; Záliš, Stanislav; Hetterscheid, D. G. H.; Tsichlis i Spithas, N.; de Bruin, B.

2009-01-01

Roč. 15, č. 44 (2009), s. 11878-11889 ISSN 0947-6539 R&D Projects: GA MŠk OC 139; GA AV ČR KAN100400702 Institutional research plan: CEZ:AV0Z40400503 Keywords : bis(picolyl)amine * iridium * ligand radical * oxygenation Subject RIV: CG - Electrochemistry Impact factor: 5.382, year: 2009

Hot rocket plume experiment - Survey and conceptual design. [of rhenium-iridium bipropellants

Science.gov (United States)

Millard, Jerry M.; Luan, Taylor W.; Dowdy, Mack W.

1992-01-01

Attention is given to a space-borne engine plume experiment study to fly an experiment which will both verify and quantify the reduced contamination from advanced rhenium-iridium earth-storable bipropellant rockets (hot rockets) and provide a correlation between high-fidelity, in-space measurements and theoretical plume and surface contamination models. The experiment conceptual design is based on survey results from plume and contamination technologists throughout the U.S. With respect to shuttle use, cursory investigations validate Hitchhiker availability and adaptability, adequate remote manipulator system (RMS) articulation and dynamic capability, acceptable RMS attachment capability, adequate power and telemetry capability, and adequate flight altitude and attitude/orbital capability.

Solid-phase extraction of iridium from soil and water samples by using activated carbon cloth prior to its spectrophotometric determination.

Science.gov (United States)

Ozkantar, Nebiye; Yilmaz, Erkan; Soylak, Mustafa; Tuzen, Mustafa

2015-08-01

A solid-phase extraction method for separation and preconcentration of Ir(IV) ion by using activated carbon cloth (ACC) has been presented. Ir(IV) as their 1-(2-pyridylazo) 2-naphtol (PAN) chelate was adsorbed on ACC at pH 2.0 and was eluted from ACC with acidic dimethylformamide (DMF). The Ir(IV) concentration was determined at 536 nm as Ir(IV)-PAN complex by using UV-vis spectrophotometer. The analytical parameters including pH, sample and eluent flow rates, amount of PAN, eluent type, concentration, and sample volume were optimized. The effects of foreign ions on the recoveries of iridium were also investigated. The preconcentration factor was calculated as 60. The limit of detection (LOD) and the limit of quantification (LOQ) of the method were found as 0.039 and 0.129 μg L(-1), respectively. The method was applied to soil and water samples for iridium determination.

Cationic Heteroleptic Cyclometalated Iridium Complexes with 1-Pyridylimidazo[1,5-alpha]pyridine Ligands: Exploitation of an Efficient Intersystem Crossing

Czech Academy of Sciences Publication Activity Database

Volpi, G.; Garino, C.; Salassa, L.; Fiedler, Jan; Hardcastle, K.; Gobetto, R.; Nervi, C.

2009-01-01

Roč. 15, č. 26 (2009), s. 6415-6427 ISSN 0947-6539 R&D Projects: GA MŠk OC 140; GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : density functional calculation * fluorescence * intersystem crossing * iridium * phosphorescence Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.382, year: 2009

Liisa Kruusmäe juhuslikult pealt kuuldud hetked / Kaarel Kressa

Index Scriptorium Estoniae

Kressa, Kaarel, 1983-

2011-01-01

Liisa Kruusmäe näitus "Overheard Stories / Pealtkuuldud lood" Tallinnas Draakoni galeriis. 2010. a. Eesti Kunstiakadeemia maaliosakonna lõpetanud Liisa Kruusmägi omandab EKA-s joonistamise alal magistrikraadi

Enantiopure Ferrocene-Based Planar-Chiral Iridacycles: Stereospecific Control of Iridium-Centred Chirality.

Science.gov (United States)

Arthurs, Ross A; Ismail, Muhammad; Prior, Christopher C; Oganesyan, Vasily S; Horton, Peter N; Coles, Simon J; Richards, Christopher J

2016-02-24

Reaction of [IrCp*Cl2 ]2 with ferrocenylimines (Fc=NAr, Ar=Ph, p-MeOC6 H4 ) results in ferrocene C-H activation and the diastereoselective synthesis of half-sandwich iridacycles of relative configuration Sp *,RIr *. Extension to (S)-2-ferrocenyl-4-(1-methylethyl)oxazoline gave highly diastereoselective control over the new elements of planar chirality and metal-based pseudo-tetrahedral chirality, to give both neutral and cationic half-sandwich iridacycles of absolute configuration Sc ,Sp ,RIr . Substitution reactions proceed with retention of configuration, with the planar chirality controlling the metal-centred chirality through an iron-iridium interaction in the coordinatively unsaturated cationic intermediate. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dosimetry of wires and single ribbons of Iridium 192; Dosimetria de alambres y ribbons individuales de Iridio-192

Energy Technology Data Exchange (ETDEWEB)

Mazzucco, L.D. [Centro Medico Nuclear S.R.L. San Juan (Argentina)

1998-12-31

The objective of this work is in order to present in table formats the dosimetry of wires and single ribbons of Iridium with lengths 1-12 cm for each one linear source along the bisector which is perpendicular at tissue sources (water) computed for linear activity 1 mCi/cm in the case of wires, and 1 mCi/seed for ribbons. The above tables are of direct use, adaptable at particular cases so they facilitate logarithmic graphics of doses in function of the distance for interpolation and use in the treatments planning. It was shown that for two sources with identical linear activity and total length, one of the equidistant seeds at 1 cm (ribbon) and one wire on the other hand, the differences in dose rates in near positions can be about the 15% so corroborating that it is not possible to use wire tables for seeds neither vice versa. Moreover it was elaborated tables of practical direct use for dose rate in water at c Gy/hr for wires and Ribbons 1-12 cm length and from 0.5-10 cm of distance in the perpendicular bisector at the Iridium implant. (Author)

High-latitude poynting flux from combined Iridium and SuperDARN data

Directory of Open Access Journals (Sweden)

C. L. Waters

2004-09-01

Full Text Available Field-aligned currents convey stress between the magnetosphere and ionosphere, and the associated low altitude magnetic and electric fields reflect the flow of electromagnetic energy to the polar ionosphere. We introduce a new technique to measure the global distribution of high latitude Poynting flux, S||, by combining electric field estimates from the Super Dual Auroral Radar Network (SuperDARN with magnetic perturbations derived using magnetometer data from the Iridium satellite constellation. Spherical harmonic methods are used to merge the data sets and calculate S|| for any magnetic local time (MLT from the pole to 60° magnetic latitude (MLAT. The effective spatial resolutions are 2° MLAT, 2h MLT, and the time resolution is about one hour due to the telemetry rate of the Iridium magnetometer data. The technique allows for the assessment of high-latitude net S|| and its spatial distribution on one hour time scales with two key advantages: (1 it yields the net S|| including the contribution of neutral winds; and (2 the results are obtained without recourse to estimates of ionosphere conductivity. We present two examples, 23 November 1999, 14:00-15:00 UT, and 11 March 2000, 16:00-17:00 UT, to test the accuracy of the technique and to illustrate the distributions of S|| that it gives. Comparisons with in-situ S|| estimates from DMSP satellites show agreement to a few mW/m2 and in the locations of S|| enhancements to within the technique's resolution. The total electromagnetic energy flux was 50GW for these events. At auroral latitudes, S|| tends to maximize in the morning and afternoon in regions less than 5° in MLAT by two hours in MLT having S||=10 to 20mW/m2 and total power up to 10GW. The power poleward of the Region 1 currents is about one-third of the total power, indicating significant energy flux over the polar cap.

Lugupeetud kunstnikud, arhitektid ja sõbrad!

Index Scriptorium Estoniae

2001-01-01

Eesti Kunstnike Liidu ja Eesti Arhitektide Liidu aastavahetuspeo kava 28. XII. Esinevad Raivo Kelomees (EKA ja Tartu Kõrgema Kunstikooli videoprojektid), EKA moeosakond. Nova Moda esitleb: Ruta Depp, Ketlin Bachman, Riina Põldroos, Kati Simpson

Rhodium, iridium and nickel complexes with a 1,3,5-triphenylbenzene tris-MIC ligand. Study of the electronic properties and catalytic activities

Directory of Open Access Journals (Sweden)

Carmen Mejuto

2015-12-01

Full Text Available The coordination versatility of a 1,3,5-triphenylbenzene-tris-mesoionic carbene ligand is illustrated by the preparation of complexes with three different metals: rhodium, iridium and nickel. The rhodium and iridium complexes contained the [MCl(COD] fragments, while the nickel compound contained [NiCpCl]. The preparation of the tris-MIC (MIC = mesoionic carbene complex with three [IrCl(CO2] fragments, allowed the estimation of the Tolman electronic parameter (TEP for the ligand, which was compared with the TEP value for a related 1,3,5-triphenylbenzene-tris-NHC ligand. The electronic properties of the tris-MIC ligand were studied by cyclic voltammetry measurements. In all cases, the tris-MIC ligand showed a stronger electron-donating character than the corresponding NHC-based ligands. The catalytic activity of the tri-rhodium complex was tested in the addition reaction of arylboronic acids to α,β-unsaturated ketones.

Cyclometalated Iridium(III) Carbene Phosphors for Highly Efficient Blue Organic Light-Emitting Diodes.

Science.gov (United States)

Chen, Zhao; Wang, Liqi; Su, Sikai; Zheng, Xingyu; Zhu, Nianyong; Ho, Cheuk-Lam; Chen, Shuming; Wong, Wai-Yeung

2017-11-22

Five deep blue carbene-based iridium(III) phosphors were synthesized and characterized. Interestingly, one of them can be fabricated into deep blue, sky blue and white organic light-emitting diodes (OLEDs) through changing the host materials and exciton blocking layers. These deep and sky blue devices exhibit Commission Internationale de l'Éclairage (CIE) coordinates of (0.145, 0.186) and (0.152, 0.277) with external quantum efficiency (EQE) of 15.2% and 9.6%, respectively. The EQE of the deep blue device can be further improved up to 19.0% by choosing a host with suitable energy level of its lowest unoccupied molecular orbital (LUMO).

Iridium emissions from Hawaiian volcanoes

International Nuclear Information System (INIS)

Finnegan, D.L.; Zoller, W.H.; Miller, T.M.

1988-01-01

Particle and gas samples were collected at Mauna Loa volcano during and after its eruption in March and April, 1984 and at Kilauea volcano in 1983, 1984, and 1985 during various phases of its ongoing activity. In the last two Kilauea sampling missions, samples were collected during eruptive activity. The samples were collected using a filterpack system consisting of a Teflon particle filter followed by a series of 4 base-treated Whatman filters. The samples were analyzed by INAA for over 40 elements. As previously reported in the literature, Ir was first detected on particle filters at the Mauna Loa Observatory and later from non-erupting high temperature vents at Kilauea. Since that time Ir was found in samples collected at Kilauea and Mauna Loa during fountaining activity as well as after eruptive activity. Enrichment factors for Ir in the volcanic fumes range from 10,000 to 100,000 relative to BHVO. Charcoal impregnated filters following a particle filter were collected to see if a significant amount of the Ir was in the gas phase during sample collection. Iridium was found on charcoal filters collected close to the vent, no Ir was found on the charcoal filters. This indicates that all of the Ir is in particulate form very soon after its release. Ratios of Ir to F and Cl were calculated for the samples from Mauna Loa and Kilauea collected during fountaining activity. The implications for the KT Ir anomaly are still unclear though as Ir was not found at volcanoes other than those at Hawaii. Further investigations are needed at other volcanoes to ascertain if basaltic volcanoes other than hot spots have Ir enrichments in their fumes

Iridium emissions from Hawaiian volcanoes

Science.gov (United States)

Finnegan, D. L.; Zoller, W. H.; Miller, T. M.

1988-01-01

Particle and gas samples were collected at Mauna Loa volcano during and after its eruption in March and April, 1984 and at Kilauea volcano in 1983, 1984, and 1985 during various phases of its ongoing activity. In the last two Kilauea sampling missions, samples were collected during eruptive activity. The samples were collected using a filterpack system consisting of a Teflon particle filter followed by a series of 4 base-treated Whatman filters. The samples were analyzed by INAA for over 40 elements. As previously reported in the literature, Ir was first detected on particle filters at the Mauna Loa Observatory and later from non-erupting high temperature vents at Kilauea. Since that time Ir was found in samples collected at Kilauea and Mauna Loa during fountaining activity as well as after eruptive activity. Enrichment factors for Ir in the volcanic fumes range from 10,000 to 100,000 relative to BHVO. Charcoal impregnated filters following a particle filter were collected to see if a significant amount of the Ir was in the gas phase during sample collection. Iridium was found on charcoal filters collected close to the vent, no Ir was found on the charcoal filters. This indicates that all of the Ir is in particulate form very soon after its release. Ratios of Ir to F and Cl were calculated for the samples from Mauna Loa and Kilauea collected during fountaining activity. The implications for the KT Ir anomaly are still unclear though as Ir was not found at volcanoes other than those at Hawaii. Further investigations are needed at other volcanoes to ascertain if basaltic volcanoes other than hot spots have Ir enrichments in their fumes.

Catalytic dehydroaromatization of n-alkanes by pincer-ligated iridium complexes

Science.gov (United States)

Ahuja, Ritu; Punji, Benudhar; Findlater, Michael; Supplee, Carolyn; Schinski, William; Brookhart, Maurice; Goldman, Alan S.

2011-02-01

Aromatic hydrocarbons are among the most important building blocks in the chemical industry. Benzene, toluene and xylenes are obtained from the high temperature thermolysis of alkanes. Higher alkylaromatics are generally derived from arene-olefin coupling, which gives branched products—that is, secondary alkyl arenes—with olefins higher than ethylene. The dehydrogenation of acyclic alkanes to give alkylaromatics can be achieved using heterogeneous catalysts at high temperatures, but with low yields and low selectivity. We present here the first catalytic conversion of n-alkanes to alkylaromatics using homogeneous or molecular catalysts—specifically ‘pincer’-ligated iridium complexes—and olefinic hydrogen acceptors. For example, the reaction of n-octane affords up to 86% yield of aromatic product, primarily o-xylene and secondarily ethylbenzene. In the case of n-decane and n-dodecane, the resulting alkylarenes are exclusively unbranched (that is, n-alkyl-substituted), with selectivity for the corresponding o-(n-alkyl)toluene.

Crystal structures of fac-trichloridotris(trimethylphosphane-κPrhodium(III monohydrate and fac-trichloridotris(trimethylphosphane-κPrhodium(III methanol hemisolvate: rhodium structures that are isotypic with their iridium analogs

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Joseph S. Merola

2015-02-01

Full Text Available The crystal structures of two solvates of fac-trichloridotris(trimethylphosphane-κPrhodium(III are reported, i.e. one with water in the crystal lattice, fac-[RhCl3(Me3P3]·H2O, and one with methanol in the crystal lattice, fac-[RhCl3(Me3P3]·0.5CH3OH. These rhodium compounds exhibit distorted octahedral coordination spheres at the metal and are isotypic with the analogous iridium compounds previously reported by us [Merola et al. (2013. Polyhedron, 54, 67–73]. Comparison is made between the rhodium and iridium compounds, highlighting their isostructural relationships.

Hydrogen transfer reduction of polyketones catalyzed by iridium complexes: a novel route towards more biocompatible materials.

Science.gov (United States)

Milani, Barbara; Crottib, Corrado; Farnetti, Erica

2008-09-14

Transfer hydrogenation from 2-propanol to CO/4-methylstyrene and CO/styrene polyketones was catalyzed by [Ir(diene)(N-N)X] (N-N = nitrogen chelating ligand; X = halogen) in the presence of a basic cocatalyst. The reactions were performed using dioxane as cosolvent, in order to overcome problems due to low polyketone solubility. The polyalcohols were obtained in yields up to 95%, the conversions being markedly dependent on the nature of the ligands coordinated to iridium as well as on the experimental conditions.

Neutron activation determination of iridium, gold, platinum, and silver in geologic samples

International Nuclear Information System (INIS)

Millard, H.T. Jr.

1987-01-01

In the procedure developed in this study, samples irradiated in the epithermal neutron facility of the U.S. Geological Survey TRIGA Reactor (Denver, Colorado) are treated with a mini-free assay technique. The iridium, gold, and silver are collected in a 1-gram metallic lead button. Primary contaminants at this stage are arsenic and antimony. These can be removed by heating the button with a mixture of sodium peroxide and sodium hydroxide. The resulting 0.2-gram lead bead is counted in a Compton suppression spectrometer. Carrier yields are determined by reirradiation of the lead beads. This procedure was applied to the U.S.G.S. Standard Rock PCC-1 and samples from K-T boundary sites in the Western Interior of North America. (author)

Coupling of Electron Transfer and Bond Dissociation Processes in Dinuclear Complexes with Rhodium and Iridium Reaction Centers Bridged by 2,2'-Bipyrimidine

Czech Academy of Sciences Publication Activity Database

Kaim, W.; Reinhardt, R.; Greulich, S.; Sieger, M.; Klein, A.; Fiedler, Jan

2001-01-01

Roč. 66, č. 2 (2001), s. 291-306 ISSN 0010-0765 R&D Projects: GA MŠk OC D15.10 Institutional research plan: CEZ:AV0Z4040901 Keywords : EPR spectroscopy * iridium complexes * rhodium complexes Subject RIV: CG - Electrochemistry Impact factor: 0.778, year: 2001

Miks meile vaja maastikuarhitektuuri? = Why do we need landscape architecture? / Reinhard Micheller, Günther Schalk, Katrin Koov

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Micheller, Reinhard, 1977-

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise ülesande raames on vestlusringis maastikuarhitektuurse osa juhendajad Reinhard Micheller ja Günther Schalk (michellerundschalk, München) ning Katrin Koov (KAVAKAVA, EKA maastikuarhitektuuri õppekava juht)

Diastereo- and enantioselective iridium-catalyzed allylation of cyclic ketone enolates: synergetic effect of ligands and barium enolates.

Science.gov (United States)

Chen, Wenyong; Chen, Ming; Hartwig, John F

2014-11-12

We report asymmetric allylic alkylation of barium enolates of cyclic ketones catalyzed by a metallacyclic iridium complex containing a phosphoramidite ligand derived from (R)-1-(2-naphthyl)ethylamine. The reaction products contain adjacent quaternary and tertiary stereocenters. This process demonstrates that unstabilized cyclic ketone enolates can undergo diastereo- and enantioselective Ir-catalyzed allylic substitution reactions with the proper choice of enolate countercation. The products of these reactions can be conveniently transformed to various useful polycarbocyclic structures.

Electron-beam welding of thorium-doped iridium alloy sheets

International Nuclear Information System (INIS)

David, S.A.; Liu, C.T.; Hudson, J.D.

1979-04-01

Modified iridium alloys containing 100 ppM Th were found to be very susceptible to hot-cracking during gas tungsten-arc and electron-beam welding. However, the electron-beam welding process showed greater promise of success in welding these alloys, in particular Ir--0.3% W doped with 200 ppM Th and 50 ppM Al. The weldability of this particular alloy was extremely sensitive to the welding parameters, such as beam focus condition and welding speed, and the resulting fusion zone structure. At low speed successful electron-beam welds were made over a narrow range of beam focus conditions. However, at high speeds successful welds can be made over an extended range of focus conditions. The fusion zone grain structure is a strong function of welding speed and focus condition, as well. In the welds that showed hot-cracking, a region of positive segregation of thorium was identified at the fusion boundary. This highly thorium-segregated region seems to act as a potential source for the nucleation of a liquation crack, which later grows as a centerline crack

Radiation dose evaluation for hypothetical accident with transport package containing Iridium-192 source

International Nuclear Information System (INIS)

Trontl, K.; Bace, M.; Pevec, D.

2002-01-01

The aim of this paper is to evaluate dose rates for a hypothetical accident with transport package containing Iridium-192 source and to design additional shielding necessary for the safe unloading of the container, assuming that during the unloading process the whole contents of a radioactive source is unshielded and that the operation is going to take place at the site where a working area exists in the vicinity of the unloading location. Based on the calculated radiation dose rates, a single arrangement of the additional concrete shields necessary for reduction of the gamma dose rates to the permitted level is proposed. The proposed solution is optimal considering safety on one hand and costs on the other.(author)

Iridium-191m radionuclide angiocardiography detection and quantitation of left-to-rigth shunts

International Nuclear Information System (INIS)

Treves, S.; Fujii, A.; Cheng, C.; Kuruc, A.

1983-01-01

The purpose of this study was to determine whether Iridium-191m (Ir-191m) could replace Technetium-99m (Tc-99m) in the detection and quantitation of left-to-right shunts. It was demonstrated that Ir-191m radionuclide angiography is a safe, rapid, and accurate method for the detection and quantitation of left-to-right shunts with very low radiation dose to the patient. It is also possible with this radiotracer to evaluate other aspects of the anatomy and physiology of the circulation such as ventricular function, patency of major vessels, renal and cerebral perfusion. Further improvements on 0s-191 production, generator design and gamma cameras would expand the use of this ultrashort-lived radionuclide

Influence of oxidation state on the pH dependence of hydrous iridium oxide films

International Nuclear Information System (INIS)

Steegstra, Patrick; Ahlberg, Elisabet

2012-01-01

Many electrochemical reactions taking place in aqueous solution consume or produce protons. The pH in the diffusion layer can therefore be significantly altered during the reaction and there is a need for in situ pH measurements tracing this near surface pH. In the present paper the rotating ring disc technique was used to measure near surface pH changes during oxygen reduction, utilising hydrous iridium oxide as the pH sensing probe. Before such experiments a good understanding of the pH sensing properties of these films is required and the impact of the oxidation state of the film on the pH sensing properties was investigated as well as the influence of solution redox species. The pH sensitivity (depicted by dE/dpH) was found to depend on the average oxidation state of the film in a manner resembling the cyclic voltammetry response. In all cases the pH response is “supernernstian” with more than one proton per electron. The origin of this behaviour is discussed in the context of acid-base properties of the film and the existence of both hydrous and anhydrous oxide phases. The pH response depends also on the redox properties of the solution but can be optimised for various purposes by conditioning the film at different potentials. This was clearly illustrated by adding hydrogen peroxide, an intermediate in the oxygen reduction reaction, to the solution. It was shown that hydrous iridium oxide can be used as a reliable in situ pH sensor provided that care is taken to optimise the oxidation state of the film.

Bibliographies on radiation chemistry. 9. Metal ions and complexes. Part A: Cobalt, rhodium, iridium

Energy Technology Data Exchange (ETDEWEB)

Hoffman, M Z; Ross, A B

1986-01-01

The one-electron oxidation and reduction of metal ions and complexes can yield species in unusual oxidation states, and ligand-radicals coordinated to the central metal. These often unstable species can be mechanistically important intermediates in thermal, photochemical, and electrochemical reactions involving metal-containing substances. Their generation via radiolysis provides an alternate means of characterizing them using kinetic and spectroscopic techniques. We hope these bibliographies on the radiation chemistry of metal ions and complexes, presented according to periodic groups, will prove useful to researchers in metallo-redox chemistry. These bibliographies contain only primary literature sources; reviews are not included. However, a list of general review articles on the radiation chemistry of metal ions and complexes is presented here in the first section which covers cobalt, rhodium and iridium, Group 9 in the new IUPAC notation. Additional parts of the bibliography are planned, covering other periodic groups. Part A of the bibliography was prepared by a search of the Radiation Chemistry Data Center Bibliographic Data Base (RCDCbib) through January 1986 for papers on rhodium, iridium and cobalt compounds, and radiolysis (both continuous and pulsed). Papers in which the use of metal compounds was incidental to the primary objective of the study were excluded. Excluded also were publications in unrefereed and obscure sources such as meeting proceedings, internal reports, dissertations, and patents. The majority of the studies in the resultant compilation deal with experiments performed on solutions, mainly aqueous, although a substantial fraction is devoted to solid-state esr measurements. The references are listed in separate sections for each of the metals, and are presented in approximate chronological order.

Synthesis and structure of (tricarbollide)iodide iridium complex [(eta-1-(BuNH)-N-t-1,7,9-C3B8H10)IrI2](2)

Czech Academy of Sciences Publication Activity Database

Loginov, D.A.; Miloserdov, A.M.; Starikova, ZA.; Holub, Josef; Kudinov, AR.

2013-01-01

Roč. 62, č. 5 (2013), s. 1268-1271 ISSN 1066-5285 Institutional support: RVO:61388980 Keywords : iridium * metallacarboranes * tricarbollide Subject RIV: CA - Inorganic Chemistry Impact factor: 0.509, year: 2013

High-latitude poynting flux from combined Iridium and SuperDARN data

Directory of Open Access Journals (Sweden)

C. L. Waters

2004-09-01

Full Text Available Field-aligned currents convey stress between the magnetosphere and ionosphere, and the associated low altitude magnetic and electric fields reflect the flow of electromagnetic energy to the polar ionosphere. We introduce a new technique to measure the global distribution of high latitude Poynting flux, S_||, by combining electric field estimates from the Super Dual Auroral Radar Network (SuperDARN with magnetic perturbations derived using magnetometer data from the Iridium satellite constellation. Spherical harmonic methods are used to merge the data sets and calculate S_|| for any magnetic local time (MLT from the pole to 60° magnetic latitude (MLAT. The effective spatial resolutions are 2° MLAT, 2h MLT, and the time resolution is about one hour due to the telemetry rate of the Iridium magnetometer data. The technique allows for the assessment of high-latitude net S_|| and its spatial distribution on one hour time scales with two key advantages: (1 it yields the net S_|| including the contribution of neutral winds; and (2 the results are obtained without recourse to estimates of ionosphere conductivity. We present two examples, 23 November 1999, 14:00-15:00 UT, and 11 March 2000, 16:00-17:00 UT, to test the accuracy of the technique and to illustrate the distributions of S_|| that it gives. Comparisons with in-situ S_|| estimates from DMSP satellites show agreement to a few mW/m² and in the locations of S_|| enhancements to within the technique's resolution. The total electromagnetic energy flux was 50GW for these events. At auroral latitudes, S_|| tends to maximize in the morning and afternoon in regions less than 5° in MLAT by two hours in MLT having S_||=10 to 20mW/m² and total power up to 10GW. The power poleward of the Region 1 currents is about one

Kunstiteaduslik doktoritöö EKA-s kaitstud / Ingrid Ruudi

Index Scriptorium Estoniae

Ruudi, Ingrid

2005-01-01

Heie Treier "Kohalik modernsus kunstis. Eesti varamodernistliku kunsti teoreetiline ja ajalooline kontseptualiseerimine ning Karl Pärsimägi paradigmaleidmise perioodil". Juhendaja Thomas McEvilley, eelretsensent Katrin Kivimaa ja Ene Lamp. Oponent Jaak Kangilaski

Iridium containing honeycomb Delafossites by topotactic cation exchange.

Science.gov (United States)

Roudebush, John H; Ross, K A; Cava, R J

2016-06-07

We report the structure and magnetic properties of two new iridium-based honeycomb Delafossite compounds, Cu3NaIr2O6 and Cu3LiIr2O6, formed by a topotactic cation exchange reaction. The starting materials Na2IrO3 and Li2IrO3, which are based on layers of IrO6 octahedra in a honeycomb lattice separated by layers of alkali ions, are transformed to the title compounds by a topotactic exchange reaction through heating with CuCl below 450 °C; higher temperature reactions cause decomposition. The new compounds display dramatically different magnetic behavior from their parent compounds - Cu3NaIr2O6 has a ferromagnetic like magnetic transition at 10 K, while Cu3LiIr2O6 retains the antiferromagnetic transition temperature of its parent compound but displays significantly stronger dominance of antiferromagnetic coupling between spins. These results reveal that a surprising difference in the magnetic interactions between the magnetic Ir ions has been induced by a change in the non-magnetic interlayer species. A combination of neutron and X-ray powder diffraction is used for the structure refinement of Cu3NaIr2O6 and both compounds are compared to their parent materials.

Kaasaegse Kunsti Eesti Keskus kui kunstidiiler / Rael Artel, Kai Kaljo, Marco Laimre, Marge Monko ; intervjueerinud Reet Varblane

Index Scriptorium Estoniae

2010-01-01

Vestlusringis osalenud vabakutseline kuraator Rael Artel, Tallinna Ülikooli dotsent, kunstnik Kai Kaljo, EKA fotoosakonna professor, kunstnik Marco Laimre ja EKA fotoosakonna dotsent, kunstnik Marge Monko arutavad, millist rolli peaks KKEK täitma praegu, 21. sajandi teisel kümnendil avatud maailma tingimustes

Kunst on töö hing / Signe Kivi

Index Scriptorium Estoniae

Kivi, Signe, 1957-

2009-01-01

Eesti Kunstiakadeemia 95. Kunstikõrgkooli minevikust, olevikust ja tulevikust, 95. aastapäeva tähistamisest. 10. detsembril promoveeritakse EKA audoktoriteks Helsingi ülikooli emeriitprofessor Riitta Nikula ja Leideni ülikooli graafilise disaini õppejõud Gerard Unger. Uueks EKA auliikmeks on nimetatud Meelis Milder

Effect of the substituents on the photophysical, electrochemical and electroluminescence properties of OLED dopant Iridium bis(2-phenylbenzothiozolato- N,C2')(acetylacetonate)

Science.gov (United States)

Ivanov, P.; Tomova, R.; Petrova, P.

2014-12-01

The effect of two substituents: clorine and 1,3-diphenylpropane-1,3-dionate, placed on different position in the molecule of Iridium (III) bis(2-phenylbenzothiozolato-N,C2')- (acetylacetonate) (bt)2Ir(acac), on its electrochemical behaviour, photophysical and electroluminescence properties were investigated. Three complexes (bt)2Ir(acac), Iridium (III) bis[2-(4-chlorophenyl)benzothiazolato-N,C2']-acetylacetonate (Clbt)2Ir(acac), in which the Cl atom was introduced on the 4-position in the benzothiazole ring, and the new Iridium (Ill) bis[2 -phenylbenzothiazolato -N,C2'] -(1,3 -diphenylpropane-1,3 -dionate) (bt)2Ir(dbm), where ancillary acetylacetonate ligand was replaced by 1,3-diphenylpropane-1,3-dionate, were synthesized and characterised by 1H-NMR and elemental analysis. The HOMO/LUMO energy levels of the complexes were determined by cyclic voltammetry (CV) and their properties were established by UV-Visible and fluorescence spectroscopy. The application of (Clbt)2Ir(acac), (bt)2Ir(bsm) and (bt)2Ir(acac) as dopants in hole transporting layer (HTL) of Organic light- emitting diodes(OLEDs). It was found that with respect to the reference (bt)2Ir(acac): both LUMO and HOMO of the substituted complexes were shifted to more positive values accordingly with 0.23 and 0.19 eV for (Clbt)2Ir(acac) and 0.14 and 0.12 eV for (bt)2Ir(dbm). OLEDs doped with 1 w% of the complexes irradiated the warm white light with Commission internationale de l'eclairage (CIE) coordinates: 0.24;0.38 for (Clbt)2Ir(acac), 0.30;0.44 for (bt)2Ir(acac) and 0.28;0.46 for (bt)2Ir(dbm). Devices doped with 10 w% of all complexes irradiated in the yellow orange region of the spectrum.

Highly efficient and concentration-insensitive organic light-emitting devices based on self-quenching-resistant orange–red iridium complex

Energy Technology Data Exchange (ETDEWEB)

Qi, Yige; Wang, Xu [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu 610064 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2014-11-15

Orange–red phosphorescent organic light-emitting devices (PHOLEDs) with high efficiency and concentration insensitivity based on a novel iridium complex, bis[2-(biphenyl-4-yl)benzothiazole-N,C{sup 2}′]iridium(III) (acetylacetonate) [(4Phbt){sub 2}Ir(acac)], were fabricated. With the heavily doped emissive layer (EML) of 4,4′-N,N′-dicarbazolylbiphenyl (CBP): (4Phbt){sub 2}Ir(acac) in a wide and easily controlled dopant concentration range from 12 wt% to 24 wt%, a maximum power efficiency of 29 lm/W and an external quantum efficiency of >16% of the PHOLEDs were obtained, implying the insensitivity of electroluminescence (EL) properties to doping concentration. Meanwhile, a maximum power efficiency of 5.0 lm/W was achieved from a non-doped device with neat (4Phbt){sub 2}Ir(acac) as the EML, indicating a superior property of self-quenching resistance. The mechanism of direct exciton formation, in which exciton-formation regions are distributed throughout the EML, is responsible for the significant alleviation of triplet–triplet annihilation and superior EL performance. - Highlights: • Highly efficient and concentration-insensitive PHOLEDs were obtained. • The high efficiency of non-doped PHOLEDs indicated a quenching-resistant property. • The independence of EL spectra on doping concentration was observed. • The heavily doped devices were dominated by mechanism of direct exciton formation.

Joonistamine Narvas

Index Scriptorium Estoniae

2003-01-01

EKA korraldatud aktsioon "Joonistus kui identiteet" 14. ja 15. VIII Narvas. Kuraator Elnara Taidre, korraldaja Aili Vahtrapuu. 15. VIII avati Narva muuseumi kunstigaleriis joonistuste näitus "Nulla Dies Sine Linea", toimus seminar. Narva-Jõesuus landart-likus liivajoonistusprojektis osalesid Narva kunstnikud ja EKA üliõpilased

Syntheses of the hexahydroindene cores of indanomycin and stawamycin by combinations of iridium-catalyzed asymmetric allylic alkylations and intramolecular Diels-Alder reactions.

Science.gov (United States)

Gärtner, Martin; Satyanarayana, Gedu; Förster, Sebastian; Helmchen, Günter

2013-01-02

Short and concise syntheses of the hexahydroindene cores of the antibiotics indanomycin (X-14547 A) and stawamycin are presented. Key methods used are an asymmetric iridium-catalyzed allylic alkylation, a modified Julia olefination, a Suzuki-Miyaura coupling, and an intramolecular Diels-Alder reaction. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Blue phosphorescent mono-cyclometalated iridium(III) complexes

International Nuclear Information System (INIS)

Ham, Ho Wan; Yang, Yoon A; Kim, Young Sik

2010-01-01

New deep blue phosphorescent iridium(III) complexes comprised of one cyclometalate, two phosphines trans to each other and two cis-ancillary ligands, such as Ir(F 2 Meppy)(PPh 2 Me) 2 (H)(Cl), Ir(F 2 Meppy)(PPh 2 Me) 2 (H)(NCMe) + , and Ir(F 2 Meppy)(PPh 2 Me) 2 (H)(CN), [F 2 Meppy = 2-(2', 4'- difluorophenyl)-4-methyl-pyridine] were synthesized and studied to tune the phosphorescence wavelength to the deep blue region and to enhance the luminescence efficiencies. We investigated the strong field effects of ancillary ligands to gain insight into the factors responsible for the emission color change and the different luminescence efficiency. Reducing the molecular weight of the phosphine ligand with PPh 2 Me leads to more efficient deep-blue organic light-emitting devices (OLED) by thermal processing instead of through solution processing. The electron-withdrawing difluoro group substituted on the phenyl ring, the electron-donating methyl group on the pyridyl ring, and the cyano strong field ancillary ligand increased the HOMO-LUMO gap and achieved a hypsochromic shift in the emission color. As a result, the maximum emission spectra of Ir(F 2 Meppy)-(PPh 2 Me) 2 (H)(Cl), Ir(F 2 Meppy)(PPh 2 Me) 2 (H)(NCMe) + , and Ir(F 2 Meppy)(PPh 2 Me) 2- (H)(CN) were in the ranges of 440.5, 437, 436 nm, respectively.

Phosphorescent light-emitting iridium complexes serve as a hypoxia-sensing probe for tumor imaging in living animals

Science.gov (United States)

Takeuchi, Toshiyuki; Zhang, Shaojuan; Negishi, Kazuya; Yoshihara, Toshitada; Hosaka, Masahiro; Tobita, Seiji

2010-02-01

Iridium complex, a promising organic light-emitting diode material for next generation television and computer displays, emits phosphorescence. Phosphorescence is quenched by oxygen. We used this oxygen-quenching feature for imaging tumor hypoxia. Red light-emitting iridium complex Ir(btp)2(acac) (BTP) presented hypoxia-dependent light emission in culture cell lines, whose intensity was in parallel with hypoxia-inducible factor (HIF)-1 expression. BTP was further applied to imaging five nude mouse-transplanted tumors. All tumors presented a bright BTP-emitting image as early as 5 min after the injection. The BTP-dependent tumor image peaked at 1 to 2 h after the injection, and was then removed from tumors within 24 h. The minimal BTP image recognition size was at least 2 mm in diameter. By morphological examination and phosphorescence lifetime measurement, BTP is presumed to localize to the tumor cells, not to stay in the tumor microvessels by binding to albumin. The primary problem on suse of luminescent probe for tumor imaging is its weak penetrance to deep tissues from the skin surface. Since BTP is easily modifiable, we made BTP analogues with a longer excitation/emission wavelength to improve the tissue penetrance. One of them, BTPHSA, displayed 560/720 wavelength, and depicted its clear imaging from tumors transplanted over 6-7 mm deep from the skin surface. We suggest that BTP analogues have a vast potential for imaging hypoxic lesions such as tumor tissues.

Serendipitous preparation of fac-(acetonitrile-κNtrichlorido[(1,2,5,6-η-cycloocta-1,5-diene]iridium(III

Directory of Open Access Journals (Sweden)

David M. Morris

2015-04-01

Full Text Available A reaction between [(CODIrCl]2 (COD is cycloocta-1,5-diene, HCl and indene failed to provide the hoped for chloridoindenyliridium dimer, but instead produced the title compound, [IrCl3(CH3CN(C8H12], which is an octahedral complex of iridium(III with a chelating cycloocta-1,5-diene ligand, three chloride ligands in a fac arrangement, and one acetonitrile ligand. Attempts to devise a rational synthesis for the title compound were unsuccessful.

Local structure of Iridium organometallic catalysts covalently bonded to carbon nanotubes.

Science.gov (United States)

Blasco, J.; Cuartero, V.; Subías, G.; Jiménez, M. V.; Pérez-Torrente, J. J.; Oro, L. A.; Blanco, M.; Álvarez, P.; Blanco, C.; Menéndez, R.

2016-05-01

Hybrid catalysts based on Iridium N-heterocyclic carbenes anchored to carbon nanotubes (CNT) have been studied by XAFS spectroscopy. Oxidation of CNT yields a large amount of functional groups, mainly hydroxyl groups at the walls and carboxylic groups at the tips, defects and edges. Different kinds of esterification reactions were performed to functionalize oxidized CNT with imidazolium salts. Then, the resulting products were reacted with an Ir organometallic compound to form hybrid catalysts efficient in hydrogen transfer processes. XANES spectroscopy agree with the presence of Ir(I) in these catalysts and the EXAFS spectra detected differences in the local structure of Ir atoms between the initial Ir organometallic compound and the Ir complexes anchored to the CNT. Our results confirm that the halide atom, present in the Ir precursor, was replaced by oxygen from -OH groups at the CNT wall in the first coordination shell of Ir. The lability of this group accounts for the good recyclability and the good efficiency shown by these hybrid catalysts.

User-friendly aerobic reductive alkylation of iridium(III) porphyrin chloride with potassium hydroxide: scope and mechanism.

Science.gov (United States)

Zuo, Huiping; Liu, Zhipeng; Yang, Wu; Zhou, Zhikuan; Chan, Kin Shing

2015-12-21

Alkylation of iridium 5,10,15,20-tetrakistolylporphyrinato carbonyl chloride, Ir(ttp)Cl(CO) (1), with 1°, 2° alkyl halides was achieved to give (ttp)Ir-alkyls in good yields under air and water compatible conditions by utilizing KOH as the cheap reducing agent. The reaction rate followed the order: RCl < RBr < RI (R = alkyl), and suggests an SN2 pathway by [Ir(I)(ttp)](-). Ir(ttp)-adamantyl was obtained under N2 when 1-bromoadamantane was utilized, which could only undergo bromine atom transfer pathway. Mechanistic investigations reveal a substrate dependent pathway of SN2 or halogen atom transfer.

Eletrodeposição de irídio em tubo de grafite como modificador químico permanente em espectrometria de absorção atômica Electrodeposition of iridium in graphite tube as permanent chemical modifier in atomic absorption spectrometry

Directory of Open Access Journals (Sweden)

Juliana Naozuka

2003-12-01

Full Text Available A tubular electrochemical flow-cell for iridium deposition on the inner surface of pyrolytic graphite tube for permanent chemical modification is proposed. A transversal heated graphite tube was used as working electrode, a cylindrical piece of graphite inserted into the graphite tube as auxiliary electrode, and a micro Ag/AgCl(sat as reference electrode. Iridium solution in 1.0 mol L-1 HCl, flowing at 0.55 mL min-1 for 60 min was used to perform the electrochemical modification. The applied potential to the flow-cell was - 0.700 V vs Ag/AgCl. Scanning electron microscopy images were taken for thermal and electrochemical modified graphite surface in order to evaluate the iridium distribution. Selenium hydride trapping was used to verify the performance of the proposed permanent chemical modifier.

Neutron capture cross sections of rhodium, thulium, iridium, and gold between 0.5 and 3.0 MeV

International Nuclear Information System (INIS)

Joly, S.; Voignier, J.; Grenier, G.; Drake, D.M.; Nilsson, L.

1979-01-01

Measurements of the neutron capture cross sections of rhodium, thulium, gold, and iridium were carried out in the 0.5- to 3.0-MeV energy range. The cross sections are deduced from the capture gamma-ray spectra recorded by a NaI spectrometer consisting of central and annulus detectors. Time-of-flight techniques are used to improve the signal-to-background ratio. When comparison is possible, the present results are found to be in general agreement with the previous data. 5 figures, 3 tables

Limited external irradiation and interstitial 192iridium implant in the treatment of squamous cell carcinoma of the tonsillar region

International Nuclear Information System (INIS)

Puthawala, A.A.; Syed, A.M.; Eads, D.L.; Neblett, D.; Gillin, L.; Gates, T.C.

1985-01-01

Between January 1976 and March 1982, 80 patients with histologically proven diagnosis of squamous cell carcinoma of the tonsillar region were treated with definitive radiotherapy. Sixty-five (81%) of these patients had locally advanced tumors (Stage III and IV); 49% of patients had clinically palpable cervical lymphadenopathy. All patients received a combined external megavoltage and interstitial irradiation. The dose of external irradiation was limited to 4500-5000 cGy over 41/2 to 51/2 weeks. This was followed by interstitial 192 iridium implants to doses of 2000-2500 cGy in 50-60 hours for T1, T2 lesions and 3000-4000 cGy in 60-100 hours for T3, T4 lesions. The neck masses were also separately implanted to deliver additional doses of 2000-4000 cGy in 50-80 hours. Overall local tumor control was observed in 84% of patients with a minimum follow-up period of 2 years. An absolute 3-year disease free survival of the entire group was 72%. Treatment related complications such as soft tissue necrosis or osteoradionecrosis occurred in 6% (5/80) of patients. The salvage of neck failures and local failures was possible in 78 and 38% of patients, respectively, either by surgery or by re-irradiation employing interstitial 192 iridium implants. Functional and esthetic integrity was well preserved in most cases

Real-Time Verification of a High-Dose-Rate Iridium 192 Source Position Using a Modified C-Arm Fluoroscope

Energy Technology Data Exchange (ETDEWEB)

Nose, Takayuki, E-mail: nose-takayuki@nms.ac.jp [Department of Radiation Oncology, Nippon Medical School Tamanagayama Hospital, Tama (Japan); Chatani, Masashi [Department of Radiation Oncology, Osaka Rosai Hospital, Sakai (Japan); Otani, Yuki [Department of Radiology, Kaizuka City Hospital, Kaizuka (Japan); Teshima, Teruki [Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka (Japan); Kumita, Shinichirou [Department of Radiology, Nippon Medical School Hospital, Tokyo (Japan)

2017-03-15

Purpose: High-dose-rate (HDR) brachytherapy misdeliveries can occur at any institution, and they can cause disastrous results. Even a patient's death has been reported. Misdeliveries could be avoided with real-time verification methods. In 1996, we developed a modified C-arm fluoroscopic verification of an HDR Iridium 192 source position prevent these misdeliveries. This method provided excellent image quality sufficient to detect errors, and it has been in clinical use at our institutions for 20 years. The purpose of the current study is to introduce the mechanisms and validity of our straightforward C-arm fluoroscopic verification method. Methods and Materials: Conventional X-ray fluoroscopic images are degraded by spurious signals and quantum noise from Iridium 192 photons, which make source verification impractical. To improve image quality, we quadrupled the C-arm fluoroscopic X-ray dose per pulse. The pulse rate was reduced by a factor of 4 to keep the average exposure compliant with Japanese medical regulations. The images were then displayed with quarter-frame rates. Results: Sufficient quality was obtained to enable observation of the source position relative to both the applicators and the anatomy. With this method, 2 errors were detected among 2031 treatment sessions for 370 patients within a 6-year period. Conclusions: With the use of a modified C-arm fluoroscopic verification method, treatment errors that were otherwise overlooked were detected in real time. This method should be given consideration for widespread use.

Blue phosphorescent mono-cyclometalated iridium(III) complexes

Energy Technology Data Exchange (ETDEWEB)

Ham, Ho Wan; Yang, Yoon A; Kim, Young Sik [Hongik University, Seoul (Korea, Republic of)

2010-12-15

New deep blue phosphorescent iridium(III) complexes comprised of one cyclometalate, two phosphines trans to each other and two cis-ancillary ligands, such as Ir(F{sub 2}Meppy)(PPh{sub 2}Me){sub 2}(H)(Cl), Ir(F{sub 2}Meppy)(PPh{sub 2}Me){sub 2}(H)(NCMe){sup +}, and Ir(F{sub 2}Meppy)(PPh{sub 2}Me){sub 2}(H)(CN), [F{sub 2}Meppy = 2-(2', 4'- difluorophenyl)-4-methyl-pyridine] were synthesized and studied to tune the phosphorescence wavelength to the deep blue region and to enhance the luminescence efficiencies. We investigated the strong field effects of ancillary ligands to gain insight into the factors responsible for the emission color change and the different luminescence efficiency. Reducing the molecular weight of the phosphine ligand with PPh{sub 2}Me leads to more efficient deep-blue organic light-emitting devices (OLED) by thermal processing instead of through solution processing. The electron-withdrawing difluoro group substituted on the phenyl ring, the electron-donating methyl group on the pyridyl ring, and the cyano strong field ancillary ligand increased the HOMO-LUMO gap and achieved a hypsochromic shift in the emission color. As a result, the maximum emission spectra of Ir(F{sub 2}Meppy)-(PPh{sub 2}Me){sub 2}(H)(Cl), Ir(F{sub 2}Meppy)(PPh{sub 2}Me){sub 2}(H)(NCMe){sup +}, and Ir(F{sub 2}Meppy)(PPh{sub 2}Me){sub 2-}(H)(CN) were in the ranges of 440.5, 437, 436 nm, respectively.

trans-(2-Benzoylpyridine-κ2N,Odichlorido[2-(2-pyridylcarbonylphenyl-κ2C1,N]iridium(III dichloromethane solvate

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available The title compound, [Ir(C12H8NOCl2(C12H9NO]·CH2Cl2, which was obtained from the reaction of iridium(III chloride trihydrate and 2-benzoylpyridine, contains an IrIII atom coordinated by two N, one O, one C and two Cl atoms in trans positions, forming a distorted octahedral environment. The solvent molecule CH2Cl2 is disordered over two positions with an occupancy of 0.8:0.2.

Synthesis, photophysical and electrochemical properties, and protein-binding studies of luminescent cyclometalated iridium(III) bipyridine estradiol conjugates.

Science.gov (United States)

Lo, Kenneth Kam-Wing; Zhang, Kenneth Yin; Chung, Chi-Keung; Kwok, Karen Ying

2007-01-01

A new series of luminescent cyclometalated iridium(III) bipyridine estradiol conjugates [Ir(N-C)2(N-N)](PF6) (N-N = 5-(4-(17alpha-ethynylestradiolyl)phenyl)-2,2'-bipyridine, bpy-est, HN-C = 2-phenylpyridine, Hppy (1 a), 1-phenylpyrazole, Hppz (2 a), 7,8-benzoquinoline, Hbzq (3 a), 2-phenylquinoline, Hpq (4 a), 2-((1,1'-biphenyl)-4-yl)benzothiazole, Hbsb (5 a); N-N = 4-(N-(6-(4-(17alpha-ethynylestradiolyl)benzoylamino)hexyl)aminocarbonyl)-4'-methyl-2,2'-bipyridine, bpy-C6-est, HN-C = Hppy (1 b), Hppz (2 b), Hbzq (3 b), Hpq (4 b), Hbsb (5 b)) was synthesized, characterized, and their photophysical and electrochemical properties studied. Upon photoexcitation, all the complexes displayed intense and long-lived emission in fluid solutions at 298 K and in low-temperature glass. The emission of complexes 1 a-3 a and 1 b-3 b was assigned to a triplet metal-to-ligand charge-transfer ((3)MLCT) (dpi(Ir)-->pi*(bpy-est and N-C-)) state mixed with some triplet intraligand ((3)IL) (pi-->pi*) (N-C- and N-N) character. However, the emissive states of the pq- and bsb- complexes 4 a, 4 b, 5 a, and 5 b showed substantial (3)IL (pi-->pi*) (pq-/bsb-) character. The lipophilicity of all the complexes was determined by reversed-phase HPLC. Upon binding to estrogen receptor alpha, all of these iridium(III) estradiol conjugates exhibited emission enhancement and lifetime extension, rendering them a novel series of luminescent probes for this receptor.

[New calculation algorithms in brachytherapy for iridium 192 treatments].

Science.gov (United States)

Robert, C; Dumas, I; Martinetti, F; Chargari, C; Haie-Meder, C; Lefkopoulos, D

2018-05-18

Since 1995, the brachytherapy dosimetry protocols follow the methodology recommended by the Task Group 43. This methodology, which has the advantage of being fast, is based on several approximations that are not always valid in clinical conditions. Model-based dose calculation algorithms have recently emerged in treatment planning stations and are considered as a major evolution by allowing for consideration of the patient's finite dimensions, tissue heterogeneities and the presence of high atomic number materials in applicators. In 2012, a report from the American Association of Physicists in Medicine Radiation Therapy Task Group 186 reviews these models and makes recommendations for their clinical implementation. This review focuses on the use of model-based dose calculation algorithms in the context of iridium 192 treatments. After a description of these algorithms and their clinical implementation, a summary of the main questions raised by these new methods is performed. Considerations regarding the choice of the medium used for the dose specification and the recommended methodology for assigning materials characteristics are especially described. In the last part, recent concrete examples from the literature illustrate the capabilities of these new algorithms on clinical cases. Copyright © 2018 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Closed-shell and open-shell square-planar iridium nitrido complexes

Science.gov (United States)

Scheibel, Markus G.; Askevold, Bjorn; Heinemann, Frank W.; Reijerse, Edward J.; de Bruin, Bas; Schneider, Sven

2012-07-01

Coupling reactions of nitrogen atoms represent elementary steps to many important heterogeneously catalysed reactions, such as the Haber-Bosch process or the selective catalytic reduction of NOx to give N2. For molecular nitrido (and related oxo) complexes, it is well established that the intrinsic reactivity, for example nucleophilicity or electrophilicity of the nitrido (or oxo) ligand, can be attributed to M-N (M-O) ground-state bonding. In recent years, nitrogen (oxygen)-centred radical reactivity was ascribed to the possible redox non-innocence of nitrido (oxo) ligands. However, unequivocal spectroscopic characterization of such transient nitridyl {M=N•} (or oxyl {M-O•}) complexes remained elusive. Here we describe the synthesis and characterization of the novel, closed-shell and open-shell square-planar iridium nitrido complexes [IrN(Lt-Bu)]+ and [IrN(Lt-Bu)] (Lt-Bu=N(CHCHP-t-Bu2)2). Spectroscopic characterization and quantum chemical calculations for [IrN(Lt-Bu)] indicate a considerable nitridyl, {Ir=N•}, radical character. The clean formation of IrI-N2 complexes via binuclear coupling is rationalized in terms of nitrido redox non-innocence in [IrN(Lt-Bu)].

Elektroonilise kunsti sümpoosion

Index Scriptorium Estoniae

2004-01-01

ISEA 2004 Tallinna näitused avatakse 17. VIII Rotermanni soolalaos, Tallinna Kunstihoones, Ku galeriis, Tallinna Linnagaleriis, Eesti Tarbekunsti- ja Disainimuuseumis, Elioni majas, Viru Keskuses, Eesti Kunstiakadeemias, Bon-Boni ööklubis, Multikultuurimajas. Loetletud osalejaid, toimuvad klubiõhtud, moedemonstratsioon, töötoad. 17. ja 18. VIII kinos "Kosmos" ja EKA-s toimuval konverentsil esinejaid. Programmi koordinaator Mare Tralla

Transpapillary iridium-192 wire in the treatment of malignant bile duct obstruction

International Nuclear Information System (INIS)

Levitt, M.D.; Laurence, B.H.; Cameron, F.; Klemp, P.F.B.

1988-01-01

Twenty four patients with malignant bile duct obstruction were treated with intraluminal radiotherapy using iridium-192 wire inserted through an endoscopically placed nasobiliary catheter. Biliary drainage after treatment was maintained by an endoprosthesis. The median dose of intraluminal radiotherapy was 6000 cGy; two patients with cholangiocarcinoma were given a second course because of disease extension; four patients with pancreatic carcinoma received additional external irradiation (3000 cGy). There was one early death from a cerebrovascular accident (30 day mortality, 4.2%). Cholangitis (30%) was the major early complication and stent blockage (40%) the major late complication; there were no complications directly attributable to radiotherapy. The median survival for patients with pancreatic carcinoma was 250 days and for cholangiocarcinoma, 300 days. This method is technically feasible and may prove safer than the transhepatic technique. The ability of intraluminal irradiation to improve palliation or lengthen survival in patients with malignant bile duct obstruction remains uncertain. (author)

Transpapillary iridium-192 wire in the treatment of malignant bile duct obstruction

Energy Technology Data Exchange (ETDEWEB)

Levitt, M D; Laurence, B H; Cameron, F; Klemp, P F.B.

1988-02-01

Twenty four patients with malignant bile duct obstruction were treated with intraluminal radiotherapy using iridium-192 wire inserted through an endoscopically placed nasobiliary catheter. Biliary drainage after treatment was maintained by an endoprosthesis. The median dose of intraluminal radiotherapy was 6000 cGy; two patients with cholangiocarcinoma were given a second course because of disease extension; four patients with pancreatic carcinoma received additional external irradiation (3000 cGy). There was one early death from a cerebrovascular accident (30 day mortality, 4.2%). Cholangitis (30%) was the major early complication and stent blockage (40%) the major late complication; there were no complications directly attributable to radiotherapy. The median survival for patients with pancreatic carcinoma was 250 days and for cholangiocarcinoma, 300 days. This method is technically feasible and may prove safer than the transhepatic technique. The ability of intraluminal irradiation to improve palliation or lengthen survival in patients with malignant bile duct obstruction remains uncertain.

Versatile deprotonated NHC: C,N-bridged dinuclear iridium and rhodium complexes

Directory of Open Access Journals (Sweden)

Albert Poater

2016-01-01

Full Text Available Bearing the versatility of N-heterocyclic carbene (NHC ligands, here density functional theory (DFT calculations unravel the capacity of coordination of a deprotonated NHC ligand (pNHC to generate a doubly C2,N3-bridged dinuclear complex. Here, in particular the discussion is based on the combination of the deprotonated 1-arylimidazol (aryl = mesityl (Mes with [M(cod(μ-Cl] (M = Ir, Rh generated two geometrical isomers of complex [M(cod{µ-C3H2N2(Mes-κC2,κN3}]2. The latter two isomers display conformations head-to-head (H-H and head-to-tail (H-T of CS and C2 symmetry, respectively. The isomerization from the H-H to the H-T conformation is feasible, whereas next substitutions of the cod ligand by CO first, and PMe3 later confirm the H-T coordination as the thermodynamically preferred. It is envisaged the exchange of the metal, from iridium to rhodium, confirming here the innocence of the nature of the metal for such arrangements of the bridging ligands.

High-dose rate iridium-192 brachytherapy with flexible applicator. A trial toward decrease of stress during treatment and improvement of quality of life

International Nuclear Information System (INIS)

Inoue, Keiji; Kasahara, Kotaro; Karashima, Takashi; Inoue, Yuichiro; Kariya, Shinji; Inomata, Taisuke; Yoshida, Shoji; Shuin, Taro

2001-01-01

We tried to improve the materials and methods of high-dose rate Iridium-192 brachytherapy for localized prostate cancer and evaluated the stress during the treatment in 20 patients with whom the therapy was performed. Rigid applicators made of stainless steel of 1.6 mm in diameter were indwelt with a template as usual for 30 hours in 14 patients (group A). Flexible applicators made of polyoxymethylene rosin (POM) of 2.0 mm in diameter were indwelt without a template for 30 hours after the applicator insertion in 6 patients (group B). We made inquiries about lumbago, inconvenience and necessity of assistant help and sleep in the course of therapy, and urinary incontinence and erectile function after the course of therapy as the QOL. The stress during the course of therapy in the patients of group B was obviously less than that of group A. There were no significant differences in urinary incontinence and erectile function after the course of therapy between group A and B. In this study, our trial successfully reduced the stress during the course of therapy in the patients with localized prostate cancer in the course of high-dose rate Iridium-192 brachytherapy. (author)

High-dose rate iridium-192 brachytherapy with flexible applicator. A trial toward decrease of stress during treatment and improvement of quality of life

Energy Technology Data Exchange (ETDEWEB)

Inoue, Keiji; Kasahara, Kotaro; Karashima, Takashi; Inoue, Yuichiro; Kariya, Shinji; Inomata, Taisuke; Yoshida, Shoji; Shuin, Taro [Kochi Medical School, Nankoku (Japan)

2001-07-01

We tried to improve the materials and methods of high-dose rate Iridium-192 brachytherapy for localized prostate cancer and evaluated the stress during the treatment in 20 patients with whom the therapy was performed. Rigid applicators made of stainless steel of 1.6 mm in diameter were indwelt with a template as usual for 30 hours in 14 patients (group A). Flexible applicators made of polyoxymethylene rosin (POM) of 2.0 mm in diameter were indwelt without a template for 30 hours after the applicator insertion in 6 patients (group B). We made inquiries about lumbago, inconvenience and necessity of assistant help and sleep in the course of therapy, and urinary incontinence and erectile function after the course of therapy as the QOL. The stress during the course of therapy in the patients of group B was obviously less than that of group A. There were no significant differences in urinary incontinence and erectile function after the course of therapy between group A and B. In this study, our trial successfully reduced the stress during the course of therapy in the patients with localized prostate cancer in the course of high-dose rate Iridium-192 brachytherapy. (author)

The brachytherapy with low dose-rate iridium for prostate cancer

International Nuclear Information System (INIS)

Momma, Tetsuo; Saito, Shiro; Ohki, Takahiro; Satoh, Hiroyuki; Toya, Kazuhito; Dokiya, Takushi; Murai, Masaru

2000-01-01

Brachytherapy as an option for the treatment of prostate cancer has been commonly performed in USA. As the permanent seeding of the radioactive materials is strictly restricted by the law in Japan, brachytherapy must be performed by the temporary implant. This treatment has been performed at a few facilities in Japan mostly using high dose-rate iridium. Only our facility has been using low dose-rate iridium (LDR-Ir) for prostate cancer. This study evaluates the clinical results of the treatment. Since December 1997 to December 1999, 26 patients with histologically diagnosed as prostate cancer (Stage B, 92%; Stage C, 8%) underwent brachytherapy. Twenty-two patients received brachytherapy alone, three were treated with a combination of brachytherapy and external beam radiotherapy (ERT) and one was treated with a combination of brachytherapy and neoadjuvant endocrine therapy. Patients ranged in age from 61 to 84 (median 76) years old. Treatment was initiated with perineal needle placement. From 10 to 14 needles were placed through the holes on the template which was fixed to the stabilizer of the transrectal ultrasound probe. After the needle placement, CT scan was performed to draw distribution curves for the treatment planning. LDR-Ir wires were introduced to the sheath and indwelled during the time calculated from dosimetry. Peripheral dose was 70 Gy for the monotherapy of brachytherapy. For the combination therapy, 40 Gy was given by brachytherapy and 36 Gy with ERT afterwards. LDR-Ir wires were removed after completion of the radiation and patients were followed with serum PSA level and annual biopsy. During 2 to 26 (median 12) months follow-up, 8 out of 9 patients with initial PSA level above 20 ng/ml showed PSA failure. All 13 patients with initial PSA level lower than 20 ng/ml were free from PSA failure. Eight out of 11 patients with Gleason's score 7 or higher showed PSA failure, and all 14 patients (including three patients with combined therapy) with

Intra-operative placement of catheters for interstitial microwave-induced hyperthermia and iridium brachytherapy

International Nuclear Information System (INIS)

Coughlin, C.T.; Wong, T.Z.; Strohbehn, J.W.; Colacchio, T.A.; Belch, R.Z.; Sutton, J.E. Jr.; Douple, E.B.

1984-01-01

The authors have previously described a system for delivery of microwave-induced hyperthermia utilizing flexible coaxial cables that are modified to serve as microwave antennas. These small (--1.6mm o.d.) antennas ae introduced into 2mm o.d. nylon catheters implanted in the tumor. This system has been further modified for use in the treatment of surgically unresectible abdominal, pelvic, and head and neck tumors. The modifications are described that were used to treat two pelvic, one upper abdominal, and one base of tongue tumor. The nylon catheters are implanted during surgery. After a short recovery period, the microwave antennas are inserted and the tumor region is heated for --1hr. The antennas are removed, iridium-192 seeds are placed in the catheters, 2800 - 5000 rad (CGy) doses are delivered, followed by a 1hr hyperthermia treatment. The temperature distributions and future applications are discussed

Unest äratatud Alatskivi loss / Meeli Müüripeal, Sirje Pärismaa

Index Scriptorium Estoniae

Müüripeal, Meeli, 1963-

2005-01-01

Alatskivi lossist (Arved von Nolcken, 1880-1885), lossi restaureerimise käigust ja seisust. Korras on viis esindusruumi. Sisekujunduse autorid: Olev Suuder, Oleg Mellov, ARC Projekt. SA Alatskivi Loss plaanidest. Kommenteerivad sihtasutuse juhataja Külli Must, lossi taastamise eestvedajad restauraator Raivo Nisu ja senine vallavanem Maie Nisu, kes kaitses 2004. a. EKA-s magistritöö "Alatskivi mõisaansambli revitaliseerimise ideeprojekt". 14 ill

Tallinn on klaasikunsti päralt / Mare Saare, Maie-Ann Raun

Index Scriptorium Estoniae

Saare, Mare, 1955-

2001-01-01

Tallinna Kunstihoones Põhja- ja Baltimaade klaasikunsti rändnäitus "Nordic Glass 2000". EKA klaasiüliõpilaste tööde valiknäitus "Glass with care" EKA galeriis, III kursuse klaasiüliõpilaste tööde näitus tervishoiumuuseumis. Rahvusraamatukogu peanäitusesaalis eesti graveeritud klaasi näitus. Raekoja galeriis klaasinäitus "Lorupist Lorupini"

The labeling of unsaturated gamma-hydroxybutyric acid by heavy isotopes of hydrogen: iridium complex-mediated H/D exchange by C-H bond activation vs reduction by boro-deuterides/tritides

Czech Academy of Sciences Publication Activity Database

Marek, Aleš; Pedersen, M. H. F.; Vogensen, S. B.; Clausen, R. P.; Frolund, B.; Elbert, Tomáš

2016-01-01

Roč. 59, č. 12 (2016), s. 476-483 ISSN 0362-4803 Institutional support: RVO:61388963 Keywords : C-H activation * borotritides * hydrogen/deuterium exchange * iridium catalyst * tritium-labeled gamma-hydroxybutyric acid Subject RIV: CC - Organic Chemistry Impact factor: 1.745, year: 2016

Lõpetajad : Eesti Kunstiakadeemia

Index Scriptorium Estoniae

2001-01-01

Kunstiteadus - 4, maalikunst - 5, stsenograafia - 3, graafika - 9, skulptuur - 4, keraamika - 4, klaasikunst - 2, metallikunst - 8, tekstiil - 6, moekunst - 2, nahakunst - 3, sisearhitektuur - 10, graafiline disain - 6, tootedisain - 8, arhitektuur (kutsemagistri kraad) - 24; magistriõpe: kunst: 4, kunstiteadus - 3. EKA Avatud Akadeemia: kujunduskunst - 17, graafiline disain - 5, tootedisain - 3. EKA Rakenduskunsti Kolledzh: graafiline disain - 4, tootedisain - 12, tekstiil ja mood - 5, ikoonimaal ja restaureerimine - 4.

Iridium Clusters Encapsulated in Carbon Nanospheres as Nanocatalysts for Methylation of (Bio)Alcohols.

Science.gov (United States)

Liu, Qiang; Xu, Guoqiang; Wang, Zhendong; Liu, Xiaoran; Wang, Xicheng; Dong, Linlin; Mu, Xindong; Liu, Huizhou

2017-12-08

C-H methylation is an attractive chemical transformation for C-C bonds construction in organic chemistry, yet efficient methylation of readily available (bio)alcohols in water using methanol as sustainable C1 feedstock is limited. Herein, iridium nanocatalysts encapsulated in yolk-shell-structured mesoporous carbon nanospheres (Ir@YSMCNs) were synthesized for this transformation. Monodispersed Ir clusters (ca. 1.0 nm) were encapsulated in situ and spatially isolated within YSMCNs by a silica-assisted sol-gel emulsion strategy. A selection of (bio)alcohols (19 examples) was selectively methylated in aqueous phase with good-to-high yields over the developed Ir@YSMCNs. The improved catalytic efficiencies in terms of activity and selectivity together with the good stability and recyclability were contributable to the ultrasmall Ir clusters with oxidation chemical state as a consequence of the confinement effect of YSMCNs with interconnected nanostructures. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Atomic structure of self-organizing iridium induced nanowires on Ge(001)

Energy Technology Data Exchange (ETDEWEB)

Kabanov, N.S., E-mail: n.kabanov@utwente.nl [Faculty of Physics, Moscow State University, 119991 (Russian Federation); Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P. O. Box 217, Enschede 7500 AE (Netherlands); Heimbuch, R.; Zandvliet, H.J.W. [Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P. O. Box 217, Enschede 7500 AE (Netherlands); Saletsky, A.M.; Klavsyuk, A.L. [Faculty of Physics, Moscow State University, 119991 (Russian Federation)

2017-05-15

Highlights: • Ir/Ge(001) structure has been studied with DFT calculations and scanning tunneling microscopy. • Ir/Ge(001) nanowires are composed of Ge atoms and Ir atoms are located in subsurface positions. • The regions in the vicinity of the nanowires are very dynamic, even at temperatures as low as 77 K. - Abstract: The atomic structure of self-organizing iridium (Ir) induced nanowires on Ge(001) is studied by density functional theory (DFT) calculations and variable-temperature scanning tunneling microscopy. The Ir induced nanowires are aligned in a direction perpendicular to the Ge(001) substrate dimer rows, have a width of two atoms and are completely kink-less. Density functional theory calculations show that the Ir atoms prefer to dive into the Ge(001) substrate and push up the neighboring Ge substrate atoms. The nanowires are composed of Ge atoms and not Ir atoms as previously assumed. The regions in the vicinity of the nanowires are very dynamic, even at temperatures as low as 77 K. Time-resolved scanning tunneling microscopy measurements reveal that this dynamics is caused by buckled Ge substrate dimers that flip back and forth between their two buckled configurations.

The labeling of unsaturated γ-hydroxybutyric acid by heavy isotopes of hydrogen: iridium complex-mediated H/D exchange by C─H bond activation vs reduction by boro-deuterides/tritides.

Science.gov (United States)

Marek, Aleš; Pedersen, Martin H F; Vogensen, Stine B; Clausen, Rasmus P; Frølund, Bente; Elbert, Tomáš

2016-10-01

3-Hydroxycyclopent-1-ene-1-carboxylic acid (HOCPCA (1)) is a potent ligand for high-affinity γ-hydroxybutyric acid binding sites in the central nervous system. Various approaches to the introduction of a hydrogen label onto the HOCPCA skeleton are reported. The outcomes of the feasible C─H activation of olefin carbon (C-2) by iridium catalyst are compared with the reduction of the carbonyl group (C-3) by freshly prepared borodeuterides. The most efficient iridium catalysts proved to be Kerr bulky phosphine N-heterocyclic species providing outstanding deuterium enrichment (up to 91%) in a short period of time. The highest deuterium enrichment (>99%) was achieved through the reduction of ketone precursor 2 by lithium trimethoxyborodeuteride. Hence, analogical conditions were used for the tritiation experiment. [ 3 H]-HOCPCA selectively labeled on the position C-3 was synthetized with radiochemical purity >99%, an isolated yield of 637 mCi and specific activity = 28.9 Ci/mmol. Copyright © 2016 John Wiley & Sons, Ltd.

Reversible Interconversion between 2,5-Dimethylpyrazine and 2,5-Dimethylpiperazine by Iridium-Catalyzed Hydrogenation/Dehydrogenation for Efficient Hydrogen Storage.

Science.gov (United States)

Fujita, Ken-Ichi; Wada, Tomokatsu; Shiraishi, Takumi

2017-08-28

A new hydrogen storage system based on the hydrogenation and dehydrogenation of nitrogen heterocyclic compounds, employing a single iridium catalyst, has been developed. Efficient hydrogen storage using relatively small amounts of solvent compared with previous systems was achieved by this new system. Reversible transformations between 2,5-dimethylpyrazine and 2,5-dimethylpiperazine, accompanied by the uptake and release of three equivalents of hydrogen, could be repeated almost quantitatively at least four times without any loss of efficiency. Furthermore, hydrogen storage under solvent-free conditions was also accomplished. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Attitudes and treatment outcome of breast conservation therapy for stage I and II breast cancer using peroperative iridium-192 implant boost to the tumour bed

International Nuclear Information System (INIS)

Deo, S.V.S.; Shukla, N.K.; Mohanti, B.K.; Chawla, S.; Julka, P.K.; Rath, G.K.; Raina, V.

2001-01-01

Breast conservation therapy for early breast cancer is an established but grossly under-utilized treatment option in India for various reasons. Breast conservation therapy was offered to 200 suitable breast cancer patients between June 1993 and June 1998. Fifty-one patients (25%) opted for breast conservation and the remaining preferred mastectomy. In patients agreeing to conservation therapy, surgery was performed first along with peroperative implantation of iridium-192 to deliver a boost. Whole breast irradiation of 45 Gy was delivered 3-4 weeks after the boost. Cosmesis was assessed at the end of 6 months from completion of therapy. The main reason for refusal of breast conservation therapy was fear of recurrence in the remaining breast (60%). There were no loco-regional failures in our study at a median follow up of 42 months; one patient experienced a systemic relapse. Cosmesis was good to excellent in 80% of patients. Breast conservation therapy using peroperative iridium-192 implant provides excellent loco-regional disease control and cosmesis. The results of our study indicate that patient preference for mastectomy is an important reason for the under-utilization of breast conservation therapy in India. Copyright (2001) Blackwell Science Pty Ltd

New iridium complex as additive to the spiro-OMeTAD in perovskite solar cells with enhanced stability

Directory of Open Access Journals (Sweden)

Laura Badia

2014-08-01

Full Text Available A new iridium complex, IrCp*Cl(PyPyz[TFSI], has been synthesized and used as additive for the hole transporter material, spiro-OMeTAD, in perovskite solar cells. The cells prepared with this Ir additive present higher efficiency than reference cells, and similar to cells prepared with Co additive. We have determined that the presence of metal complexes as additives decreases the recombination rate, as it has been observed by impedance spectroscopy. Very interestingly, while the efficiency after 3 months decreases by 22% and 70% for reference cell and cell with Co additive, respectively, the efficiency of devices containing the Ir additive is only decreased by a 4%.

"Rindemehed" Tallinna Kunstihoones

Index Scriptorium Estoniae

2004-01-01

7. XI avatakse Tallinna Kunstihoones ja Kunstihoone galeriis Ilya ja Emilia Kabakovi ning Raul Meele näitus, Tallinna Linnagaleriis New Yorgis Kabakovi ateljees töötanud Villu Plingi ja Jan Bergi näitus. 8. XI Eesti Kunstiakadeemias toimuval EKA nõukogu avalikul koosolekul promoveeritakse EKA 85. aastapäeval audoktoriks Ilya Kabakov, kes peab pärast tseremooniat akadeemilise loengu. Repliik Ilya Kabakovilt ja Raul Meelelt

Leach test of six 192-iridium pellets based on the IAEA 'special form' test procedures

International Nuclear Information System (INIS)

Gordon, G.; Gerdingh, R.

1981-07-01

The designation 'special form' may be applied to indispersible solid radioactive material if the material meets the requirements of the tests described in the International Atomic Energy Agency Regulations for the Safe Transport of Radioactive Type Materials. This report presents the procedures and results of a leach test performed as specified in the regulations on 6 'as received' active 192-iridium pellets. Mechanical tests were not carried out prior to or following the leach test. The activity of each of the first 6 water baths was found to be between 2.3 and 12.6 μCi, (8.5 x 10 4 and 4.7 x 10 5 Bq) and of the second 6, between 1.3 to 6.0 μCi, (4.8 x 10 4 to 2.2 x 10 5 Bq) thus exceeding the allowable limit

Ultrafine Iridium Oxide Nanorods Synthesized by Molten Salt Method toward Electrocatalytic Oxygen and Hydrogen Evolution Reactions

International Nuclear Information System (INIS)

Ahmed, Jahangeer; Mao, Yuanbing

2016-01-01

Highlights: • Ultrafine iridium oxide nanorods were synthesized by a molten salt method at 650 °C. • They show enhanced electrocatalytic activity to oxygen and hydrogen evolution reactions. • These results are comparable with, and in most cases, higher than reported data in the literature. • This study reports a novel synthetic process for IrO_2 but also a high efficient IrO_2 nanostructure. • These IrO_2 NRs are expected to serve as a benchmark to develop active electrocatalysts. - Abstract: Ultrafine iridium oxide nanorods (IrO_2 NRs) were successfully synthesized using a molten salt method at 650 °C. The structural and morphological characterizations of these IrO_2 NRs were carried out by powder X-ray diffraction, Raman spectroscopy and electron microscopic techniques. Compared to commercial IrO_2 nanoparticles (IrO_2 NPs) and previous reports, these IrO_2 NRs show enhanced electrocatalytic activity to oxygen and hydrogen evolution reactions by passing either N_2 or O_2 gas in a 0.5 M KOH electrolyte before electrochemical measurements, including cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Specifically, the current densities from the as-synthesized IrO_2 NRs and commercial IrO_2 NPs were measured in 0.5 M KOH electrolyte to be 70 and 58 (OER, deaerated, at 0.6 V versus Ag/AgCl), 71 and 61 (OER, O_2, from −0.10 to 1.0 V versus Ag/AgCl at 50 mV/s), and 25 and 14 (HER, deaerated, at −1.4 V versus Ag/AgCl) mA/cm"2, respectively. These results are comparable with, and in most cases, higher than reported data in the literature. Therefore, the current study reports not only a novel synthetic process for IrO_2 but also a high efficient IrO_2 nanostructure, and it is expected that these IrO_2 NRs can serve as a benchmark in the development of active OER and HER (photo)electrocatalysts for various applications.

Possible world-wide middle miocene iridium anomaly and its relationship to periodicity of impacts and extinctions

Science.gov (United States)

Asaro, F.; Alvarez, W.; Michel, H. V.; Alvarez, L. W.; Anders, Mark H.; Montanari, A.; Kennett, James P.

1988-01-01

In a study of one million years of Middle Miocene sediment deposition in ODP Hole 689B in the Weddell Sea near Antarctica, a single iridium (Ir) anomaly of 44 (+ or - 10) x 10 to the 12th gram Ir per gram rock (ppt) was observed in core 6H, section 3, 50 to 60 cm, after background contributions associated with manganese precipitates and clay are subtracted. The ODP Hole 689B is 10,000 km away from another site, DSDP Hole 588B in the Tasman Sea north of New Zealand, where a single Ir anomaly of 144 + or - 7 ppt over a background of 11 ppt was found in an earlier study of 3 million years of deposition. From chemical measurements the latter deposition was thought to be impact-related. Ir measurements were made, following neutron activation, with the Iridium Coincidence Spectrometer. The age vs depth calibration curves given in the DSDP and ODP preliminary reports indicate the ages of the Iranomalies are identical, 11.7 million years, but the absolute and relative uncertainties in the curves are not known. Based on the newest age data the age estimate is 10 million years. As the Ir was deposited at the two sites at about the same time and they are one quarter of the way around the world from each other it seems likely that the deposition was world-wide. The impact of a large asteroid or comet could produce the wide distribution, and this data is supportive of the impact relationship deduced for Deep Sea Drilling Project (DSDP) 588B from the chemical evidence. If the surface densities of Ir at the two sites are representative of the world-wide average, the diameter of a Cl type asteroid containing the necessary Ir would be 3 + or - 1 km, which is large enough to cause world-wide darkness and hence extinctions although the latter point is disputed.

The influence of different cyclometalated ligand substituents and ancillary ligand on the phosphorescent properties of iridium(III) complexes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qing; Li, Yuanyuan; Wang, Xin; Wang, Li, E-mail: chemwangl@henu.edu.cn; Zhang, Jinglai, E-mail: zhangjinglai@henu.edu.cn

2016-07-01

Four iridium(III) complexes, (dfpmpy){sub 2}Ir(pic), (1), (dfpmpy){sub 2}Ir(EO{sub 2}-pic) (2), (dfpmpy){sub 2}Ir(pic-N-O) (3), and (dfpmpy){sub 2}Ir(EO{sub 2}-pic-N-O) (4) (dfpmpy = 2-(2,4-difluorophenyl)-4-methylpyridine, pic = picolinic acid, EO{sub 2}-pic = 4-(2-ethoxyethoxy) picolinic acid, pic-N-O = picolinic acid N-oxide, and EO{sub 2}-pic-N-O = 4-(2-ethoxyethoxy) picolinic acid N-oxide) are investigated by means of the density functional theory/time-dependent density functional theory (DFT/TD-DFT) to explore the influence of the ancillary ligand on the electronic structures, phosphorescent properties, and organic light-emitting diode (OLED) performance. Employing pic-N-O and EO{sub 2}-pic-N-O as the ancillary ligands would decrease the vertical energy and result in the red-shifted wavelength. Then, other four iridium(III) complexes (2a-2d) (See Scheme 1) are designed by introduction of the phenyl and −CHO substituents on the pyridine ring and phenyl ring of complex 2, respectively. As compared with complex 2, theoretical results show that newly designed complexes 2a-2c might be potential candidates for blue-emitting phosphors with better/comparable quantum yield and Δλ. Moreover, the performance of complexes 2a and 2c, i.e., introducing phenyl on the para-position of pyridine ring and phenyl ring in dfpmpy ligand, are better than that of 2b. - Highlights: • The structure-property relationship of Ir(III) complexes are investigated. • The effect of different substituents/positions on properties is explored. • Do the emissions follow the Kasha or non-Kasha scenario? • Newly possible blue-emitting Ir(III) complexes are theoretically designed.

Ajalooliselt ebakorrektne Robert Baines / Robert Baines ; interv. Kadri Mälk

Index Scriptorium Estoniae

Baines, Robert

2004-01-01

Ajaloolist ehtekunsti erinevates muuseumides uurinud R. Baines pidas aprilli lõpul loengu EKAs ja viis läbi meistriklassi. R. Baines uurimistööst muuseumis, oma loomingust, galerii ja muuseumi vahekorrast, eesti ehtekunstist tarbekunsti- ja disainimuuseumis ja näitusel Ku galeriis (B. Lillemets, K. Maran), ehtekunstiõpetusest EKAs jm. R. Bainesi uurimustel põhinev näitus avati aprillis Müncheni antiigimuuseumis ja tema ehteloomingu näitus Biro galeriis

An iridium oxide microelectrode for monitoring acute local pH changes of endothelial cells.

Science.gov (United States)

Ng, Shu Rui; O'Hare, Danny

2015-06-21

pH sensors were fabricated by anodically electrodepositing iridium oxide films (AEIROFs) onto microelectrodes on chips and coated with poly(ethyleneimine) (PEI) for mechanical stability. These demonstrate super-Nernstian response to pH from pH 4.0 to 7.7 in chloride-free phosphate buffer. The surface of the chip was coated with fibronectin for the attachment of porcine aortic endothelial cells (PAECs). The working capability of the pH sensor for monitoring acute local pH changes was investigated by stimulating the PAECs with thrombin. Our results show that thrombin induced acute extracellular acidification of PAECs and dissolution of fibronectin, causing the local pH to decrease. The use of PD98059, a mitogen-activated protein kinase (MAPK) inhibitor, reduced extracellular acidification and an increase in local pH was observed. This study shows that our pH sensors can facilitate the investigation of acute cellular responses to stimulation by monitoring the real-time, local pH changes of cells attached to the sensors.

Organometallic rhodium(III) and iridium(III) cyclopentadienyl complexes with curcumin and bisdemethoxycurcumin co-ligands.

Science.gov (United States)

Pettinari, Riccardo; Marchetti, Fabio; Pettinari, Claudio; Condello, Francesca; Petrini, Agnese; Scopelliti, Rosario; Riedel, Tina; Dyson, Paul J

2015-12-21

A series of half-sandwich cyclopentadienyl rhodium(III) and iridium(III) complexes of the type [Cp*M(curc/bdcurc)Cl] and [Cp*M(curc/bdcurc)(PTA)][SO3CF3], in which Cp* = pentamethylcyclopentadienyl, curcH = curcumin and bdcurcH = bisdemethoxycurcumin as O^O-chelating ligands, and PTA = 1,3,5-triaza-7-phosphaadamantane, is described. The X-ray crystal structures of three of the complexes, i.e. [Cp*Rh(curc)(PTA)][SO3CF3] (5), [Cp*Rh(bdcurc)(PTA)][SO3CF3] (6) and [Cp*Ir(bdcurc)(PTA)][SO3CF3] (8), confirm the expected "piano-stool" geometry. With the exception of 5, the complexes are stable under pseudo-physiological conditions and are moderately cytotoxic to human ovarian carcinoma (A2780 and A2780cisR) cells and also to non-tumorigenic human embryonic kidney (HEK293) cells, but lack the cancer cell selectivity observed for related arene ruthenium(II) complexes.

Phase and group velocities for Lamb waves in DOP-26 iridium alloy sheet

International Nuclear Information System (INIS)

Simpson, W.A.; McGuire, D.J.

1994-07-01

The relatively coarse grain structure of iridium weldments limits the ultrasonic inspection of these structures to frequencies in the low megahertz range. As the material thickness is nominally 0.635 mm for clad vent set capsules, the low frequencies involved necessarily entail the generation of Lamb waves m the specimen. These waves are, of course, dispersive and detailed knowledge of both the phase and group velocities is required in order to determine accurately the location of flaws detected using Lamb waves. Purpose of this study is to elucidate the behavior of Lamb waves propagating in the capsule alloy and to quantify the velocities so that accurate flaw location is ensured. We describe a numerical technique for computing the phase velocities of Lamb waves (or of any other type of guided wave) and derive the group velocities from this information. A frequency-domain method is described for measuring group velocity when multiple Lamb modes are present and mutually interfering in the time domain, and experimental confirmation of the group velocity is presented for the capsule material

Development and application of an iridium tracer for tracking tailings in the central Red Sea

International Nuclear Information System (INIS)

Schnier, C.; Fanger, H.U.

1983-01-01

In order to investigate the distribution of disposed tailings, the element iridium was applied as a tracer during the prepilot mining test in the Red Sea 1979. In the sediment matrix, Ir can be detected in quantities as small as 25 x 10 -12 g by means of neutron activation analysis. The tracer was obtained by melting down a mixture of 50 kg quartz and 1 kg IrO 2 , then grinding and pulverizing the material to an appropriate grain size distribution. An amount of 480 m 3 tracer-added tailings was disposed in a depth of 400 m close to the Atlantis II deep. Subsequently, in the period 1 month to 2 1/2 years later, 32 sediment samples were taken from the deposition area and analysed for Ir. The Ir concentration observed were surprisingly low and give only vague indications of the spreading of the tailings. (orig.) [de

Postoperative irradiation of endometrial cancer by iridium afterloading technique

International Nuclear Information System (INIS)

Kucera, H.; Weghaupt, K.

1988-01-01

From 1981 to 1986 708 patients were operated and postoperativly treated by total hysterectomy, bilateral salpingo-oophorectomy and postoperative vaginal irradiation with high-dose-afterloading (iridium 192). A percutaneous irradiation (cobalt 60) was done in stage I cases only when myometrial infiltration was deep. Highly differentiated tumors with infiltration of the first and second thirth of the myometrium were treated by vaginal irradiation alone. Poorly differentiated tumors with infiltration of the second and third thirth of the myometrium were treated by vaginal and percutaneous irradiation. A group of 125 cases with good prognosis and with postoperative vaginal irradiation alone had the same five-year-survival of 83% as a group of 152 cases with bad prognosis treated by vaginal and percutaneous irrradiation. This result shows clearly the importance of additional irradiation of the pelvis in cases with bad prognosis factors. The incidence of radiation side effect in all 708 cases was: cystitis 4.6%, proctitis 5.2%, vaginal or rectal ulcera 1.4% and fistulas 0.2%. Cases with vaginal irradiation alone and with the optimal intravaginal fraction dose of 700 cGy (twice) had the lowest level of side effects: cystitis 3.8% proctitis 2.1%, vaginal necrosis 0.7%, no further severe complications. None of the patients with postoperative vaginal irradiation alone had a vaginal recurrence. The incidence of recurrences in 708 patients was 1.6%. All recurrence cases in stage I (0.7%) had bad prognosis factors and were treated with vaginal and percutaneous irradiation. (orig./MG) [de

Evolution of microbial communities during electrokinetic treatment of antibiotic-polluted soil.

Science.gov (United States)

Li, Hongna; Li, Binxu; Zhang, Zhiguo; Zhu, Changxiong; Tian, Yunlong; Ye, Jing

2018-02-01

The evolution of microbial communities during the electrokinetic treatment of antibiotic-polluted soil (EKA) was investigated with chlortetracycline (CTC), oxytetracycline (OTC) and tetracycline (TC) as template antibiotics. The total population of soil microorganisms was less affected during the electrokinetic process, while living anti-CTC, anti-OTC, anti-TC and anti-MIX bacteria were inactivated by 10.48%, 31.37%, 34.76%, and 22.08%, respectively, during the 7-day treatment compared with antibiotic-polluted soil without an electric field (NOE). Accordingly, samples with NOE treatment showed a higher Shannon index than those with EKA treatment, indicating a reduction of the microbial community diversity after electrokinetic processes. The major taxonomic phyla found in the samples of EKA and NOE treatment were Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria. And the distribution of Actinobacteria, Cyanobacteria, and Chloroflexi was greatly decreased compared with blank soil. In the phylum Proteobacteria, the abundance of Alphaproteobacteria was greatly reduced in the soils supplemented with antibiotics (from 13.40% in blank soil to 6.43-10.16% after treatment); while Betaproteobacteria and Deltaproteobacteria showed a different trend with their abundance increased compared to blank soil, and Gammaproteobacteria remained unchanged for all treatments (2.36-2.78%). The varied trends for different classes indicated that the major bacterial groups changed with the treatments due to their different adaptability to the antibiotics as well as to the electric field. SulI being an exception, the reduction ratio of the observed antibiotic resistance genes (ARGs) including tetC, tetG, tetW, tetM, intI1, and sulII in the 0-2cm soil sampled with EKA versus NOE treatment reached 55.17%, 3.59%, 99.26%, 89.51%, 30.40%, and 27.92%, respectively. Finally, correlation analysis was conducted between antibiotic-resistant bacteria, ARGs and taxonomic bacterial classes. It

Sihtasutus Eesti Rahvuskultuuri Fond võtab 15. oktoobrini vastu...

Index Scriptorium Estoniae

2003-01-01

Võetakse vastu 2004. a. stipendiumide ja kultuuriprojektide finantseerimise taotlusi. Esimest korda määratakse 2003. a. stipendiume järgmistest nimelistest allfondidest: Arvo Nenni ja Ingrid Nenni (Nõges) Fond toetab EKMi eesti kunstipärandi ostmisel, Edmund Valtmani Fond toetab stipendiumiga EKA üliõpilast või alla 30-aastast EKA vilistlast parima graafilise teose eest, Natalie Mei Fond toetab professionaalsete ja tulemuslike lava- ning kostüümikujundajate tegevust ja täiendusõpet jt.

Relative abundance of PcP energy in explosion seismic signals from Eastern Kazakh and South Western Russia recorded at Eskdalemuir, Yellowknife and Gauribidanur arrays

International Nuclear Information System (INIS)

Basu, T.K.; Arora, S.K.

1991-01-01

In this study further evidence of relative abundance of PcP (core reflected P) energy in explosion seismic records is gathered. It is based on the analysis of temporal and spectral characteristics of P and PcP digital seismograms of twenty-three underground nuclear explosions in Eastern Kazakh and Southern Russia recorded at Eskdalemuir (EKA) and Yellowkinfe (YKA) arrays. The results are compared with those obtained earlier using Gauribidanur array (GBA) data. It is found that seismic sources in Southwestern Russia give consistently large values of the PcP identifier when both EKA and YKA data are used thus corroborating authors' earlier finding with regard to this Soviet region of typical Q-structure inferred from GBA data. As regards relative levels of PcP energy in explosion generated seismic waves, it is found to be substantially large at GBA, moderate at YKA and least at EKA. (author). 8 figs., 3 tabs

Pentamethylcyclopentadienyl-rhodium and iridium complexes containing (N^N and N^O) bound chloroquine analogue ligands: synthesis, characterization and antimalarial properties.

Science.gov (United States)

Ekengard, Erik; Kumar, Kamlesh; Fogeron, Thibault; de Kock, Carmen; Smith, Peter J; Haukka, Matti; Monari, Magda; Nordlander, Ebbe

2016-03-07

The synthesis and characterization of twenty new pentamethylcyclopentadienyl-rhodium and iridium complexes containing N^N and N^O-chelating chloroquine analogue ligands are described. The in vitro antimalarial activity of the new ligands as well as the complexes was evaluated against the chloroquine sensitive (CQS) NF54 and the chloroquine resistant (CQR) Dd2 strains of Plasmodium falciparum. The antimalarial activity was found to be good to moderate; although all complexes are less active than artesunate, some of the ligands and complexes showed better activity than chloroquine (CQ). In particular, rhodium complexes were found to be considerably more active than iridium complexes against the CQS NF54 strain. Salicylaldimine Schiff base ligands having electron-withdrawing groups (F, Cl, Br, I and NO2) in para position of the salicyl moiety and their rhodium complexes showed good antiplasmodial activity against both the CQS-NF54 and the CQR-Dd2 strains. The crystal structures of (η(5)-pentamethylcyclopentadienyl){N(1)-(7-chloroquinolin-4-yl)-N(2)-(pyridin-2-ylmethyl)ethane-1,2-diamine)} chlororhodium(III) chloride and (η(5)-pentamethylcyclopentadienyl){(4-chloro-2-(((2-((7-chloroquinolin-4-yl)amino)ethyl)imino)methyl)phenolate)}chlororhodium(III) chloride are reported. The crystallization of the amino-pyridyl complex (η(5)-pentamethylcyclopentadienyl){(N(1)-(7-chloroquinolin-4-yl)-N(2)-(pyridin-2-ylmethyl)ethane-1,2-diamine)}chloroiridium(III) chloride in acetone resulted in the formation of the imino-pyridyl derivative (η(5)-pentamethylcyclopentadienyl){(N1-(7-chloroquinolin-4-yl)-N2-(pyridin-2-ylmethylene)ethane-1,2-diamine)}chloroiridium(III) chloride, the crystal structure of which is also reported.

Synthesis of Fischer carbene complexes of iridium by C-H bond activation of methyl and cyclic ethers: Evidence for reversible {alpha}-hydrogen migration

Energy Technology Data Exchange (ETDEWEB)

Luecke, H.F.; Arndtsen, B.A.; Burger, P.; Bergman, R.G. [Lawrence Berkeley Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States)

1996-03-13

We report here a mild and versatile route to Fischer carbene complexes of iridium via the activation of C-H bonds of methyl and cyclic ethers, along with our preliminary studies of this rare family of carbene complexes. Theoretical studies suggest that {alpha}-hydrogen migrations can be kinetically favorable if a coordinatively unsaturated species can be accessed. Thus, the lability of the triflate ligand presumably facilitates this process. Further evidence for the rapidity, as well as reversibility, of this rearrangement was obtained by NMR analysis. 20 refs.

Electrochemical Dissolution of Iridium and Iridium Oxide Particles in Acidic Media: Transmission Electron Microscopy, Electrochemical Flow Cell Coupled to Inductively Coupled Plasma Mass Spectrometry, and X-ray Absorption Spectroscopy Study.

Science.gov (United States)

Jovanovič, Primož; Hodnik, Nejc; Ruiz-Zepeda, Francisco; Arčon, Iztok; Jozinović, Barbara; Zorko, Milena; Bele, Marjan; Šala, Martin; Šelih, Vid Simon; Hočevar, Samo; Gaberšček, Miran

2017-09-13

Iridium-based particles, regarded as the most promising proton exchange membrane electrolyzer electrocatalysts, were investigated by transmission electron microscopy and by coupling of an electrochemical flow cell (EFC) with online inductively coupled plasma mass spectrometry. Additionally, studies using a thin-film rotating disc electrode, identical location transmission and scanning electron microscopy, as well as X-ray absorption spectroscopy have been performed. Extremely sensitive online time-and potential-resolved electrochemical dissolution profiles revealed that Ir particles dissolve well below oxygen evolution reaction (OER) potentials, presumably induced by Ir surface oxidation and reduction processes, also referred to as transient dissolution. Overall, thermally prepared rutile-type IrO 2 particles are substantially more stable and less active in comparison to as-prepared metallic and electrochemically pretreated (E-Ir) analogues. Interestingly, under OER-relevant conditions, E-Ir particles exhibit superior stability and activity owing to the altered corrosion mechanism, where the formation of unstable Ir(>IV) species is hindered. Due to the enhanced and lasting OER performance, electrochemically pre-oxidized E-Ir particles may be considered as the electrocatalyst of choice for an improved low-temperature electrochemical hydrogen production device, namely a proton exchange membrane electrolyzer.

Tallinna Ülikool tulekul / Sirje Tohver

Index Scriptorium Estoniae

Tohver, Sirje

2002-01-01

Ajaloo Instituudi, EAR-i, Eesti Humanitaarinstituudi, EKA ja TPÜ juhid kirjutasid 15.05.2002 Tallinna Raekojas alla ühise tegevuse lepingule ning ühiste kavatsuste deklaratsioonile. Tallinna Ülikooli alustab 2003/04. õa. Kirjutati alla ka koostöölepingule Tallinna linnaga, mis sätestab lepingupoolte tegevuse urbanistikaalase õppetöö ning linnauuringute korraldamisel. Kommenteerivad TPÜ rektor M. Heidmets, EKA rektor A. Keskküla, Ajaloo Instituudi direktor P. Raudkivi, EHI Sihtasutuse Nõukogu esimees R. Raud, EHI rektor J. Tamm

BOWIEITE: A NEW RHODIUM-IRIDIUM-PLATINUM SULFIDE IN PLATINUM-ALLOY NUGGETS, GOODNEWS BAY, ALASKA.

Science.gov (United States)

Desborough, George A.; Criddle, Alan J.

1984-01-01

Bowieite (Rh,Ir,Pt)//2S//3, a new mineral species, is found in three nuggets of platinum from Goodnews Bay, Alaska. In linearly polarized reflected light, and compared to the host, higher reflecting white platinum-iridium alloy, bowieite is pale gray to pale gray-brown; neither bireflectance nor reflectance pleochroism is apparent. With polars crossed, its anisotropic rotation tints vary from gray to dark brown. Luminance values (relative to the CIE illuminant C) for R//1 and R//2, computed from full spectral data for the most bireflectant grain, are 45. 8% and 48. 2% in air, and 30. 5% and 33. 0% in oil, respectively. VHN//1//0//0 1288 (858 to 1635). Bowieite is orthorhombic, space group Pnca, with a 8. 454(7) -8. 473(8), b 5. 995(1)-6. 002(7), c 6. 143(1)-6. 121(8) A, Z equals 4. Some grains that are 2. 6 to 3. 8 atomic % metal-deficient occur as an optically coherent rim on bowieite; the rim and the bowieite grain are not optically continuous.

Instrumental measurement of iridium abundances in the part-per-trillion range following neutron activation

International Nuclear Information System (INIS)

Alvarez, L.W.; Asaro, F.; Goulding, F.S.; Landis, D.A.; Madden, N.W.; Malone, D.F.

1988-01-01

An automated gamma-ray coincidence spectrometer has been constructed which, following neutron activation, can measure iridium (Ir) abundances of the order of 25 parts-per-trillion (ppt) in rock samples 500 times more rapidly than previously possible by instrumental techniques used at the Lawrence Berkeley Laboratory. Twin intrinsic Ge gamma-ray detectors count coincidences between the 316.5 and 468.1 keV gamma rays of 192 Ir, and together with a mineral-oil-based Compton suppression shield provide a sensitivity of 50 ppt Ir in 7 minute measurements of 100 mg limestone samples subsequent to irradiation in the University of Missouri reactor. Over 3000 samples have been measured, and in collaboration with many geologists and paleontologists from around the world, anomalous amounts of Ir have been detected in rocks with approximate ages of 12, 39, 67, 91, 150 and 3500 million years. Modifications are nearly complete to measure ten other elements very important to geochemical studies simultaneously (in the singles rather than the coincidence mode) with the Ir measurements

Single Pot Selective Hydrogenation of Furfural to 2-Methylfuran Over Carbon Supported Iridium Catalysts

KAUST Repository

Date, Nandan S; Hengne, Amol Mahalingappa; Huang, Kuo-Wei; Chikate, Rajeev C.; Rode, C. V.

2018-01-01

Various iridium supported carbon catalysts were prepared and screened for direct hydrogenation of furfural (FFR) to 2-methyl furan (2-MF). Amongest these, 5% Ir/C showed excellent results with complete FFR conversion and highest selectivity of 95% to 2-MF at very low H2 pressure of 100 psig. Metallic (Iro) and oxide ( IrO2) phases of Ir catalyzed first step hydrogenation involving FFR to FAL and subsequent hydrogenation to 2-MF,respecively. This was confirmed by XPS analysis and some controlled experiments. At low temperature of 140 oC, almost equal selectivities of FAL (42%) and 2-MF (43%) were observed, while higher temperature (220oC) favored selective hydrodeoxygenation. At optimized temperature, 2-MF formed selectively while higher pressure and higher catalyst loading favored ring hydrogenation of furfural rather than side chain hydrogenation. With combination of several control experimental results and detailed catalyst characterization, a plausible reaction pathway has been proposed for selective formation of 2-MF. The selectivity to various other products in FFR hydrogenation can be manipulated by tailoring the reaction conditions over the same catalyst.

Single Pot Selective Hydrogenation of Furfural to 2-Methylfuran Over Carbon Supported Iridium Catalysts

KAUST Repository

Date, Nandan S

2018-03-20

Various iridium supported carbon catalysts were prepared and screened for direct hydrogenation of furfural (FFR) to 2-methyl furan (2-MF). Amongest these, 5% Ir/C showed excellent results with complete FFR conversion and highest selectivity of 95% to 2-MF at very low H2 pressure of 100 psig. Metallic (Iro) and oxide ( IrO2) phases of Ir catalyzed first step hydrogenation involving FFR to FAL and subsequent hydrogenation to 2-MF,respecively. This was confirmed by XPS analysis and some controlled experiments. At low temperature of 140 oC, almost equal selectivities of FAL (42%) and 2-MF (43%) were observed, while higher temperature (220oC) favored selective hydrodeoxygenation. At optimized temperature, 2-MF formed selectively while higher pressure and higher catalyst loading favored ring hydrogenation of furfural rather than side chain hydrogenation. With combination of several control experimental results and detailed catalyst characterization, a plausible reaction pathway has been proposed for selective formation of 2-MF. The selectivity to various other products in FFR hydrogenation can be manipulated by tailoring the reaction conditions over the same catalyst.

Organic Light-Emitting Diodes Using Multifunctional Phosphorescent Dendrimers with Iridium-Complex Core and Charge-Transporting Dendrons

Science.gov (United States)

Tsuzuki, Toshimitsu; Shirasawa, Nobuhiko; Suzuki, Toshiyasu; Tokito, Shizuo

2005-06-01

We report a novel class of light-emitting materials for use in organic light-emitting diodes (OLEDs): multifunctional phosphorescent dendrimers that have a phosphorescent core and dendrons based on charge-transporting building blocks. We synthesized first-generation and second-generation dendrimers consisting of a fac-tris(2-phenylpyridine)iridium [Ir(ppy)3] core and hole-transporting phenylcarbazole-based dendrons. Smooth amorphous films of these dendrimers were formed by spin-coating them from solutions. The OLEDs using the dendrimer exhibited bright green or yellowish-green emission from the Ir(ppy)3 core. The OLEDs using the film containing a mixture of the dendrimer and an electron-transporting material exhibited higher efficiency than those using the neat dendrimer film. The external quantum efficiency of OLEDs using the film containing a mixture of the first-generation dendrimer and an electron-transporting material was as high as 7.6%.

Global iridium anomaly, mass extinction, and redox change at the Devonian-Carboniferous boundary

Energy Technology Data Exchange (ETDEWEB)

Wang, K. (Geological Survey of Canada, Calgary, Alberta (Canada) Univ. of Calgary, Alberta (Canada)); Attrep, M. Jr.; Orth, C.J. (Los Alamos National Lab., NM (United States))

1993-12-01

Iridium abundance anomalies have been found on a global scale in the Devonian-Carboniferous (D-C) boundary interval, which records one of the largest Phanerozoic mass-extinction events, an event that devastated many groups of living organisms, such as plants, ammonoids, trilobites, conodonts, fish, foraminiferans, brachiopods, and ostracodes. At or very close to the D-C boundary, there exists a geographically widespread black-shale interval, and Ir abundances reach anomalous maxima of 0.148 ppb (Montagne Noire, France), 0.138 ppb (Alberta, Canada) 0.140 ppb (Carnic Alps, Austria), 0.156 ppb (Guangxi, China), 0.258 ppb (Guizhou, China), and 0.250 ppb (Oklahoma). The discovery of global D-C Ir anomalies argues for an impact-extinction model. However, nonchondritic ratios of Ir to other important elements and a lack of physical evidence (shocked quartz, microtektites) do not support such a scenario. The fact that all Ir abundance maxima are at sharp redox boundaries in these sections leads us to conclude that the Ir anomalies likely resulted from a sudden change in paleo-redox conditions during deposition and/or early diagenesis. 36 refs., 2 figs., 1 tab.

"Nägemus" EKA galeriis

Index Scriptorium Estoniae

2003-01-01

Tartu Kõrgema Kunstikooli tekstiilikunsti osakonna gobeläänide näitus "Nägemus". Osalejad: Triinu Pungits, Signe Vilde, Jaanika Terasmaa, Leeda Ots, Gerli Aimla, Merike Uiga, Irina Vizner-Laur, Mari Vaaderpall, Heike Sepp

Fabergé fondi tunnustus Eesti ehtekunstile

Index Scriptorium Estoniae

2002-01-01

Mais Peterburis toimunud Fabergé fondi noorte ehtekunsti rahvusvahelisel konkurssnäitusel võitis nooremas vanuserühmas I preemia EKA sepakunsti üliõpilane Argo Männik, II-III preemiat jagas ehtekunsti magistrant Andrus Rumm. Mais oli EKA ehteväljapanek Genfis kaasaegse ehtekunsti suursündmusel "L' ornement est-il toujours un crime". Väljapanekud koostas Kadri Mälk. Genfi kunstimuuseumis šveitsi XX sajandi ehtekunsti erinäitus. Muuseum avaldas soovi võtta oma püsikogusse Eve Margus-Villemsi objekt "Enesepettus"

Crystal structure of chlorido(dimethyl sulfoxide-κSbis[4-(pyridin-2-ylbenzaldehyde-κ3C2,N]iridium(III acetonitrile monosolvate

Directory of Open Access Journals (Sweden)

Andrew J. Peloquin

2017-09-01

Full Text Available The title compound, [IrCl(C12H8NO2{(CH32SO}]·H3CCN or [IrCl(fppy2(DMSO]·H3CCN [where fppy is 4-(pyridin-2-ylbenzaldehyde and DMSO is dimethyl sulfoxide], is a mononuclear iridium(III complex including two fppy ligands, a sulfur-coordinating DMSO ligand, and one terminal chloride ligand that define a distorted octahedral coordination sphere. The complex crystallizes from 1:1 DMSO–acetonitrile as an acetonitrile solvate. In the crystal, weak C—H...O and C—H...N hydrogen-bonding interactions between adjacent complexes and between the acetonitrile solvent and the complex consolidate the packing.

Production of iridium-192 radiation sources: Indian Experience

International Nuclear Information System (INIS)

Sastry, K.V.S.; Kolhe, O.T.; Nagarja, P.S.; Paramr, Y.D.

2002-01-01

Board of Radiation and Isotope Technology (BRIT), a unit under the Department of Atomic Energy is fabricating and supplying Ir-192 industrial radiography sources for various models of radiography cameras for use in the industry for non-destructive testing. Basically these sources are fabricated by encapsulating the required quantity of the activity in stainless steel 316 L capsules using Tungsten Inert gas welding process and crimping/attaching to the respective pigtail assemblies of the radiography cameras. The inactive iridium pellets are irradiated in the DHRUVA reactor at a flux on 1.8 X 10 14 n/cm 2 /sec. The performance classification of these source encapsulation for various conditions of normal and accidental nature are tested by subjecting the prototype sources as per the standard laid down by the regulatory authority, Atomic Energy Regulatory Board, in India. The sources are fabricated as per the national and international standards. Activity of the sources varies from 37O GBq (10 Ci ) to 2.96 TBq (80 Ci ) source strength depending on the requirement of the user. The specific activity of the Ir-192 sources supplied is around 7.4 TBq/gm (200 Ci/gm ). Quality control /Assurance for the manufacture of the source begins from the procurement of the raw material and ends with the finished source. Ir- 192 in the form of -0.3 mm diameter (0.1 mm dia wire of Ir-25 % and Pt-75% sheathed in pure platinum of 0.1 mm thick) is being supplied for use in the treatment of cancer of cervix, tongue etc. by brachytherapy. This is supplied in lengths of 50 cm / 100 cm with 37 - 185 GBq/cm ( 1-5 mCi/cm) activity. Annually 925 TBq (25 kCi) of Ir-192 for industrial radiography and about 60 meters of wire for brachytherapy are being fabricated and supplied. Because of the quality of these sources BRIT not only caters to the Indian industry but also is able to export sources to the third world countries. (Author)

Recovery from Iridium-192 flakes of a radioactive source for industrial use after a radiation incident

International Nuclear Information System (INIS)

Cruz, W.H.; Zapata, L.A.

2013-01-01

The Iridium-192 ( 192 Ir) is the most used and ideal for industrial radiography applications, especially in petrochemical plants and pipelines and provides better contrast sensitivity for thick (25.4 mm). This source has constructive sealed double encapsulation, the internal capsule containing stainless steel to radioactive material in the form of flakes and welded with TIG process. The radiological incident happened at a gas station fuel sales in circumstances in which there was a homogeneity test welds a tank, the flakes or Ir-192 fell off his ponytail and left scattered over an area of 2 m 2 , some fell flat areas and other land so collected in lead shielding and metal container and ground source. Full recovery of the leaflets was performed at the Division of radioactive waste management (GRRA) gaining a total of 22 flakes with no radiation risk to staff performance and installation and the conclusion was reached that the misapplicaion of TIG welding was the main cause the incident. (author)

Atmospheric behavior of urban diesel soot tagged with an iridium tracer

International Nuclear Information System (INIS)

Suarez, A.E.; Caffrey, P.F.; Borgoul, P.V.; Ondov, J.M.

1995-01-01

An important source of polynuclear aromatic hydrocarbons depositing to the Chesapeake Bay is diesel emissions, including, those from the heavily-industrial City of Baltimore which lies 3 of diesel fuel burned by the City of Baltimore's sanitation truck fleet for a 20-day period in August, 1995. Size-segregated aerosol was collected daily using 80-L min -1 dichotomous samplers at four land-bas3ed sites and aboard ship at two locations on the Chesapeake Bay. Shipboard samples were collected on the EPA's Research Vessel Anderson, either east or southeast of Baltimore, off Annapolis. Three of the land sites, i.e., those at Catonsville, MD, the Eastern Avenue Fire Station (14 km from the Bay), and the Coast Guard Station at Still pond (30 km northeast of Baltimore) were chosen to be aligned with prevailing westerly winds. The fourth site was located on Hart Miller Island, about 14 km southeast of the Fire Station to take advantage of drainage flow along the Patapsco River. In addition, 10-stage Micro-Orifice Impactors were operated daily aboard ship and at all but the Catonsville site. Deposition plates were exposed aboard ship and at two of the land sites. Finally, several samples of tagged diesel emissions were collected with an MOI mounted on one of the sanitation trucks. Iridium and ≤ 40 other elements were determined by neutron activation analysis or X-ray fluorescence; graphitic carbon by light transmission, and aerosol mass by gravimetry

Satellite Collision Modeling with Physics-Based Hydrocodes: Debris Generation Predictions of the Iridium-Cosmos Collision Event and Other Impact Events

International Nuclear Information System (INIS)

Springer, H.K.; Miller, W.O.; Levatin, J.L.; Pertica, A.J.; Olivier, S.S.

2010-01-01

Satellite collision debris poses risks to existing space assets and future space missions. Predictive models of debris generated from these hypervelocity collisions are critical for developing accurate space situational awareness tools and effective mitigation strategies. Hypervelocity collisions involve complex phenomenon that spans several time- and length-scales. We have developed a satellite collision debris modeling approach consisting of a Lagrangian hydrocode enriched with smooth particle hydrodynamics (SPH), advanced material failure models, detailed satellite mesh models, and massively parallel computers. These computational studies enable us to investigate the influence of satellite center-of-mass (CM) overlap and orientation, relative velocity, and material composition on the size, velocity, and material type distributions of collision debris. We have applied our debris modeling capability to the recent Iridium 33-Cosmos 2251 collision event. While the relative velocity was well understood in this event, the degree of satellite CM overlap and orientation was ill-defined. In our simulations, we varied the collision CM overlap and orientation of the satellites from nearly maximum overlap to partial overlap on the outermost extents of the satellites (i.e, solar panels and gravity boom). As expected, we found that with increased satellite overlap, the overall debris cloud mass and momentum (transfer) increases, the average debris size decreases, and the debris velocity increases. The largest predicted debris can also provide insight into which satellite components were further removed from the impact location. A significant fraction of the momentum transfer is imparted to the smallest debris (< 1-5mm, dependent on mesh resolution), especially in large CM overlap simulations. While the inclusion of the smallest debris is critical to enforcing mass and momentum conservation in hydrocode simulations, there seems to be relatively little interest in their

Iridium oxide pH sensor for biomedical applications. Case urea-urease in real urine samples.

Science.gov (United States)

Prats-Alfonso, Elisabet; Abad, Llibertat; Casañ-Pastor, Nieves; Gonzalo-Ruiz, Javier; Baldrich, Eva

2013-01-15

This work demonstrates the implementation of iridium oxide films (IROF) grown on silicon-based thin-film platinum microelectrodes, their utilization as a pH sensor, and their successful formatting into a urea pH sensor. In this context, Pt electrodes were fabricated on Silicon by using standard photolithography and lift-off procedures and IROF thin films were growth by a dynamic oxidation electrodeposition method (AEIROF). The AEIROF pH sensor reported showed a super-Nerstian (72.9±0.9mV/pH) response between pH 3 and 11, with residual standard deviation of both repeatability and reproducibility below 5%, and resolution of 0.03 pH units. For their application as urea pH sensors, AEIROF electrodes were reversibly modified with urease-coated magnetic microparticles (MP) using a magnet. The urea pH sensor provided fast detection of urea between 78μM and 20mM in saline solution, in sample volumes of just 50μL. The applicability to urea determination in real urine samples is discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Exciplex emission and Auger process assistant green organic electrophosphorescence devices with very low doped level of iridium complex

International Nuclear Information System (INIS)

Zhang Dongyu; Li Wenlian; Chu Bei; Li Xiao; Su Zisheng; Han Liangliang; Li Tianle; Chen Yiren; Yan Fei; Wu Shuanghong; Zhang Zhiqiang; Hu Zhizhi

2008-01-01

We demonstrate efficient and simple structure phosphorescence organic light-emitting diodes, in which 4, 4', 4''-tris[3-methyl-pheny(phenyl)-amino]triphenyl -amine (m-MTDATA) and 4,7-diphenyl-1,10-phenanthroline (Bphen) are used as hole transport and electron transport layers, respectively, accompanied by 3 wt% fac-tris(2-phenylpyridine) iridium doped in 1,3,5-tris(N-phenylbenzimidazol-2-yl)-benzene (Ir : TPBi) as the emitting layer. As a result, a 29 lm W -1 peak power efficiency and 2.2 V turn-on voltage are achieved, respectively. The achievement of excellent electroluminescence (EL) properties was attributed to the contribution of exciplex formation at the interface of m-MTDATA/Ir : TPBi and the Auger-type two-step process of charge carrier injection. The competition between the interfacial exciplex and Ir-complex emissions in the EL processes was also discussed.

Reversible hydrogen storage using CO2 and a proton-switchable iridium catalyst in aqueous media under mild temperatures and pressures.

Science.gov (United States)

Hull, Jonathan F; Himeda, Yuichiro; Wang, Wan-Hui; Hashiguchi, Brian; Periana, Roy; Szalda, David J; Muckerman, James T; Fujita, Etsuko

2012-03-18

Green plants convert CO(2) to sugar for energy storage via photosynthesis. We report a novel catalyst that uses CO(2) and hydrogen to store energy in formic acid. Using a homogeneous iridium catalyst with a proton-responsive ligand, we show the first reversible and recyclable hydrogen storage system that operates under mild conditions using CO(2), formate and formic acid. This system is energy-efficient and green because it operates near ambient conditions, uses water as a solvent, produces high-pressure CO-free hydrogen, and uses pH to control hydrogen production or consumption. The extraordinary and switchable catalytic activity is attributed to the multifunctional ligand, which acts as a proton-relay and strong π-donor, and is rationalized by theoretical and experimental studies.

New cyclometalated iridium(III) complex as a phosphorescent dopant in organic light emitting devices

Science.gov (United States)

Ivanov, P.; Tomova, R.; Petrova, P.; Stanimirov, S.; Petkov, I.

2014-05-01

A new cyclometalated iridium (III) bis[2-(4-chlorophenyl)benzothiazolato-N,C2]-acetylacetonate, (Cl-bt)2Ir(acac), was synthesized and identified by 1H NMR and elemental analysis. The application was studied of the new compound as a dopant in the hole transporting layer (HTL) of the following organic light emitting diode (OLED) structure: HTL/EL/ETL, where HTL was 4,4'-bis(9H-carbazol-9-yl)biphenyl (CBP) or N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD), incorporated in a poly(N-vinylcarbazole) (PVK) matrix; EL was an electroluminescent layer of bis(8-hydroxy-2-methylquinoline)-(4-phenylpheno-xy) aluminum (BAlq); and ETL was an electron-transporting layer of bis[2-(2-benzothiazoly) phenolato]zinc(II) (Zn(btz)2). We established that the electroluminescence spectra of the OLEDs at different dopant concentrations were basically the sum of the greenish-blue emission of BAlq and the yellowish-green emission of the Ir complex. It was also found that increasing the dopant concentration resulted in an increase in the relative electroluminescent intensity of the Ir complex emission, while that of BAlq decreased, thus a fine tuning of the OLED color was observed.

Uued raamatud

Index Scriptorium Estoniae

2005-01-01

Constructed happiness - domestic environment in the cold war era / Võistlevad õnned - elukeskkond külma sõja perioodil (EKA, 2005; toimetajad Mart Kalm, Ingrid Ruudi, kujundajad Martin Lazarev, Tiit Lepp, Andrus Kõresaar); Ruumipilt : Eesti parimad interjöörid ja disain : konkurss 2004 / Eesti Sisearhitektide Liit (Minuskel, 2005; projektijuht Mati Veermets, kujundaja Tiiu Prisko, tekstid: Ell-Maaja Randküla); Eesti Kunstiakadeemia ajakirja 1. number (toimetajad Karolin Kuusik, Kristina Paju, kujundajad Kadri-Maria Mitt, Tuuli Aule, fotod: Tatjana Muravskaja); Eesti Kunstiakadeemia lõputööd 2005 (EKA, 2005; koostajad Karin Laansoo, Alo Paistik, kujundajad T. Aule, K.-M. Mitt, fotograafid Pelle Kalmo, Riikka Tauriainen, Anu Vahtra); Hallas-Murula, Karin. Suurlinn Tallinn : Eliel Saarineni "Suur-Tallinna" projekt. 1913 (Eesti Arhitektuurimuuseum, 2005; kujundaja Tiit Jürna); Kivi, Raul-Levroit. Tartu planeerimisest ja arhitektuurist : artikleid ja mälestusi (Eesti Arhitektuurimuuseum, 2005; koostajad Jaan Malin, K. Hallas-Murula); Arhitektuuriaasta 2004 : arhitektuuripreemiate nominendid (Solnessi Arhitektuurikirjastus, 2005; tekst: Epp Lankots, kujundaja Arhitektuuri Domeen); Archiprix International 2005 : world's best graduation projects (Rotterdam, 2005; EKA lõpetanud arhitektidest on publitseeritud Ralf Lõokese magistritöö "Superrand")

Crystal structure of an iridium(III complex of the [C(dppm2] PCP pincer ligand system and its conjugate CH acid form

Directory of Open Access Journals (Sweden)

Christian Reitsamer

2018-05-01

Full Text Available After the successful creation of the newly designed PCP carbodiphosphorane (CDP ligand [Reitsamer et al. (2012. Dalton Trans. 41, 3503–3514; Stallinger et al. (2007. Chem. Commun. pp. 510–512], the treatment of this PCP pincer system with the transition metal iridium and further the analysis of the structures by single-crystal diffraction and by NMR spectroscopy were of major interest. Two different iridium complexes, namely (bis{[(diphenylphosphanylmethyl]diphenylphosphanylidene}methane-κ3P,C,P′carbonylchloridohydridoiridium(III chloride dichloromethane trisolvate, [IrIII(CO{C(dppm2-κ3P,C,P′}ClH]Cl·3CH2Cl2 (1 and the closely related (bis{[(diphenylphosphanylmethyl]diphenylphosphanylidene}methanide(1+-κ3P,C,P′carbonylchloridohydridoiridium(III dichloride–hydrochloric acid–water (1/2/5.5, [IrIII(CO{CH(dppm2-κ3P,C,P′ClH]Cl}2 (2, have been designed and both complexes show a slightly distorted octahedral coordinated IrIII centre. The PCP pincer ligand system is arranged in a meridional manner, the CO ligand is located trans to the central PCP carbon and a hydride and chloride are located perpendicular above and below the P2C2 plane. With an Ir—CCDP distance of 2.157 (5 Å, an Ir—CO distance of 1.891 (6 Å and a quite short C—O distance of 1.117 (7 Å, complex 1 presents a strong carbonyl bond. Complex 2, the corresponding CH acid of 1, shows an additionally attached proton at the carbodiphosphorane carbon atom located antiperiplanar to the hydride of the metal centre. In comparison with complex 1, the Ir—CCDP distance of 2.207 (3 Å is lengthened and the Ir—C—O values indicate a weaker trans influence of the central carbodiphosphorane carbon atom.

Exciplex emission and Auger process assistant green organic electrophosphorescence devices with very low doped level of iridium complex

Energy Technology Data Exchange (ETDEWEB)

Zhang Dongyu; Li Wenlian; Chu Bei; Li Xiao; Su Zisheng; Han Liangliang; Li Tianle; Chen Yiren; Yan Fei; Wu Shuanghong [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Zhang Zhiqiang; Hu Zhizhi [Organic Photoelectronic Materials and Technology Development Center, Liaoning University of Science and Technology, Anshan (China)], E-mail: wllioel@yahoo.com.cn, E-mail: beichu@163.com

2008-12-21

We demonstrate efficient and simple structure phosphorescence organic light-emitting diodes, in which 4, 4', 4''-tris[3-methyl-pheny(phenyl)-amino]triphenyl -amine (m-MTDATA) and 4,7-diphenyl-1,10-phenanthroline (Bphen) are used as hole transport and electron transport layers, respectively, accompanied by 3 wt% fac-tris(2-phenylpyridine) iridium doped in 1,3,5-tris(N-phenylbenzimidazol-2-yl)-benzene (Ir : TPBi) as the emitting layer. As a result, a 29 lm W{sup -1} peak power efficiency and 2.2 V turn-on voltage are achieved, respectively. The achievement of excellent electroluminescence (EL) properties was attributed to the contribution of exciplex formation at the interface of m-MTDATA/Ir : TPBi and the Auger-type two-step process of charge carrier injection. The competition between the interfacial exciplex and Ir-complex emissions in the EL processes was also discussed.

NAA of an iridium tracer to determine soot exposure of students commuting on Baltimore`s buses

Energy Technology Data Exchange (ETDEWEB)

Ondov, J.M.; Wu, C.C.; Lin, Zhibo; Kidwell, C.B. [Univ. of Maryland, College Park, MD (United States)

1997-12-01

Epidemiologic studies suggest that short-term increases in indices of particulate air pollution are associated with increased mortality and morbidity from respiratory and cardiovascular diseases. An important component of urban aerosol, diesel soot, is a known respiratory irritant and contains mutagenic and carcinogenic organic compounds. In the United States, motor vehicles are thought to be the largest single source of atmospheric soot and account for {approximately}36% of the annual anthropogenic emission of toxic polynuclear aromatic hydrocarbons (PAH). Much of the motor-vehicle-derived PAH originates from diesel-powered vehicles because their PAH emissions are up to 50-fold greater than those from gasoline engines. In Baltimore, city high school students take public buses to school and, often, must stand at bus stops while many diesel buses pass or stop before their own buses arrive. To estimate student exposures to soot emitted from public diesel buses (MTA) during commutes to city high schools, the Baltimore municipal fuel supply was tagged with an iridium tracer, and exposure was monitored during commutes with personal aerosol monitors as a part of the Baltimore Environmental Justice Project.

High-efficiency red-light emission from polyfluorenes grafted with cyclometalated iridium complexes and charge transport moiety.

Science.gov (United States)

Chen, Xiwen; Liao, Jin-Long; Liang, Yongmin; Ahmed, M O; Tseng, Hao-En; Chen, Show-An

2003-01-22

We report a new route for the design of electroluminescent polymers by grafting high-efficiency phosphorescent organometallic complexes as dopants and charge transport moieties onto alky side chains of fully conjugated polymers for polymer light-emitting diodes (PLED) with single layer/single polymers. The polymer system studied involves polyfluorene (PF) as the base conjugated polymer, carbazole (Cz) as the charge transport moiety and a source for green emission by forming an electroplex with the PF main chain, and cyclometalated iridium (Ir) complexes as the phosphorescent dopant. Energy transfer from the green Ir complex or an electroplex formed between the fluorene main chain and side-chain carbazole moieties, in addition to that from the PF main chain, to the red Ir complex can significantly enhance the device performance, and a red light-emitting device with the high efficiency 2.8 cd/A at 7 V and 65 cd/m2, comparable to that of the same Ir complex-based OLED, and a broad-band light-emitting device containing blue, green, and red peaks (2.16 cd/A at 9 V) are obtained.

New Therapeutic Agent against Arterial Thrombosis: An Iridium(III-Derived Organometallic Compound

Directory of Open Access Journals (Sweden)

Chih-Wei Hsia

2017-12-01

Full Text Available Platelet activation plays a major role in cardio and cerebrovascular diseases, and cancer progression. Disruption of platelet activation represents an attractive therapeutic target for reducing the bidirectional cross talk between platelets and tumor cells. Platinum (Pt compounds have been used for treating cancer. Hence, replacing Pt with iridium (Ir is considered a potential alternative. We recently developed an Ir(III-derived complex, [Ir(Cp*1-(2-pyridyl-3-(2-hydroxyphenylimidazo[1,5-a]pyridine Cl]BF4 (Ir-11, which exhibited strong antiplatelet activity; hence, we assessed the therapeutic potential of Ir-11 against arterial thrombosis. In collagen-activated platelets, Ir-11 inhibited platelet aggregation, adenosine triphosphate (ATP release, intracellular Ca2+ mobilization, P-selectin expression, and OH· formation, as well as the phosphorylation of phospholipase Cγ2 (PLCγ2, protein kinase C (PKC, mitogen-activated protein kinases (MAPKs, and Akt. Neither the adenylate cyclase inhibitor nor the guanylate cyclase inhibitor reversed the Ir-11-mediated antiplatelet effects. In experimental mice, Ir-11 prolonged the bleeding time and reduced mortality associated with acute pulmonary thromboembolism. Ir-11 plays a crucial role by inhibiting platelet activation through the inhibition of the PLCγ2–PKC cascade, and the subsequent suppression of Akt and MAPK activation, ultimately inhibiting platelet aggregation. Therefore, Ir-11 can be considered a new therapeutic agent against either arterial thrombosis or the bidirectional cross talk between platelets and tumor cells.

High Strain Rate Testing of Welded DOP-26 Iridium

Energy Technology Data Exchange (ETDEWEB)

Schneibel, J. H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, R. G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carmichael, C. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fox, E. E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ulrich, G. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); George, E. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-08-01

The iridium alloy DOP-26 is used to produce Clad Vent Set cups that protect the radioactive fuel in radioisotope thermoelectric generators (RTGs) which provide electric power for spacecraft and rovers. In a previous study, the tensile properties of DOP-26 were measured over a wide range of strain rates and temperatures and reported in ORNL/TM-2007/81. While that study established the properties of the base material, the fabrication of the heat sources requires welding, and the mechanical properties of welded DOP-26 have not been extensively characterized in the past. Therefore, this study was undertaken to determine the mechanical properties of DOP-26 specimens containing a transverse weld in the center of their gage sections. Tensile tests were performed at room temperature, 750, 900, and 1090°C and engineering strain rates of 1×10^-3 and 10 s^-1. Room temperature testing was performed in air, while testing at elevated temperatures was performed in a vacuum better than 1×10^-4 Torr. The welded specimens had a significantly higher yield stress, by up to a factor of ~2, than the non-welded base material. The yield stress did not depend on the strain rate except at 1090°C, where it was slightly higher for the faster strain rate. The ultimate tensile stress, on the other hand, was significantly higher for the faster strain rate at temperatures of 750°C and above. At 750°C and above, the specimens deformed at 1×10^-3 s^-1 showed pronounced necking resulting sometimes in perfect chisel-edge fracture. The specimens deformed at 10 s^-1 exhibited this fracture behavior only at the highest test temperature, 1090°C. Fracture occurred usually in the fusion zone of the weld and was, in most cases, primarily intergranular.

Synthesis of 2.5 nm colloidal iridium nanoparticles with strong surface enhanced Raman scattering activity

International Nuclear Information System (INIS)

Cui, Malin; Zhao, Yuan; Wang, Chan; Song, Qijun

2016-01-01

Colloidal iridium nanoparticles (IrNPs) were synthesized through an environmentally friendly approach by using trisodium citrate as the capping molecule in an aqueous medium. The resulting colloidal IrNPs have a typical diameter of 2.5 nm and display absorption bands at 250, 400 and 600 nm. They possess uniform morphology, good dispersibility, excellent stability in water, and exhibit strong surface enhanced Raman scattering (SERS) activity with an enhancement factor (EF) of 3.5 × 10 5 at the 1512 cm -1 peak when using Rhodamine 6G as the probe molecule. The excellent SERS performance of the IrNPs was exemplarily applied to the determination of the industrial colorant Sudan Red I. The peak intensity of the Raman band at 1236 cm -1 is linearly related to the concentration of Sudan Red I which can be determined by SERS in the 2 nM to 8 μM concentration range with a limit of detection as low as 0.6 nM. In our perception, this strong SERS activity of the IrNPs has a large potential in the SERS-based quantitation of various chemical substances. (author)

Solution and solid-state electrochemiluminescence of a fac-tris(2-phenylpyridyl)iridium(III)-cored dendrimer

International Nuclear Information System (INIS)

Reid, Ellen F.; Burn, Paul L.; Lo, Shih-Chun; Hogan, Conor F.

2013-01-01

The solution phase and solid-state electrochemistry and electrochemiluminescence (ECL) of an iridium(III) complex-cored dendrimeric analogue of Ir(ppy) 3 , (G1pIr), are reported. The solid-state electrochemistry and solid-state ECL of Ir(ppy) 3 itself is also described for the first time. In solution phase, the dendrimer displays greater immunity to oxygen quenching in photoluminescence (PL) experiments and exhibits greater ECL efficiency compared to the parent Ir(ppy) 3 core under the same conditions, despite a lower photoluminescence quantum yield. It is proposed that the dendrons which effectively shield the core from PL quenching interactions in the solid-state counteract the effects of parasitic side-reactions during the solution ECL experiments. Electroactive and ECL-active solid-state films of both Ir(ppy) 3 and G1pIr were produced by drop-coating on boron doped diamond electrodes. Films of Ir(ppy) 3 produced stable co-reactant ECL. However, films of G1pIr produced lower than expected ECL intensity. This was attributed to poorer charge transport and the lipophilicity of the film limiting the rate of interaction with the co-reactant required for formation of the excited state

Nanocomposites of iridium oxide and conducting polymers as electroactive phases in biological media.

Science.gov (United States)

Moral-Vico, J; Sánchez-Redondo, S; Lichtenstein, M P; Suñol, C; Casañ-Pastor, N

2014-05-01

Much effort is currently devoted to implementing new materials in electrodes that will be used in the central nervous system, either for functional electrostimulation or for tests on nerve regeneration. Their main aim is to improve the charge capacity of the electrodes, while preventing damaging secondary reactions, such as peroxide formation, occurring while applying the electric field. Thus, hybrids may represent a new generation of materials. Two novel hybrid materials are synthesized using three known biocompatible materials tested in the neural system: polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) (PEDOT) and iridium oxide (IrO2). In particular, PPy-IrO2 and PEDOT-IrO2 hybrid nanocomposite materials are prepared by chemical polymerization in hydrothermal conditions, using IrO2 as oxidizing agent. The reaction yields a significant ordered new hybrid where the conducting polymer is formed around the IrO2 nanoparticles, encapsulating them. Scanning electron microscopy and backscattering techniques show the extent of the encapsulation. Both X-ray photoelectron and Fourier transform infrared spectroscopies identify the components of the phases, as well as the absence of impurities. Electrochemical properties of the final phases in powder and pellet form are evaluated by cyclic voltammetry. Biocompatibility is tested with MTT toxicity tests using primary cultures of cortical neurons grown in vitro for 6 and 9days. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Radiation control in the intensive care unit for high intensity iridium-192 brain implants

International Nuclear Information System (INIS)

Sewchand, W.; Drzymala, R.E.; Amin, P.P.; Salcman, M.; Salazar, O.M.

1987-01-01

A bedside lead cubicle was designed to minimize the radiation exposure of intensive care unit staff during routine interstitial brain irradiation by removable, high intensity iridium-192. The cubicle shields the patient without restricting intensive care routines. The design specifications were confirmed by exposure measurements around the shield with an implanted anthropomorphic phantom simulating the patient situation. The cubicle reduces the exposure rate around an implant patient by as much as 90%, with the exposure level not exceeding 0.1 mR/hour/mg of radium-equivalent 192 Ir. Evaluation of data accumulated for the past 3 years has shown that the exposure levels of individual attending nurses are 0.12 to 0.36 mR/mg of radium-equivalent 192 Ir per 12-hour shift. The corresponding range for entire nursing teams varies between 0.18 and 0.26. A radiation control index (exposure per mg of radium-equivalent 192 Ir per nurse-hour) is thus defined for individual nurses and nursing teams; this index is a significant guide to the planning of nurse rotations for brain implant patients with various 192 Ir loads. The bedside shield reduces exposure from 192 Ir implants by a factor of about 20, as expected, and the exposure from the lower energy radioisotope iodine-125 is barely detectable

Preparation of Ti/IrO2 Anode with Low Iridium Content by Thermal Decomposition Process: Electrochemical removal of organic pollutants in water

Science.gov (United States)

Yaqub, Asim; Isa, Mohamed Hasnain; Ajab, Huma; Kutty, S. R. M.; Ezechi, Ezerie H.; Farooq, Robina

2018-04-01

In this study IrO2 (Iridium oxide) was coated onto a titanium plate anode from a dilute (50 mg/10 ml) IrCl3×H2O salt solution. Coating was done at high temperature (550∘C) using thermal decomposition. Surface morphology and characteristics of coated surface of Ti/IrO2 anode were examined by FESEM and XRD. The coated anode was applied for electrochemical removal of organic pollutants from synthetic water samples in 100 mL compartment of batch electrochemical cell. About 50% COD removal was obtained at anode prepared with low Ir content solution while 72% COD removal was obtained with anode prepared at high Ir content. Maximum COD removal was obtained at 10 mA/cm2 current density.

EKA tootedisaini üliõpilane...

Index Scriptorium Estoniae

2005-01-01

Eesti Kunstiakadeemia tootedisaini osakonna IV kursuse üliõpilane Riho Tiivel võitis Itaalias toimunud disainikonkursi "ReAL 13 - Eating Anywhere" peapreemia oma alumiiniumist lusikaga "Spoon Container"

2. XI esitles EKA aulas...

Index Scriptorium Estoniae

2005-01-01

Kunstidoktor Kärt Summatavet esitles oma raamatut "Folk Tradition and Artistic Inspiration. A Woman's Life in Traditional Estonian Jewelry and Crafts as Told by Anne and Roosi" ("Pärimus ja inspiratsioon. Kõnelusi Anne ja Roosiga naise elukaarest eesti pärimuslikus ehtekultuuris ning käsitöös". Raamat on Helsingi kunsti- ja disainiülikoolis kaitstud doktoritöö publikatsioon

11. X esitleti EKA raamatukogus...

Index Scriptorium Estoniae

2005-01-01

Esitleti artiklite kogumikku "Constructed Happiness. Domestic Environment in the Cold War Era/Võistlevad õnned. Elukeskkond külma sõja ajal", kuhu on koondatud 2004. a. kunstiteaduste instituudis peetud rahvusvahelise konverentsi materjalid

EKA e-meedia keskus korraldab...

Index Scriptorium Estoniae

2005-01-01

Adobe AfterEffects'i (algkursus 28.-31. III, 1. IV, registreerimine kuni 23. III, edasijõudnute kursus 22.-24. III, registreerimine kuni 18. III, juhendab Manuel Zadok Prantsusmaalt) ja Macromedia Flash'i (juhendab Raitis Smits Lätist) kursused

Strong ligand field effects of blue phosphorescent mono-cyclometalated iridium(III) complexes

International Nuclear Information System (INIS)

Ham, Ho Wan; Jung, Kyung Yoon; Kim, Young Sik

2010-01-01

A series of mono-cyclometalated blue phosphorescent iridium(III) complexes with two phosphines trans to each other and two cis-ancillary ligands, such as Ir(F 2 Meppy)(PPhMe 2 ) 2 (H)(Cl), [Ir(F 2 Meppy)(PPhMe 2 ) 2 (H)(NCMe)] + and Ir(F 2 Meppy)(PPhMe 2 ) 2 -(H)(CN), [F 2 Meppy = 2-(2',4'-difluorophenyl)-4-methyl-pyridine] were synthesized and studied to tune the phosphorescence wavelength to the deep blue region and to enhance the luminescence efficiencies. We investigate the electron-withdrawing capabilities of ancillary ligands using the DFT and TD-DFT calculations on the ground and excited states of the three complexes to gain insight into the factors responsible for the emission color change and the different luminescence efficiency. Reducing the molecular weight of phosphine ligand with PPhMe 2 leads to a strategy of the efficient deep blue organic light-emitting devices (OLED) by thermal processing instead of the solution processing. The electron-withdrawing difluoro group substituted on the phenyl ring and the cyano strong field ancillary ligand in the trans position to the carbon atom of phenyl ring increased HOMO-LUMO gap and achieved the hypsochromic shift in emission color. As a result, the maximum emission spectra of Ir(F 2 Meppy)(PPhMe 2 ) 2 (H)(Cl), [Ir(F 2 Meppy)(PPhMe 2 ) 2 (H)-(NCMe)] + and Ir(F 2 Meppy)(PPh-Me 2 ) 2 (H)(CN) were in the ranges of 446, 440, 439 nm, respectively.

Production of the sealed gamma-radiation sources of with iridium-192 radionuclide at the WWR-K research reactor

International Nuclear Information System (INIS)

Petukhov, V.K.; Chernayev, V.P.; Chabeyev, N.T.; Ermakov, E.L.; Chakrov, P.V.

2005-01-01

Full text: Conversion orientation of the WWR-K research reactor activity was established after renewal of its operation in 1997. A priority in reactor works was determined in the decision of tasks of practical use of nuclear technologies in a national economy in the next directions: in an industry, public health services and agriculture. The items of prime tasks: development and introduction of radiation technologies and manufacturing of radioisotopes for industry. This task included both scientific and technical program in the list of works of the Republican goals. At the WWR-K reactor within the framework of the this task solution the works on pilot production of the sealed sources of radioactive radiations (SSRR) with Ir-192 radionuclide for an industry of Republic of Kazakhstan were made. Organizational questions related to the Kazakhstan authority body and the regulating documentation were solved the first of all. The second stage was the development of the techniques of creating of devices providing an samples irradiation in reactor, control of sources sealing, measurements of the equivalent radiation doze from sources and high-quality support of SSRR manufacture over all technological way. At the third stage was made a little quantity SSRR with Ir-192 radionuclide, such as GIID-A1 (G6), for 'TEKOPS-660' Gammaray Projectors. This work served as experimental check of the decisions correctness, and has allowed to remove those lacks, to find out which it was possible only during direct manufacturing of radioactive sources. During performance of all these works the following was carried out: development and release of the documents and specifications regulating work on SSRR manufacture at the Institute of Nuclear Physics; personnel preparation and certification; preparation and equipment providing of reactor hot chambers by additional devices for work with irradiated iridium samples; development and manufacturing of the devices for iridium samples irradiation in

Red phosphorescent organic light-emitting diodes (PhOLEDs) based on a heteroleptic cyclometalated Iridium (III) complex

Energy Technology Data Exchange (ETDEWEB)

Lepeltier, Marc [Institut Lavoisier de Versailles, UMR 8180 CNRS, Université de Versailles Saint-Quentin en Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France); Dumur, Frédéric, E-mail: frederic.dumur@univ-amu.fr [Aix-Marseille Université, CNRS, ICR, UMR 7273, F-13397 Marseille (France); Wantz, Guillaume, E-mail: guillaume.wantz@ims-bordeaux.fr [University of Bordeaux, IMS, UMR 5218, F-33400 Talence (France); CNRS, IMS, UMR 5218, F-33400 Talence (France); Vila, Neus; Mbomekallé, Israel [Institut Lavoisier de Versailles, UMR 8180 CNRS, Université de Versailles Saint-Quentin en Yvelines, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France); Bertin, Denis; Gigmes, Didier [Aix-Marseille Université, CNRS, ICR, UMR 7273, F-13397 Marseille (France); Mayer, Cédric R., E-mail: cmayer@lisv.uvsq.fr [Laboratoire d’Ingénierie des Systèmes de Versailles LISV – EA 4048, Université de Versailles Saint Quentin en Yvelines, 10/12 avenue de l’Europe, 78140 Vélizy (France)

2013-11-15

Highly efficient red-emitting Phosphorescent Organic Light-Emitting Diodes (PhOLEDs) based on a neutral vacuum-sublimatable heteroleptic iridium (III) complex have been designed and studied. Heteroleptic complex Ir(piq){sub 2}(acac) was prepared in one step with acetylacetone (acac) as the ancillary ligand. Electronic and spectroscopic properties of Ir(piq){sub 2}(acac) were investigated by UV–visible absorption, fluorescence spectroscopy and cyclic voltammetry. Electrophosphorescent devices comprising Ir(piq){sub 2}(acac) as dopant of TCTA exhibited outstanding electroluminescence performance with a current efficiency of 10.0 cd A{sup −1}, a maximum power efficiency of 7.2 lm W{sup −1} and a maximal brightness of 3540 cd m{sup −2} was reached at 8.0 V. CIE coordinates close to the standard red of the national television system committee were obtained (0.67, 0.33). -- Highlights: • A saturated red OLED has been prepared. • High power efficiency and brightness were obtained. • Thickness of the device was determined as a parameter determining the overall performance. • CIE coordinates close to the standard red of the national television system committee were obtained.

Complexes of rhodium (I) and iridium (I) with mixed phosphorus-oxygen and phosphorus-nitrogen glands

International Nuclear Information System (INIS)

Meintjies, E.; Singleton, E.; Schmutzler, R.; Sell, M.

1985-01-01

A series of four- and five-coordinate rhodium(I) and iridium(I) complexes of the type [MCl(cod)L] and [M(COD)L 2 ] sup(+)[M = Rh or Ir;cod = cycloocta-1,5-diene; L = P(C 6 H 4 OMe-o) 3 ,PMe 2 (C 6 H 4 OMe-o), PPh 2 (C 6 H 4 OMe-o),PPh 2 -(C 6 H 4 NMe 2 -o),PMe(C 6 H 4 OMe-o) 2 and PPh 2 (C 6 H 4 OPr sup(i)-o)] have been prepared from the reactions of [(MCl(cod)) 2 ] (M = Rh or Ir) with the appropriate stoichiometric amount of L in diethyl ether or methanol solution. N.m.r. evidence ( 1 H and 13 C) is presented for non-chelation in the case of the ether ligands and chelation for the amine ligand. Thus, the complexes [MCl(cod)L](L = ether ligand) are mononuclear square-planar species, whereas the amine ligand chelates to the metal atom, and a distorted trigonal bipyramidal structure is proposed. Attempts at displacing cod from the complexes [MCl(cod)L] with these ether and amine ligands, or with small phosphines, were unsuccessful. However, treatment of [MCl(cod)[P(C 6 H 4 OMe-o) 3

Performance enhancement in organic photovoltaic solar cells using iridium (Ir) ultra-thin surface modifier (USM)

Science.gov (United States)

Pandey, Rina; Lim, Ju Won; Kim, Jung Hyuk; Angadi, Basavaraj; Choi, Ji Won; Choi, Won Kook

2018-06-01

In this study, Iridium (Ir) metallic layer as an ultra-thin surface modifier (USM) was deposited on ITO coated glass substrate using radio frequency magnetron sputtering for improving the photo-conversion efficiency of organic photovoltaic cells. Ultra-thin Ir acts as a surface modifier replacing the conventional hole transport layer (HTL) PEDOT:PSS in organic photovoltaic (OPV) cells with two different active layers P3HT:PC60BM and PTB7:PC70BM. The Ir USM (1.0 nm) coated on ITO glass substrate showed transmittance of 84.1% and work function of >5.0 eV, which is higher than that of ITO (4.5-4.7 eV). The OPV cells with Ir USM (1.0 nm) exhibits increased power conversion efficiency of 3.70% (for P3HT:PC60BM active layer) and 7.28% (for PTB7:PC70BM active layer) under 100 mW/cm2 illumination (AM 1.5G) which are higher than those of 3.26% and 6.95% for the same OPV cells but with PEDOT:PSS as HTL instead of Ir USM. The results reveal that the chemically stable Ir USM layer could be used as an alternative material for PEDOT:PSS in organic photovoltaic cells.

Accurate simulation of geometry, singlet-singlet and triplet-singlet excitation of cyclometalated iridium(III) complex.

Science.gov (United States)

Wang, Jian; Bai, Fu-Quan; Xia, Bao-Hui; Zhang, Hong-Xing; Cui, Tian

2014-03-01

In the current contribution, we present a critical study of the theoretical protocol used for the determination of the electronic spectra properties of luminescent cyclometalated iridium(III) complex, [Ir(III)(ppy)₂H₂dcbpy]⁺ (where, ppy = 2-phenylpyridine, H₂dcbpy = 2,2'-bipyridine-4,4'-dicarboxylic acid), considered as a representative example of the various problems related to the prediction of electronic spectra of transition metal complex. The choice of the exchange-correlation functional is crucial for the validity of the conclusions that would be drawn from the numerical results. The influence of the exchange-correlation on geometry parameter and absorption/emission band, the role of solvent effects on time-dependent density function theory (TD-DFT) calculations, as well as the importance of the chosen proper procedure to optimize triplet excited geometry, have been thus examined in detail. From the obtained results, some general conclusions and guidelines are presented: i) PBE0 functional is the most accurate in prediction of ground state geometry; ii) the well-established B3LYP, B3P86, PBE0, and X3LYP have similar accuracy in calculation of absorption spectrum; and iii) the hybrid approach TD-DFT//CIS gives out excellent agreement in the evaluation of triplet excitation energy.

Iridium concentration and noble gas composition of Cretaceous-Tertiary boundary clay from Stevens Klint, Denmark

International Nuclear Information System (INIS)

Osawa, Takahito; Hatsukawa, Yuichi; Nagao, Keisuke; Koizumi, Mitsuo; Oshima, Masumi; Toh, Yosuke; Kimura, Atsushi; Furutaka, Kazuyoshi

2009-01-01

The Cretaceous-Tertiary (K-T) boundary about 65 million years ago records a mass extinction event caused by a bolide impact. K-T boundary clay collected from Stevns Klint, Denmark was investigated in this work. Iridium concentrations of eight clays across the K-T boundary were determined using a multiple gamma-ray analysis system after neutron activation. Anomalously high Ir concentrations were detected in five marl samples, with the highest concentration being 29.9 ppb. Four samples were analyzed for all noble gases. NO extraterrestrial Ar, Kr, and Xe were discovered in any of the samples, although most of the 3 He which was detected was extraterrestrial. Solar-like Ne was observed only in the sample SK4, which had an Ir concentration of 14.3 ppb, indicating the presence of micrometeorites. The solar-like Ne clearly did not originate from an asteroid/comet associated with the bolide impact, as that asteroid is thought to have been extremely large. Also, because there was no sign of a high accretion rate of micrometeorites at the boundary it could not be ascertained whether the solar-like Ne was related to a catastrophic event that led to the extinction of the dinosaurs. (author)

Luminescent cyclometalated iridium(III) polypyridine indole complexes--synthesis, photophysics, electrochemistry, protein-binding properties, cytotoxicity, and cellular uptake.

Science.gov (United States)

Lau, Jason Shing-Yip; Lee, Pui-Kei; Tsang, Keith Hing-Kit; Ng, Cyrus Ho-Cheong; Lam, Yun-Wah; Cheng, Shuk-Han; Lo, Kenneth Kam-Wing

2009-01-19

A series of luminescent cyclometalated iridium(III) polypyridine indole complexes, [Ir(N--C)(2)(N--N)](PF(6)) (HN--C = 2-phenylpyridine (Hppy), N--N = 4-((2-(indol-3-yl)ethyl)aminocarbonyl)-4'-methyl-2,2'-bipyridine (bpy-ind) (1a), N--N = 4-((5-((2-(indol-3-yl)ethyl)aminocarbonyl)pentyl)aminocarbonyl)-4'-methyl-2,2'-bipyridine (bpy-C6-ind) (1b); HN--C = 7,8-benzoquinoline (Hbzq), N--N = bpy-ind (2a), N--N = bpy-C6-ind (2b); and HN--C = 2-phenylquinoline (Hpq), N--N = bpy-ind (3a), N--N = bpy-C6-ind (3b)), have been synthesized, characterized, and their photophysical and electrochemical properties and lipophilicity investigated. Photoexcitation of the complexes in fluid solutions at 298 K and in alcohol glass at 77 K resulted in intense and long-lived luminescence (lambda(em) = 540-616 nm, tau(o) = 0.13-5.15 mus). The emission of the complexes has been assigned to a triplet metal-to-ligand charge-transfer ((3)MLCT) (dpi(Ir) --> pi*(N--N)) excited state, probably with some mixing of triplet intraligand ((3)IL) (pi --> pi*) (pq) character for complexes 3a,b. Electrochemical measurements revealed that all the complexes showed an irreversible indole oxidation wave at ca. +1.1 V versus SCE, a quasi-reversible iridium(IV/III) couple at ca. +1.3 V, and a reversible diimine reduction couple at ca. -1.3 V. The interactions of these complexes with an indole-binding protein, bovine serum albumin (BSA), have been studied by emission titrations, and the K(a) values are on the order of 10(4) M(-1). Additionally, the cytotoxicity of the complexes toward human cervix epithelioid carcinoma (HeLa) cells has been examined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. The IC(50) values of the complexes ranged from 1.1 to 6.3 microM, which are significantly smaller than that of cisplatin (30.7 microM) under the same experimental conditions. Furthermore, the cellular uptake of the complexes has been investigated by flow cytometry and laser

Trapping interference effects of arsenic, antimony and bismuth hydrides in collection of selenium hydride within iridium-modified transversally-heated graphite tube atomizer

Energy Technology Data Exchange (ETDEWEB)

Furdikova, Zuzana [Department of Environmental Chemistry and Technology, Faculty of Chemistry, Brno University of Technology, Purkynova 118, CZ-61200 Brno (Czech Republic); Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic v.v.i., Veveri 97, CZ-60200, Brno (Czech Republic); Docekal, Bohumil [Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic v.v.i., Veveri 97, CZ-60200, Brno (Czech Republic)], E-mail: docekal@iach.cz

2009-04-15

Interference effects of co-generated hydrides of arsenic, antimony and bismuth on trapping behavior of selenium hydride (analyte) within an iridium-modified, transversely heated graphite tube atomizer (THGA) were investigated. A twin-channel hydride generation system was used for independent separate generation and introduction of analyte and interferent hydrides, i.e. in a simultaneous and/or sequential analyte-interferent and interferent-analyte mode of operation. The influence of the analyte and modifier mass, interferent amount, trapping temperature and composition of the gaseous phase was studied. A simple approach for the elimination of mutual interference effects by modification of the gaseous phase with oxygen in a substoichiometric ratio to chemically generated hydrogen is proposed and the suppression of these interference effects is demonstrated. A hypothesis on the mechanism of trapping and mutual interference effects is drawn.

Study of electrocatalytic properties of iridium carbonyl cluster and rhodium carbonyl cluster compounds for the oxygen reduction and hydrogen oxidation reactions in 0.5 MH{sub 2}SO{sub 4} in presence and absence of methanol and carbon monoxide, respectively

Energy Technology Data Exchange (ETDEWEB)

Uribe-Godinez, J.; Borja-Arco, E.; Castellanos, R.H. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Escobedo (Mexico); Jimenez-Sandoval, O. [Centro de Investigacion y de Estudios Avanzados del Inst. Politecnico Nacional, Querataro (Mexico)

2006-07-01

The suitability of carbonyl cluster compounds as a substitute to platinum (Pt) in fuel cell catalysts was investigated. Iridium (Ir{sub 4}(CO){sub 12} and rhodium (Rh{sub 6}(CO){sub 116}) cluster compounds were investigated as potential new electrocatalysts for oxygen reduction reaction (ORR) in the presence and absence of methanol at different concentrations, as well as for the hydrogen oxidation reaction (HOR) with pure hydrogen and a hydrogen/carbon monoxide mixture. The materials were studied using room temperature rotating disk electrode (RDE) measurements and cyclic and linear sweep voltammetry techniques (LSV). Tafel slope and exchange current density were calculated using the LSV polarization curves. Cyclic voltamperometry results suggested that the electrocatalysts were tolerant to methanol. However, electrochemical behaviour of the materials altered in the presence of CO, and peaks corresponding to CO oxidation were observed in both cases. The rhodium carbonyl showed a higher current density for the ORR than the iridium carbonyl. The current potential curves in the presence of methanol were similar to those obtained without methanol. Results confirmed the tolerance properties of the materials to perform the ORR. Decreased current density values were observed during HOR, and were attributed to changes in the hydrogen solubility and diffusion coefficient due to the presence of CO. The Tafel slopes indicated that the mechanics of the HOR were Heyrovsky-Volmer. Results showed that the materials are capable of performing both ORR and HOR in an acid medium. It was noted that the iridium carbonyl cluster followed a 4-electron transfer mechanism towards the formation of water. It was concluded that the compounds are suitable for use as both cathodes and anodes in proton exchange membrane fuel cells (PEMFCs) and as cathodes in direct methanol fuel cells (DMFCs). 3 refs., 2 tabs., 3 figs.

Rohelised koridorid: Raekoda maastikus = Green corridors: Town Hall in landscape / Kristiina Remmelkoor

Index Scriptorium Estoniae

Remmelkoor, Kristiina

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahendus, kus Admiraliteedi bassein koos uue raekojahoonega saavad osaks suurest avalikust pargist

Lävimine: aatrium kommunikatsiooni loojana = Interaction: atrium as generator of communication / Maie Raud, Anni Haldre

Index Scriptorium Estoniae

Raud, Maie

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahendus, kus aatrium on konstruktiivne, logistiline ja infovahetuse sõlmpunkt raekoja hoones

Sulandumine: brändimaastik = Blending in: brandscape / Artur Staškevitš

Index Scriptorium Estoniae

Staškevitš, Artur

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahendus koosneb kolmest selgest arhitektuursest ja ehituslikust mahust, mis sujuvalt linnakeskkonda sulanduvad

Eriilmeline Tallinn: identiteetide paljususe soodustamine = Diverse Tallinn: fostering diversity of identities / Alvin Järving, Marten Kaevats, Kadri Klementi...[jt.

Index Scriptorium Estoniae

2010-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna IV kursuse 2009-2010 õppeaastal uuritakse linnaehituslikke probleeme. Tallinna linna visioonidest. Iga linnaasum vajab omale tugevat identiteeti. Kodukant kui linnaruumi tasand

Ars longa vita brevis / Endrik Mänd

Index Scriptorium Estoniae

Mänd, Endrik, 1972-

2011-01-01

EKA uue hoone ehitusloa menetlemisega seotud pöördumisest Tallinna Linnaplaneerimise Ametile. Linn represseerivat kinnisvaraomanikku, sest viimane ei nõustu kooskõlastama Eesti Kunstiakadeemia ehitusluba

Väljak: esindusväljak = Square: the city square / Merilin Jürimets

Index Scriptorium Estoniae

Jürimets, Merilin

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahendus,kus strateegilises asukohas olev raekoda avab tänavapinna maksimaalselt avalikkusele

Strong ligand field effects of blue phosphorescent mono-cyclometalated iridium(III) complexes

Energy Technology Data Exchange (ETDEWEB)

Ham, Ho Wan [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Jung, Kyung Yoon [International Design School for Advanced Studies, Hongik University, Seoul 121-791 (Korea, Republic of); Kim, Young Sik, E-mail: youngkim@hongik.ac.k [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of)

2010-09-01

A series of mono-cyclometalated blue phosphorescent iridium(III) complexes with two phosphines trans to each other and two cis-ancillary ligands, such as Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}(H)(Cl), [Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}(H)(NCMe)]{sup +} and Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}-(H)(CN), [F{sub 2}Meppy = 2-(2',4'-difluorophenyl)-4-methyl-pyridine] were synthesized and studied to tune the phosphorescence wavelength to the deep blue region and to enhance the luminescence efficiencies. We investigate the electron-withdrawing capabilities of ancillary ligands using the DFT and TD-DFT calculations on the ground and excited states of the three complexes to gain insight into the factors responsible for the emission color change and the different luminescence efficiency. Reducing the molecular weight of phosphine ligand with PPhMe{sub 2} leads to a strategy of the efficient deep blue organic light-emitting devices (OLED) by thermal processing instead of the solution processing. The electron-withdrawing difluoro group substituted on the phenyl ring and the cyano strong field ancillary ligand in the trans position to the carbon atom of phenyl ring increased HOMO-LUMO gap and achieved the hypsochromic shift in emission color. As a result, the maximum emission spectra of Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}(H)(Cl), [Ir(F{sub 2}Meppy)(PPhMe{sub 2}){sub 2}(H)-(NCMe)]{sup +} and Ir(F{sub 2}Meppy)(PPh-Me{sub 2}){sub 2} (H)(CN) were in the ranges of 446, 440, 439 nm, respectively.

Laminar iridium coating produced by pulse current electrodeposition from chloride molten salt

Energy Technology Data Exchange (ETDEWEB)

Zhu, Li’an, E-mail: mr_zla@163.com; Bai, Shuxin; Zhang, Hong; Ye, Yicong

2013-10-01

Due to the unique physical and chemical properties, Iridium (Ir) is one of the most promising oxidation-resistant coatings for refractory materials above 1800 °C in aerospace field. However, the Ir coatings prepared by traditional methods are composed of columnar grains throughout the coating thickness. The columnar structure of the coating is considered to do harm to its oxidation resistance. The laminar Ir coating is expected to have a better high-temperature oxidation resistance than the columnar Ir coating does. The pulse current electrodeposition, with three independent parameters: average current density (J{sub m}), duty cycle (R) and pulse frequency (f), is considered to be a promising method to fabricate layered Ir coating. In this study, laminar Ir coatings were prepared by pulse current electrodeposition in chloride molten salt. The morphology, roughness and texture of the coatings were determined by scanning electron microscope (SEM), profilometer and X-ray diffraction (XRD), respectively. The results showed that the laminar Ir coatings were composed of a nucleation layer with columnar structure and a growth layer with laminar structure. The top surfaces of the laminar Ir coatings consisted of cauliflower-like aggregates containing many fine grains, which were separated by deep grooves. The laminar Ir coating produced at the deposition condition of 20 mA/cm{sup 2} (J{sub m}), 10% (R) and 6 Hz (f) was quite smooth (R{sub a} 1.01 ± 0.09 μm) with extremely high degree of preferred orientation of 〈1 1 1〉, and its laminar structure was well developed with clear boundaries and uniform thickness of sub-layers.

Täna kell 14 avatakse Eesti Kunstiakadeemias...

Index Scriptorium Estoniae

2002-01-01

Avatakse mälestustahvel (autor Mare Mikof) EKA keraamikaosakonna asutajale Géza Jak̤le. Janos Probstnerilt ettekanne G. Jak̤ tegevusest, ungari kaasegsest keraamikast ja Kecskemeti keraamikastuudiost

Sulandumine: jalajälg = Blending in: the footprint / Anni Haldre, Marilin Tuulemets

Index Scriptorium Estoniae

Haldre, Anni, 1990-

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahendus raekojale, kus vormimäärajaks sai olemasoleva krundi maksimaalne mahuline ärakasutamine

On the determination of iridium in diverse geological samples employing HPGe-coincidence/NaI(Tl)-anticoincidence spectrometry

Science.gov (United States)

Murali, A. V.; Parekh, P. P.; Cumming, J. B.

1990-01-01

This paper reports the Ir content of a variety of geological samples determined by the high-purity Ge-coincidence/NaI(Tl)-anticoincidence gamma-ray spectrometry (henceforth referred to as coincidence/anticoincidence technique) and by the conventional INAA. The advantages of this technique are: (1) the Ir content of the samples is obtained (ppm to a fraction of ppb ranges) not only by the 468.1 keV peak as in the conventional INAA but also by the 784.6 keV and 920.9 keV sum peaks, which gives more confidence in the values obtained; and (2) it is well suited for the samples with high Compton background for which it is difficult to measure the Ir content by the conventional INAA technique. The practical sensitivity of this technique depends on the sample matrix. Under present experimental conditions, it varied from 0.1 ng for Mn nodules and 0.004 ng for Libyan Desert Glass. Iridium values obtained on small (about 1 microg) olivine grains demonstrate the potential application of this new technique to microsamples. The principle and methodology of this new technique as well as its advantages and disadvantages over the conventional INAA are discussed.

Development of a new osmium-191: Iridium-191m radionuclide generator: Final report

International Nuclear Information System (INIS)

Treves, S.; Packard, A.B.

1986-01-01

The use of iridium-191m (T/sub 1/2/ = 5s) for first-pass radionuclide angiography offers the potential advantages of lower patient radiation dose and the ability to obtain repeated studies without interference from the previously administered radioisotope. These potential advantages have been offset by the absence of satisfactory 191 Os-/sup 191m/Ir generators. The goal of this project was, therefore, the development of an 191 Os-/sup 191m/Ir generator that would be suitable for clinical use. This goal was first sought through modifications of an existing 191 Os-/sup 191m/Ir generator design (i.e., changes in the ion exchange material and eluent) but these changes did not lead to the required improvements. A new approach was then undertaken in which different chemical forms of the 191 Os parent were evaluated in prototype generators. The complex trans-dioxobisoxalatoosmate (VI) led to a generator with higher /sup 191m/Ir yield (25 to 30%/mL) and lower 191 Os breakthrough ( -4 %) with a more physiologically compatible eluent than had been previously achieved. Toxicity studies were conducted on the eluate and an IND subsequently obtained. While this is not a final solution to the problem of developing a clinically acceptable 191 Os-/sup 191m/Ir generator, the ''oxalate'' generator is the most significant improvement of the 191 Os-/sup 191m/Ir generator to date and will be used in an expanded program of clinical studies. 16 refs., 16 tabs

Determination of platinum, palladium, iridium and gold on selected geological reference materials by radiochemical neutron activation analysis: comparison of procedures based on aqua regia leaching and sodium peroxide sintering

International Nuclear Information System (INIS)

Nogueira, C.A.; Figueiredo, A.M.G.

1995-01-01

A rapid and sensitive neutron activation method for the determination of platinum, palladium, iridium and gold in rocks is described. The procedure consists of thermal neutron irradiation of about 250 mg of sample, followed by chemical treatment of the rock, precipitation of gold and the platinum group elements with tellurium and high-resolution gamma-ray spectrometry with a hyper-pure Ge detector. Two different methods were used for the chemical treatment of the rock: aqua regia leaching and sintering with sodium peroxide. The procedures were evaluated by analysis of the certified reference material SARM-7 and the reference material CHR-Pt+. (author)

Determination of platinum, palladium, iridium and gold on selected geological reference materials by radiochemical neutron activation analysis: comparison of procedures based on aqua regia leaching and sodium peroxide sintering

Energy Technology Data Exchange (ETDEWEB)

Nogueira, C.A.; Figueiredo, A.M.G. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

1995-05-01

A rapid and sensitive neutron activation method for the determination of platinum, palladium, iridium and gold in rocks is described. The procedure consists of thermal neutron irradiation of about 250 mg of sample, followed by chemical treatment of the rock, precipitation of gold and the platinum group elements with tellurium and high-resolution gamma-ray spectrometry with a hyper-pure Ge detector. Two different methods were used for the chemical treatment of the rock: aqua regia leaching and sintering with sodium peroxide. The procedures were evaluated by analysis of the certified reference material SARM-7 and the reference material CHR-Pt+. (author).

Thermal stability of pulsed laser deposited iridium oxide thin films at low oxygen atmosphere

Science.gov (United States)

Gong, Yansheng; Wang, Chuanbin; Shen, Qiang; Zhang, Lianmeng

2013-11-01

Iridium oxide (IrO2) thin films have been regarded as a leading candidate for bottom electrode and diffusion barrier of ferroelectric capacitors, some process related issues need to be considered before integrating ferroelectric capacitors into memory cells. This paper presents the thermal stability of pulsed laser deposited IrO2 thin films at low oxygen atmosphere. Emphasis was given on the effect of post-deposition annealing temperature at different oxygen pressure (PO2) on the crystal structure, surface morphology, electrical resistivity, carrier concentration and mobility of IrO2 thin films. The results showed that the thermal stability of IrO2 thin films was strongly dependent on the oxygen pressure and annealing temperature. IrO2 thin films can stably exist below 923 K at PO2 = 1 Pa, which had a higher stability than the previous reported results. The surface morphology of IrO2 thin films depended on PO2 and annealing temperature, showing a flat and uniform surface for the annealed films. Electrical properties were found to be sensitive to both the annealing temperature and oxygen pressure. The room-temperature resistivity of IrO2 thin films with a value of 49-58 μΩ cm increased with annealing temperature at PO2 = 1 Pa. The thermal stability of IrO2 thin films as a function of oxygen pressure and annealing temperature was almost consistent with thermodynamic calculation.

Admiraliteedi bassein: tühermaa = Admirality basin: wasteland / Kaisa Lillemets

Index Scriptorium Estoniae

Lillemets, Kaisa, 1986-

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodava raekoja asukohana valitud Admiraliteedi basseini äärse ümbruse kirjeldus Kaisa Lillemetsa planšetilt

Tavasti stipendium = Tavast scholarship

Index Scriptorium Estoniae

2014-01-01

Ennesõjaaegse Eesti tuntuima juveelitöösturi Roman Tavasti poja Raul-Roman Tavasti 1998. aastal asutatud stipendium professionaalse ehtekunsti järelkasvu toetamiseks EKA ehtekunsti eriala üliõpilastele

Testing of electroformed deposited iridium/powder metallurgy rhenium rockets

Science.gov (United States)

Reed, Brian D.; Dickerson, Robert

1996-01-01

High-temperature, oxidation-resistant chamber materials offer the thermal margin for high performance and extended lifetimes for radiation-cooled rockets. Rhenium (Re) coated with iridium (Ir) allow hours of operation at 2200 C on Earth-storable propellants. One process for manufacturing Ir/Re rocket chambers is the fabrication of Re substrates by powder metallurgy (PM) and the application of Ir coatings by using electroformed deposition (ED). ED Ir coatings, however, have been found to be porous and poorly adherent. The integrity of ED Ir coatings could be improved by densification after the electroforming process. This report summarizes the testing of two 22-N, ED Ir/PM Re rocket chambers that were subjected to post-deposition treatments in an effort to densify the Ir coating. One chamber was vacuum annealed, while the other chamber was subjected to hot isostatic pressure (HIP). The chambers were tested on gaseous oxygen/gaseous hydrogen propellants, at mixture ratios that simulated the oxidizing environments of Earth-storable propellants. ne annealed ED Ir/PM Re chamber was tested for a total of 24 firings and 4.58 hr at a mixture ratio of 4.2. After only 9 firings, the annealed ED Ir coating began to blister and spall upstream of the throat. The blistering and spalling were similar to what had been experienced with unannealed, as-deposited ED Ir coatings. The HIP ED Ir/PM Re chamber was tested for a total of 91 firings and 11.45 hr at mixture ratios of 3.2 and 4.2. The HIP ED Ir coating remained adherent to the Re substrate throughout testing; there were no visible signs of coating degradation. Metallography revealed, however, thinning of the HIP Ir coating and occasional pores in the Re layer upstream of the throat. Pinholes in the Ir coating may have provided a path for oxidation of the Re substrate at these locations. The HIP ED Ir coating proved to be more effective than vacuum annealed and as-deposited ED Ir. Further densification is still required to

Väljak: siseväljak = Square: inner plaza / Kristi Tuurmann, Tiia Vahula, Riin Kersalu, Kerstin Kivila

Index Scriptorium Estoniae

Tuurmann, Kristi

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahendus, kus ei teki raekoja ette traditsioonilist väljakut, pigem "kolib" see avaliku ruumina linnavalitsuse sisse

Mitochondria-targeting cyclometalated iridium(III)-PEG complexes with tunable photodynamic activity.

Science.gov (United States)

Li, Steve Po-Yam; Lau, Chris Tsan-Shing; Louie, Man-Wai; Lam, Yun-Wah; Cheng, Shuk Han; Lo, Kenneth Kam-Wing

2013-10-01

We present a new class of phosphorescent cyclometalated iridium(III) polypyridine poly(ethylene glycol) (PEG) complexes [Ir(N(^)C)2(bpy-CONH-PEG)](PF6) (bpy-CONH-PEG = 4-(N-(2-(ω-methoxypoly-(1-oxapropyl))ethyl)aminocarbonyl)-4'-methyl-2,2'-bipyridine, number average molecular weight (Mn) = 5272.23, weight average molecular weight (Mw) = 5317.38, polydispersity index (PDI) = 1.009; HN(^)C = 2-phenylpyridine, Hppy (1a), 2-((1,1'-biphenyl)-4-yl)pyridine, Hpppy (2a), 2-phenylquinoline, Hpq (3a), 2-phenylbenzothiazole, Hbt (4a), 2-(1-naphthyl)benzothiazole, Hbsn (5a)). The photophysical, photochemical, and biological properties of these complexes have been compared with those of their PEG-free counterparts [Ir(N(^)C)2(bpy-CONH-Et)](PF6) (bpy-CONH-Et = 4-(N-ethylaminocarbonyl)-4'-methyl-2,2'-bipyridine; HN(^)C = Hppy (1b), Hpppy (2b), Hpq (3b), Hbt (4b), Hbsn (5b)). Upon irradiation, all the complexes exhibited intense and long-lived green to orange-red emission under ambient conditions. The emission was phosphorescence in nature and can be quenched by O2 with the generation of singlet oxygen ((1)O2). The quantum yields for (1)O2 production of the complexes in aerated DMSO (0.24-0.83) were found to be dependent on the excited-state lifetimes of the complexes, which can be altered using different cyclometalating ligands (N(^)C). Cell-based assays indicated that the PEG complexes were noncytotoxic in the dark (IC50 > 300 μM); however, most of them became significantly cytotoxic upon irradiation (IC50 = 3.4 - 23.2 μM). Laser-scanning confocal microscopy images revealed localization of complex 3a in the mitochondrial region of HeLa cells and the induction of rapid necrotic cell death upon light activation. Additionally, the lack of dark toxicity and potential application of the PEG complexes as a visualizing reagent have been demonstrated using zebrafish (Danio rerio) as an animal model. Copyright © 2013 Elsevier Ltd. All rights reserved.

Aed: ajastatud = Garden: timed / Eve Komp

Index Scriptorium Estoniae

Komp, Eve, 1982-

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahenduses on iga avalik ruum ümber raekoja hoone kujundatud erinevalt, vastavalt päeva rütmile

Väljak: satelliitväljakud = Square: satellite squares / Siim Tiisvelt

Index Scriptorium Estoniae

Tiisvelt, SIim, 1987-

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahendus, kus uue raekoja linnaehituslik idee lähtub antud piirkonnas ruumiliselt kõige domineerivamast elemendist - Admiraliteedi basseinist

Reprogramming of rabbit induced pluripotent stem cells toward epiblast and chimeric competency using Krüppel-like factors

Directory of Open Access Journals (Sweden)

Yann Tapponnier

2017-10-01

Full Text Available Rabbit induced pluripotent stem cells (rbiPSCs possess the characteristic features of primed pluripotency as defined in rodents and primates. In the present study, we reprogrammed rbiPSCs using human Krüppel-like factors (KLFs 2 and 4 and cultured them in a medium supplemented with fetal calf serum and leukemia inhibitory factor. These cells (designated rbEKA were propagated by enzymatic dissociation for at least 30 passages, during which they maintained a normal karyotype. This new culturing protocol resulted in transcriptional and epigenetic reconfiguration, as substantiated by the expression of transcription factors and the presence of histone modifications associated with naïve pluripotency. Furthermore, microarray analysis of rbiPSCs, rbEKA cells, rabbit ICM cells, and rabbit epiblast showed that the global gene expression profile of the reprogrammed rbiPSCs was more similar to that of rabbit ICM and epiblast cells. Injection of rbEKA cells into 8-cell stage rabbit embryos resulted in extensive colonization of ICM in 9% early-blastocysts (E3.5, epiblast in 10% mid-blastocysts (E4.5, and embryonic disk in 1.4% pre-gastrulae (E6. Thus, these results indicate that KLF2 and KLF4 triggered the conversion of rbiPSCs into epiblast-like, embryo colonization-competent PSCs. Our results highlight some of the requirements to achieve bona fide chimeric competency.

Rohelised koridorid: vöö = Green corridors: the belt / Kaisa Lillemets

Index Scriptorium Estoniae

Lillemets, Kaisa, 1986-

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahenduse põhiideeks on kaks teistest eristuvat hoonet (raekoda ja sadam), mis ühendavad basseini ja rohevöö

Kas sent või sant? / Riin Kübarsepp

Index Scriptorium Estoniae

Kübarsepp, Riin, 1978-

2000-01-01

Silja Saarepuu näitusest "Sent" Tallinna Linnagaleriis, kerjuste piltidest Von Krahli teari akendel ja kerjuste kujutistega plakatitest reklaamtulpadel. Võrdluseks EKA graafikatudengi Elisabeth Salmini grafititest sõnumiga "Sa oled aus, tark ja seksikas".

Struktuur eri pikkusskaaladel = Structure on different length-scales / Salmaan Craig, Martin Melioranski

Index Scriptorium Estoniae

Craig, Salmaan

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonnaõppejõu Martin Melioranski vestluskaaslane Salmaan Craig on Harvard Graduate School of Design külalislektor ja töötab ühtlasi arhitektuuribüroos Foster + Partners

Sadama ala planeering = Harbour area master plan / Ivan Sergejev, Helen Rebane, Karina Niinepuu

Index Scriptorium Estoniae

Sergejev, Ivan, 1987-

2010-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna IV kursuse 2009-2010 õppeaastal erialase projekteerimise raames kavandatud planeeringu eesmärgiks on tihendada Tallinna sadama ala ning arendada sellest välja mitmekesine ja efektiivne linnaruum

A contribution to the search for the element 114 in nature

International Nuclear Information System (INIS)

McMinn, J.

1975-09-01

Starting from a lead ore having an age of 1.3 x 10 9 years, an already chemically pre-enriched material up to a factor of about 2 to 3 x 10 8 was available for the search of the element 114 based on the properties predicted for eka lead. A further physical enrichment was undertaken using the Juelich high performance electromagnetic isotope separator. The exposed target material (synthetic quartz glass plates)in the mass range 278 to 290 in the mass separator was irradiated with thermal neutrons and the fission tracks were counted under an optical microscope. The background due to fissionable impurities in the quartz ( -13 atoms per SiO 2 molecule) and that due to the use of the mass separator were studied in preliminary experiments. The possible escape of the presumably volatile element 114 from the fission track detectors during irradiation as a result of nuclear γ-heating was also investigated in simulation experiments. The diffusion behaviour of carrier-free 203 Hg implanted into quartz plates in the mass separator, as determined by a radiometric analysis, showed that the expected losses are negligible below 200 0 C. The counting results from the fission track detectors gave a maximum value of 5.1 x 10 -22 barns for the product of the fission cross section sigmasub(f) and the number of eka-lead atoms per lead carrier atom. In order to be able to make an estimate of the absolute concentration limits, the fission cross sections of eka-lead for thermal neutrons were approximated using an extrapolation method. Assuming these approximate fission cross sections, the absolute concentration limits of 8 x 10sup(-24), 3 x 10 -22 and 1 x 10 -19 share of eka-lead atoms per carrier atom were obtained for the isotopes 295, 297 and 298 (sigma = 70 barns, 2 barns and 4 gbarns). (orig./LH) [de

Determination of the tissue inhomogeneity correction in high dose rate Brachytherapy for Iridium-192 source

Directory of Open Access Journals (Sweden)

Barlanka Ravikumar

2012-01-01

Full Text Available In Brachytherapy treatment planning, the effects of tissue heterogeneities are commonly neglected due to lack of accurate, general and fast three-dimensional (3D dose-computational algorithms. In performing dose calculations, it is assumed that the tumor and surrounding tissues constitute a uniform, homogeneous medium equivalent to water. In the recent past, three-dimensional computed tomography (3D-CT based treatment planning for Brachytherapy applications has been popularly adopted. However, most of the current commercially available planning systems do not provide the heterogeneity corrections for Brachytherapy dosimetry. In the present study, we have measured and quantified the impact of inhomogeneity caused by different tissues with a 0.015 cc ion chamber. Measurements were carried out in wax phantom which was employed to measure the heterogeneity. Iridium-192 (192 Ir source from high dose rate (HDR Brachytherapy machine was used as the radiation source. The reduction of dose due to tissue inhomogeneity was measured as the ratio of dose measured with different types of inhomogeneity (bone, spleen, liver, muscle and lung to dose measured with homogeneous medium for different distances. It was observed that different tissues attenuate differently, with bone tissue showing maximum attenuation value and lung tissue resulting minimum value and rest of the tissues giving values lying in between those of bone and lung. It was also found that inhomogeneity at short distance is considerably more than that at larger distances.

SISU sümpoosion Ruumimõju = The Impact of Space / Tüüne-Kristin Vaikla

Index Scriptorium Estoniae

Vaikla, Tüüne-Kristin, 1961-

2015-01-01

Eesti Sisearhitektide Liit koos EKA sisearhitektuuri osakonnaga korraldas 27.-30. mail Tallinnas rahvusvahelise sümpoosioni "Sisu. Ruumimõju / The Impact of Space, kus kohtusid sisearhitektuuri valdkonna tunnustatud teoreetikud ja praktikud üle maailma

Cross section of α-induced reactions on iridium isotopes obtained from thick target yield measurement for the astrophysical γ process

Directory of Open Access Journals (Sweden)

T. Szücs

2018-01-01

Full Text Available The stellar reaction rates of radiative α-capture reactions on heavy isotopes are of crucial importance for the γ process network calculations. These rates are usually derived from statistical model calculations, which need to be validated, but the experimental database is very scarce. This paper presents the results of α-induced reaction cross section measurements on iridium isotopes carried out at first close to the astrophysically relevant energy region. Thick target yields of 191Ir(α,γ195Au, 191Ir(α,n194Au, 193Ir(α,n196mAu, 193Ir(α,n196Au reactions have been measured with the activation technique between Eα=13.4 MeV and 17 MeV. For the first time the thick target yield was determined with X-ray counting. This led to a previously unprecedented sensitivity. From the measured thick target yields, reaction cross sections are derived and compared with statistical model calculations. The recently suggested energy-dependent modification of the α+nucleus optical potential gives a good description of the experimental data.

Spectroscopic, Electrochemical and DFT Studies of Phosphorescent Homoleptic Cyclometalated Iridium(III) Complexes Based on Substituted 4-Fluorophenylvinyl- and 4-Methoxyphenylvinylquinolines.

Science.gov (United States)

Adeloye, Adewale O; Mphahlele, Malose J; Adekunle, Abolanle S; Rhyman, Lydia; Ramasami, Ponnadurai

2017-09-21

This study reports the synthesis and comparative investigation of the substituent effects of a new series of highly luminescent homoleptic tris-cyclometalated iridium(III) complexes of the type [Ir(N ˄ C)₃]. These are based on two ligand type derivatives comprising of 4-fluorophenylvinylquinolines and 4-methoxyphenylvinylquinolines with electron-donating and/or electron-withdrawing groups as aryl substituents at 2-position. The structures of the ligands and their complexes were characterized by means of FT-IR, UV-Vis and NMR spectrometry complemented with photoluminescence and cyclic voltammetry. The photophysical properties of 2-aryl-4-(4-fluorophenylvinyl)quinoline and its corresponding complex were also studied using the density functional theory method. The photoluminescent properties of the ligands and the corresponding complexes showed high fluorescent intensities and quantum yields in solvents of different polarities. The photoluminescence spectra of the complexes in solid film, showed common transmission curves at longer wavelengths maximum (λ em = 697 nm) possibly originating from the interference of scattered light of higher-order transmission of monochromators.

EKA urbanistika osakond / Lilia del Rio

Index Scriptorium Estoniae

Rio, Lilia del

2006-01-01

Lilia del Rio magistritöö "Beyond the player's manual / Mänguõpetus edasijõudnutele. Experiencing the world (and the city) as a playground / Kogedes maailma (ja linna) mänguväljakuna". Juhendaja Andres Kurg

6.-15. X on EKA galeriis...

Index Scriptorium Estoniae

2003-01-01

Keraamika eriala magistrantide näitus "Argilla neljale". Eksponeeritakse Reeli Haameri, Kadri Kivi, Annika Vilippuse ja Matthew Graziano magistriõppe meistriklassi raames valminud töid koos tehnikaid tutvustavate tekstidega

Community lab kunstihoones ja Arsenales / Harry Liivrand

Index Scriptorium Estoniae

Liivrand, Harry, 1961-

2003-01-01

Taani kaasaegse kunsti näitus "Projekt" Tallinna Kunstihoones, kus osalevad EKA üliõpilased ja külalised Lätist. Kuraatorite Molly Nesbiti, Hans Ulrich Obristi ja Rirkrit Tiravanija projekt "Utopia Station" Veneetsia biennaalil

Väikeste asjade kunst - The Art of Small Things / Martin Pärn

Index Scriptorium Estoniae

Pärn, Martin, 1971-

2003-01-01

Uued liinid disainihariduses, EKA tootedisaini osakonna osalemine viie kooli vahelises SPARK!- programmis, tavalise disaini roll (Väikeste Asjade Tegemise Kunst). Kompaktsuse positiivne näide - 1859. a. Thonet' loodud tool nr. 14. Õnnestunud disain

Tudengipreemia 2012 = Student award 2012

Index Scriptorium Estoniae

2013-01-01

Eesti Sisearhitektide Liidu 2012. aasta tudengipreemia pälvis Eesti Kunstiakadeemia sisearhitektuuri ja mööblidisaini üliõpilane Ivo Rannaste. EKA professor, sisearhitektuuri ja mööblidisaini osakonna juhataja Toivo Raidmets Ivo Rannastest

Eesti noordisainerid rahvusvahelises koguteoses

Index Scriptorium Estoniae

2000-01-01

"Graphise" koguteoses "New Talent Design Annual 2000" on esindatud Eesti Kunstiakadeemia graafilise disaini üliõpilased (nüüdseks EKA lõpetanud) Taavi Torim (illustratsioon) ja Maris Lindoja (kaks postmargikavandit). Juhendajaks oli Jüri Hain

Electrochemistry of transition metal complex catalysts Part 10. Intra- and intermolecular electrochemically activated C-H addition to the central metal atom of a P-C-P-pincer iridium complex

International Nuclear Information System (INIS)

Novak, Filip; Speiser, Bernd; Mohammad, Hani A.Y.; Mayer, Hermann A.

2004-01-01

The electrochemical properties of a promising catalyst for C-H bond activation are investigated. This P-C-P-pincer complex of iridium exhibits an intramolecular C-H oxidative addition at room temperature, which becomes enhanced upon oxidation. The reaction product is detected by cyclic voltammetry. Mechanistic, kinetic, and thermodynamic information is extracted from experiments in combination with digital simulation. Multicycle voltammograms and voltammograms of mixtures consistently suggest an extended square scheme as the electrode reaction mechanism. The unsubstituted parent compound shows a more complex redox behavior including a coupled ECE sequence. Intermolecular C-H activation by reaction of the complex in the presence of cyclooctane is indicated by characteristic changes in the cyclic voltammograms

V poiskah garmonii / Rafael Danieljants ; interv. Tamara Unanova

Index Scriptorium Estoniae

Danieljants, Rafael

2000-01-01

Armeenia päritolu skulptor Rafael Danieljants (EKA, 1984) oma töödest, õpetajatööst Maardu kunstikoolis jm. Viimane tema tööde näitus oli Armeenia kultuurikeskuses Tallinnas : eksponeeriti armeeniateemalisi skulptuure

Rohelised koridorid: kanal = Green corridors: canal / Kristel Niisuke

Index Scriptorium Estoniae

Niisuke, Kristel

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud töö keskseks ruumiliseks ideeks on Admiraliteedi basseini põhjakülge merega ühendav kanal ja selle kõrval kulgev promenaad

Aed: kaldapealne = Garden: the waterfront / Eva Kedelauk, Maie Raud

Index Scriptorium Estoniae

Kedelauk, Eva

2013-01-01

EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise raames loodud lahendus, kus Admiraliteedi basseini kaldal kulgeva promenaadi linna suunas deformeerumine loob raekoja ja projekt pakub välja linnaehitusliku tiheduse jätkamise

Theoretical characterization and design of highly efficient iridium (III) complexes bearing guanidinate ancillary ligand.

Science.gov (United States)

Ren, Xin-Yao; Wu, Yong; Wang, Li; Zhao, Liang; Zhang, Min; Geng, Yun; Su, Zhong-Min

2014-06-01

A density functional theory/time-depended density functional theory was used to investigate the synthesized guanidinate-based iridium(III) complex [(ppy)2Ir{(N(i)Pr)2C(NPh2)}] (1) and two designed derivatives (2 and 3) to determine the influences of different cyclometalated ligands on photophysical properties. Except the conventional discussions on geometric relaxations, absorption and emission properties, many relevant parameters, including spin-orbital coupling (SOC) matrix elements, zero-field-splitting parameters, radiative rate constants (kr) and so on were quantitatively evaluated. The results reveal that the replacement of the pyridine ring in the 2-phenylpyridine ligand with different diazole rings cannot only enlarge the frontier molecular orbital energy gaps, resulting in a blue-shift of the absorption spectra for 2 and 3, but also enhance the absorption intensity of 3 in the lower-energy region. Furthermore, it is intriguing to note that the photoluminescence quantum efficiency (ΦPL) of 3 is significantly higher than that of 1. This can be explained by its large SOC value(n=3-4) and large transition electric dipole moment (μS3), which could significantly contribute to a larger kr. Besides, compared with 1, the higher emitting energy (ET1) and smaller (2) value for 3 may lead to a smaller non-radiative decay rate. Additionally, the detailed results also indicate that compared to 1 with pyridine ring, 3 with imidazole ring performs a better hole injection ability. Therefore, the designed complex 3 can be expected as a promising candidate for highly efficient guanidinate-based phosphorescence emitter for OLEDs applications. Copyright © 2014 Elsevier Inc. All rights reserved.

Isomerization of Internal Alkynes to Iridium(III Allene Complexes via C–H Bond Activation: Expanded Substrate Scope, and Progress towards a Catalytic Methodology

Directory of Open Access Journals (Sweden)

Neha Phadke

2015-11-01

Full Text Available The synthesis of a series of allene complexes (POCOPIr(η2-RC=.=CR’ 1b–4b (POCOP = 2,6-bis(di-tert-butylphosphonitobenzene via isomerization of internal alkynes is reported. We have demonstrated that the application of this methodology is viable for the isomerization of a wide variety of alkyne substrates. Deuterium labeling experiments support our proposed mechanism. The structures of the allene complexes 1b–4b were determined using spectroscopic data analysis. Additionally, the solid-state molecular structure of complex 2b was determined using single crystal X-ray diffraction studies and it confirmed the assignment of an iridium-bound allene isomerization product. The rates of isomerization were measured using NMR techniques over a range of temperatures to allow determination of thermodynamic parameters. Finally, we report a preliminary step towards developing a catalytic methodology; the allene may be liberated from the metal center by exposure of the complex to an atmosphere of carbon monoxide.

Rae planeering: Rae talu / Eerika Alev

Index Scriptorium Estoniae

Alev, Eerika

2013-01-01

EKA arhitektuuri ja linnaplaneerimise IV kursuse üliõpilaste 2011- 2012 õppeaastal loodud Rae küla planeeringus on aktivaatori roll talul, mis pakub tööd ja elukohta nii peredele kui hooaja töölistele.

Rae planeering: 2x Rae / Eerika Alev, Kaisa Lillemets, Siim Tiisvelt

Index Scriptorium Estoniae

Alev, Eerika

2013-01-01

EKA arhitektuuri ja linnaplaneerimise IV kursuse üliõpilaste 2011- 2012 õppeaastal loodud planeeringu eesmärk oli säilitada Rae küla senine valglinnastunud struktuur ja panna see toimima ka tõelise külana.

Ehitusmaailma stipendiumid / Triin Ojari

Index Scriptorium Estoniae

Ojari, Triin, 1974-

2001-01-01

Ehitusmaailma kaupluseketi omanik AS "Fanaal" jagas kolmandat korda välja stipendiumid ehitus-, arhitektuuri- ja restaureerimisala üliõpilastele. Stipendiumi said: Mati Raal (EKA), Andrus Räämet, Eero Tuhkanen (TTÜ), Priit Lõhmus, Mauro Ilves, Maidu Saar (EPÜ)

F(akt)

Index Scriptorium Estoniae

2009-01-01

EKA tudengite Johannes Säre, Taaniel Raudsepa, Karel Koplimetsa, Sigrid Viiru fotode näitus Eesti Kunstiakadeemia galeriis 14.01.-23.01.2009. Juhendaja Tanja Muravskaja. Näitusel eksponeeritud töödest, nende valmimisest vestlevad fotode autorid

Meedialabor Tallinnas / Sirje Helme

Index Scriptorium Estoniae

Helme, Sirje, 1949-

2001-01-01

KKEK aastanäitus "Interstanding 4" alapealkirjaga "end repeat" Rotermanni soolalaos. "Interstanding" on valminud koostöös EKA-ga Ando Keskküla initsiatiivil. "Interstanding 4" programmi "end repeat" autor Mare Tralla. Medialabist. Konverentsi kava lk. 21.

Vaikus moefotograafias / Kristina Paju

Index Scriptorium Estoniae

Paju, Kristina

2007-01-01

EKA moemagistrandi Kristina Paju ja fotograafide Anna-Stina Treumundi ning Kaisa Eiche näitusest "Vaikus moefotograafias", mille eesmärgiks on kirjeldada võimalusi, millised võiksid olla vaikuse eri aspektid, ka moefotograafias, toetudes Jean Baudrillardi teooriale

24. V avati Vaalas...

Index Scriptorium Estoniae

2005-01-01

Rumeenia kunstniku Calin Dani näitus "Emotional architecture 2. Lost in transition", mis põhineb postsotsialistlike linnade Bukaresti ja Tallinna võrdlusel, esitleb kunstniku veel protsessis olevat tööd, milles osalesid ka EKA üliõpilased

Kunstiakadeemia disainikonverents

Index Scriptorium Estoniae

2003-01-01

8.-10. V Rotermanni soolalaos ja Eesti Kunstiakadeemias rahvusvaheline disainikonverents "VALID : VALue in Design", mille korraldab EKA koostöös rahvusvahelise kunsti-, disaini- ja arhitektuurikõrgkoolide assotsiatsiooniga CUMULUS. Peaesinejad Diana Crane, Natasha Vita-More (USA), Carlo Vezzoli (Itaalia)

Theoretical characterization of quaternary iridium based hydrides NaAeIrH{sub 6} (Ae = Ca, Ba and Sr)

Energy Technology Data Exchange (ETDEWEB)

Bouras, S. [Laboratory of Studies Surfaces and Interfaces of Solids Materials, Department of Physics, Faculty of Science, University of Setif 1, 19000 (Algeria); Ghebouli, B., E-mail: bghebouli@yahoo.fr [Laboratory of Studies Surfaces and Interfaces of Solids Materials, Department of Physics, Faculty of Science, University of Setif 1, 19000 (Algeria); Benkerri, M. [Laboratory of Studies Surfaces and Interfaces of Solids Materials, Department of Physics, Faculty of Science, University of Setif 1, 19000 (Algeria); Ghebouli, M.A., E-mail: med.amineghebouli@yahoo.fr [Microelectronic Laboratory (LMSE), University of Bachir Ibrahimi, Bordj-Bou-Arreridj 34000 (Algeria); Research Unit on Emerging Materials (RUEM), University of Setif 1, 19000 (Algeria); Choutri, H. [Microelectronic Laboratory (LMSE), University of Bachir Ibrahimi, Bordj-Bou-Arreridj 34000 (Algeria); Louail, L.; Chihi, T.; Fatmi, M. [Research Unit on Emerging Materials (RUEM), University of Setif 1, 19000 (Algeria); Bouhemadou, A. [Laboratory for Developing New Materials and Their Characterization, Department of Physics, Faculty of Science, University of Setif 1, 19000 (Algeria); Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Khenata, R.; Khachai, H. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 (Algeria)

2015-01-15

The quaternary iridium based hydrides NaAeIrH{sub 6} (Ae = Ca, Ba and Sr) are promising candidates as hydrogen storage materials. We have studied the structural, elastic, electronic, optical and thermodynamic properties of NaAeIrH{sub 6} (Ae = Ca, Ba and Sr) within the generalized gradient approximation, the local density approximation (LDA) and mBj in the frame of density functional perturbation theory. These alloys have a large indirect Γ–X band gap. The thermodynamic functions were computed using the phonon density of states. The origin of the possible transitions from valence band to conduction band was illustrated. By using the complex dielectric function, the optical properties such as absorption, reflectivity, loss function, refractive index and optical conductivity have been obtained. - Graphical abstract: Real and imaginary parts of the dielectric function, the absorption spectrum α(ω), reflectivity R(ω) and energy-loss spectrum L(ω). - Highlights: • NaAeIrH{sub 6} (Ae = Ca, Ba and Sr) alloys have been investigated. • The elastic moduli, energy gaps are predicted. • The optical and thermal properties were studied.

Westwoodi lakk-king Tallinnas

Index Scriptorium Estoniae

2002-01-01

Tallinna Kunstihoone galeriis ja Linnagaleriis briti moekunstnike aksessuaaride - peakatted, jalanõud, kotid - näitus "Satellites of Fashion", mis avati Jaanus Orgusaare rõiva- ja aksessuaari-showga. Mai algul viib nahkaksessuaaride disainer Paul Thomas läbi seminarid ja workshopid EKAs

Kunstnikuks pürgija vajab paari õigeaegset impulssi / Kaido Ole, Eva Unt

Index Scriptorium Estoniae

Ole, Kaido

2006-01-01

Antonia Claudio Carvalho meistriklass "Ava oma silmad/Open Your Eyes" 23.-27. I ja näitus 27. I-9. II Eesti Kunstiakadeemia galeriis. Meistriklassist vestlesid EKA maaliosakonna juhataja Kaido Ole ja maalieriala III kursuse üliõpilane Eva Unt

Maastikuarhitektuuri koolitusest Eesti Kunstiakadeemias = Schooling in Landscape Architecture at the Estonian Academy of Art / Katrin Koov

Index Scriptorium Estoniae

Koov, Katrin, 1973-

2003-01-01

Maastikukool tegutseb EKA arhitektuuriosakonna juures neljandat hooaega. Seni oli tegemist valikkursusega, 2003/2004. õppeaastast on see lülitatud arhitektuuriüliõpilaste põhiõppesse. Maastikukooli eesmärgist ja plaanidest, ülevaade aastatel 2000-2003 toimunud maastikukoolidest. 6 ill

Jiri Shibori konstruktivistlik kujundimaailm / Eilve Manglus

Index Scriptorium Estoniae

Manglus, Eilve, 1977-

2004-01-01

Metallide tehnoloogiat õppinud Jiri Shibori näitus "Ehtekunsti ja skulptuuri vahel" Deco galeriis kuni 10. IV. Personaalnäitus toimub EKA ehte- ja sepakunsti osakonna kutsel, et viia läbi külmkinnituslike konstruktsioonidega metallitöö workshop

Kõrgkoolidesse saab astuda internetis / Tarmu Kurm

Index Scriptorium Estoniae

Kurm, Tarmu

2006-01-01

Sel aastal kasutavad ühist sisseastumise infosüsteemi SAIS Audentese Ülikool, EBS, Kaitseväe Ühendatud Õppeasutused, TLÜ, Eesti Infotehnoloogia Kolledž, TTÜ, EKA, Tartu Tervishoiu Kõrgkool, TÜ, EMÜ, Tallinna Tervishoiu Kõrgkool ja Eesti-Ameerika Äriakadeemia

Direct electrocatalytic reduction of coenzyme NAD{sup +} to enzymatically-active 1,4-NADH employing an iridium/ruthenium-oxide electrode

Energy Technology Data Exchange (ETDEWEB)

Ullah, Nehar, E-mail: nehar.ullah@mail.mcgill.ca; Ali, Irshad; Omanovic, Sasha

2015-01-15

A thermally prepared iridium/ruthenium-oxide coating (Ir{sub 0.8}Ru{sub 0.2}-oxide) formed on a titanium substrate was investigated as a possible electrode for direct electrochemical regeneration of enzymatically-active 1,4-NADH from its oxidized form NAD{sup +}, at various electrode potentials, in a batch electrochemical reactor. The coating surface was characterized by ‘cracked mud’ morphology, yielding a high surface roughness. The NADH regeneration results showed that the percentage of enzymatically-active 1,4-NADH present in the product mixture (i.e. recovery) is strongly dependent on the electrode potential, reaching a maximum (88%) at −1.70 V vs. MSE. The relatively high recovery was explained on the basis of availability of adsorbed ‘active’ hydrogen (H{sub ads}) on the Ir/Ru-oxide surface, i.e. on the basis of electrochemical hydrogenation. - Highlights: • Ir{sub 0.8}Ru{sub 0.2}-oxide coating was formed thermally on a Ti substrate. • Electrochemical regeneration of enzymatically-active 1,4-NADH was investigated. • The 1,4-NADH recovery percentage is strongly dependent on the electrode potential. • A highest recovery, 88%, was obtained at −1.70 V vs. MSE. • The NADH regeneration process involved electrochemical hydrogenation.

Prantslased otsisid eestlaste juurest virmalisi / Henry Schmidt

Index Scriptorium Estoniae

Schmidt, Henry

2002-01-01

XI Põhjamaade kultuurifestival "Les Boréales" Prantsusmaal Caenis kutsus peakülaliseks Eesti. Eesti kunsti esindanud Raivo Kelomees Tartu Kõrgema Kunstikooli ja Jaan Toomik EKA üliõpilastega näitasid oma videokunsti, Liina Siibi näitus oli Alam-Normandia kunstikeskuses

Hulgi asju, mis asja? / Anneli Porri, Triin Männik

Index Scriptorium Estoniae

Porri, Anneli, 1980-

2003-01-01

Briti seeriadisaini näitus "Multiplication" Tallinna raekojas 10. I-16. II. Mitmiklus kunstis.12. II pidas John Frankland loengu EKAs, 13. II osales Tallinna Kunstihoones diskussioonis briti 1990ndate kunsti üle, 14. II viis läbi workshopi Tallinna raekojas

7. I kell 18 avatakse Pärnu Muuseumi Aidas...

Index Scriptorium Estoniae

2006-01-01

Urmas Viigi juhendatud EKA graafikaüliõpilaste tööde näitus, toimuvad ka Pink Pungi, Ernest Truely, Lexxxa, Ville-Karel Viirelaiu, Egle Veske, Remo Randveri, Toomas Kuusingu, Meeland Sepa, Sorge, Sirami (Mari Kartau), Billeneeve, Tanel Saare performance'id

Avastatud klaas / Kai Lobjakas

Index Scriptorium Estoniae

Lobjakas, Kai, 1975-

2006-01-01

Euroopa kõrgkoolide klaasieriala üliõpilaste tööde näitus "Discovery / Avastusretk" Kullo galeriis kuni 19. V. Rahvusvahelise ürituse korraldajaks oli EKA klaasikunsti osakond eesotsas Mare Saare ja Tiina Sarapuga. Pikemalt Ave Maseri tööst "Maandumine"

Viru tunnel saab uue ilme urbanistliku grafiti abil / Ilmar Kahro

Index Scriptorium Estoniae

Kahro, Ilmar

2011-01-01

MTÜ Linnalabor koostöös Tallinn 2011 SA-ga viis läbi Tallinnas Gonsiori ja Laikmaa tänava ristmiku all paikneva Viru tunneli kujunduskonkursi "Viru tunnel kunstigaleriiks". EKA skulptuuri eriala tudengi Eldar Jakubovi võidutööst "Avame linna"

The mechanical system design of the iridium-192 isotope wire in cervical cancer brachytherapy with medium dose rate

International Nuclear Information System (INIS)

Ari Satmoko; Sanda; Tri Harjanto; Atang Susila

2010-01-01

In 2010, brachytherapy engineering activities have a purpose to establish a detailed design of the cervical cancer brachytherapy with medium dose rate. The brachytherapy will use an Iridium-92 source with the emiting radiation of 5 to 10 Curies. The source is wrapped in SS-316 capsule and carried by a SS-316 wire having diameter of about 1 mm dan length of 1800 mm. As part of this activity, the preliminary design of the mechanical drive systems for the isotope source has been developed. The technical specifications for the main components of the mechanical drive system have been successfully determined. This is started by studying the concept design, performing calculations, determining technical specifications, and finally defining the main components. From the evaluation, some components were decided: a stepper motor PK264A1-SG10, needle bearing NKI-10/20, spiral tube in SS316-1/8'' with 120 mm in diameter, rubber-based belts with a width of 20 mm, and aluminium drum with a diameter of 100 mm. Not all components could be identified in detail, especially for the components that do not exist in the market place and have to be created ourself. Since the main components have been identified, the detailed design step of the mechanical drive systems for the isotope source can be performed. (author)

A mechanical system design of the iridium-192 isotope wire in cervical cancer brachytherapy with medium dose rate

International Nuclear Information System (INIS)

Ari Satmoko; Sanda; Tri Harjanto; Atang Susila

2010-01-01

In 2010, brachytherapy engineering development activities have a purpose to establish a detailed design of the cervical cancer brachytherapy with medium dose rate. The brachytherapy will use an Iridium-92 source with the emitting radiation of 5 to 10 Curies. The source is wrapped in SS-316 capsule and carried by a SS-316 wire having diameter of about 1 mm dan length of 1800 mm. As part of this activity, the preliminary design of the mechanical drive systems for the isotope source has been developed. The technical specifications for the main components of the mechanical drive system have been successfully determined. This is started by studying the concept design, performing calculations, determining technical specifications, and finally defining the main components. From the evaluation, some components were decided: a stepper motor PK264A1-SG10, needle bearing NKI-10/20, spiral tube in SS316-1/8'' with 120 mm in diameter, rubber-based belts with a width of 20 mm, and aluminium drum with a diameter of 100 mm. Not all components could be identified in detail, especially for the components that do not exist in the marketplace and have to be created ourself Since the main components have been identified, the detailed design step of the mechanical drive systems for the isotope source can be performed. (author)

High performance yellow organic electroluminescent devices by doping iridium(III) complex into host materials with stepwise energy levels

Energy Technology Data Exchange (ETDEWEB)

Cui, Rongzhen; Zhou, Liang, E-mail: zhoul@ciac.ac.cn; Jiang, Yunlong; Li, Yanan; Zhao, Xuesen; Zhang, Hongjie, E-mail: hongjie@ciac.ac.cn

2015-10-15

In this work, we aim to further improve the electroluminescent (EL) performances of a yellow light-emitting iridium(III) complex by designing double light-emitting layers (EMLs) devices having stepwise energy levels. Compared with single-EML devices, these designed double-EML devices showed improved EL efficiency and brightness attributed to better balance in carriers. In addition, the stepwise distribution in energy levels of host materials is instrumental in broadening the recombination zone, thus delaying the roll-off of EL efficiency. Based on the investigation of carriers' distribution, device structure was further optimized by adjusting the thickness of deposited layers. Finally, yellow EL device (Commission Internationale de l'Eclairage (CIE) coordinates of (0.446, 0.542)) with maximum current efficiency, power efficiency and brightness up to 78.62 cd/A (external quantum efficiency (EQE) of 21.1%), 82.28 lm/W and 72,713 cd/m{sup 2}, respectively, was obtained. Even at the high brightness of 1000 cd/m{sup 2}, EL efficiency as high as 65.54 cd/A (EQE=17.6%) can be retained. - Highlights: • Yellow electroluminescent devices were designed and fabricated. • P-type and n-type materials having stepwise energy levels were chosen as host materials. • Better balance of holes and electrons causes the enhanced efficiencies. • Improved carriers' trapping suppresses the emission of host material.

Effect of thermal treatment on the characteristics of iridium Schottky barrier diodes on n-Ge (1 0 0)

International Nuclear Information System (INIS)

Chawanda, A.; Coelho, S.M.M.; Auret, F.D.; Mtangi, W.; Nyamhere, C.; Nel, J.M.; Diale, M.

2012-01-01

Highlights: ► Ir/n-Ge (1 0 0) Schottky diodes were characterized using I–V, C–V and SEM techniques under various annealing conditions. ► The variation of the electrical and structural properties can be due to effects phase transformation during annealing. ► Thermal stability of these diodes is maintained up to 500 °C anneal. ► SEM results depicts that the onset temperature for agglomeration in 20 nm Ir/n-Ge (1 0 0) system occurs between 600 and 700 °C. - Abstract: Iridium (Ir) Schottky barrier diodes were deposited on bulk grown (1 0 0) Sb-doped n-type germanium by using the electron beam deposition system. Electrical characterization of these contacts using current–voltage (I–V) and capacitance–voltage (C–V) measurements was performed under various annealing conditions. The variation of the electrical properties of these Schottky diodes can be attributed to combined effects of interfacial reaction and phase transformation during the annealing process. Thermal stability of the Ir/n-Ge (1 0 0) was observed up to annealing temperature of 500 °C. Furthermore, structural characterization of these samples was performed by using a scanning electron microscopy (SEM) at different annealing temperatures. Results have also revealed that the onset temperature for agglomeration in a 20 nm Ir/n-Ge (1 0 0) system occurs between 600 and 700 °C.

A mitochondrial targeted two-photon iridium(III) phosphorescent probe for selective detection of hypochlorite in live cells and in vivo.

Science.gov (United States)

Li, Guanying; Lin, Qian; Sun, Lingli; Feng, Changsheng; Zhang, Pingyu; Yu, Bole; Chen, Yu; Wen, Ya; Wang, Hui; Ji, Liangnian; Chao, Hui

2015-01-01

Endogenous hypochlorite ion (ClO(-)) is a highly reactive oxygen species (ROS) that is produced from hydrogen peroxide and chloride ions catalyzed by myeloperoxidase (MPO). And mitochondrion is one of the major sources of ROS including ClO(-). In the present work, a two-photon phosphorescent probe for ClO(-) in mitochondria was developed. An iridium(III) complex bearing a diaminomaleonitrile group as ClO(-) reactive moiety specifically responded to ClO(-) over other ions and ROSs. When the probe was reacted with ClO(-) to form an oxidized carboxylate product, a significant enhancement in phosphorescence intensity was observed under one-photon (402 nm) and two-photon (750 nm) excitation, with a two-photon absorption cross-section of 78.1 GM at 750 nm. More importantly, ICP-MS results and cellular images co-stained with Mito-tracker Green demonstrated that this probe possessed high specificity for mitochondria. This probe was applied in the one- and two-photon imaging of ClO(-) in vitro and in vivo. The results suggested endotoxin lipopolysaccharide (LPS) induced ClO(-) mostly generated in the liver of zebrafish. Copyright © 2015 Elsevier Ltd. All rights reserved.

Crystal structures of fac-tri?chlorido?tris?(tri?methyl?phosphane-?P)rhodium(III) monohydrate and fac-tri?chlorido?tris?(tri?methyl?phosphane-?P)rhodium(III) methanol hemisolvate: rhodium structures that are isotypic with their iridium analogs

OpenAIRE

Merola, Joseph S.; Franks, Marion A.

2015-01-01

The crystal structures of two solvates of fac-tri-chlorido-tris-(tri-methyl-phosphane-κP)rhodium(III) are reported, i.e. one with water in the crystal lattice, fac-[RhCl3(Me3P)3]·H2O, and one with methanol in the crystal lattice, fac-[RhCl3(Me3P)3]·0.5CH3OH. These rhodium compounds exhibit distorted octahedral coordination spheres at the metal and are isotypic with the analogous iridium compounds previously reported by us [Merola et al. (2013 ▶). Polyhedron, 54, 67-73]. Comparison is made bet...

Disain+juhtimine : disainjuhtimise peaauhind Eestisse / Triin Ojari

Index Scriptorium Estoniae

Ojari, Triin, 1974-

2012-01-01

Ühe 2012. a. Euroopa disainjuhtimise auhinna DME peaauhindadest sai Tallinna Transpordiameti uuendusprotsess kommunikatsiooni ja teenuse parandamiseks. Võidu taga on EKA tudengid Kristi Rummel, Brit Pavelson, Norman Orro ja Ronald Pihlapson, kes tegid seda alguses graafilise disaini osakonna 3. kursuse semestritööna

Teekann - keraamiku proovikivi

Index Scriptorium Estoniae

2001-01-01

Tallinna Linnagaleriis teekannude näitus "Time for Tea", mis annab ülevaate originaal- (Bernard Leachi koolkonna keraamikute tööd jm.) ja tööstusliku keraamika arengust Suurbritannias 20. sajandil. Kaasaegset keraamikat esindava Kate Malone'i workshop EKA keraamikaosakonnas 16.-19. IV.

Piero Castiglioni - praktilise ilu looja / Karin Paulus

Index Scriptorium Estoniae

Paulus, Karin, 1975-

2005-01-01

Itaalia disaineritest Castiglioni'dest, pikemalt Piero Castiglionist (sünd. 1944), kes külastas 2005. aasta märtsis Eestit. Loetletud tema tähtsamad tööd. Kommenteerivad sisearhitekt Hannes Praks, sisearhitekt Juta Lember, valgusdisainer Tarmo Luisk ja EKA professor Toivo Raidmets

Nahast väljunud V.A.V.A. / Lii Pihl

Index Scriptorium Estoniae

Pihl, Lii

2003-01-01

EKA nahakunsti eriala üliõpilastest ja vilistlastest koosneva rühmituse V.A.V.A. (välja arvatud ja väga austatud) installatsiooninäitus "Nihe" (alapealkiri "21. sajandi köiteväljund") Kuressaare linnuses kuni 14. IX. Kuraator Reet Viira

Kõrgkoolidesse saab astuda Internetis / Liivia Mahlapuu

Index Scriptorium Estoniae

Mahlapuu, Liivia

2006-01-01

Käesoleval aastal kasutavad veebipõhist infosüsteemi SAIS tudengite vastuvõtmisel Audentese Ülikool, EBS, Kaitseväe Ühendatud Õppeasutused, TLÜ, Eesti Infotehnoloogia Kolledž, TTÜ, EKA, Tartu Tervishoiu Kõrgkool, TÜ, EMÜ, Tallinna Tervishoiu Kõrgkool ja Eesti-Ameerika Äriakadeemia

Value of palliation and improvement in quality of life in oesophageal cancer patients treated with iridium - 192 HDR fractionated brachytherapy

International Nuclear Information System (INIS)

Biaias, B.; Kaleta, R.; Fijaikowski, M.

1996-01-01

During December 1992 - November 1995 twenty-two patients with oesophageal cancer were treated with palliative HDR brachytherapy. Sixteen patients had local recurrence or progression after external radiotherapy and the remaining six patients were treated with brachytherapy alone. All patients received fractions of 7.5 Gy at the reference point 2 - 4 time weekly. Reference point was calculated at 0.5 cm distance from applicator surface. Microselectron HDR device with Iridium-192 source were used. Criteria for palliative effect were as follow: relive of symptoms time of occurrence and duration of palliative effect. Quality of life during and after treatment were evaluated by patients and staff independently. In majority of patients both palliative effect and significant improvement of quality of life were noted. Detail results include: - improvement in swallowing in 63,6% ((14(22))); - increase in body weight in 45% ((10(22))); - pain relive 70% ((12(17))); - appearance of palliation 1 hour - 8 days; - duration of palliation - 3-12 mo. (median 5 mo.); Quality of live - improvement - 59% ((13(22))); - no improvement - 27.3% ((6(22))); - worsening - 13.7% ((3(22))); No improvement or worsening in quality of life were observed only in patients who obtained radical radiotherapy previously. Brachytherapy is an effective method of palliative treatment for as well primary and recurrent oesophageal cancer

The Photoluminescent Properties of New Cationic Iridium(III Complexes Using Different Anions and Their Applications in White Light-Emitting Diodes

Directory of Open Access Journals (Sweden)

Hui Yang

2015-09-01

Full Text Available Three cationic iridium(III complexes [Ir(ppy2(phen][PF6] (C1, [Ir(ppy2(phen]2SiF6 (C2 and [Ir(ppy2(phen]2TiF6 (C3 (ppy: 2-phenylpyridine, phen: 1, 10-phenanthroline using different anions were synthesized and characterized by 1H Nuclear magnetic resonance (1HNMR, mass spectra (MS, Fourier transform infrared (FTIR spectra and element analysis (EA. After the ultraviolet visible (UV-vis absorption spectra, photoluminescent (PL properties and thermal properties of the complexes were investigated, complex C1 and C3 with good optical properties and high thermal stability were used in white light-emitting diodes (WLEDs as luminescence conversion materials by incorporation with 460 nm-emitting blue GaN chips. The integrative performances of the WLEDs fabricated with complex C1 and C3 are better than those fabricated with the widely used yellow phosphor Y3Al5O12:Ce3+ (YAG. The color rendering indexes of the WLEDs with C1 and C3 are 82.0 and 82.6, the color temperatures of them are 5912 K and 3717 K, and the maximum power efficiencies of them are 10.61 Lm·W−1 and 11.41 Lm·W−1, respectively.

The Photoluminescent Properties of New Cationic Iridium(III) Complexes Using Different Anions and Their Applications in White Light-Emitting Diodes.

Science.gov (United States)

Yang, Hui; Meng, Guoyun; Zhou, Yayun; Tang, Huaijun; Zhao, Jishou; Wang, Zhengliang

2015-09-14

Three cationic iridium(III) complexes [Ir(ppy)₂(phen)][PF₆] (C1), [Ir(ppy)₂(phen)]₂SiF₆ (C2) and [Ir(ppy)₂(phen)]₂TiF₆ (C3) (ppy: 2-phenylpyridine, phen: 1, 10-phenanthroline) using different anions were synthesized and characterized by ¹H Nuclear magnetic resonance (¹HNMR), mass spectra (MS), Fourier transform infrared (FTIR) spectra and element analysis (EA). After the ultraviolet visible (UV-vis) absorption spectra, photoluminescent (PL) properties and thermal properties of the complexes were investigated, complex C1 and C3 with good optical properties and high thermal stability were used in white light-emitting diodes (WLEDs) as luminescence conversion materials by incorporation with 460 nm-emitting blue GaN chips. The integrative performances of the WLEDs fabricated with complex C1 and C3 are better than those fabricated with the widely used yellow phosphor Y₃Al₅O 12 :Ce 3+ (YAG). The color rendering indexes of the WLEDs with C1 and C3 are 82.0 and 82.6, the color temperatures of them are 5912 K and 3717 K, and the maximum power efficiencies of them are 10.61 Lm·W -1 and 11.41 Lm·W -1 , respectively.

Täna kell 20 esitletakse EKA galerii...

Index Scriptorium Estoniae

2004-01-01

Esitletakse norra kunstnike (loetletud) videosid "Darling, don't leave me all by myself". Korraldaja Bergeni kuraatoriduo Rakett (Asa Lövgren, Karolin Tampere). 4. IV näeb Tallinna projekti Von Krahli teatris

15. XI kell 17 avatakse EKA galeriis...

Index Scriptorium Estoniae

2004-01-01

Näitus "ERKI moe-show" 10 aastat", mille koostasid Karolin Kuusik, Gerli Liivamägi, Kristina Paju, Külli-Kerttu Siplane ja Agne Talu. Eksponeeritakse ka Jaanus Orgusaare, Vassilissa, Aldo Järvsoo ning Hula noortekollektsiooni esinemiste meeldejäävamaid hetki. 20. XI kinos Kosmos ERKI moeetendus "Go". Lavastuse autorid Taavet Jansen ja Oksana Titova, kunstiline juht Ain Nurmela, videokunstnik Taavi Warm, graafiline kujundus Martin Eelmalt, helikujundus Remi Prualilt

9. VI avati Deco galeriis...

Index Scriptorium Estoniae

2004-01-01

EKA graafikaosakonna magistrandi Anna Arho magistritööd tutvustav näitus "Still Life with Mothers and Daughters". A. Arho kaitses samas oma magistritöö, mille teooriaosas "Külalisena Graafikamaal" on vaatluse alla võetud eesti ja soome vabagraafika tänapäev

Nukufilm, mis pani kihama kogu Soome / Tiit Tuumalu

Index Scriptorium Estoniae

Tuumalu, Tiit, 1971-

2008-01-01

Nukufilm "Uurali liblikas" (peategelaseks marssal Mannerheim) : režissöör Katariina Lillqvist : Soome 2008. Filmi esitleb Tallinnas K. Lillqvist uuel sariüritusel Animateek, mille taga seisavad festival Animated Dreams, EKA ja Kumu auditoorium. Lisatud andmed režissööri ja Animateegi kohta

Materjalid muudavad maailma = Materials change the world / Jaak Kikas

Index Scriptorium Estoniae

Kikas, Jaak

2005-01-01

Jaak Kikas TÜ materjaliteaduse instituudist mõnedest olulistest tendentsidest ja suundumustest uute materjalide otsingutel ning nendega kaasnevatest probleemidest. Materjaliteaduse artikli kommentaariks tutvustavad Kalle Komissarov (intervjueerija) ja Martin Pärn EKA disaini- ja tekstiilikateedri projekti "Arukate toodete disain - tuleviku eriala", millele saadi toetust SA Innove europrojektide raames

Kuni 24. XII on Y-galerii P- ja T-saalis vaadata näitus "Võõras mure"...

Index Scriptorium Estoniae

2005-01-01

Näitusel "Võõras mure" on väljas EKA avatud akadeemia lõpetanud kunstnike Anniki Kari, Ellen-Reet Türi ja Ulvi Kuldkepi maalid. A- ja E-saalis avatud Lauri Pajose näitusel "Tonal" näeb suuremõõtmelisi sürreaalabstraktseid maale

Chemical experiments with superheavy elements.

Science.gov (United States)

Türler, Andreas

2010-01-01

Unnoticed by many chemists, the Periodic Table of the Elements has been extended significantly in the last couple of years and the 7th period has very recently been completed with eka-Rn (element 118) currently being the heaviest element whose synthesis has been reported. These 'superheavy' elements (also called transactinides with atomic number > or = 104 (Rf)) have been artificially synthesized in fusion reactions at accelerators in minute quantities of a few single atoms. In addition, all isotopes of the transactinide elements are radioactive and decay with rather short half-lives. Nevertheless, it has been possible in some cases to investigate experimentally chemical properties of transactinide elements and even synthesize simple compounds. The experimental investigation of superheavy elements is especially intriguing, since theoretical calculations predict significant deviations from periodic trends due to the influence of strong relativistic effects. In this contribution first experiments with hassium (Hs, atomic number 108), copernicium (Cn, atomic number 112) and element 114 (eka-Pb) are reviewed.

Theoretical study on electronic structures and optical properties of blue phosphorescent Iridium(III) complexes with C{sup ∧}N and N{sup ∧}N ligands

Energy Technology Data Exchange (ETDEWEB)

Shang, Xiaohong [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); College of Chemistry and Life Science, Changchun University of Technology, Changchun 130024 (China); Liu, Yuqi; Qu, Xiaochun [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Wu, Zhijian, E-mail: zjwu@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2013-11-15

We report a quantum-chemical study on the electronic structures and optical properties of two series of heteroleptic iridium(III) complexes [(dfb-pz){sub 2}Ir(N{sup ∧}N+sub)], [dfb-pz=2,4-difluorobenzyl-N-pyrazole, sub indicates substituent group, N{sup ∧}N+sub=tphppz=4-tert-butyl-2-(5-phenyl-[1,2,4]triazol-3-yl)-pyridine (1a), tmppz=4-tert-butyl-2-(5-methyl-[1,2,4]triazol-3-yl)-pyridine (1b), fphppz=4-fluoro-phenyl-5-(2-pyridyl)pyrazole (1c), and fmphppz=4-trifluoromehtyl-phenyl-5-(2-pyridyl)pyrazole (1d)]; with [(C{sup ∧}N+sub){sub 2}Ir(fppz)], [C{sup ∧}N=b-pz=benzyl-N-pyrazole, fppz=3-trifluoromethyl-5-(2-pyridyl)pyrazole, C{sup ∧}N+sub=dfb-pz=2,4-difluorobenzyl-N-pyrazole (2a), tfmfb-pz=2-trifluoromethyl-5-fluorobenzyl-N-pyrazole (2b), phb-pz=3-phenyl-benzyl-N-pyrazole (2c), and dfphb-pz=3-phenyl-2,4-difluorobenzyl-N-pyrazole (2d)]. The calculated results shed light on the reasons of the remarkably manipulated excited-state and electroluminescent properties through substitution effect. The phenyl ring on main ligands can enhance the π-conjugation of the main ligands moiety and increase the metal-ligand bond strength for 2c and 2d, then enhancing the transition strength. From 1c, 1d, 2c, and 2d, it can also be seen that substituents on the terminal phenyl ring have a slight effect on the excited energy because the distance between the substituents and the ancillary (or main) ligand is interrupted by the phenyl moiety. The calculated absorption and luminescence properties of the four complexes 1a, 1b, 2a, and 2b are compared with the available experimental data and a good agreement is obtained. Furthermore, the assumed complex 1c, 2c, and 2d possess better charge transfer abilities and more balanced charge transfer rates. The designed complexes 2c and 2d are potential candidates for blue phosphorescent materials. -- Highlights: • Two series of electroluminescent iridium(III) complexes have been studied. • The charge transfer properties are affected

Supramolecular Dendriphores: Anionic Organometallic Phosphors Embedded in Polycationic Dendritic Species

NARCIS (Netherlands)

McDonald, A.R.; Mores, D.; de Mello-Donega, C.; van Walree, C.A.; Klein Gebbink, R.J.M.; Lutz, M.; Spek, A.L.; Meijerink, A.; van Klink, G.P.M.; van Koten, G.

2009-01-01

Heteroleptic iridium(III) organometallic complexes have been functionalized with sulfate tethers. These systems have been thoroughly characterized spectroscopically. Subsequently these iridium(III) complexes were reacted with polyionic dendritic materials yielding iridium(III) organometallic

Effect of thermal treatment on the characteristics of iridium Schottky barrier diodes on n-Ge (1 0 0)

Energy Technology Data Exchange (ETDEWEB)

Chawanda, A., E-mail: albert.chawanda@up.ac.za [Department of Physics, University of Pretoria, 0002 (South Africa); Department of Physics, Midlands State University, Bag 9055, Gweru (Zimbabwe); Coelho, S.M.M.; Auret, F.D.; Mtangi, W. [Department of Physics, University of Pretoria, 0002 (South Africa); Nyamhere, C. [Department of Physics, Nelson Mandela Metropolitan University, Box 77000, Port Elizabeth 6031 (South Africa); Nel, J.M.; Diale, M. [Department of Physics, University of Pretoria, 0002 (South Africa)

2012-02-05

Highlights: Black-Right-Pointing-Pointer Ir/n-Ge (1 0 0) Schottky diodes were characterized using I-V, C-V and SEM techniques under various annealing conditions. Black-Right-Pointing-Pointer The variation of the electrical and structural properties can be due to effects phase transformation during annealing. Black-Right-Pointing-Pointer Thermal stability of these diodes is maintained up to 500 Degree-Sign C anneal. Black-Right-Pointing-Pointer SEM results depicts that the onset temperature for agglomeration in 20 nm Ir/n-Ge (1 0 0) system occurs between 600 and 700 Degree-Sign C. - Abstract: Iridium (Ir) Schottky barrier diodes were deposited on bulk grown (1 0 0) Sb-doped n-type germanium by using the electron beam deposition system. Electrical characterization of these contacts using current-voltage (I-V) and capacitance-voltage (C-V) measurements was performed under various annealing conditions. The variation of the electrical properties of these Schottky diodes can be attributed to combined effects of interfacial reaction and phase transformation during the annealing process. Thermal stability of the Ir/n-Ge (1 0 0) was observed up to annealing temperature of 500 Degree-Sign C. Furthermore, structural characterization of these samples was performed by using a scanning electron microscopy (SEM) at different annealing temperatures. Results have also revealed that the onset temperature for agglomeration in a 20 nm Ir/n-Ge (1 0 0) system occurs between 600 and 700 Degree-Sign C.

Narva-teemaline magistritöö Pariisis / Merike Trubert

Index Scriptorium Estoniae

Trubert, Merike

2002-01-01

27. XI kaitsesid prantsuse arhitektuuriüliõpilased David Trubert ja Guillaume Blanchard (1999-2001 vahetusüliõpilased EKAs) Pariisi arhitektuurikoolis (Ecole d'Architecture de Paris Val-de-Seine) Narva linnaplaneeringut käsitleva magistritöö "Narva. Urban planning for social approach". Kaitsmiskomisjoni juhataja Mart Kalm

Urmo Raus : "Maalimine on mäluline protsess" / Urmo Raus ; interv. Reet Varblane

Index Scriptorium Estoniae

Raus, Urmo, 1969-

2003-01-01

Tallinna Kunstihoones Urmo Rausi maalinäituse avamise puhul intervjuu kunstnikuga, kes on õppinud Eesti Kunstiakadeemias, Pariisi Ecole Nationale Superieure des Beaux-Arts'is, on teinud näitusi Prantsusmaal, Itaalias, Venemaal, Eestis, elab Haagis. U. Raus kunstiõpetusest Pariisis ja EKA maaliosakonnas, kaasaegsest vitraažikunstist, oma maalikunstist

Tagasiviitavad tõendid: teine pilk pilditeadusele / Beat Wyss ; intervjueerinud Ivar-Kristjan Hein

Index Scriptorium Estoniae

Wyss, Beat, 1947-

2011-01-01

Intervjuus Karlsruhe kunsti- ja disainiülikooli kunstiajaloo ja meediateooria professori Beat Wyssiga on teemaks Zürichis tema juhitav uurimisprojekt, mille keskmes on Venezia biennaal Ida-Euroopa riikide positsioonilt, tema EKA Kunstiteaduse Instituudi doktorantidele peetud seminar "Tagasiviitavad tõendid. Teine pilk pilditeadusele", tema kaasaegse kunsti universaalsed põhimõtted

Lineaarse kunstiajaloo aeg on otsas / Edit András ; intervjueerinud R[eet] V[arblane

Index Scriptorium Estoniae

András, Edit

2010-01-01

Vestlus ungari kunstiteoreetiku- ja ajaloolase Edit Andrásiga, kes osales Tallinnas USA Clarki instituudi ja EKA Kunstiteaduste Instituudi seminaril, kus arutati Kesk- ja Ida-Euroopa kunstiajaloo kirjutamisviiside üle. Seminari tekkimisest, kokkusaamise põhjustest, seminari järeldustest, Eesti ja Ungari kunstiajaloo kirjutamise erinevatest põhimõtetest jm.

Beyond Iron: Iridium-Containing P450 Enzymes for Selective Cyclopropanations of Structurally Diverse Alkenes

International Nuclear Information System (INIS)

Key, Hanna M.; Dydio, Paweł; Liu, Zhennan

2017-01-01

Enzymes catalyze organic transformations with exquisite levels of selectivity, including chemoselectivity, stereoselectivity, and substrate selectivity, but the types of reactions catalyzed by enzymes are more limited than those of chemical catalysts. Thus, the convergence of chemical catalysis and biocatalysis can enable enzymatic systems to catalyze abiological reactions with high selectivity. Recently, we disclosed artificial enzymes constructed from the apo form of heme proteins and iridium porphyrins that catalyze the insertion of carbenes into a C-H bond. Here, we postulated that the same type of Ir(Me)-PIX enzymes could catalyze the cyclopropanation of a broad range of alkenes with control of multiple modes of selectivity. Here, we report the evolution of artificial enzymes that are highly active and highly stereoselective for the addition of carbenes to a wide range of alkenes. These enzymes catalyze the cyclopropanation of terminal and internal, activated and unactivated, electron-rich and electron-deficient, conjugated and nonconjugated alkenes. In particular, Ir(Me)-PIX enzymes derived from CYP119 catalyze highly enantio- and diastereoselective cyclopropanations of styrene with ±98% ee, > 70:1 dr, > 75% yield, and ~10,000 turnovers (TON), as well as 1,2-disubstituted styrenes with up to 99% ee, 35:1 dr, and 54% yield. Moreover, Ir(Me)-PIX enzymes catalyze cyclopropanation of internal, unactivated alkenes with up to 99% stereoselectivity, 76% yield, and 1300 TON. They also catalyze cyclopropanation of natural products with diastereoselectivities that are complementary to those attained with standard transition metal catalysts. Finally, Ir(Me)-PIX P450 variants react with substrate selectivity that is reminiscent of natural enzymes; they react preferentially with less reactive internal alkenes in the presence of more reactive terminal alkenes. Altogether, the studies reveal the suitability of Ir-containing P450s to combine the broad reactivity and

Warm White Light-Emitting Diodes Based on a Novel Orange Cationic Iridium(III) Complex.

Science.gov (United States)

Tang, Huaijun; Meng, Guoyun; Chen, Zeyu; Wang, Kaimin; Zhou, Qiang; Wang, Zhengliang

2017-06-16

A novel orange cationic iridium(III) complex [(TPTA)₂Ir(dPPOA)]PF₆ (TPTA: 3,4,5-triphenyl-4 H -1,2,4-triazole, dPPOA: N,N-diphenyl-4-(5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl)aniline) was synthesized and used as a phosphor in light-emitting diodes (LEDs). [(TPTA)₂Ir(dPPOA)]PF₆ has high thermal stability with a decomposition temperature ( T d ) of 375 °C, and its relative emission intensity at 100 °C is 88.8% of that at 25°C. When only [(TPTA)₂Ir(dPPOA)]PF₆ was used as a phosphor at 6.0 wt % in silicone and excited by a blue GaN (GaN: gallium nitride) chip (450 nm), an orange LED was obtained. A white LED fabricated by a blue GaN chip (450 nm) and only yellow phosphor Y₃Al₅O 12 :Ce 3+ (YAG:Ce) (1.0 wt % in silicone) emitted cold white light, its CIE (CIE: Commission International de I'Eclairage ) value was (0.32, 0.33), color rendering index (CRI) was 72.2, correlated color temperature (CCT) was 6877 K, and luminous efficiency ( η L ) was 128.5 lm∙W -1 . Such a cold white LED became a neutral white LED when [(TPTA)₂Ir(dPPOA)]PF₆ was added at 0.5 wt %; its corresponding CIE value was (0.35, 0.33), CRI was 78.4, CCT was 4896 K, and η L was 85.2 lm∙W -1 . It further became a warm white LED when [(TPTA)₂Ir(dPPOA)]PF₆ was added at 1.0 wt %; its corresponding CIE value was (0.39, 0.36), CRI was 80.2, CCT was 3473 K, and η L was 46.1 lm∙W -1 . The results show that [(TPTA)₂Ir(dPPOA)]PF₆ is a promising phosphor candidate for fabricating warm white LEDs.

Earth Radiation Imbalance from a Constellation of 66 Iridium Satellites: Climate Science Aspects

Science.gov (United States)

Wiscombe, W.; Chiu, CJ. Y.

2012-01-01

The "global warming hiatus" since the 1998 El Nino, highlighted by Meehl et al., and the resulting "missing energy" problem highlighted by Trenberth et al., has opened the door to a more fundamental view of climate change than mere surface air temperature. That new view is based on two variables which are strongly correlated: the rate of change of ocean heat content d(OHC)/dt; and Earth Radiation Imbalance (ERI) at the top of the atmosphere, whose guesstimated range is 0.4 to 0.9 Watts per square meters (this imbalance being mainly due to increasing CO2). The Argo float array is making better and better measurements of OHC. But existing satellite systems cannot measure ERI to even one significant digit. So, climate model predictions of ERI are used in place of real measurements of it, and the satellite data are tuned to the climate model predictions. Some oceanographers say "just depend on Argo for understanding the global warming hiatus and the missing energy", but we don't think this is a good idea because d(OHC)/dt and ERI have different time scales and are never perfectly correlated. We think the ERB community needs to step up to measuring ERI correctly, just as oceanographers have deployed Argo to measure OHC correctly. This talk will overview a proposed constellation of 66 Earth radiation budget instruments, hosted on Iridium satellites, that will actually be able to measure ERI to at least one significant digit, thus enabling a crucial test of climate models. This constellation will also be able to provide ERI at two-hourly time scales and 500-km spatial scales without extrapolations from uncalibrated narrowband geostationary instruments, using the highly successful methods of GRACE to obtain spatial resolution. This high time resolution would make ERI a synoptic variable like temperature, and allow studies of ERI's response to fast-evolving phenomena like dust storms and hurricanes and even brief excursions of Total Solar Irradiance. Time permitting, we

DFT/TDDFT investigation on the electronic structures and photophysical properties of phosphorescent iridium(III) complexes with 2-(pyridin-2-yl)-benzo[d]imidazole ligand

Energy Technology Data Exchange (ETDEWEB)

Shang, Xiaohong, E-mail: shangxiaohong58@aliyun.com [College of Chemistry and Life Science, Changchun University of Technology, Changchun 130012 (China); Han, Deming [School of Life Science and Technology, Changchun University of Science and Technology, Changchun 130022 (China); Li, Dongfeng [College of Chemistry and Life Science, Changchun University of Technology, Changchun 130012 (China); Zhang, Gang [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023 (China)

2014-03-15

We have reported a theoretical analysis of a series of heteroleptic iridium(III) complexes (mpmi){sub 2}Ir(pybi) [mpmi=1-(4-tolyl)-3-methyl-imidazole, pybi=2-(pyridin-2-yl)-benzo[d]imidazole] (1a), (fpmi){sub 2}Ir(pybi) [fpmi=1-(4-fluoro-phenyl)-3-methyl-imidazole] (1b), (tfpmi){sub 2}Ir(pybi) [tfpmi=1-methyl-3-(4-trifluoromethyl-phenyl)-imidazole] (1c), (pypmi){sub 2}Ir(pybi) [pypmi=3-(3-methyl-imidazol)-pyrazole] (2a), (phpymi){sub 2}Ir(pybi) [phpymi=3-(3-methyl-imidazol)-5-phenyl-pyrazole] (2b), and (inpymi){sub 2}Ir(pybi) [inpymi=3-(3-methyl-imidazol)-indeno[1,2-c]pyrazole] (2c) by using the density functional theory (DFT) method to investigate their electronic structures and photophysical properties and obtain further insights into the phosphorescent efficiency mechanism. By changing cyclometalated ligands, the conjugation length, and substituents of the cyclometalated ligands, one can tune the emission color from green (λ{sub em}=520 nm) to orange (λ{sub em}=592 nm). Complexes 1a, 1b, 2a, and 2b have the almost identical emission wavelength about 550 nm, while 592 nm for 1c and 520 nm for 2c are red shifted and blue shifted, respectively, relative to 1a. The calculated results indicate that, for 1b and 1c, the substituents of −F and −CF{sub 3} at the phenyl moiety cause a poor hole-injection ability compared with that of 1a. For all these complexes studied, the hole-transporting performances are better than the electron-transporting ones. The difference between reorganization energies for hole transport (λ{sub ih}) and reorganization energies for electron transport (λ{sub ie}) for complex 1c are relatively smaller, indicating that the hole and electron transfer balance could be achieved more easily in the emitting layer. The alteration of cyclometalated ligands with different conjugation lengths and substituents has an impact on the optoelectronic properties of these complexes. It is believed that the larger metal to ligand charge transfer (MLCT

27. V kell 16 avatakse Niguliste kirikus...

Index Scriptorium Estoniae

2002-01-01

EKA interdistsiplinaarsete kunstide eriala magistritööde näitus "Nagu aamen kirikus". Eksponeeritud Kristin Kalamehe lühimängufilm "Igavene tuli", Mirja-Mari Smidti video ja maaliseeria "Kaaluta olek", Allan Tõnissoo videoskulptuur "Kristus", Avangardi (Sandra Jõgeva, Margus Tamm) fotoseeria ja video "Sõda ja rahu". Avamisel Avangardi performance

Taani-Eesti disaini ühisprojekt / Toivo Raidmets, Morten Lund

Index Scriptorium Estoniae

Raidmets, Toivo, 1955-

1998-01-01

14.-25. sept.-ni Tallinnas näituse "Elava disaini dialoog" raames EKA sisearhitektuuri osakonna ja Taani Disaini Kooli üliõpilaste workshop Tallinna Vineeri- ja Mööblikombinaadis. Valminud töid eksponeeritakse 25.-29. sept.-ni EestiKunstiakadeemia galeriis. Näitus ja workshop kuuluvad Taani Kultuuriinstituudi programmi "Baltimaade naasmine".

A rapid and practical strategy for the determination of platinum, palladium, ruthenium, rhodium, iridium and gold in large amounts of ultrabasic rock by inductively coupled plasma optical emission spectrometry combined with ultrasound extraction

Science.gov (United States)

Zhang, Gai; Tian, Min

2015-04-01

This proposed method regulated the determination of platinum, palladium, ruthenium, rhodium, iridium and gold in platinum-group ores by nickel sulfide fire assay—inductively coupled plasma optical emission spectrometry (ICP-OES) combined with ultrasound extraction for the first time. The quantitative limits were 0.013-0.023μg/g. The samples were fused to separate the platinum-group elements from matrix. The nickel sulfide button was then dissolved with hydrochloric acid and the insoluble platinum-group sulfide residue was dissolved with aqua regia by ultrasound bath and finally determined by ICP-OES. The proposed method has been applied into the determination of platinum-group element and gold in large amounts of ultrabasic rocks from the Great Dyke of Zimbabwe.

Iridium-192 curietherapy for T1 and T2 epidermoid carcinomas of the floor of mouth

International Nuclear Information System (INIS)

Mazeron, J.J.; Grimard, L.; Raynal, M.; Haddad, E.; Piedbois, P.; Martin, M.; Marinello, G.; Nair, R.C.; Le Bourgeois, J.P.; Pierquin, B.

1990-01-01

From 1970 to 1986, 117 patients with T1 (47) or T2 (70) epidermoid carcinomas of the floor of the mouth (SCC) were treated by iridium-192 implantation (192 Ir). The dose was prescribed according to the Paris System and varied over those years. Follow-up information was available on 116 patients. There were 46 T1N0, 47 T2N0, and 23 T2N1-3. Neck management varied for the 93 N0 patients consisting of surveillance (24 T1, 17 T2) or elective neck dissection (22 T1:all pN-, 30 T2: 20 pN-, 10 pN+). Cause specific survival rates were 94% for T1N0, 61.5% for T2N0, and 28% for T2N1-3 at 5 years. Primary local control was 93.5%, 74.5%, and 65%, respectively, and 98%, 79%, and 65% after salvage. Patients with gingival extension or a tumor size over 3 cm (T2b) had a local control of 50% (9/18) and 58% (15/26), respectively. Nodal control was 93.5% for Stage I, 85% for Stage II, and 48% for T2N1-3 patients. There was no difference in nodal control with regard to treatment policy for Stage I-II patients. There were few complications including three deaths: two from surgery and one from 192 Ir. Nodal status, tumor size defined as T1, T2a (less than or equal to 3 cm), T2b (greater than 3 cm), and gingival extension were the only independent prognostic factors. The management of T1N0 and T2N0 SCC by 192 Ir to a dose of 65 or 70 Gy, using the Paris System, is recommended for lesions 3 cm or less and without gingival extension

Distribution of C-myc Antisense Oligonucleotides in Rabbits after Local Delivery by Implanted Gelatin Coated Piatinium -iridium Stent

Institute of Scientific and Technical Information of China (English)

张新霞; 庞志功; 崔长琮; 许香广; 胡雪松; 方卫华

2003-01-01

Objectives To assess the feasibility, efficiency and tissue distribution of localdelivered c - myc antisense oligonucleotides (ASODN)by implanted gelatin coated Platinium- Iridium (Pt-Ir) stent. Methods Gelatin coated Pt- Ir stentwhich absorbed carboxyfluorescein - 5 - succimidylester (FAM) labeled c -myc ASODN were implantedin the right carotid arteries of 6 rabbits under vision.Blood samples were collected at the indicated times.The target artery、 left carotid artery、 heart、 liver andkidney obtained at 45 minutes、 2 hours and 6hours. The concentration of c - myc ASODN in plasmaand tissues were determined by Thin Layer Fluorome-try. Tissue distribution of c- myc ASODN were as-sessed by fluorescence microscopy. Results At 45min, 2 h, 6 h, the concentration of FAM labeled c -myc ASODN in target artery was 244.39, 194.44,126.94(μg/g tissues) respectively, and the deliveryefficiency were 44.4% 、 35.4% and 23.1% respec-tively. At the same indicated time point, the plasmaconcentration was 8.41, 5. 83, 14.75 (μg/ml) respec-tively. Therefore c -myc ASODN concentrations in thetarget vessel were 29、 33 and 9 -fold higher than thatin the plasma. There was circumferential distribution oflabeled c -myc in the area of highest fluorescein co-inciding with the site of medial dissecting from stent-ing, and the label was most intense in target vesselmedia harvested at 45 min time point and then dis-persed to adventitia. Conclusions Gelatin coated Pt- Ir stent mediated local delivery of c - myc ASODN isfeasible and efficient. The localization of ASODN ismainly in target vessel wall.

Värske kunsti paraad / Karin Laansoo

Index Scriptorium Estoniae

Laansoo, Karin, 1976-

2003-01-01

30. V-8. VI Rotermanni soolalaos näitus "Eesti Kunstiakadeemia lõputööd 2003", mille on kujundanud Oliver Soomets ja Kaiko Kivi. Trükised on kujundanud Maya Zerebtsova. 6. VI moeetendus. Academia Grata lõpetajate teoseid esitletakse Pärnus, meediagraafika lõputöid kaitstakse 11. VI EKA aulas

Complexes of rhodium (I) and iridium (I) with mixed phosphorus-oxygen and phosphorus-nitrogen glands

Energy Technology Data Exchange (ETDEWEB)

Meintjies, E.; Singleton, E.; Schmutzler, R.; Sell, M.

1985-09-01

A series of four- and five-coordinate rhodium(I) and iridium(I) complexes of the type (MCl(cod)L) and (M(COD)L/sub 2/) sup(+)(M = Rh or Ir;cod = cycloocta-1,5-diene; L = P(C/sub 6/H/sub 4/OMe-o)/sub 3/, PMe/sub 2/(C/sub 6/H/sub 4/OMe-o), PPh/sub 2/(C/sub 6/H/sub 4/OMe-o), PPh/sub 2/-(C/sub 6/H/sub 4/NMe/sub 2/-o), PMe(C/sub 6/H/sub 4/OMe-o)/sub 2/ and PPh/sub 2/(C/sub 6/H/sub 4/OPr sup(i)-o)) have been prepared from the reactions of ((MCl(cod))/sub 2/) (M = Rh or Ir) with the appropriate stoichiometric amount of L in diethyl ether or methanol solution. N.M.R. evidence (/sup 1/H and /sup 13/C) is presented for non-chelation in the case of the ether ligands and chelation for the amine ligand. Thus, the complexes (MCl(cod)L)(L = ether ligand) are mononuclear square-planar species, whereas the amine ligand chelates to the metal atom, and a distorted trigonal bipyramidal structure is proposed. Attempts at displacing cod from the complexes (MCl(cod)L) with these ether and amine ligands, or with small phosphines, were unsuccessful. However, treatment of (MCl(cod)(P(C/sub 6/H/sub 4/OMe-o)/sub 3/))(M = Rh or Ir) with carbon monoxide gave (MCl(CO)/sub 2/ (P(C/sub 6/H/sub 4/OMe-o)/sub 3/)). In contrast, a disproportionation product, (RhCl(CNBu sup(t)/sub 2/(PPh/sub 2/ (C/sub 6/H/sub 4/OPr sup(i)-o))/sub 2/), was obtained from treatment of (RhCl(cod)(PPh/sub 2/(C/sub 6/H/sub 4/OPr sup(i)-o))) with t-butyl isocyanide. N.M.R. data (/sup 1/H and /sup 13/C) for the complexes are described.

Characterization of the EMOSFET, a novel one-electrode chemical transducer for redox measurements

NARCIS (Netherlands)

Hendrikse, J.; Olthuis, Wouter; Bergveld, Piet

1998-01-01

A sensor device consisting of a MOSFET with an iridium oxide gate contact and denoted an EMOSFET is presented. When the gate of this device is in contact with an electrolyte, the iridium oxide can take part in a redox reaction, enabling thermodynamic equilibrium between the electrons in the iridium

Safety aspects and safety measures for the refrigerants N{sub 3} and F-CFC and CFC; Sicherheitsaspekte/Sicherheitsmassnahmen fuer Kaeltemittel NH{sub 3} und FCKW/FKW

Energy Technology Data Exchange (ETDEWEB)

Stuerchler, P. [GfG AG, Binz (Switzerland)

2001-09-01

Experts agree that ammonia is the best and most economical refrigerant for a number of applications, e.g. in skating rinks, the food industry, chemical plants, etc. It has good thermodynamic properties and a low ozone-depleting potential, but it is also an aggressive and toxic substance. The potential hazard to humans and plants can be reduced, however, by early detection of leaks. There are different specifications in different European countries. In Switzerland, the EKAS regulations apply. [German] In der Kaelteindustrie herrscht eine Uebereinstimmung, dass fuer eine Vielzahl von Anlagen, z.B. Eissportanlagen, Lebensmittelbetriebe, Chemieanlagen u.v.m., Ammoniak als das beste und wirtschaftlichste Kaeltemittel betrachtet wird. Die guten thermodynamischen Eigenschaften und das geringe Ozonabbaupotential haben Ammoniak zum wichtigsten Kaeltemittel in mittleren und Grossanlagen gemacht. Die aggressive und giftige Chemikalie Ammoniak birgt jedoch ein nicht zu unterschaetzendes Gefahrenpotential fuer Mensch und Anlage. Diese Gefahr kann weitestgehend eingedaemmt werden. Eine fruehe und zuverlaessige Erkennung von Leckagen minimiert deren Auswirkungen und Schaeden. Die Vorschriften hierzu sind laenderspezifisch in den Verordnungen und Richtlinien festgelegt. Fuer die Schweiz gelten die Richtlinien der EKAS. (orig.)

Ba-bah on tulnud / Liina Jänes

Index Scriptorium Estoniae

Jänes, Liina, 1977-

2005-01-01

Eesti noori disainereid-sisearhitekte ühendavast disainiagentuurist Ba-bah, selle eesmärgist. Agentuuri juhib Veiko Jääger. Mais 2005 Disaini- ja Arhitektuurigaleriis toimunud Ba-bahi avanäitusest, kus oli väljas töid EKA sisearhitektuuri, klaasi-, ehte- ja sepakunsti eriala üliõpilastelt ning metallmööbli valmistajalt Kalle Pruudenilt

Eilne, tänane ja homne ehtekunst Marzees / Eilve Manglus

Index Scriptorium Estoniae

Manglus, Eilve, 1977-

2004-01-01

Euroopa ehtekunstikoolide lõputööde väljapanek Marzee galeriis kuni 6. X. Kuraator Manuel Vilhena. Eestit esindanud Kertu Tubergi, Maarja Niinemäe ja Epp Perteli ning Bas Boumani, Jantine Bindelsi (Holland) ja Andrew Lambi (London) töödest. Marzee kollektsiooni kuuluvad EKA lõpetanud ehtekunstnike Villu Plingi, Piret Hirve ja Kristiina Lauritsa ehted

75 FR 15679 - Initiation of Antidumping and Countervailing Duty Administrative Reviews and Request for...

Science.gov (United States)

2010-03-30

... S.A. India: Certain Preserved Mushrooms, A-533-813 2/1/09-1/31/10 Agro Dutch Foods Limited (Agro.../09-1/31/10 Indonesia: Certain Preserved Mushrooms, A-560-802 2/1/09-1/31/10 PT Eka Timur Raya (ETIRA... of China: Certain Preserved Mushrooms,\\6\\ A-570-851....... 2/1/09-1/31/10 Ayecue (Liaocheng...

offline@online / Rael Artel

Index Scriptorium Estoniae

Artel, Rael, 1980-

1999-01-01

Raivo Kelomehe kureeritud offline@online meediakunsti festival alapealkirjaga "Media non grata" EKA küberkohvikus "Enter". Peamiselt Eesti ekspositsioonist. CD-ROMe esitlesid: R. Kelomees, M. Mäetamm, R. Keller, K. Sibul, I. Kivi, T. Lepik. M. Lillaku, J. Orgussaare, R. Kelleri, Pusa ja J. Bergi filmidest. Moskva Kaasaegse Kunsti Keskuse MediaArtLabi, M. Holboomi, G. Mülleri esinemisest

Tudengid tulid appi / Kaupo Kala ; kommenteerinud Heikki Zoova

Index Scriptorium Estoniae

Kala, Kaupo

2010-01-01

Koristustarvikuid ja -vahendeid tootval ettevõttel KH Teh Production OÜ valmisid koostöös Eesti Kunstiakadeemia tootedisaini osakonnaga ettevõtte tootearendusprojekt, disaini juhtimise kava, uus pakendisüsteem, stiiliraamat, arendati uusi tooteid. Töörühma, kuhu kuulusid neli üliõpilast ja kaks firma töötajat, juhtis EKA tootedisaini osakonna juhataja Heikki Zoova

Carbon Dioxide Utilization by the Five-Membered Ring Products of Cyclometalation Reactions

Science.gov (United States)

Omae, Iwao

2016-01-01

In carbon dioxide utilization by cyclometalated five-membered ring products, the following compounds are used in four types of applications: 1. 2-Phenylpyrazole iridium compounds, pincer phosphine iridium compounds and 2-phenylimidazoline iridium compounds are used as catalysts for both formic acid production from CO2 and H2, and hydrogen production from the formic acid. This formic acid can be a useful agent for H2 production and storage for fuel cell electric vehicles. 2. Other chemicals, e.g., dimethyl carbonate, methane, methanol and CO, are produced with dimethylaminomethylphenyltin compounds, pincer phosphine iridium compounds, pincer phosphine nickel compound and ruthenium carbene compound or 2-phenylpyridine iridium compounds, and phenylbenzothiazole iridium compounds as the catalysts for the reactions with CO2. 3. The five-membered ring intermediates of cyclometalation reactions with the conventional substrates react with carbon dioxide to afford their many types of carboxylic acid derivatives. 4. Carbon dioxide is easily immobilized at room temperature with immobilizing agents such as pincer phosphine nickel compounds, pincer phosphine palladium compounds, pincer N,N-dimethylaminomethyltin compounds and tris(2-pyridylthio)methane zinc compounds. PMID:28503084

Long Term Measurement of the Earth's Radiation Budget using a constellation of Broadband Radiometers hosted on Iridium NEXT

Science.gov (United States)

Gupta, Om Prakash; Thoma, Donald; Chaloner, Chris; Russell, Jacqueline; Simpson, Bill; Spilling, David; Morris, Nigel; Caldwell, Martin; Oneill, Alan

The WMO called for "bringing new missions to operational status" and that "ERB should be measured through a constellation of sensors". A unique opportu-nity exists to host a set of Earth Radiation Budget (ERB) sensors on the Iridium NEXT (NEXT) LEO constellation in a cost effective manner that can deliver these requirements. The NEXT constellation, with 66 interconnected satellites in 6 near polar orbiting planes, provides a unique platform for hosting a variety of Earth observation missions including ERB. Launches are planned to begin in 2014 through 2016. The ERB both drives and responds to global climate and monitoring it can provide much insight into the climate system and how it might be changing. A climate quality measurement of the ERB requires high absolute accuracy and excellent stability and a long-term (decades) data record in order to inform the debate about global warming. Measurement of the ERB in terms of the broadband reflected solar (0.3 to 4 µm) and emitted thermal (4 to 200 µm) components have been identified as high priority by the WMO for climate observations. High temporal resolution is the key advantage offered by the NEXT platform and can provide a great step forward in accurately monitoring the energy balance of the planet. The sensor we propose will consist of a broad band instrument and associated imager for scene identification and cloud classification. There is the chance to place two such sensors in each of six different orbital planes this will improve the product refresh time from currently 12 hours to 3 hours. The increased temporal resolution will allow direct measure-ment of the changes to the broadband radiances that result from rapidly varying components of the climate such as cloud and aerosol, and avoid the need of relying on narrow band sensors to infer such changes. Considering that the prediction of cloud response to climate change is still a major source of uncertainty; improved measurement of the cloud effect and

Efficient blue-green and green electroluminescent devices obtained by doping iridium complexes into hole-block material as supplementary light-emitting layer

Energy Technology Data Exchange (ETDEWEB)

Zhou, Liang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zheng, Youxuan, E-mail: yxzheng@mail.nju.edu.cn [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Deng, Ruiping; Feng, Jing; Song, Mingxing; Hao, Zhaomin [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhang, Hongjie, E-mail: hongjie@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zuo, Jinglin; You, Xiaozeng [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

2014-04-15

In this work, organic electroluminescent (EL) devices with dominant and supplementary light-emitting layers (EMLs) were designed to further improve the EL performances of two iridium{sup III}-based phosphorescent complexes, which have been reported to provide EL devices with slow EL efficiency roll-off. The widely used hole-block material 2,2′,2''-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) was selected as host material to construct the supplementary EML. Compared with single-EML devices, double-EMLs devices showed higher EL efficiencies, higher brightness, and lower operation voltage attributed to wider recombination zone and better balance of carriers. In addition, the insertion of supplementary EML is instrumental in facilitating carriers trapping, thus improving the color purity. Finally, high performance blue-green and green EL devices with maximum current efficiencies of 35.22 and 90.68 cd/A, maximum power efficiencies of 26.36 and 98.18 lm/W, and maximum brightness of 56,678 and 112,352 cd/m{sup 2}, respectively, were obtained by optimizing the doping concentrations. Such a device design strategy extends the application of a double EML device structure and provides a chance to simplify device fabrication processes. -- Highlights: • Electroluminescent devices with supplementary light-emitting layer were fabricated. • Doping concentrations and thicknesses were optimized. • Better balance of holes and electrons causes the enhanced efficiency. • Improved carrier trapping suppresses the emission of host material.

mer-Bis[3,5-difluoro-2-(2-pyridylphenyl-κ2C1,N]{5-(2-pyridyl-κN-3-[3-(4-vinylbenzyloxyphenyl]-1,2,4-triazol-1-ido}iridium(III methanol solvate

Directory of Open Access Journals (Sweden)

Peter G. Jones

2010-01-01

Full Text Available In the title compound, [Ir(C11H6F2N2(C22H17N4O]·CH3OH, the coordination at iridium is essentially octahedral, but with distortions associated with the bite angles of the ligands [76.25 (9–80.71 (12°] and the differing trans influences of C and N ligands [Ir—N = 2.04 Å (average trans to N but 2.14 Å trans to C]. All three bidentate ligands have coordinating ring systems that are almost coplanar [interplanar angles = 1.7 (1–3.8 (2°]. The vinylbenzyl group is disordered over two positions with occupations of 0.653 (4 and 0.347 (4. The methanol solvent molecule is involved in a classical O—H...N hydrogen bond to a triazole N atom.

Geochemical study of trace elements in micrograin minerals

Energy Technology Data Exchange (ETDEWEB)

Toyoda, Kazuhiro; Shinozuka, Yoshitsugu; Imai, Shiho; Baba, Naoho; Machii, Tami; Shimada, Mitsuo; Hasebe, Kiyoshi [Hokkaido Univ., Sapporo (Japan)

1998-01-01

Abstract of five papers are contained in this paper. 1. Neutron activation analysis of iridium in Japan P/T boundary layer sample. Iridium of Permian/Triassic (P/T) boundary layer samples in Japan are determined. A collision of materials outside of the earth was not proved. 2. Adsorbability of rare earth elements by biogenic phosphate salt particles. Phosphate minerals are very strong adsorbent of rare earth elements, so that they can use as the removal materials of them in radioactive waste. 3. Analysis of undecomposed minerals and irresoluble compounds in acid decomposed residue. In order to investigate the past global changes, a micro wave heat method was studied and good results were obtained. 4. Determination of iridium in tsunami deposits in Cuba. Very small amount of iridium was discovered in the samples. 5. Activation analysis of iridium in the sample of 300 m core of Baikal lake. (Plan). (S.Y.)

Teine nahk ehk Ornament ja meie / Hanno Soans

Index Scriptorium Estoniae

Soans, Hanno, 1974-

2003-01-01

Arhitekt Adolf Loosi suhtumine ornamenti ja nahakaunistustesse, tattoo tagasitulek käibesse läänes XX sajandi II poolel. EKA nahakunsti eriala diplomandi Kerstin Raidma lõputööst, mis sisaldas seeria levinumaid tätoveeringupiirkondi katvaid nahast ehteid, lühidalt sama eriala lõpetaja Agnetha Kurusoni lõputööst "Kest" ja lõputööde hinnetest

Learned Helplessness Encountered by Michael Oher in the Blind Side Movie

OpenAIRE

PAMUNGKAS, DIMAS PROBO

2014-01-01

Pamungkas, Dimas Probo. 2014. Learned Helplessness Encountered by Michael Oher in The Blind Side Movie. Study Program of English, Department of Languages and Literature, Faculty of Culture Studies, Universitas Brawijaya. Supervisor: Dyah Eko Hapsari;Co-supervisor: Sarlettina Vidyayani EkaKeywords: Learned Helplessness, African-American, Psychological, Social Behavior, Depression, The Blind Side.Social behavior shows several interactions between person and social situations, which stress...

Näitused kunstiakadeemias

Index Scriptorium Estoniae

2003-01-01

EKA galeriis näitusel "Kirju pall" esitavad "krutskilist ökokunsti" rühmitus Puhas Rõõm, Mart Viljus, Anu Vahtra, Maris Mändel, Katrin Tees, Reimo Võsa-Tangsoo, Erki Kasemets, Raivo Hool. Aula fuajees näeb Jaak Soansi juhendamisel valminud skulptuuriosakonna õppetöid, valdavalt poliitikute skulptuurportreid. Osalevad Kristiina Järvelaid, Jelena Levtshenkova, Rene Reinumäe, Kaisa Uusoksa, Marju Vaher

Kuni 3. X on Frankfurdi lennujaamas (terminal 2)...

Index Scriptorium Estoniae

2004-01-01

Kaasaegse ehtekunsti noorima põlvkonna ehtete väljapanek. Näitusele valiti kahe EKA ehtekunsti eriala lõpetaja tööd. Maarja Niinemäe käevõrud pälvisid III preemia, Anni Kagovere mokume gane tehnikas hõbevaagnad äramärkimise. Septembris sai Maarja Niinemägi Leipzigi Midora messil ajakirja "GZ (Goldschmiede Zeitung) preemia "Best Graduate"

Reactivity of the parent amido complexes of iridium with olefins: C-NH2 bond formation versus C-H activation.

Science.gov (United States)

Mena, Inmaculada; García-Orduña, Pilar; Polo, Víctor; Lahoz, Fernando J; Casado, Miguel A; Oro, Luis A

2017-08-29

Herein we report on the different chemical reactivity displayed by two mononuclear terminal amido compounds depending on the nature of the coordinated diene. Hence, treatment of amido-bridged iridium complexes [{Ir(μ-NH 2 )(tfbb)} 3 ] (1; tfbb = tetrafluorobenzobarrelene) with dppp (dppp = bis(diphenylphosphane)propane) leads to the rupture of the amido bridges forming the mononuclear terminal amido compound [Ir(NH 2 )(dppp)(tfbb)] (3) in the first stage. On changing the reaction conditions, the formation of a C-NH 2 bond between the amido moiety and the coordinated diene is observed and a new dinuclear complex [{Ir(1,2-η 2 -4-κ-C 12 H 8 F 4 N)(dppp)} 2 (μ-dppp)] (4) has been isolated. On the contrary, the diiridium amido-bridged complex [{Ir(μ-NH 2 )(cod)} 2 ] (2; cod = 1,5-cyclooctadiene) in the presence of dppb (dppb = bis(diphenylphosphane)butane) allows the isolation of a mononuclear complex [Ir(1,2,3-η 3 -6-κ-C 8 H 10 )H(dppb)] (5), as a consequence of the extrusion of ammonia. The monitoring of the reaction of 2 with dppb (and dppp) allowed us to detect terminal amido complexes [Ir(NH 2 )(P-P)(cod)] (P-P = dppb (6), dppp (7)) in solution, as confirmed by an X-ray analysis of 7. Complex 7 was observed to evolve into hydrido species 5 at room temperature. DFT studies showed that C-H bond activation occurs through the deprotonation of one methylene fragment of the cod ligand by the highly basic terminal amido moiety instead of C-H oxidative addition to the Ir(i) center.

Handling of radiation emergency involving accidental detachment of 20 Ci iridium-192 source in a guide tube of a radiographic equipment in industrial radiography site

International Nuclear Information System (INIS)

Zaparde, S.P.; Murthy, B.K.S.; Vora, V.B.; Subramanian, G.

1979-01-01

The source capsule containing about 17.2 Ci of iridium-192 got accidently unscrewed in a guide tube of a gamma radiography equipment while carrying out the radiography of the spiral casing at construction site of a Hydroelectric Power Station. Immediately after the incident about 10 meter distance all around the spiral casing was cordoned off. The unscrewed capsule along with the source pellet was transferred to a lead container by raising the closed end of the guide tube of about 1/2 meters in length. The source pencil cable and cap of source capsule were separated from the source pellet. The source pellet was further shielded by a steel container and lead sheets. The source pellet was reloaded in the source capsule with limited facilities available at the work site. The source capsule cap was perfectly screwed by standing behind the L bench temporarily constructed out of lead sheets for the above jobs. During the above operation, the person received a whole body dose of 2000 mR and extrimety dose of 3000 mR. Handling of one more radiation emergency of similar type is described. A few appliances designed and fabricated for use in such emergencies are briefly described. (auth.)

Muscle invasive bladder cancer treated by transurethral resection, followed by external beam radiation and interstitial iridium-192

International Nuclear Information System (INIS)

Wijnmaalen, Arendjan; Helle, Peter A.; Koper, Peter C.M.; Jansen, Peter P.; Hanssen, Patrick E.; Kruger, Cornelis G.G. Boeken; Putten, Wim L.J. van

1997-01-01

Purpose: To evaluate the results of transurethral resection (TUR), external beam radiotherapy (EBRT), and interstitial radiation (IRT) with iridium-192, using the afterloading technique in patients with muscle invasive bladder cancer. Methods and Materials: From May 1989 until September 1995, 66 patients with primary, solitary muscle invasive bladder cancer were treated with TUR, EBRT, and IRT, aiming at bladder preservation. According to the protocol, in three patients low-dose EBRT was applied, whereas 63 patients received high-dose EBRT. Immediately prior to IRT, 42 patients underwent a lymphnode dissection, and in 16 cases a partial cystectomy was performed. For IRT, two to five catheters were used and IRT was started within 24 h after surgery. The majority of patients received 30 Gy of IRT, with a mean dose rate of .58 Gy/h. In three patients, additional EBRT was applied following IRT. Follow-up consisted of regular cystoscopies, mostly done during joint clinics of urologist and radiation oncologist, with urine cytology routinely performed. The median follow-up period was 26 months. The Kaplan-Meier method was used for the determination of survival rates. Results: In seven patients, a bladder relapse developed. The probability of remaining bladder relapse free at 5 years was 88%. The bladder was preserved in 98% of the surviving patients. Metastases developed in 16 patients, and the probability of remaining metastasis free at 5 years was 66%. The cumulative 5-year overall and bladder and distant relapse free survival were 48% and 69%, respectively. Acute toxicity was not serious in the majority of cases; surgical correction of a persisting vesicocutaneous fistula was necessary in two patients, whereas a wound toilet had to be performed in another patient. Serious late toxicity (bladder, RTOG Grade 3) was experienced by only one patient. Conclusions: Interstitial radiation preceded by TUR and EBRT, in a selected group of patients with muscle invasive bladder

Kunstiakadeemia kolib ajutiselt Estonia puiesteele / Mari Kodres

Index Scriptorium Estoniae

Kodres, Mari

2009-01-01

Eesti Kunstiakadeemia on 2010. a. alguseks vanadest ruumidest kolinud hoonesse aadressil Estonia pst. 7. Rüütelkonna hoones leidis endale ajutise kodu vabade kunstide teaduskonna enamik erialasid. Veebruari algul toimuvast tühjendamispeost. EKA uue maja arhitektuurikonkursi võitis Taani arhitektuuribüroodes Sea ja Effekt valminud töö "Art Plaza". Uue hoone ehitus algab aprillis, valmimistähtajaks on 2012. a. kevad

Elu- ja mõtterännakud, minemised ja saatmised / Kaljo Põllu ; interv. Jonathan Roper, Marika Alver

Index Scriptorium Estoniae

Põllu, Kaljo, 1934-2010

2007-01-01

Kaljo Põllu oma kunstiõpingutest, loomingust, tööst Tartu Ülikooli kunstikabineti juhatajana, käikudest soomeugrilaste juurde, soome-ugri ekpeditsioonide korraldamisest kunstiinstituudis, ekspeditsioonide mõjust üliõpilaste mõtteviisile ja kunstile, rühmitusest Ydi, soomeugrilisusest eemaldumisest. Leedsi ülikooli inglise filoloogia lektor Jonathan Rops on käinud koos EKA üliõpilastega ekspeditsioonidel 1998., 1999. ja 2003. aastal

Talv 2015 = Winter 2015

Index Scriptorium Estoniae

2015-01-01

Aasta võitjad: Mart Kalm EKA rektoriks, Jaanus Samma Veneetsia biennaalil, Kris Lemsalu New Yorgi kunstimessil, Anu Vahtrale Köler Prize 2015, Raymond Pettiboni ja Marko Mäetamme isiknäitused Kumus, Katja Novitskova MoMa-s, Tanja Muravskajale Sadolini kunstipreemia, Tõnis Saadojale Konrad Mäe medal ja preemia, EKKM uued tegevjuhid on Marten Esko ja Johannes Säre, kunstnikupalka hakkavad saama viis Eesti kunstnikku

Eksperimendid ruumis / Toomas Tammis

Index Scriptorium Estoniae

Tammis, Toomas, 1969-

2014-01-01

EKA arhitektuuriteaduskonnas tehakse erialaprojekti kõrval väga erinevaid ruumilisi harjutusi. Esitletud on valik väiksemate töötubade ja kursuste töid: Kineetilise arhitektuuri töötuba "Volditav, klapitav, rullitav, pakitav", 2014 (juhendaja Renee Puusepp); Parameetrilise disaini valikaine, 2011 (juhendaja Raul Kalvo, assistent Kristjan Männigo); Maketistuudio, 2014 (juhendaja Paco Ulman); Eksperimentaalse arhitektuuri problemaatika, 2014 (juhendajad Martin Melioranski ja Paco Ulman)

Täna kell 19 avatakse Kultuuritehases Polymer...

Index Scriptorium Estoniae

2005-01-01

EKA Erasmuse programmi vahetusüliõpilaste ja nende eesti sõprade multimeediaüritus "PC - rahvusvahelised lained Tallinnas!". Osalevad Austria, Mehhiko, Saksamaa, Itaalia, Soome, Eesti, Poola, Hispaania, Prantsusmaa, Belgia, Šveitsi, Portugali, Tšehhi, USA ja Läti 2004. ja 2005. a. Eestis elanud kunstiüliõpilased. Kunstiprogrammile järgneb kontsert ja pidu DJde Andres Lõo, Valner Valme ja Christoph Höschele osavõtul

Meediakunsti mainet saab tõsta ainult järjekindla tööga / Jane Suviste, Piibe Piirma ; interv. Reet Varblane

Index Scriptorium Estoniae

Suviste, Jane

2006-01-01

Intervjuu 2006. a. jaanuaris loodud Eesti Meediakunstnike Ühingu asutajaliikmetega. Ühingu eesmärgist, MediaLabist Polümeeri tehases, koostööst EKA e-meedia keskusega, plaanitavast koostööst Tartu Kõrgema Kunstikooli ja Mooste külalisateljeega, austria kunstniku Barbara Musili videote näitusest MediaLabis 7. IV, mai algul toimunud üritusest "Switch", laste ja noorte kaasamisest jm.

Characterisation of thin films of organic phosphorescent materials using synchrotron radiation

International Nuclear Information System (INIS)

Thompson, J.; Arima, V.; Matino, F.; Cingolani, R.; Blyth, R.I.R.

2005-01-01

Synchrotron radiation photoemission and X-ray absorption spectroscopy (NEXAFS) have been used to investigate the electronic structure of evaporated films of the phosphorescent organic iridium complexes iridium tris-(2-(4-totyl)pyridinato-N,C 2 ), iridium bis(2-(4,6-difluorophenyl)pyridinato-N,C 2 )picolinate, and iridium bis(2-(2'-benzothienyl)pyridinato-N,C 3 )-(acetylacetonate) and spin coated films of these materials in a polymer host. Resonant photoemission at the Ir N 6,7 edge indicates that the Ir 5d states are hybridised with the π orbitals of the organic ligands, in agreement with recent calculations. The nitrogen K-edge NEXAFS shows the difference in the unoccupied orbitals induced by the acetylacetonate group compared to those of the pyridinate ligands. Although the valence bands of the ex situ prepared films are not accessible to photoemission, the Ir 4f core levels remain visible, and demonstrate that the polymer host serves to lower the electron injection barrier in the iridium complexes in comparison to the pure films

Characterisation of thin films of organic phosphorescent materials using synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Thompson, J. [Float-Lux srl., via Ravenna 14, 73100 Lecce (Italy); Arima, V. [National Nanotechnology Laboratory of INFM, Distretto Tecnologico ISUFI, Universita di Lecce, via per Arnesano, 73100 Lecce (Italy); Matino, F. [National Nanotechnology Laboratory of INFM, Distretto Tecnologico ISUFI, Universita di Lecce, via per Arnesano, 73100 Lecce (Italy); Cingolani, R. [National Nanotechnology Laboratory of INFM, Distretto Tecnologico ISUFI, Universita di Lecce, via per Arnesano, 73100 Lecce (Italy); Blyth, R.I.R. [National Nanotechnology Laboratory of INFM, Distretto Tecnologico ISUFI, Universita di Lecce, via per Arnesano, 73100 Lecce (Italy)]. E-mail: rob.blyth@unile.it

2005-07-30

Synchrotron radiation photoemission and X-ray absorption spectroscopy (NEXAFS) have been used to investigate the electronic structure of evaporated films of the phosphorescent organic iridium complexes iridium tris-(2-(4-totyl)pyridinato-N,C{sup 2}), iridium bis(2-(4,6-difluorophenyl)pyridinato-N,C{sup 2})picolinate, and iridium bis(2-(2'-benzothienyl)pyridinato-N,C{sup 3})-(acetylacetonate) and spin coated films of these materials in a polymer host. Resonant photoemission at the Ir N{sub 6,7} edge indicates that the Ir 5d states are hybridised with the {pi} orbitals of the organic ligands, in agreement with recent calculations. The nitrogen K-edge NEXAFS shows the difference in the unoccupied orbitals induced by the acetylacetonate group compared to those of the pyridinate ligands. Although the valence bands of the ex situ prepared films are not accessible to photoemission, the Ir 4f core levels remain visible, and demonstrate that the polymer host serves to lower the electron injection barrier in the iridium complexes in comparison to the pure films.

When two are better than one: bright phosphorescence from non-stereogenic dinuclear iridium(III) complexes.

Science.gov (United States)

Daniels, Ruth E; Culham, Stacey; Hunter, Michael; Durrant, Marcus C; Probert, Michael R; Clegg, William; Williams, J A Gareth; Kozhevnikov, Valery N

2016-04-28

A new family of eight dinuclear iridium(iii) complexes has been prepared, featuring 4,6-diarylpyrimidines L(y) as bis-N^C-coordinating bridging ligands. The metal ions are also coordinated by a terminal N^C^N-cyclometallating ligand L(X) based on 1,3-di(2-pyridyl)benzene, and by a monodentate chloride or cyanide. The general formula of the compounds is {IrL(X)Z}2L(y) (Z = Cl or CN). The family comprises examples with three different L(X) ligands and five different diarylpyrimidines L(y), of which four are diphenylpyrimidines and one is a dithienylpyrimidine. The requisite proligands have been synthesised via standard cross-coupling methodology. The synthesis of the complexes involves a two-step procedure, in which L(X)H is reacted with IrCl3·3H2O to form dinuclear complexes of the form [IrL(X)Cl(μ-Cl)]2, followed by treatment with the diarylpyrimidine L(y)H2. Crucially, each complex is formed as a single compound only: the strong trans influence of the metallated rings dictates the relative disposition of the ligands, whilst the use of symmetrically substituted tridentate ligands eliminates the possibility of Λ and Δ enantiomers that are obtained when bis-bidentate units are linked through bridging ligands. The crystal structure of one member of the family has been obtained using a synchrotron X-ray source. All of the complexes are very brightly luminescent, with emission maxima in solution varying over the range 517-572 nm, according to the identity of the ligands. The highest-energy emitter is the cyanide derivative whilst the lowest is the complex with the dithienylpyrimidine. The trends in both the absorption and emission energies as a function of ligand substituent have been rationalised accurately with the aid of TD-DFT calculations. The lowest-excited singlet and triplet levels correlate with the trend in the HOMO-LUMO gap. All the complexes have quantum yields that are close to unity and phosphorescence lifetimes - of the order of 500 ns - that are

[Eesti Kunstiakadeemia uue hoone rahvusvaheline arhitektuurivõistlus] : EKA maja

Index Scriptorium Estoniae

2008-01-01

Žürii hääletustulemused ja hinnangud. I preemia - "Art Plaza", taani arhitektid Uffe Leth Laursen, Tue Hesselberg Foged, Karsten Gori, Sinus Lynge, Greta Tedje, Simon Sorensen, Lawrence Aeberhard, Lyndal Brown, Morgan Jacobsen (AB Sea + Effekt). II - "TLN 247", Hollandi AB NAT Architecten bv, M. van Zijl, V. van der Klei, F. A. van Manen, B. de Graaf, T. M. van Dijkhuizen, S. van der Meer, D. Awe, N. Limburg, J. Kuilman. III - "Arts Factory", Portugali AB Neralp-Arquitectura Engenharia e Construcoes Lda, Paulo Sergio Goncalves Teixeira de Sousa. Ergutuspreemia - "Publicsection", Hollandi AB BOARD, Bernd Upmeyer, kaastöö: Claudia Hess ja "Sashimi", jaapani arhitekt Francois Blanciak

Inimesed linnas = People in the city / Kaja Pae

Index Scriptorium Estoniae

Pae, Kaja

2006-01-01

Eesti näitus "Joint Space" Veneetsia 10. arhitektuuribiennaalil. AB Urban Mark: Ülar Mark, Indrek Tiigi, Kaja Pae, Yoko Alender, Raul Kalvo, Tartu Ülikooli Geograafiainstituut: Rein Ahas, Anto Aasa, Siiri Silm, Positium ICT: Margus Tiru, Erki Saluveer. Näitusel oli eksponeeritud kolm mobiilpositsioneerimisega läbi viidud case study (EKA liikmete liikumisuuring, Eestit külastanud turistide uuring, Tallinna regiooni pendelrändajate uuring). Bibliograafia lk. 33

Impact of metal nano layer thickness on tunneling oxide and memory performance of core-shell iridium-oxide nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Banerjee, W.; Maikap, S. [Thin Film Nano Tech. Lab., Department of Electronic Engineering, Chang Gung University, Tao-Yuan, Taiwan 333, Taiwan (China); Tien, T.-C. [Material Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan 310, Taiwan (China); Li, W.-C.; Yang, J.-R. [Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan (China)

2011-10-01

The impact of iridium-oxide (IrO{sub x}) nano layer thickness on the tunneling oxide and memory performance of IrO{sub x} metal nanocrystals in an n-Si/SiO{sub 2}/Al{sub 2}O{sub 3}/IrO{sub x}/Al{sub 2}O{sub 3}/IrO{sub x} structure has been investigated. A thinner (1.5 nm) IrO{sub x} nano layer has shown better memory performance than that of a thicker one (2.5 nm). Core-shell IrO{sub x} nanocrystals with a small average diameter of 2.4 nm and a high density of {approx}2 x 10{sup 12}/cm{sup 2} have been observed by scanning transmission electron microscopy. The IrO{sub x} nanocrystals are confirmed by x-ray photoelectron spectroscopy. A large memory window of 3.0 V at a sweeping gate voltage of {+-}5 V and 7.2 V at a sweeping gate voltage of {+-} 8 V has been observed for the 1.5 nm-thick IrO{sub x} nano layer memory capacitors with a small equivalent oxide thickness of 8 nm. The electrons and holes are trapped in the core and annular regions of the IrO{sub x} nanocrystals, respectively, which is explained by Gibbs free energy. High electron and hole-trapping densities are found to be 1.5 x 10{sup 13}/cm{sup 2} and 2 x 10{sup 13}/cm{sup 2}, respectively, due to the small size and high-density of IrO{sub x} nanocrystals. Excellent program/erase endurance of >10{sup 6} cycles and good retention of 10{sup 4} s with a good memory window of >1.2 V under a small operation voltage of {+-} 5 V are obtained. A large memory size of >10 Tbit/sq. in. can be designed by using the IrO{sub x} nanocrystals. This study is not only important for the IrO{sub x} nanocrystal charge-trapping memory investigation but it will also help to design future metal nanocrystal flash memory.

Impact of metal nano layer thickness on tunneling oxide and memory performance of core-shell iridium-oxide nanocrystals

International Nuclear Information System (INIS)

Banerjee, W.; Maikap, S.; Tien, T.-C.; Li, W.-C.; Yang, J.-R.

2011-01-01

The impact of iridium-oxide (IrO x ) nano layer thickness on the tunneling oxide and memory performance of IrO x metal nanocrystals in an n-Si/SiO 2 /Al 2 O 3 /IrO x /Al 2 O 3 /IrO x structure has been investigated. A thinner (1.5 nm) IrO x nano layer has shown better memory performance than that of a thicker one (2.5 nm). Core-shell IrO x nanocrystals with a small average diameter of 2.4 nm and a high density of ∼2 x 10 12 /cm 2 have been observed by scanning transmission electron microscopy. The IrO x nanocrystals are confirmed by x-ray photoelectron spectroscopy. A large memory window of 3.0 V at a sweeping gate voltage of ±5 V and 7.2 V at a sweeping gate voltage of ± 8 V has been observed for the 1.5 nm-thick IrO x nano layer memory capacitors with a small equivalent oxide thickness of 8 nm. The electrons and holes are trapped in the core and annular regions of the IrO x nanocrystals, respectively, which is explained by Gibbs free energy. High electron and hole-trapping densities are found to be 1.5 x 10 13 /cm 2 and 2 x 10 13 /cm 2 , respectively, due to the small size and high-density of IrO x nanocrystals. Excellent program/erase endurance of >10 6 cycles and good retention of 10 4 s with a good memory window of >1.2 V under a small operation voltage of ± 5 V are obtained. A large memory size of >10 Tbit/sq. in. can be designed by using the IrO x nanocrystals. This study is not only important for the IrO x nanocrystal charge-trapping memory investigation but it will also help to design future metal nanocrystal flash memory.

Loss of an iridium-192 source and therapy misadministration at Indiana Regional Cancer Center, Indiana, Pennsylvania, on November 16, 1992

International Nuclear Information System (INIS)

1993-02-01

On December 1, 1992, the Indiana Regional Cancer Center reported to the US Nuclear Regulatory Commission's (NRC) Region I that they believed a 1.37 E + 11 becquerel (3.7-curie) iridium-192 source from their Omnitron 2000 high dose rate remote brachytherapy afterloader had been found at a biohazard waste transfer station in Carnegie, Pennsylvania. After notifying the NRC, this cancer center, one of several operated by the licensee, Oncology Services Corporation, retrieved the source, and Region I dispatched an inspector and a supervisor to investigate the event. The source was first detected when it triggered radiation alarms at a waste incinerator facility in. Warren, Ohio. The licensee informed the NRC that the source wire had apparently broken during treatment of a patient on November 16, 1992, leaving the source in the patient. On the basis of the seriousness of the incident, the NRC elevated its response to an Incident Investigation. The Incident Investigation Team initiated its investigation on December 3, 1992. The investigation team concluded that the patient received a serious misadministration and died on November 21, 1992, and that over 90 individuals were exposed to radiation from November 16 to December 1, 1992. In a press release dated January 26, 1993, the Indiana County Coroner stated that the cause of death listed in the official autopsy report was ''Acute Radiational Exposure and Consequences Thereof'' An almost identical source wire failure occurred with an afterloader in Pittsburgh, Pennsylvania, on December 7, 1992, but with minimal radiological consequences. This incident was included in the investigation. This report discusses the Omnitron 2000 high dose rate afterloader source-wire failure, the reasons why the failure was not detected by Indiana Regional Cancer Center, the potential consequences to the patient, the estimated radiological doses to workers and the public, and regulatory aspects associated with this incident

Recovery from Iridium-192 flakes of a radioactive source for industrial use after a radiation incident; Recuperacion de hojuelas de Iridio-192 provenientes de una fuente radiactivas de uso industrial despues de un incidente radiologico

Energy Technology Data Exchange (ETDEWEB)

Cruz, W.H.; Zapata, L.A., E-mail: wcruz@ipen.gob.pe, E-mail: lzapata@ipen.gob.pe [Instituto Peruano de Energia Nuclear (GRRA/IPEN), Lima (Peru). Division de Gestion de Residuos Radiactivos

2013-07-01

The Iridium-192 ({sup 192}Ir) is the most used and ideal for industrial radiography applications, especially in petrochemical plants and pipelines and provides better contrast sensitivity for thick (25.4 mm). This source has constructive sealed double encapsulation, the internal capsule containing stainless steel to radioactive material in the form of flakes and welded with TIG process. The radiological incident happened at a gas station fuel sales in circumstances in which there was a homogeneity test welds a tank, the flakes or Ir-192 fell off his ponytail and left scattered over an area of 2 m{sup 2}, some fell flat areas and other land so collected in lead shielding and metal container and ground source. Full recovery of the leaflets was performed at the Division of radioactive waste management (GRRA) gaining a total of 22 flakes with no radiation risk to staff performance and installation and the conclusion was reached that the misapplicaion of TIG welding was the main cause the incident. (author)

Theoretical study on the electronic structures and phosphorescent properties of a series of iridium(III) complexes with the different positional N-substitution in the pyridyl moiety

Energy Technology Data Exchange (ETDEWEB)

Han, Deming; Hao, Fengqi [School of Life Science and Technology, Changchun University of Science and Technology, Changchun 130022 (China); Tian, Jian [Clean Energy Technology Laboratory, Changchun University of Science and Technology, Changchun 130022 (China); Pang, Chunying; Li, Jingmei [School of Life Science and Technology, Changchun University of Science and Technology, Changchun 130022 (China); Zhao, Lihui, E-mail: zhaolihui@yahoo.com [School of Life Science and Technology, Changchun University of Science and Technology, Changchun 130022 (China); Zhang, Gang [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023 (China)

2015-03-15

The geometry structures, electronic structures, absorption and phosphorescent properties of a series of iridium(III) complexes with the different N-substitution cyclometalating ligand and the same benzyldiphenylphosphine auxiliary ligand have been theoretically investigated by using the density functional theory method. The lowest energy absorption wavelengths are located at 378 nm for A, 430 nm for B, 411 nm for C, 436 nm for D, and 394 nm for E. The introduction of N atom substitution at 1-, 2-, 3-, and 4-positions on the pyridyl moiety of complex A leads to an obvious redshifted absorption. The lowest energy emissions for complexes A–E are localized at 450, 409, 438, 483, and 429 nm, respectively, simulated in CH{sub 2}Cl{sub 2} medium at M052X level. Ionization potential and electron affinity have been calculated to evaluate the injection abilities of holes and electrons into these complexes. For complex C, the calculated results showed that it can possibly possess the larger radiative decay rate (k{sub r}) value than those of other four complexes. It is anticipated that the theoretical studies can provide valuable information for designing new phosphorescent metal complexes of organic light-emitting diodes. - Highlights: • Five Ir(III) complexes have been theoretically investigated. • The effect of N-substitution cyclometalating ligand has been studied. • The complex C possibly possesses the largest radiative decay rate value.

Kui vana on kunstnik? / Anneli Porri

Index Scriptorium Estoniae

Porri, Anneli, 1980-

2003-01-01

Rahvusvahelise kunstihariduse konverentsi "InSea on Sea" raames Kunstiakadeemia galeriis Karin Laansoo kureeritud Tallinna Kunstikooli õpilaste tööde näitus "MÄRKmed", Draakoni galeriis Mari Sobolevi kureeritud Viljandi Maagümnaasiumi kunstistuudio näitus "Sisseastumiseksam maailma", rahvusraamatukogus Anneli Porri kureeritud näitus "Kokkuvõte" EKA tänavuste lõpetajate töödest ja näitus "Leitud tagahoovist", Kullo galeriis rahvusvaheline näitus "Dialoog erinevuste vahel"

Leonardo da Vinci maali näidatakse peagi Kadriorus / Gianni Glinni, Orest Kormašov ; intervjueerinud Mart Zirnask

Index Scriptorium Estoniae

Glinni, Gianni

2009-01-01

Kadrioru Kunstimuuseumis eksponeeritakse 5.-12. veebruarini 2010. a. Leonardo da Vinci arvatavat autoportreed ning 6. veebruaril toimub Tallinna Ülikoolis maali analüüse tutvustav konverents. Portree leiti 2008. aastal ühest Lõuna-Itaalia erakogust. TLÜ kunstiosakonna juhataja Orest Kormašov valmistas maali järgi skulptuuri ja EKA tudeng ja graafiline disainer Helen Kokk arvutimudeli. Intervjuus jagavad teemakohaseid selgitusi üks uuringute eestvedaja Gianni Glinni ja Orest Kormašov

Kas praegune triennaal õnnestus? : tarbekunst / Ketli Tiitsar ; interv. R[eet] V[arblane

Index Scriptorium Estoniae

Tiitsar, Ketli

2006-01-01

Tallinna IV rakenduskunsti triennaali töögrupi liige K. Tiitsar triennaalist, näituse kujundusest (3+1 Arhitektid), eesti tarbekunstist, seminarist ja esitluste päevast (Mecky van den Brinki, Heli Hietala, Marie-Louise Kristenseni, Outi Liusvaara esinemine), satelliitnäitustest (Anneli Porri ja Pille-Triin Männiku kuraatoriprojekt "Teadus ja tänapäev", Hollandi Gerrit Rietveldi akadeemia ehteosakonna üliõpilaste tööde näitus EKA galeriis)

Possible impact of iridium-192 source centering on restenosis rate after femoro-popliteal angioplasty and endovascular brachytherapy in Vienna-2 study

International Nuclear Information System (INIS)

Pokrajac, Boris; Schmid, Rainer; Kirisits, Christian; Mock, Ulrike; Fellner, Claudia; Wambersie, Andre; Poetter, Richard; Minar, Erich

2002-01-01

Purpose: Endovascular brachytherapy (EVBT) has been proven to significantly reduce restenosis after percutaneous transluminal angioplasty (PTA). The object of this analysis was to assess the possible correlation between iridium-192 source non-centering and angiographic-determined restenosis. Materials and methods: A total of 113 patients with long-segment lesions of the superficial femoro-popliteal artery (SFA) were randomized to receive either PTA alone or PTA followed by EVBT in the Vienna-2 study. This analysis was performed on a subgroup of 34 out of 57 patients, who received PTA+EVBT. Angiographic restenosis was defined as lumen reduction of more than 50%. Angiograms taken immediately after PTA (34 patients) and at follow-up (25 patients) were analyzed. The distance between the vessel wall and the actual position of the source at the time of EVBT was measured (in mm) and correlated with the follow-up vessel lumen diameter. Measurements were performed at points at a distance of 10 mm from each other. The dose was determined at the luminal surface and at the reference depth of 2 mm into the vessel wall for different distances from the source. Results: Among the 622 measured points, 62 (10.0%) were within restenotic areas; 560 (90.0%) were in arterial segments without proven angiographic restenosis. As far as source centering is concerned, 7.9% of restenotic points were observed when the maximum distance to the arterial wall was 5 mm. Conclusions: The proportion of restenotic points significantly increased with source non-centering. This observation was interpreted as being related to a decrease in dose at the target. When the maximum distance between the source and the vessel surface was >5 mm, the dose at the reference depth (2 mm into the vessel wall) decreased to values lower than 5 Gy

238Pu fuel form processes. Final report, January-September 1983

International Nuclear Information System (INIS)

Mosley, W.C.; Taylor, D.H.

1983-01-01

Progress is reported on the following: analytical studies of weld-quench cracking in DOP-26 iridium alloy, iridium/ 238 PuO 2 compatibility test, surface area measurements of 238 PuO 2 using the Blaine air permeability apparatus, and helium release from 238 PuO 2

Disaini ja rahvaste saatusest / Daniel Van der Velden ; interv. Kristjan Mändmaa

Index Scriptorium Estoniae

Van der Velden, Daniel

2008-01-01

17.-27. X 2008 oli Eesti Kunstiakadeemias näitus "Marsilt. Omaalgatuslikud projektid graafilises disainis". Kuraatorid: tšehhi disainerid Adam Machacek ja Radim Peshko. 17. X esinesid EKA saalis loengutega James Goggin Londoni firmast Practice ja Daniel van der Velden Hollandi disainikollektiivist Metahaven. 16. V osales D. van der Velden Eesti Disainiinstituudi korraldatud kohabrändingu-teemalises ümarlauas. D. van der Velden disaini, poliitika ja kohabrändingu tulevikust, Metahaveni disainitöödest

Disaini ja rahvaste saatusest / Daniel Van der Velden ; intervjueerinud Kristjan Mändmaa

Index Scriptorium Estoniae

Van der Velden, Daniel

2011-01-01

17.-27. X 2008 oli Eesti Kunstiakadeemias näitus "Marsilt. Omaalgatuslikud projektid graafilises disainis". Kuraatorid: tšehhi disainerid Adam Machacek ja Radim Peshko. 17. X esinesid EKA saalis loengutega James Goggin Londoni firmast Practice ja Daniel van der Velden Hollandi disainikollektiivist Metahaven. 16. V osales D. van der Velden Eesti Disainiinstituudi korraldatud kohabrändingu-teemalises ümarlauas. D. van der Velden disaini, poliitika ja kohabrändingu tulevikust, Metahaveni disainitöödest

Ülikoolid pole mängukannid / Sirje Tohver

Index Scriptorium Estoniae

Tohver, Sirje

2001-01-01

TPÜ korraldas 16. märtsil̀ 2001 ümarlaua "Ülikoolid pole mängukannid", kus oli arutusel riikliku koolitustellimuse vähenemine avalik-õiguslikele ülikoolidele. Osalesid TPÜ filoloogiateaduskonna dekaan dots. H. Mattisen, kultuuriteaduskonna dekaan prof. A. Avarand, akadeemiline prorektor dots. L. Jõgi, teadus- ja arendusprorektor prof. P. Normak, haridusminister T. Lukas, TPÜ rektor prof. M. Arvisto ja EKA rektor prof. A. Keskküla, TTÜ rektor prof. A. Keevallik, EMA õppeprorektor A. Pung

30. X tähistab EKA 90. aastapäeva

Index Scriptorium Estoniae

2004-01-01

Näitustest. 29. X audoktorite Udo Kultermanni ja Juhani Pallasmaa loengud ning ümarlaud "Disain, tulevik ja identiteet", kus esitavad ettekande Halldor Gislason (Reykjavik), Francois Penz (Cambridge), Bruce Brown (Brighton), Peter McGrory (Helsingi) ja Michael U. Hensel (London), ümarlauda juhib Jüri Soolep. 30. X vilistlaspäev, audoktoriteks promoveeritakse Juhani Pallasmaa, Udo Kultermann, Lars Olof Larsson ja Yrjö Sotamaa

"Art Plaza" oli vaieldamatult parim projekt : EKA maja / Indrek Allmann

Index Scriptorium Estoniae

Allmann, Indrek, 1972-

2008-01-01

Eesti Kunstiakadeemia uue hoone rahvusvahelisel arhitektuurikonkursil I preemia saanud Taani arhitektuuribüroode Sea + Effekt projektis "Art Plaza" on arvestatud ajaloolist konteksti ja jätkusuutlikkust. "Art Plaza" taustaks näiteid arhitektuuriajaloost

Platinum Group Thiophenoxyimine Complexes: Syntheses,Crystallographic and Computational Studies of Structural Properties

Energy Technology Data Exchange (ETDEWEB)

Krinsky, Jamin L.; Arnold, John; Bergman, Robert G.

2006-10-03

Monomeric thiosalicylaldiminate complexes of rhodium(I) and iridium(I) were prepared by ligand transfer from the homoleptic zinc(II) species. In the presence of strongly donating ligands, the iridium complexes undergo insertion of the metal into the imine carbon-hydrogen bond. Thiophenoxyketimines were prepared by non-templated reaction of o-mercaptoacetophenone with anilines, and were complexed with rhodium(I), iridium(I), nickel(II) and platinum(II). X-ray crystallographic studies showed that while the thiosalicylaldiminate complexes display planar ligand conformations, those of the thiophenoxyketiminates are strongly distorted. Results of a computational study were consistent with a steric-strain interpretation of the difference in preferred ligand geometries.

Tantalum carbide as a novel support material for anode electrocatalysts in polymer electrolyte membrane water electrolysers

DEFF Research Database (Denmark)

Polonský, Jakub; Petrushina, Irina; Christensen, Erik

2012-01-01

Iridium oxide (IrO2) currently represents a state of the art electrocatalyst for anodic oxygen evolution. Since iridium is both expensive and scarce, the future practical application of this process makes it essential to reduce IrO2 loading on the anodes of PEM water electrolysers. In the present...

Pärnus on uus nüüdiskunsti galerii!

Index Scriptorium Estoniae

2004-01-01

17. VI Pärnus Lõuna t. 20 avatud eksperimentaalne Rael Artel Gallery keskendub esimesel hooajal eelkõige foto ja sound art'i eksponeerimisele. Kuraatorid: Anu Allas, Andreas W, EKA kunstiteaduse üliõpilased Marion Tupits, Aleksander Tsapov, Urmas Oja. Galeristi Rael Arteli kureeritud avanäitusel "Jagatud kehad" on väljas Eveli Variku, Tanja Muravskaja, Imre Malva, Andreas W ja Haide Rannakivi tööd. Galerii audiogalerii avatakse Projekt Unisoni (Hello Upan, Raul Keller, Heikki Tikas) mürateosega "DOHC"

Viis kandidaati ühele õpetajakohale / Raivo Juurak

Index Scriptorium Estoniae

Juurak, Raivo

2007-01-01

Programmist "Noored kooli", etapi lõpuks selgitati välja 13 noort, kes lähevad tänavu 1. septembril kooli õpetajaks. Oma hinnangu programmile annavad üliõpilased: TTÜ geenitehnoloogiast P. Uuemaa, TTÜ logistikast K. Lillemets, EKA tekstiilidisainist I. Gross, TÜ inglise filoloogiast R. Kurg, TÜ hispaania keele ja politoloogia üliõpilane L. Prikk, TLÜ inglise filoloogiast T.-K. Kaber, TÜ eesti keel vene koolis erialalt N. Reppo, TTÜ geenitehnoloogiast P. Ahte ja TÜ inglise filoloogiast H. Haljaste

A global MHD simulation of an event with a quasi-steady northward IMF component

Directory of Open Access Journals (Sweden)

V. G. Merkin

2007-06-01

Full Text Available We show results of the Lyon-Fedder-Mobarry (LFM global MHD simulations of an event previously examined using Iridium spacecraft observations as well as DMSP and IMAGE FUV data. The event is chosen for the steady northward IMF sustained over a three-hour period during 16 July 2000. The Iridium observations showed very weak or absent Region 2 currents in the ionosphere, which makes the event favorable for global MHD modeling. Here we are interested in examining the model's performace during weak magnetospheric forcing, in particular, its ability to reproduce gross signatures of the ionospheric currents and convection pattern and energy deposition in the ionosphere both due to the Poynting flux and particle precipitation. We compare the ionospheric field-aligned current and electric potential patterns with those recovered from Iridium and DMSP observations, respectively. In addition, DMSP magnetometer data are used for comparisons of ionospheric magnetic perturbations. The electromagnetic energy flux is compared with Iridium-inferred values, while IMAGE FUV observations are utilized to verify the simulated particle energy flux.

Investigation on the electronic structures and photophysical properties of a series of cyclometalated iridium(III) complexes based on DFT/TDDFT calculations

Energy Technology Data Exchange (ETDEWEB)

Shang, Chunyu, E-mail: shang.chun.yu@163.com; Xu, Jie; Du, Yanqiu; Zhao, Jie

2016-07-15

The electronic structures and photophysical properties of a series of cyclometalated iridium (III) complexes Ir(C{sup ∧}N){sub 2}(H{sub 2}NNHCOO), including 1 [C{sup ∧}N=2-phenyl-pyridine], 2 [C{sup ∧}N=5-fluoro-2-phenylpyridine], 3 [C{sup ∧}N=2-phenyl-5-trifluoromethylpyridine], 4 [C{sup ∧}N=6-phenyl-[2, 3] bipyridinyl], 5 [C{sup ∧}N=7-phenyl-cyclopenta [4] dipyridine] and 6 [C{sup ∧}N=8-phenyl-[1, 9] phenanthroline], have been theoretically investigated based on density functional theory (DFT) and time-dependent DFT. The characteristics in phosphorescent performances have been outlined for each of the complexes in the applications in OLED. On the basis of the two simplifications presented in this paper and the available experimental data, the magnitudes of phosphorescent radiative rates for complexes 1–6 were approximately calculated to be: 5.56×10{sup 5} s{sup −1}, 2.68×10{sup 5} s{sup −1}, 1.17×10{sup 6} s{sup −1}, 9.78×10{sup 4} s{sup −1}, 5.30×10{sup 6} s{sup −1} and 6.71×10{sup 6} s{sup −1}, respectively. Meanwhile, the sequence of phosphorescent quantum efficiencies was obtained to be: Φ{sub PL}(4)<Φ{sub PL}(2)<Φ{sub PL}(1)<Φ{sub PL}(3)<Φ{sub PL}(5)<Φ{sub PL}(6), in which Φ{sub PL}(4) is by far the lowest, Φ{sub PL}(5) is much larger and Φ{sub PL}(6) is by far the largest. In contrast to complex 1, the emission wavelengths are slightly red-shifted for 2 and 3 and significantly red-shifted for 4 and 5, while the emission wavelength of 6 is slightly blue-shifted. In comparison, complexes 6 and 5 may be singled out to be the most efficient phosphorescence emitters for the applications in OLED.

Yellow emitting Iridium (III) phenyl-benzothiazole complexes with different β-diketone ancillary ligands as dopants in white organic light-emitting diodes

Science.gov (United States)

Ivanov, P.; Petrova, P.; Tomova, R.

2018-03-01

We discuss the influence of the type of β-diketone ancillary ligand in Iridium (III) bis phenyl-benzothiazole complexes ((bt)2Ir(β-diketone)) on their photophysical and electroluminescent properties when they are used as dopants in white organic light-emitting diodes (WOLED). For this purpose, we investigated four novel yellow cyclometalated complexes: (bt)2Ir(dbm), (bt)2Ir(fmtdbm), (bt)2Ir(tta) and (bt)2Ir(bsm), where dbm = 1,3-diphenylpropane-1,3-dionate; fmtdbm = 1-(4-fluorophenyl)-3-(4-methoxyphenyl)propane-1,3-dionate; tta = 4,4,4-trifluoro-1-(thiophene-2-yl)butane-1,3-dionate; and bsm = 1-phenylicosane-1,3-dionate). To obtain white light by mixing emissions of two complementary colors (yellow emitted by the dopant and blue, by another emitter), we chose the following OLED structure: ITO/doped HTL/ElL/ETL/M, where ITO was a transparent anode of In2O3:SnO2; M, a metallic Al cathode; HTL, 4,4’-Bis(9H-carbazol-9-yl)biphenyl (CBP) involved in a poly(N-vinylcarbazole) (PVK) matrix; ElL, an electroluminescent layer of aluminum(III)bis(2-methyl-8-quninolinato)-4-phenylphenolate (BAlq); and ETL, an electron-transporting layer of zinc(II)bis(2-2-hydroxyphenyl)benzothiazole. We found that all complexes are suitable candidates for fabrication of WOLED. The best results were demonstrated by the device doped with 2 wt % of (bt)2Ir(bsm), which had twice as high luminescence (1100 cd/m2) and one-and-a-half as high current efficiency (5 cd/A) as the device doped with 1.25 wt % of the known (bt)2Ir(acac), with its 580 cd/m2 and 3.4 cd/A at approximately the same CIE (Commission Internationale de L’Eclairage) (x/y) coordinates of the warm white light emitted by the two devices.

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

We report here an unusually high concentration of iridium in some alkali basalts and alkaline rocks of Deccan region having an age of about 65Ma, similar to the age of the Cretaceous-Tertiary boundary. The alkali basalts of Anjar, in the western periphery of Deccan province, have irid-ium concentration as high as 178pg/g ...

Satellite Telemetry and Command using Big LEO Mobile Telecommunications Systems

Science.gov (United States)

Huegel, Fred

1998-01-01

Various issues associated with satellite telemetry and command using Big LEO mobile telecommunications systems are presented in viewgraph form. Specific topics include: 1) Commercial Satellite system overviews: Globalstar, ICO, and Iridium; 2) System capabilities and cost reduction; 3) Satellite constellations and contact limitations; 4) Capabilities of Globalstar, ICO and Iridium with emphasis on Globalstar; and 5) Flight transceiver issues and security.

Neutron activation analysis and the geochemistry of common and trace elements at extinction boundaries in the geological record

International Nuclear Information System (INIS)

Attrep, M. Jr.; Orth, C.J.; Quintana, L.R.

1994-01-01

The discovery of the iridium anomaly at the 65-Ma Cretaceous-Tertiary (K-T) extinction boundary initiated numerous investigations, including the search for the coupling of these extinctions with other astronomical events. One hypothesis is that these periodic extinctions are coupled to terrestrial impacts from cyclic swarms of comets or asteroids. The studies have focused on elucidating the conditions and causes of extinction of life at these geological boundaries using elemental abundance patterns. The authors use instrumental neutron activation methods to determine whole-rock abundances for about 40 trace and common elements in thousands of samples. The platinum group elements (iridium, gold, platinum, and osmium) and nickel are measured by radiochemical activation analysis. The authors can measure iridium at levels down to 1 picogram/gram level

Electrode materials for hydrobromic acid electrolysis in Texas Instruments' solar chemical converter

Energy Technology Data Exchange (ETDEWEB)

Luttmer, J.D.; Konrad, D.; Trachtenberg, I.

1985-05-01

Texas Instruments has developed a solar chemical converter (SCC) which converts solar energy into chemical energy via the electrolysis of hydrobromic acid. Various materials were evaluated as anodes and cathodes for the electrolysis of the acid. Emphasis was placed on obtaining low overvoltage electrodes with good long-term stability. Sputtered platinum-iridium thin films were identified as the best choice as the cathode material, and sputtered iridium and iridium oxide thin films were identified as the best choice as anode materials. Electrochemical measurements indicate that low overvoltage losses are encountered on these materials at operating current densitities in the SCC. Accelerated corrosion tests of the materials predict acceptable electrode stability for 20 years in an environment representative of onthe-roof service.

Kinetic experiments for evaluating the Nernst-Monod model for anode-respiring bacteria (ARB) in a biofilm anode.

Science.gov (United States)

Torres, César I; Marcus, Andrew Kato; Parameswaran, Prathap; Rittmann, Bruce E

2008-09-01

Anode-respiring bacteria (ARB) are able to transfer electrons from reduced substrates to a solid electrode. Previously, we developed a biofilm model based on the Nernst-Monod equation to describe the anode potential losses of ARB that transfer electrons through a solid conductive matrix. In this work, we develop an experimental setup to demonstrate how well the Nernst-Monod equation is able to represent anode potential losses in an ARB biofilm. We performed low-scan cyclic voltammetry (LSCV) throughout the growth phase of an ARB biofilm on a graphite electrode growing on acetate in continuous mode. The (j)V response of 9 LSCVs corresponded well to the Nernst-Monod equation, and the half-saturation potential (E(KA)) was -0.425 +/- 0.002 V vs Ag/AgCl at 30 degrees C (-0.155 +/- 0.002 V vs SHE). Anode-potential losses from the potential of acetate reached approximately 0.225 V at current density saturation, and this loss was determined by our microbial community's E(KA) value. The LSCVs at high current densities showed no significant deviation from the Nernst-Monod ideal shape, indicating that the conductivity of the biofilm matrix (kappa(bio)) was high enough (> or = 0.5 mS/cm) that potential loss did not affect the performance of the biofilm anode. Our results confirm the applicability of the Nernst-Monod equation for a conductive biofilm anode and give insights of the processes that dominate anode potential losses in microbial fuel cells.

USSR Report, Chemistry

Science.gov (United States)

1985-08-16

of the thermal interaction of polonium - 210 with palladium and iridium. The vacuum-thermal method of direct synthesis was used, a study of the... Polonium -Palladium, Iridium Systems (A. S. Abakumov, M. L. Malyshev, et al.; RADIOKHIMIYA, No 2, Mar-Apr 85) 82 Migration of Radioactive and...and energy complex, machine building, light and food industry, agriculture, transportation, and the production of household articles. Working to meet

Me aiaäärne tsivilisatsioon / Andri Ksenofontov

Index Scriptorium Estoniae

Ksenofontov, Andri, 1962-

2008-01-01

Gerhard Richteri näitus "Ülevaade" 6. VI-17. VIII ja Eha Komissarovi kureeritud eesti kunstnike linnakeskkonna-teemaline näitus "Koht, mis paneb liikuma" 20. VI-17. VIII Kumu Kunstimuuseumis. Lühidalt Tõnis Saadoja Gerhard Richteri portreede seeriast "Mainstream" Kumu Kunstimuuseumis. Maarit Murka töödest, Kaarel Nurga fotodest, Anton Kooviti, Uku ja Remi grafititoast, Raoul Kurvitza arvutiinstallatsioonist "Pentatonic Color System II" (helilooja Ariel Lagle), Reet Ausi, Marit Ahvena,Ville Hyvöneni, Hula, EKA moedisaini ja Tartu Kõrgema Kunstikooli tekstiili- ja fotoosakonna projektist "Üle prahi", Kaido Ole installatsioonist "Koosolek"

Riigikogu hoone / Herbert Voldemar Johanson, Eugen Habermann, Alar Kotli...[jt.

Index Scriptorium Estoniae

2007-01-01

23 ill.; fotod: Andres Teiss; autorid: H. Johanson, E. Habermann, saaliavade ja aknapõskede kujundamisel oli abiks J. Koort; 1935. a. rajati A. Kotli projekti järgi lossi lõunatiib; valge saal rekonstrueeriti 1936. a. A. Perna ja J. Ostrati kavandite järgi; Eesti taasiseseisvumise järel on hoonet M. Kalmu, L. Pärtelpoja, M. ja K. Kurismaa ning Ü. Saare juhendamisel renoveeritud; Riigikogu esimehe kabineti vaiba (1938) kavandas Adamson-Eric, kontorimööbli kujundasid 1997. a. EKA sisearhitektuuri üliõpilased L. Pärtelpoja juhendamisel

Oskusteabe tarbekunsti-tiritamm / Lylian Meister

Index Scriptorium Estoniae

Meister, Lylian, 1966-

2009-01-01

Tallinna 5. rakenduskunsti triennaalist. Peanäitus "Know how" Eesti Tarbekunsti- ja Disainimuuseumis kuni 21. 02. 2010 (kuraator Kärt Maran, kujundajad: Ott Kadarik, Tuuli Aule). Kolm võrdset preemiat said Marta Boan (Hispaania), autorite kollektiiv Jaan Evart (Eesti), Julian Hagen (Austria) ja Daniel Maarleveld (Holland) ning Kieren Jones (Suurbritannia). Satelliitnäitused: "EKA Know How. See on imelihtne?" (kuraatorid: Eeva Käsper, Tiina Sarapu) Eesti Kunstiakadeemia galeriis 12. 11.-10. 12. 2009, "Praktiline Kunst ja Kodu" (kuraator Kai Lobjakas, kujundaja Mikk Heinsoo) Hobusepea galeriis 14.-23. 11. 2009

Eesti disaini uudised / Kai Lobjakas

Index Scriptorium Estoniae

Lobjakas, Kai, 1975-

2006-01-01

Eesti Kunstiakadeemia üliõpilaste Kadri Kruus-Laurimaa kott-jope, Riho Tiiveli lusikas "Spoon container" ja Ülle Jehe sisustuspadjad "Roll it!" valiti Prantsusmaal toimunud rahvusvahelisel kunsti-ja disainikõrgkoolide võrgustiku CUMULUS konkursil "European Ways of Life" nominentide hulka. EKA sisearhitektuuri eriala üliõpilaste toolide hindamisest. Mari Adamsoni nimelise noore tekstiilikunstniku preemia pälvis Kadri Klampe. Eesti Ajaloomuuseumis Maarjamäe lossis avatud moenäitusest "Paula, sul on poisipea!", mille koostas Helle Avila, konsulteeris Anu Ojavee, kujundasid Krista Lepland ja Malle Jürgenson büroost Laika, Belka ja Strelka

20. VI avatakse EKA galeriis rahvusvaheline fotonäitus "Fragile Distance"

Index Scriptorium Estoniae

2003-01-01

Kuraatorid David Bate, Eve Kiiler. Osalevad Londonis elavad ja töötavad fotograafid Denny Robson, Adam Green, Michelle Atherton (Inglismaa), Eva Riegler (Austria), Andreas Hablutzel (Šveits), Angeliki Douveri, Stella Baraklianou (Kreeka), Simona Dell'Agli (Itaalia)

Synthesis of all eight L-glycopyranosyl donors using C-H activation

DEFF Research Database (Denmark)

Frihed, Tobias; Pedersen, Christian Marcus; Bols, Mikael

2014-01-01

by an intramolecular C-H activation of the methyl group in g-position; both steps were catalyzed by iridium. The following Fleming-Tamao oxidation and acetylation gave the suitably protected L-hexoses. This is the first general method for the preparation of all eight L-hexoses as their thioglycosyl donors ready...... for glycosylation and the first example of an iridium-catalyzed C(sp3)-H activation on sulfide-containing compounds....

The Death of the Dinosaurs: 27 Years Later (LBNL Summer Lecture Series)

Energy Technology Data Exchange (ETDEWEB)

Muller, Rich [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Dept. of Physics

2006-06-30

Summer Lecture Series 2006: Rich Muller, a Berkeley Lab physicist, discusses Nobel laureate Luis Alvarez and colleagues' 1979 discovery that an asteroid impact killed the dinosaurs. He also discusses what scientists have learned in the subsequent 27 years. Alvarez's team detected unusual amounts of iridium in sedimentary layers. They attributed the excess iridium to an impact from a large asteroid. His talk was presented June 30, 2006.

Promoting effects of phenobarbital on the enzyme-altered foci induced by intrahepatic γ-ray-irradiation in the rat liver

International Nuclear Information System (INIS)

Ida, Katsuya; Nakamura, Satoshi; Muro, Hiroyuki; Takai, Michikatsu; Kaneko, Masao

1995-01-01

Radiation-induced carcinogenesis of the rat liver using iridium-192 seeds as an intrahepatic radioactive source was studied by enzyme histochemical means. Rats were divided into six groups according to various combinations of one or two iridium-192 or stainless steel seeds and whether they were given a diet containing 0.05% phenobarbital (PB) or a basal diet (BD). Each group were sacrificed at 20, 40, and 60 weeks after intrahepatic insertion of the iridium-192 or stainless steel seeds. γ-Glutamyl transpeptidase (GGT), glucose-6-phosphatase (G6Pase), and adenosine triphosphatase (ATPase) were stained in the liver tissues, and GGT-positive foci were quantified. Liver neoplasm was not evident, but enzyme-altered foci (EAF) were induced by γ-ray irradiation. At every point (20, 40, and 60 weeks) after the insertion of the seeds, the GGT-positive area was larger in the rats given PB than those given BD. Moreover, despite the iridium-192 radioactivity decay, EAF developed continuously in the rats given PB, and persisted in those given BD from 40 to 60 weeks after insertion. These results indicated that phenobarbital promotes the development of EAF initiated by irradiation, as it promotes the process of chemical carcinogenesis in the rat liver. (author)

Extracellular pH monitoring for use in closed-loop vagus nerve stimulation

Science.gov (United States)

Cork, Simon C.; Eftekhar, Amir; Mirza, Khalid B.; Zuliani, Claudio; Nikolic, Konstantin; Gardiner, James V.; Bloom, Stephen R.; Toumazou, Christofer

2018-02-01

Objective. Vagal nerve stimulation (VNS) has shown potential benefits for obesity treatment; however, current devices lack physiological feedback, which limit their efficacy. Changes in extracellular pH (pHe) have shown to be correlated with neural activity, but have traditionally been measured with glass microelectrodes, which limit their in vivo applicability. Approach. Iridium oxide has previously been shown to be sensitive to fluctuations in pH and is biocompatible. Iridium oxide microelectrodes were inserted into the subdiaphragmatic vagus nerve of anaesthetised rats. Introduction of the gut hormone cholecystokinin (CCK) or distension of the stomach was used to elicit vagal nerve activity. Main results. Iridium oxide microelectrodes have sufficient pH sensitivity to readily detect changes in pHe associated with both CCK and gastric distension. Furthermore, a custom-made Matlab script was able to use these changes in pHe to automatically trigger an implanted VNS device. Significance. This is the first study to show pHe changes in peripheral nerves in vivo. In addition, the demonstration that iridium oxide microelectrodes are sufficiently pH sensitive as to measure changes in pHe associated with physiological stimuli means they have the potential to be integrated into closed-loop neurostimulating devices.