zn3 v2 o8: Topics by WorldWideScience.org

Luminescent properties of Eu3+-activated Sr3B2SiO8: A red-emitting phosphor for white light-emitting diodes

We report ab initio calculations of positron wave functions in the high-T/sub c/ superconductors YBa_2Cu_3O_7, Bi_2Sr_2CaCu_2O_8, and Tl_2Ba_2CaCu_2O_8 using the general potential linearized augmented plane-wave method. The calculated positron wave functions are fairly insensitive to whether or not electron-positron correlation is included in the calculation for YBa_2Cu_3O_7 and Tl_2Ba_2CaCu_2O_8, but the calculated positron density is quite sensitive to correlation in Bi_2Sr_2CaCu_2O_8. While the positron wave function samples primarily the chain region in YBa_2Cu_3O_7, the results indicate that positrons should be good probes of the Cu-O layer-derived electronic states near the Fermi energy in Tl_2Ba_2CaCu_2O_8 since a large overlap with these states is predicted.

Development of novel brasses to resist dezincification

Single-phased Sr3B2SiO8:Eu3+ phosphor was prepared by a solid-state method at 1020 oC. The luminescence spectra showed that Sr3B2SiO8:Eu3+ phosphor can be effectively excited by near ultraviolet light (393 nm) and blue light (464 nm). When excited at 393 or 464 nm Sr3B2SiO8:Eu3+ exhibited the main emission peaks at 611 and 620 nm, which resulted from the supersensitive 5D0#->#7F2 transition of Eu3+. The luminescence intensity of Sr3B2SiO8:Eu3+ at 611 and 620 nm reached the maximum when the doping content of Eu3+ was 4.5 mol%. Its chromaticity coordinates (0.646, 0.354) were very close to the NTSC standard values (0.67, 0.33). Thus, Sr3B2SiO8:Eu3+ is considered to be an efficient red-emitting phosphor for long-UV InGaN-based light-emitting diodes. - Highlights: ? ...

2011-07-01

Thermally stimulated luminescence of NaAlSi_3O_8 and its analysis

The effect of alloying Sn, Pb, As, Sb and P on the dezincification of commercial brass 60Cu-39Zn-1Pb has been investigated in 1% CuCl{sub 2} solution by immersion studies and electrochemical measurements. Specimens with a smooth surface finish exhibited more resistance to dezincification. Appreciable inhibitive effect on dezincification was observed for the 55Cu-40Zn-3Pb-2Sn brass composition. The galvanic coupling of lead phase with the matrix accelerated corrosion. To improve the dezincification resistance of the Sn containing brass, As, Sb and P were added at two different levels (0.05% and 0.1%). Brass of composition 48.95Cu-45Zn-5Pb-1Sn-0.05As was more resistant indicating the synergistic effect of Sn and As. The effect of 0.05 and 0.1% of arsenic addition with various concentrations of zinc was also studied. The alloy of composition 57.90Cu-40Zn-2Pb-0.1As showed better corrosion resistance than the alloy containing 1% Sn and 0.05% As ...

2007-03-15

Uranium oxides. Specific surface measurement by nitrogen adsorption

The complex thermally stimulated luminescence (TSL) pattern of NaAlSi_3O_8 has been analyzed on transparent and opaque varieties of natural crystals and synthetic pure powder. The existence of seven additional peaks in the range 20 to 450 "0C following X-irradiation at room temperature (RT) is reported, also evaluated by the curve fitting method. The validity of the analysis is discussed in the light of detailed trap analysis of KAlSi_3O_8. An attempt has been made to probe the excistence of high temperature peaks beyond 450 "0C using UV stimulation at RT. All the TSL peaks analyzed follow a second-order kinetic process.

Chemical and electrochemical dehydriding characteristics of TiV_2_._1Ni_0_._3-Raney Ni composite prepared by ball-milling in the presence of a reducing agent

Determination of the specific surface of uranium oxides: UO_2 and U_3O_8 using a simplified equation derived from the Brunauer, Emmett and Teller theory. The method is suitable for samples having a surface between 6 to 50 m"2.

Comparison of four advanced oxidation processes for the removal of naphthenic acids from model oil sands process water

Composite particles represented as TiV_2_._1Ni_0_._3-Raney Ni(R) were prepared by ball-milling a TiV_2_._1Ni_0_._3 alloy with Raney Ni in the presence of 0.01 M sodium hypophosphite (NaH_2PO_2) aqueous solution as a reducing agent. The composite particles had different morphology from original TiV_2_._1Ni_0_._3 alloy particles and TiV_2_._1Ni_0_._3-Raney Ni composite particles prepared by the ball-milling in the absence of the NaH_2PO_2 aqueous solution. In charge-discharge cycle tests, the TiV_2_._1Ni_0_._3-Raney Ni(R) composite electrode showed the maximum discharge capacity of 620 mAh g"-"1, while its cycle durability was similar to the TiV_2_._1Ni_0_._3 alloy electrode, which was explained from depth profiles of constituent elements ...

2004-02-25

British Library Electronic Table of Contents (United Kingdom)

Four advanced oxidation processes (UV/TiO2, UV/IO4^-, UV/S2O8^2^-, and UV/H2O2) were tested for their ability to mineralize naphthenic acids to inorganic carbon in a model oil sands process water containing high dissolved and suspended solids at pH values ranging from 8 to 12. A medium pressure mercury (Hg) lamp was used, and a Quartz immersion well surrounded the lamp. The treatment goal of 5mg/L naphthenic acids (3.4mg/L total organic carbon (TOC)) was achieved under four conditions: UV/S2O8^2^- (20mM) at pH 8 and 10, and UV/H2O2 (50mM) at pH 8 (all with the Quartz immersion well). Values of electrical energy required to meet the treatment goal were about equal for UV/S2O8^2^- (20mM) and UV/H2O2 (50mM) at pH 8, but three to four times larger for treatment by UV/S2O8^2^- (20mM) at pH 10. ...

2011-01-01

Remote Sensing Tutorial ... - The Remote Sensing Tutorial - NASA

Neutron transition matrix element for "6"6Sr(#alpha#,#alpha#')"6"6Sr"*(1.84 MeV, 2+)

The first space photographs were obtained from V-2 rockets fired upwards from the ..... Some fraction of the incoming solar radiation is reflected towards a sensor ...

Environmental Cracking of the Alpha-Beta Titanium Alloy, Ti ...

Published in summary form only. 6 Refs.

1987-12-01

A new unified approach to bradyons and tachyons by conformal transformations

... Accession Number : ADD120492. Title : Environmental Cracking of the Alpha-Beta Titanium Alloy, Ti-6Al-6V-2Sn,. Corporate ...

Production of pure yellow cake by ion-exchange processes employing sulphate elution

By using linearized conformal transformations in six dimensions, a new unified approach to bradyons (v"2< c"2) and tachyons (v"2>c"2) is suggested, the essential tool being (real and imaginary) dilatations. The usual ''Generalized Lorentz transformations'' are got, In six dimensions the quadrate form is always positive, both for bradyons and for tachyons.

Width of the 1.836-MeV level in "8"8Sr

Recovery of uranium by ion-exchange processes from impure acid leach liquors is described, which produce a concentrated and pure eluate employing 10% sulphuric acid elution. In situations where resin is loaded to 45 g/ltr or more the acid consumption at ambient temperature is less than 4 kg of H_2SO_4 per kilogram of U_3O_8. Precipitation with an alkali such as ammonia or magnesia produces a yellow cake of high purity. (author).

1979-06-08

Tris(2,2prime-bipyridyl)ruthenium(II) Electrogenerated Chemiluminescence Sensor Based on Sol-Gel-Derived V2O5/Nafion Composite Films

Using bremsstrahlung, the resonance fluorescence yield has been measured for the 1.836-MeV 2"+_1 level in "8"8Sr. The observed yield corresponds to a level width GAMMA = 2.94 +- 0.15 meV.

British Library Electronic Table of Contents (United Kingdom)

Mesoporous V2O5/Nafion composite films have been used for the immobilization of tris(2,2prime-bipyridyl)ruthenium (II) (Ru(bpy)$\\rm{ {_{3}^{2+}}}$) on an electrode surface to yield a solid-state electrogenerated chemiluminescence (ECL) sensor. The electrochemical and ECL behavior of Ru(bpy)$\\rm{ {_{3}^{2+}}}$ ion-exchanged into the composite films has been characterized as a function of the amount of Nafion incorporated into the V2O5/Nafion composite. The composite film with 80% Nafion content has the largest pore diameter (4.19 nm) and yields the maximum ECL response for tripropylamine (TPA) because of the fast diffusion of analyte into the film with large pores. Due to the enlarged pore size and enhanced conductivity of the V2O5/Nafion composite, the present ECL sensor based on the compo...

2006-01-01

The Subtilisin-Like Protease AprV2 Is Required for Virulence and Uses a Novel Disulphide-Tethered Exosite to Bind Substrates

UK PubMed Central (United Kingdom)

Many bacterial pathogens produce extracellular proteases that degrade the extracellular matrix of the host and therefore are involved in disease pathogenesis. Dichelobacter nodosus...Full Text Available

2010-11-01

J4P Evaluation of Externally Heated Pulsed MPD Thruster Cathodes

Improved Understanding of the Bacterial Vaginal Microbiota of Women before and after Probiotic Instillation

twenty 350 V, 2.5 mF aluminum electrolytic capacitors with 10.8 mH inductors made of multi-strand wire. The PFN discharge was controlled using an silicon ...

UK PubMed Central (United Kingdom)

The vaginal bacterial microbiota of 19 premenopausal women was examined by PCR-denaturing gradient gel electrophoresis (DGGE) and sequencing of the V2-V3 region of the 16S rRNA gene. Ten of the women...Full Text Available

2003-01-01

Azimuth Quadrupole Systematics in Au-Au Collisions

The chemical link Brazil/Portugal. Abstracts of the 23. annual meeting of the Brazilian Chemical Society. v. 2; A ligacao quimica Brasil/Portugal. Resumos da 23. reuniao anual da Sociedade Brasileira de Quimica. v. 2

We have measured $p_t$-dependent two-particle number correlations on azimuth and pseudorapidity for eleven centralities of $\\sqrt{s_{NN}} = 62$ and 200~GeV Au-Au collisions at STAR. 2D fits to these angular correlations isolate the azimuth quadrupole amplitude, denoted $2 v_2^2 \\{ 2D \\} ( p_t )$, from localized same-side correlations. Event-plane $v_2 ( p_t )$ measurements within the STAR TPC acceptance can be expressed as a sum of the azimuth quadrupole and the quadrupole component of the same-side peak. $v_2 \\{ 2D \\} ( p_t )$ can be transformed to reveal quadrupole $p_t$ spectra which are approximately described by a fixed transverse boost and universal L\\'evy form nearly independent of centrality. A parametrization of $v_2 \\{ 2D \\} ( p_t )$ can be factored into centrality and $p_t$-dependent pieces with a ...

2010-01-01

Technical papers presented at the 4. symposium of specialists in electric operational and expansion planning. v. 2; Artigos tecnicos apresentados no 4. simposio de especialistas em planejamento da operacao e expansao eletrica. v. 2

Several works about annual meeting of the Brazilian Chemical Society are present.The search for medicinal chemistry, natural products, biological chemistry, and organic chemistry are shown. Conventional methods and some techniques are discussed and developments of new methods of determining are studied. The use of new chemical compounds, materials, structures and chemical analysis are shown.

2000-07-01

Precise Measurement of the Neutron Magnetic Form Factor GMn in the Few-GeV2 Region

This symposium about electric operational and expansion planning presents several articles that approaches issues such as, monitoring the power system stability, electrical load modelling, reliability in power systems, optimization in power systems, integrated resources planning in power systems, reactive control through static compensators, power flow analysis, system modelling, etc

1994-12-31

1 2 3 4 5

Nitrilotriacetate complex of univalent astatine

The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q2=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.

2009-05-15

Constrained NBMPR analogue synthesis, pharmacophore mapping and 3D-QSAR modeling of equilibrative nucleoside transporter 1 (ENT1) inhibitory activity

Formation of the complex of the univalent astatine cation with nitrilotriacetic acid (AtL)"2"- and its stability constant (lgK_1=8.97(4), 25degC, #mu#=0.1) have been found experimentally for the first time. The complex is stable in perchlorate solutions in presence of 5 . 10"-"3 mol . l"-"1 of the oxidizer Na_2S_2O_8 in the interval 4#<=#pH#<=#8.5. The complex is supposed to be destroyed in weak alkaline solutions by reduction of astatine to astatide. The deprotonation constant of hypoastatic acid pK_d_p=5.23(9) was found to be lower than determined previously. The investigation was carried out by the method of ion electrophoresis in free electrolyte solutions. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Conformationally constrained analogue synthesis was undertaken to aid in pharmacophore mapping and 3D-QSAR analysis of nitrobenzylmercaptopurine riboside (NBMPR) congeners as equilibriative nucleoside transporter 1 (ENT1) inhibitors. In our previous study [J. Med. Chem. 2003, 46, 831-837], novel regioisomeric nitro-1,2,3,4-tetrahydroisoquinoline conformationally constrained analogues of NBMPR were synthesized and evaluated as ENT1 ligands. 7-NO2-1,2,3,4-Tetrahydroisoquino-2-yl purine riboside was identified as the analogue with the nitro group in the best orientation at the NBMPR binding site of ENT1. In the present study, further conformational constraining was introduced by synthesizing 5prime-O,8-cyclo derivatives. The flow cytometrically determined binding affinities indicated that the...

2008-01-01

Sensitivity of mitochondrial K/sup +/ and Mg/sup + +/ influx rates to thiol reactive compounds

Specialized Circuits from Primary Visual Cortex to V2 and Area MT

Various thiol reactive compounds, including phenylarsine oxide (PheAsO) and mersalyl, activate K/sup +/ transport into respiring mitochondria. Dicyclohexylcarbodiimide (DCCD) inhibits K/sup +/ influx. In the present studies, unidirectional fluxes of K/sup +/ or Mg/sup + +/ into respiring rat liver mitochondria were measured by means of /sup 42/K or /sup 28/Mg, with samples separated from incubation media by centrifugation through silicon. Experiments show that the % stimulation of K/sup +/ influx by PheAsO (8.5 nmol/mg protein) or by mersalyl (150 ..mu..M) was the same (53-55%) for control mitochondria as for samples pretreated with DCCD (30 nmol/mg protein). This means that DCCD caused the same % inhibition of K/sup +/ flux into control mitochondria and mitochondria in the presence of PheAsO or mersalyl (36-37%). Thus, the DCCD reactive site associated with the K/sup +/ influx mechanism appears to be independent of the thiol groups(s) ...

1986-05-01

British Library Electronic Table of Contents (United Kingdom)

SummaryPrimary visual cortex recombines inputs from magnocellular (M) and parvocellular (P) streams to create functionally specialized outputs. Understanding these input-output relationships is complicated by the fact that layer 4B, which provides outputs to dorsal visual areas, contains multiple cell types. Using a modified rabies virus that expresses green fluorescent protein, we show that layer 4B neurons projecting to MT are a majority spiny stellate, whereas those projecting to V2 are overwhelmingly pyramidal. Regardless of cell type, MT-projecting neurons have larger cell bodies, more dendritic length, and are deeper within layer 4B. Furthermore, MT-projecting pyramidal neurons are located preferentially underneath cytochrome oxidase blobs, indicating that MT-projecting neurons of bo...

2007-01-01

Precise Determination of the Neutron Magnetic Form Factor to Higher Q"2

A concept for the experimental determination of the nucleon electric to magnetic form factor ratio at very low Q2

The neutron elastic magnetic form factor G_M"n has been extracted from quasielastic scattering from deuterium in the CEBAF Large Acceptance Spectrometer, CLAS [B. Mecking et al., Nucl. Inst. and Meth. A 503 (2003) 513]. The kinematic coverage of the measurement is continuous over a broad range, extending from below 1 GeV"2 to nearly 5 GeV"2 in four-momentum transfer squared. High precision is achieved by employing a ratio technique in which most uncertainties cancel, and by a simultaneous in-situ calibration of the neutron detection efficiency, the largest correction to the data. Preliminary results are shown with statistical errors only.

2005-06-13

Width of the 1. 836-MeV level in /sup 88/Sr

Stationary target measurements of the nucleon form factors have been performed with high precision down to Q2 of ? 0.01 GeV2 for protons (GEp) and down to ? 0.1 GeV2 for neutrons (GMn). Conventional extraction using cross section and polarization measurement cannot be extended to very low values of Q2 due to inherent experimental limitations. We present a proposal for a new approach to a measurement, using colliding beams, which will extend the range of possible measurement at low Q2 by several orders of magnitude over stationary target limits.

2009-05-01

Semihard production of tensor mesons in #gamma##gamma#-collisions and the perturbative Odderon

Using bremsstrahlung, the resonance fluorescence yield has been measured for the 1.836-MeV 2/sup +//sub 1/ level in /sup 88/Sr. The observed yield corresponds to a level width GAMMA = 2.94 +- 0.15 meV.

1977-06-01

Range and energy loss rate of 118 MeV "2"8Si in some polymers

The cross sections of neutral tensor mesons T=a_2, f, f', ... production in the exclusive #gamma##gamma##->#TT' or semiexclusive #gamma##gamma##->#TX processes (three gluon exchange) in the semihard region s>>vertical stroketvertical stroke>1 GeV"2 are calculated. The relation of investigated processes to the problem of perturbative Odderon is discussed. The possibility of measurements at LEP and at a future #gamma##gamma#-colliders is discussed too. (orig.).

In the present work, range and energy loss rate of "2"8Si in four dielectric track detectors viz: Makrofol-KG (MFKG), Makrofol-G (MFG), Triafol-BN (TBN) and LR-115 (cellulose nitrate) have been measured. To calculate these parameters, a curve fitting method was proved to be very useful and easier with more accuracy. (author)

1999-01-01

Nuclear fuel cycle. V. 2

Highly Ordered Spatial Organization of the Structural Long Noncoding NEAT1 RNAs within Paraspeckle Nuclear Bodies

Nuclear fuel cycle information in some countries that develop, supply or use nuclear energy is presented. Data about Argentina, Australia, Belgium, Netherlands, Italy, Denmarmark, Norway, Sweden, Switzerland, Finland, Spain and India are included. The information is presented in a tree-like graphic way. (C.S.A.).

1979-06-08

UK PubMed Central (United Kingdom)

Paraspeckles (PSPs) are nuclear bodies associated with the retention in the nucleus of specific mRNAs. Two isoforms of a long noncoding RNA (NEAT1_v1/Menε and NEAT1_v2/Menβ)...Full Text Available

2010-11-15

Electroexcitation of the Roper resonance for 1.7 < Q**2 < 4.5 -GeV2 in vec-ep ---> en pi+

A critical review of the hypothesis that climate change is caused by carbon dioxide

DOI: http://dx.doi.org/10.1103/PhysRevC.78.045209
The helicity amplitudes of the electroexcitation of the Roper resonance are extracted for 1.7 < Q2 < 4.5 GeV2 from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data for pi+ electroproduction on protons at W=1.15-1.69 GeV. The analysis is made using two approaches, dispersion relations and a unitary isobar model, which give consistent results. It is found that the transverse helicity amplitude A_{1/2} for the gamma* p -> N(1440)P11 transition, which is large and negative at Q2=0, becomes large and positive at Q2 ~ 2 GeV2, and then drops slowly with Q2. The longitudinal helicity amplitude S_{1/2}, which was previously found from CLAS ep -> eppi0,enpi+ data to be large and positive at Q2=0.4,0.65 GeV2, drops with Q2. Available model predictions for ...

2008-10-01

A Search for electron neutrino appearance at the Delta m**2 ~ 1- eV**2 scale

This critical review with 28 references examines absorption and emission in the v2 band of the carbon dioxide molecule at around the 15micron wavelength. The argument for additional infrared absorption, the enhanced greenhouse effect due to increased carbon dioxide concentrations, and radiation transport and increased emissions are discussed. Experiments studying the transmission spectra of pure carbon dioxide and carbon dioxide in nitrogen, and comparing them with the results of climate modelling using the HITRAN and GEISA databases, are described.

2000-07-01

Measurement of reactor tube cladding thickness by x-ray fluorescence spectrometry

The MiniBooNE Collaboration reports first results of a search for {upsilon}{sub e} appearance in a {upsilon}{sub {mu}} beam. With two largely independent analyses, we observe no significant excess of events above background for reconstructed neutrino energies above 475 MeV. The data are consistent with no oscillations within a two neutrino appearance-only oscillation model.

2007-04-01

Crystallohydrate forms of trisubstituted uranyl orthophosphate

An x-ray fluorescence spectrometer was designed and fabricated which nondestructively determines the thickness of aluminum cladding at small suspected thin spots in the inner or outer surface of actinide reactor tubes. The analysis method is based on the difference in absorption of actinide L/sub #alpha#/ and L/sub #beta#/ fluorescent x-rays in passing through the cladding. Calibration plots of the logarithm of the L/sub #beta#//L/sub #alpha#/ x-ray intensity ratio versus cladding thickness are linear to at least 40 mils for U-Al, U_3O_8-Al, and PuO_2-Al substrates. Accuracy and precision of the experimentally determined cladding thickness and evaluated for both uranium and plutonium substrates. Experimental thickness data are reported for 618 quality assurance analyses on six Mark 41 PuO_2-Al target tubes. An x-ray fluorescence cladding thickness monitor operated with a computer-controlled fluoroscope holds considerable promise for quality ...

1978-01-01

Relations between structural and superconducting properties of bulk and thin film high-T_c materials

The conditions of production and the stability regions have been studied for the following crystallohydrates of trisubstituted uranyl orthophosphates: (UO_2)_3(PO_4)_2x6H_2O, (UO_2)_3(PO_4)_2x4H_2O, and (UO_2)_3(PO_4)_2xH_2O. Their thermal stability has been studied. It is shown that thermal dehydration of high-water hydrates at 220-240 deg C gives (UO_2)_3(PO_4)_2xH_2O. The anion composition and crystal structure of the compound remain constant up to 1000 deg C. The mixture of the composition of U_3O_8xU_3(PO_4)_4 is the final product of decomposition at 1000 deg C. The thermodynamic constants of dehydration processes have been calculated. A conclusion has been made about the polymer structure of the compound in which water is located between the uranylphosphate layers.

Direct denitration and recycling of PFBR MOX liquid waste from dissolution test using microwave heating method

The structural ordering of oxygen deficient and Co-doped YBCO (YBa_2Cu_3_-_yCo_yO_6_+_x) have been studied experimentally, and by computer simulations of the oxygen ordering in the basal plane of the structure. The calculations are based on the two-dimensional ASYNNNI model and its modifications. Good agreement is established between the ASYNNNI calculations and the experimentally observed structural properties of the double cell ortho-II structure and the oxygen disordering process from Co-doping into the basal plane. A model that relates the superconducting transition temperature T_c(x) of undoped YBCO and T_c(y) of Co-doped YBCO to the formation of specific domains of the two orthorhombic ordered oxygen phases, ortho-I and ortho-II, shows a close agreement with experimental T_c(x) and T_c(y) data of samples prepared under equilibrium conditions. The structural changes as a result of metal ion substitutions and oxidation/reduction processes have been studied by neutron powder ...

1984-02-13

ISR Hadron Production in e+e- Annihilations and Meson-Photon Transition Form Factors

Full text: Dissolution test (DT) is one of the important specifications of PFBR MOX fuel. It is a macro homogeneity test used to ascertain that the dissolution of spent fuel will be easier during reprocessing. The DT specification limit for PFBR MOX fuel is ? 1.0 wt.% residue of the whole pellet when it is dissolved in HNO3 under reflux conditions. For this test, sintered MOX pellet is dissolved in reflux condition in 60 ml of 12M HNO3 for 10 hours. This test is carried out for each batch and during complete MOX campaign a lot of MOX waste in liquid form is being generated. This liquid waste is in clean form and U and Pu is required to be recovered from the clean waste. Different methods like direct denitration, precipitation and solvent extraction are available but either the product is not of good quality for pelletization or secondary liquid wastes are generated. Microwave denitration is a faster and cleaner method which has different heat transfer mechanism and temperature profile ...

2010-11-24

Environmental cracking of the alpha-beta titanium alloy, Ti-6Al-6V-2Sn

We present several recent results from the BaBar collaboration in the areas of initial state radiation physics and transition form factors. An updated study of the processes e+e- -> K+K-pi+pi- and e+e- -> K+K-pi0pi0 provides an improved understanding of the Y(2175) meson. A very precise study of the process e+e- -> pi+pi- improves the precision on the calculated anomalous magnetic moment of the muon and provides by far the best information on excited rho states. Our previous measurements of the timelike transition form factors (TFF) of the eta and eta' mesons at Q^2=112 GeV^2, combined with new measurements of the their spacelike TFFs and those of the pi0 and eta_c mesons, provide powerful tests of QCD and models of the distribution amplitudes of quarks inside these mesons. The eta_c TFF shows the expected behavior over the Q^2 range 1-50 GeV^2, and we are sensitive to next-to-leading-order QCD ...

2011-01-01

1 2 3 4 5

Effect of mean stress (stress ratio) and aging on fatigue-crack growth in a metastable beta titanium alloy, Ti-10V-2Fe-3Al

The combined effects of environment, yield strength and stress state on the cracking susceptibility of beta-extruded Ti-6Al-6V-2Sn have been examined. At a constant yield strength and under plane strain conditions, the stress intensity required for slow crack propagation decreased as the severity of the environment increased, i.e., from laboratory air to 3.5% NaCl. Furthermore, the crack propagation rates were a function of both stress intensity, and environmental severity. Although the fracture toughness and threshold stress intensities for slow crack growth generally decreased with increasing yield strength, aging, which resulted in the precipitation of ordered Ti3Al particles in the primary alpha phase, tended to accentuate the susceptibility of this alloy to sustained load/stress corrosion cracking. Finally, at constant yield strength, the sustained load cracking threshold stress intensity was a function of stress state.

The Proton structure function F(2) in the resonance region

The effect of mean stress, or the stress ratio (R), on the fatigue-crack growth (FCG) behavior of #alpha#-aged and #omega#-aged microstructures of the beta titanium alloy Ti-10V-2Fe-3Al was investigated. While the mean stress had a negligible effect on the FCG behavior of the #alpha#-aged microstructure, a strong effect was observed in the #omega#-aged microstructure. In particular, the values of the threshold stress-intensity range (#DELTA#K_t_h) exhibited a strong dependence on R in the #omega#-aged microstructure, while this dependence was weak in the #alpha#-aged microstructure. These effects seem to arise primarily from fracture-surface roughness-induced crack closure. The crack closure levels for the #alpha#-aged microstructure were found to be very low compared to those for the #omega#-aged microstructure. Transmission electron microscopy and scanning electron microscopy studies of microstructures and fracture surfaces were performed to ...

2000-03-01

Strength and toughness of a metastable beta-titanium alloy as influenced by strain rate variations

Unique measurement of the proton structure function F2 in a wide two-dimensional region of x and Q**2 has been reported. The accessible kinematics covers entire resonance region up to W=2.5 GeV in the Q**2 interval from 0.1 to 4.5 GeV**2. Obtained data allowed for the first time an evaluation of moments of the structure function F2 directly from experimental data as well as an intensive study of the Bloom-Gilman duality phenomenon.

2003-06-01

Quark-hadron duality in structure functions

Strain rate effects for the high strength, metastable beta-titanium alloy Ti-8Mo-8V-2Fe-3Al are assessed in terms of tensile and fracture toughness behavior. It is shown that as the strain rate increases the yield strength, ultimate tensile strength, and ductility also increase. As a result of the decrease in the amount of intergranular fracture as the strain rate is increased, the dynamic fracture toughness values K/sub Id/ are greater than those obtained under static conditions as given by K/sub Q/.

Proton and deuteron spin structure function measurements in the resonance region

I review recent developments in quark-hadron duality in inclusive electron-nucleon scattering. Matrix elements of twist-4 operators extracted from moments of the spin-dependent g1 structure function suggest that duality violating higher twists are small above Q2 {approx} 1 GeV2. The x dependence of local duality is analyzed within a quark model framework, and mechanisms are identified for spin-flavor symmetry breaking which underpin the behavior of structure functions at large x.

2004-10-01

Forward Physics with the CMS experiment at the Large Hadron Collider

The RSS collaboration has measured the spin structure functions of the proton and the deuteron at Jefferson Lab using the Hall C HMS spectrometer, a polarized electron beam and a polarized solid target. The asymmetries A and A were measured in the region of the nucleon resonances (0.82 GeV < W < 1.98 GeV) at an average four momentum transfer of Q2 = 1.3 GeV2. The extracted spin structure functions and their kinematic dependence will make a significant contribution in the study of higher-twist effects and polarized duality tests. A description of the experiment and the latest findings of the analysis will be presented.

2003-07-01

Experimental study of beam optics and energy recovery for high-energy electron cooling device

multi-parton interactions and underlying event structure, $\\gamma$-mediated processes and luminosity determination, Monte Carlo tuning and even MSSM Higgs discovery in central exclusive production. In this article, the forward detector instrumentation around the CMS interaction point is described and the prospects for diffractive and forward physics using the CMS forward detectors are summarized. In addition, first observation of forward jets as well as early measurements of the forward energy flow in the pseudorapidity range $3.15V, $2.36$~TeV and $7$~TeV are presented.

2010-01-01

Development of a Stable-Beta Titanium Alloy, Quarterly Report Number 10, October 1 - December 31, 1964.

The feasibility of a high-energy electron cooling device has been studied through tests on a prototype of the electron device. The apparatus consists of a pulsed ((20-60) keV, 2#mu#s) electron gun, a drift region 1 m long and of a depressed collector for recovering the electron energy. Tests on beam optics and energy recovery have been performed, a high-energy recovery efficiency has been attained. Experimental results are discussed in this paper.

Self-consistent full-potential linearized-augmented-plane-wave local-density electronic-structure studies of magnetism and superconductivity in C15 compounds: ZrZn_2 and ZrV_2

Evaluation of ageable beta alloys Ti-17V-2Fe-2Co-3Al, Ti-17V-7.5Co-3A1 and Ti-8Mo-8V-5Co-3Al continued with room and elevated temperature smooth and notched tensile tests, creep stability, oxidation and stress-corrosion tests. Ti-17V-7.5Co-3Al aged more r...

1964-01-01

Spectral analysis of Pr3+-, Sm3+- and Dy3+-doped transparent GeO2-BaO-TiO2 glass ceramics

The electronic structure and properties of the cubic Laves phase (C15) compounds ZrZn_2 and ZrV_2 have been determined using our all-electron full-potential linearized-augmented-plane-wave (FLAPW) method for bulk solids. The computations were performed in two stages: (i) self-consistent warped muffin tin and (ii) self-consistent full potential. Spin-orbit coupling was included after either stage. The effects of the inclusion of the nonspherical terms inside the muffin tins on the eigenvalues is found to be small (of order 1 mRy). However, due to the fact that some of the bands near the Fermi level are flat, this effect leads to a much higher value of the density of states at E/sub F/ in ZnZr_2. The most important difference between the materials ZrZn_2 and ZrV_2 is the position of the d bands derived from the Zr and V atoms. Consequently, these materials have completely different Fermi surfaces. We have ...

British Library Electronic Table of Contents (United Kingdom)

In this paper, we present the photoluminescence properties of Pr3+-, Sm3+- and Dy3+-doped germanate glasses and glass ceramics. From the X-ray diffraction measurement, the host glass structure was determined. These glasses have shown strong absorption bands in the near-infrared (NIR) region. Compared to Pr3+-, Sm3+- and Dy3+-doped glasses, their respective glass ceramics have shown stronger emissions due to the Ba2TiGe2O8 crystalline phase. For Pr3+-doped glass and glass ceramic, emission bands centered at 530nm (3P03H5), 614nm (3P03H6), 647nm (3P03F2) and 686nm (3P03F3) have been observed with 485nm (3H43P0) excitation wavelength. Of them, 647nm (3P03F2) has shown bright red emission. Emission bands of 4G5/26H5/2 (565nm), 4G5/26H7/2 (602nm) and 4G5/26H9/2 (648nm) for the Sm3+:glass and gl...

2009-01-01

Production of yellow cake from rock phosphate deposits and its characterization

Luminescence and laser transition studies of Dy3+:K-Mg-Al fluorophosphate glasses

This study was carried out mainly to produce uranium trioxide (UO_3), with the standard of commercial specifications from rock phosphate deposits in eastern part of Nuba mountains, south Kurdufan state. A simplified hydrometallurgical procedure has been adopted for production of yellow cake from the ore. Elemental analysis has shown that the ore is rich in Ca and deficient in elements of potential interest such as Fe, Cu and Zn. Uranium content in ore, phosphoric acid and purified yellow cake (UO_3) obtained with different precipitants was analyzed using alpha-spectrometry. On the average, the activity concentration of uranium in ore corresponds to 82 #+-# 24 ppm (0.10%). From the data of pregnant liquor, it was observed that the addition of KCIO_3 as an oxidant improves the dissolution of uranium from the ore by almost 20%. Data has also indicated that the yellow cake purified by hydrogen peroxide has higher concentration of uranium by 44.5% over the one purified by TBP extraction. ...

2002-01-01

Unitary constraints on Deeply Virtual Compton Scattering

Dysprosium ion doped fluorophosphate glasses with compositions of PKMAFDy: (56-x/2) P2O5+17K2O+8Al2O3+(15-x/2)MgO+4AlF3+xDy2O3 (x=0.01, 0.05, 0.1, 1.0 and 2.0 mol%) have been prepared by melt quenching technique and are characterized by optical absorption, emission spectra and fluorescence lifetime measurements. The observed bands in the absorption spectrum are analysed by using free-ion Hamiltonian (HFI) model. The Judd-Ofelt (JO) analysis has been performed and the intensity parameters (??, ?=2, 4, 6) have been evaluated that are used to predict radiative properties. From emission spectra, the effective bandwidth (??eff) and the stimulated emission cross-section (?(?p)) were evaluated. The fluorescence decay from the 4F9/2 level of Dy3+ ions have been measured by monitoring the intense 4F9/2#->#6H13/2 transition (573 nm). The lifetimes (?) are found to decrease with increasing concentration due to concentration quenching. The decay curves ...

2009-02-28

Normalized noise power spectrum of full field digital mammography detector system

At moderately low momentum transfer ($-t$ up to 1 GeV$^2$) the coupling to the vector meson production channels gives the dominant contribution to real Compton and deeply virtual Compton scattering (DVCS). Starting from a Regge Pole approach that successfully describes vector meson production, the singular part of the corresponding box diagrams (where the intermediate vector meson-baryon pair propagates on-shell) is evaluated without any further assumptions (unitarity). Such a treatment explains not only the unexpectedly large DVCS unpolarized cross section that has been recently measured at Jefferson Laboratory (JLab), but also all the beam spin and charge asymmetries that has been measured at JLab and Hermes, without explicit need of Generalized Parton Distributions (GPD). The issue of the relationship between the two approaches is addressed.

2007-11-01

Normalized Noise Power Spectrum of Full Field Digital Mammography System

Full text: A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through de trending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality. (author)

Low-lying states in "9"7Mo and "1"0"1Mo by (t, d) and (d, p) reactions on the neighbouring molybdenum isotopes

A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through detrending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality.

2010-01-05

Flame retardancy of polybutylene terephthalate blended with various oxides

The values of spins, parities, and spectroscopic factors for neutron transfer have been determined for many low-lying states in "9"7Mo and "1"0"1Mo by a study of the (t, d) and (d, p) reactions on the neighbouring even-mass isotopes. Eighteen new values of J"#pi# have been obtained for these nuclei. Values of the fullness and emptiness parameters V"2 and U"2 have been suggested for the 3s_1_/_2 and 2d_5_/_s orbitals in "1"0"0Mo. (Nuclear structure "9"7Mo, "1"0"1Mo, measured J, #pi#, and spectroscopic factors for states up to #approx#2.0 MeV using (d, p) and (t, d) reactions.) (author).

1990-11-01

British Library Electronic Table of Contents (United Kingdom)

The flame retardancy of polybutylene terephthalate (PBT) was studied focusing on the effect of various oxides. Thermo-gravimetric analysis, pyrolysis/gas chromatography/mass spectrometry, and elemental analysis (EA) were used to analyze the flame retardancy, which were observed through the UL-test and a cone calorimeter. Many oxides influenced the flame retardancy and some of them could suppress the flammability of PBT. In particular, the blended-PBTs with ZnO and V2O5 accelerated the degradation and the edges of oxygen consumption were shorter than neat-PBT although the flammability became poorer. The quantitative analysis of the scission products and the results of EA showed that hydrolysis, successive dehydration, and other various reactions changed the scission route to generate less f...

2008-01-01

Characteristics of the 18 MeV medical linear accelerator 'NELAC-1018', 2. Electron beams

Biosorption of uranium (VI) by immobilized Aspergillus fumigatus beads

The performance and characteristics of a medical linear accelerator ''NELAC-1018'' for the electron beam therapy were discussed. Measurement of deep dose distribution revealed that the 80% range was 1.9 cm by 6 MeV, 2.8 cm by 9 MeV, 3.9 cm by 12 MeV, 4.9 cm by 15 MeV and 5.5 cm by 18 MeV. Iso-dose distribution with each tubus and cone showed a favorable flatness by any of the energies. The degree of flatness was extremely favorable, being +-1.7% or less.

1983-11-01

Absolute values of three neutrino masses from atmospheric mixing and an ansatz for the mixing-matrix elements

Biosorption of uranium (VI) ions by immobilized Aspergillus fumigatus beads was investigated in a batch system. The influences of solution pH, biosorbent dose, U (VI) concentration, and contact time on U (VI) biosorption were studied. The results indicated that the adsorption capacity was strongly affected by the solution pH, the biosorbent dose and initial U (VI) concentration. Optimum biosorption was observed at pH 5.0, biosrobent dose (w/v) 2.5%, initial U (VI) concentration 60 mg L{sup -1}. Biosorption equilibrium was established in 120 min. The adsorption process conformed to the Freunlich and Temkin isothermal adsorption models. The dynamic adsorption model conformed to pseudo-second order model.

2010-06-15

1 2 3 4 5

Alcoa titanium alloy Ti-10V-2Fe-3Al forgings -- Data sheets

Using data from atmospheric neutrino mixing, and a simple functional form for mixing angles, the absolute values of three neutrino masses are calculated: $m_3\\cong 5.37\\times 10^{-2} eV$, $m_2\\cong 1.94\\times 10^{-2} eV$, $m_1\\cong 1.46\\times 10^{-2} eV$. The quantities relevant for solar neutrino mixing are calculated: $(m_2^2-m_1^2) \\cong 1.63\\times 10^{-4} eV^2$, with non-maximal mixing $\\tan^2\\theta_\\sol \\cong 0.56$. The analysis gives a suggestion of a dynamical origin for the empirical, large CP-violating phase associated with an intrinsically, very small mixing angle in the quark sector.

2003-01-01

XPS study of passive films formed on molybdenum-implanted austenitic stainless steels

Ti-10V-2Fe-3Al is high strength, metastable beta titanium alloy developed by the Timet Division, Titanium Metals Corporation of America for enhanced forgeability and excellent mechanical property combinations, including deep hardening characteristics. Ti-10-2-3 has been the subject of intense thermomechanical processing (TMP) development and reduction to commercial practice for the full range of open die, closed-die and precision forged products utilized in aerospace and other applications. With commercially proven TMP, Ti-10-2-3 forgings provide a range of strength-fracture toughness combinations from 180 Ksi (1,240 MPa) minimum U.T.S. to 140 Ksi (965 MPa) minimum U.T.S with commensurate fracture toughness. With optimal TMP and these strength-toughness combinations, Ti-10-2-3 forgings are found provide superior smooth and notched fatigue properties critical to aerospace applications over incumbent alpha-beta alloys. The alloy retains 80 ...

1993-02-21

XPS study of passive films formed on molybdenum-implanted austenitic stainless steels

Austenitic stainless steels have been implanted with molybdenum ions (Mo[sup +], 100 keV, 2.5 x 10[sup 16] atoms cm[sup -2]). The implanted material has been characterized by XPS and RBS. The implanted region has a thickness of [approx] 1000 A with a maximum molybdenum concentration of [approx] 9 at.% Mo located at [approx] 210 A from the surface. The effects of implanted molybdenum on the passivation of the alloy in 0.5 M H[sub 2]SO[sub 4] have been investigated by electrochemistry and XPS. After XPS analysis the samples were transferred without exposure to air into a glove-box with an inert atmosphere. The electrochemical behaviour of the alloy is significantly modified by the implanted molybdenum. The major effect is that the activation peak disappears. A bilayer structure (outer hydroxide/inner oxide) of the passive film is observed for both the implanted and non-implanted alloys and the thicknesses of the films are similar. On the ...

1992-06-01

Pulsed-plasma nitriding of a niobium-alloyed PM tool steel

Austenitic stainless steels have been implanted with molybdenum ions (Mo"+, 100 keV, 2.5 x 10"1"6 atoms cm"-"2). The implanted material has been characterized by XPS and RBS. The implanted region has a thickness of #approx# 1000 A with a maximum molybdenum concentration of #approx# 9 at.% Mo located at #approx# 210 A from the surface. The effects of implanted molybdenum on the passivation of the alloy in 0.5 M H_2SO_4 have been investigated by electrochemistry and XPS. After XPS analysis the samples were transferred without exposure to air into a glove-box with an inert atmosphere. The electrochemical behaviour of the alloy is significantly modified by the implanted molybdenum. The major effect is that the activation peak disappears. A bilayer structure (outer hydroxide/inner oxide) of the passive film is observed for both the implanted and non-implanted alloys and the thicknesses of the films are similar. On the implanted alloy the outer ...

1991-10-01

Pulsed-plasma nitriding of a niobium-alloyed PM tool steel

The aim of this work is to describe the processes during plasma nitriding of Nb-containing, powder metallurgy prepared (PM) tool steel. PM steel was studied containing 2.5% C, 3.3% Si, 6.2% Cr, 2.2% Mo, 2.6% V, 2.6% Nb and 1.0% W, produced by melt atomization and hot isostatic pressing. The hardened and tempered steel was plasma nitrided at temperatures ranging from 470 to 530 deg. C. The nitriding time was 30-180 min. Optical microscopy, electron microscopy, XRD, EDS, WDS and hardness measurements were used to study the steel's properties, microstructure, phases and chemical composition. The nitriding temperature of 470 deg. C was found to be unsuitable for practical use because the layers prepared at this temperature were non-uniform. The compound layer formed by M{sub 2,3}(C,N) and M{sub 4}N was found after nitriding at temperatures of 500 and 530 deg. C for at least 60 min. The effect of niobium on the formation of this layer was ...

2005-02-25

Preparation, characterization and properties of thermochromic tungsten-doped vanadium dioxide by thermal reduction and annealing

The aim of this work is to describe the processes during plasma nitriding of Nb-containing, powder metallurgy prepared (PM) tool steel. PM steel was studied containing 2.5% C, 3.3% Si, 6.2% Cr, 2.2% Mo, 2.6% V, 2.6% Nb and 1.0% W, produced by melt atomization and hot isostatic pressing. The hardened and tempered steel was plasma nitrided at temperatures ranging from 470 to 530 deg. C. The nitriding time was 30-180 min. Optical microscopy, electron microscopy, XRD, EDS, WDS and hardness measurements were used to study the steel's properties, microstructure, phases and chemical composition. The nitriding temperature of 470 deg. C was found to be unsuitable for practical use because the layers prepared at this temperature were non-uniform. The compound layer formed by M_2_,_3(C,N) and M_4N was found after nitriding at temperatures of 500 and 530 deg. C for at least 60 min. The effect of niobium on the formation of this layer was studied.

2005-02-25

Pre-oxidized and nitrided stainless steel alloy foil for proton exchange membrane fuel cell bipolar plates: Part 1. Corrosion, interfacial contact resistance, and surface structure

Thermochromic tungsten-doped vanadium dioxide (VO2) powders were successfully synthesized by thermal reduction using V2O5 as a vanadium precursor. The products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The results indicated that W was successfully doped into the crystal lattice of VO2 matrix, and prepared tungsten-doped VO2 had a rod-like morphology. The effects of reducing temperature and annealing temperature on the crystallographic structures were also discussed. The phase transition temperature (Tt) of VO2 could be simply tuned by changing the doping concentration of tungsten. When the doping concentration was 1.58 mol%, the Tt could be reduced to 37.8 oC from initial 69.5 oC, suggesting that tungsten-doped VO2 possesses prominent thermochromic properties and optical switching characters. It has shown that this ...

2010-08-20

British Library Electronic Table of Contents (United Kingdom)

Thermal (gas) nitridation of stainless steel alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr2N, CrN, TiN, V2N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of scale-up studies to determine the feasibility of extending the nitridation approach to thin 0.1mm stainless steel alloy foils for proton exchange membrane fuel cell (PEMFC) bipolar plates. Developmental Fe-20Cr-4V alloy and type 2205 stainless steel foils were treated by pre-oxidation and nitridation to form low-ICR, corrosion-resistant surfaces. As-treated Fe-20Cr-4V foil exhibited target (low) ICR values, whereas 2205 foil suffered from run-to-run variation in ICR values, ranging up to 2x the...

2010-01-01

Pre-oxidized and nitrided stainless steel alloy foil for proton exchange membrane fuel cell bipolar plates. Part 2: Single-cell fuel cell evaluation of stamped plates

British Library Electronic Table of Contents (United Kingdom)

Thermal (gas) nitridation of stainless steel alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr2N, CrN, TiN, V2N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of proton exchange membrane (PEM) single-cell fuel cell studies of stamped and pre-oxidized/nitrided developmental Fe-20Cr-4V weight percent (wt.%) and commercial type 2205 stainless steel alloy foils. The single-cell fuel cell behavior of the stamped and pre-oxidized/nitrided material was compared to as-stamped (no surface treatment) 904L, 2205, and Fe-20Cr-4V stainless steel alloy foils and machined graphite of similar flow field design. The best fuel cell behavior among the alloys was exhibited...

2010-01-01

Microstructure fracture toughness and fatigue crack growth rate in titanium alloys; Proceedings of the 1987 TMS-AIME Annual Symposium, Denver, CO, Feb. 24, 25, 1987

Long-term corrosion study at nuclear power plant Bohunice (Slovakia)

The papers contained in this volume provide an overview of recent theoretical and experimental research related to the fracture toughness and fatigue crack growth characteristics of titanium alloys. Topics discussed include room temperature fatigue crack propagation in beta-titanium alloys, fatigue crack growth rate acceleration in alpha+beta Ti alloys, influence of transformed beta microstructures on fatigue crack growth rates in Ti-6Al-4V, and the role of inclusion and pore content on the fracture toughness of powder processed blended elemental Ti-10V-2Fe-3Al. Papers are also presented on fatigue crack growth measurements in an alpha-beta titanium alloy, the effects of thermal processing variation on the properties of Ti-6Al-4V, and the effect of microstructure on ductility and fracture toughness of alpha+beta titanium alloys.

1987-01-01

Light Sterile Neutrino Effects at theta_13-Sensitive Reactor Neutrino Experiments

Steam generators of four VVER-440 units at nuclear power plants V-1 and V-2 in Jaslovske Bohunice (Slovakia) were gradually changed by new original 'Bohunice' design in period 1994-1998. Corrosion processes before and after these design and material changes in Bohunice secondary circuit were studied using Moessbauer spectroscopy during last 25 years. Innovations in the feed water pipeline design as well as material composition improvements were evaluated positively. Moessbauer spectroscopy studies of phase composition of corrosion products were performed on real specimens scrapped from water pipelines or in form of filter deposits. The corrosion of new feed water pipelines system (from austenitic steel) in combination to innovated operation regimes goes dominantly to magnetite. The hematite presence is mostly on the internal surface of steam generator body and its concentration increases towards the top of the body. In the results ...

2010-03-01

High-energy neutron irradiation of superconducting compounds

We study the impact of very light sterile neutrinos (Delta m^2_new around 1 to 10 times 10^(-2) eV^2, sin^2 2theta_new<10^(-1)) on upcoming theta_13-driven reactor antineutrino experiments like Double-CHOOZ and Daya Bay. Oscillations driven by these vales of Delta m^2_new affect data in the near and far detectors differently and hence potentially modify the capability of these experimental setups to constrain and measure sin^2 2theta_13. We find that the hypothesis theta_new different from zero negatively impacts one's ability to either place an upper bound on sin^2 2theta_13 in the advent of no oscillation signal or measure sin^2 2theta_13 if a theta_13-driven signal is observed. The impact of sterile neutrino effects, however, depends significantly on one's ability to measure the recoil positron energy spectrum. If sin^2 2theta_new is larger than 10^(-2), upcoming theta_13-driven reactor antineutrino experiments should be able to measure ...

2008-01-01

Detections of SiO and H$_2$O Masers in the Bipolar Nebula IRAS 19312+1950

The effect of high-energy neutron irradiation (E greater than 1 MeV) at ambient reactor temperatures on the superconducting properties of a variety of superconducting compounds is reported. The materials studied include the A-15 compounds Nb_3Sn, Nb_3Al, Nb_3Ga, Nb_3Ge and V_3Si, the C-15 Laves phase HfV_2, the ternary molybdenum sulfide Mo_3Pb/sub 0.5/S_4 and the layered dichalcogenide NbSe_2. The superconducting transition temperature has been measured for all of the above materials for neutron fluences up to 5 x 10"1"9 n/cm"2. The critical current for multifilamentary Nb_3Sn has also been determined for fields up to 16 T and fluences between 3 x 10"1"7 n/cm"2 and 1.1 x 10"1"9 n/cm"2.

1976-03-01

Aluminum assisted electrodeposition of europium in LiCl-KCl molten salt

We report on the detection of SiO and water masers toward a newly found bipolar nebula, IRAS 19312+1950. This object exhibits extreme red IRAS color log (F25/F12)=0.5 and log (F60/F25)=0.7 and a nebulosity having a size of about 30" extended to the South-West in the 2MASS near-infrared image. Toward this object, we have detected emission from the H2O 6(1,6)-5(2,3) transition, the SiO J=1-0, v=1 and 2, and J=2-1, v=1 transitions, and the SO 2(2)--1(1) and H13CN J=1-0 transitions. The thermal lines of SO and H13CN are shifted by about 12 km/s in radial velocity with respect to the maser lines, indicating that thermal emission comes from the background molecular cloud. However, the SiO J=2-1, v=2 spectrum shows another component of SiO emission separated by 26 km/s from the main component, that might be formed in a rotating or expanding shell.

2000-01-01

Aluminum assisted electrodeposition of europium in LiCl-KCl molten salt

Cyclic voltammetry (CV), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were employed to investigate the electrodeposition of Eu and Al in an LiCl-KCl eutectic melt containing Eu{sup 2+} and Al{sup 3+} at 450 deg. C. In order to deposit a pure Eu and Al alloy, the stoichiometrically lower concentration of Al{sup 3+} than that of Eu{sup 2+} and Al wires as a counter electrode was introduced into the bath of LiCl-KCl melt for the electrodeposition. The electrodeposition takes place at a potential more negative than -1.95 V vs. Ag|Ag{sup +} while the deposit is oxidized at more positive potential than -1.92 V. Two new reduction peaks and an anodic peak on a W working electrode were observed at -2.39 V, -2.42 V, and -2.1 V, vs. Ag|Ag{sup +}, respectively, suggesting that the potential window of the Al system in LiCl-KCl melt can be extended to -2.43 V vs. Ag|Ag{sup +}. The EDS analysis indicated that AlEu can be ...

2010-03-01

Wear and friction coefficient of particle reinforced Ti-alloys

Cyclic voltammetry (CV), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were employed to investigate the electrodeposition of Eu and Al in an LiCl-KCl eutectic melt containing Eu2+ and Al3+ at 450 deg. C. In order to deposit a pure Eu and Al alloy, the stoichiometrically lower concentration of Al3+ than that of Eu2+ and Al wires as a counter electrode was introduced into the bath of LiCl-KCl melt for the electrodeposition. The electrodeposition takes place at a potential more negative than -1.95 V vs. Ag|Ag+ while the deposit is oxidized at more positive potential than -1.92 V. Two new reduction peaks and an anodic peak on a W working electrode were observed at -2.39 V, -2.42 V, and -2.1 V, vs. Ag|Ag+, respectively, suggesting that the potential window of the Al system in LiCl-KCl melt can be extended to -2.43 V vs. Ag|Ag+. The EDS analysis indicated that AlEu can be deposited at the potential more negative than ...

2010-03-01

Two-gigawatt burst-mode operation of the intense microwave prototype (IMP) free-electron laser (FEL) for the microwave tokamak experiment (MTX)

Particulate Reinforced Titanium matrix composites (PRTi) exhibit some improved specific mechanical properties in comparison with those of unreinforced titanium alloys as a result of the combination of the high strength and stiffness of ceramic particles with the toughness and damage tolerance provided by the metal matrix. The poor tribological properties of the titanium exclude titanium alloys from applications where wear resistance is required (brakes, rotating parts, sliding parts). The addition of ceramic particles improves the tribological properties of metals sensitive to adhesive and /or abrasive wear significantly. In this work, the wear resistance and the friction coefficient of Ti6Al-6V-2Sn reinforced with TiC particles and Ti6Al-4V reinforced with SiC particles (prototype material) are compared with the unreinforced alloys. Pin on disc and pin on ring tests were carried out against standard steel (100Cr6) as a function of pressure, ...

2004-11-01

Tomographic measurements of carbon monoxide temperature and concentration in a Bunsen flame using diode laser absorption

The MTX explored the plasma heating effects of 140 GHz microwaves from both Gyrotrons and from the IMP FEL wiggler. The Gyrotron was long pulse length (0.5 seconds maximum) and the FEL produced short-pulse length, high-peak power, single and burst modes of 140 GHZ microwaves. Full-power operations of the IMP FEL wiggler were commenced in April of 1992 and continued into October of 1992. The Experimental Test Accelerator H (ETA-II) provided a 50-nanosecond, 6-MeV, 2--3 kAmp electron beam that was introduced co-linear into the IMP FEL with a 140 GHz Gyrotron master oscillator (MO). The FEL was able to amplify the MO signal from approximately 7 kW to peaks consistently in the range of 1--2 GW. This microwave pulse was transmitted into the MTX and allowed the exploration of the linear and non-linear effects of short pulse, intense power in the MTX plasma. Single pulses were used to explore and gain operating experience in the parameter space of the ...

1993-10-06

Pre-Oxidized and Nitrided Stainless Steel Foil for Proton Exchange Membrane Fuel Cell Bipolar Plates: Part 1 Corrosion, Interfacial Contact Resistance, and Surface Structure

Temperature and concentration profiles of CO in a laminar, axisymmetric, premixed methane-air Bunsen flame are measured using line-of-sight diode laser absorption spectroscopy and computer tomographic (CT) reconstruction. Absorption spectra for P(20) (v=2<-1) and P(27) (v=1<-0) vibrotational transitions of CO were measured at 21 evenly spaced positions over a 1.33 cm span for a 1.3 cm radius flame. CT reconstruction algorithm was based on Fourier convolution. The tomographically reconstructed normalized transmission profiles derived from absorption spectra, in conjunction with a quantum mechanical model for vibrotational behavior of CO, yielded both temperature and concentration profiles. The Bunsen flame had 3 distinct zones: an inner rich-premixed flame zone, an outer non-premixed flame zone and an unburnt core region. The reconstructed temperature profile showed that the core region temperature was close to ambient and rapidly ...

1993-12-01

Photodissociation dynamics of doubly excited Rydberg states of molecular hydrogen

Thermal (gas) nitridation of stainless steels can yield low interfacial contact resistance (ICR), electrically-conductive and corrosion-resistant nitride containing surfaces (Cr2N, CrN, TiN, V2N, VN, etc) of interest for fuel cells, batteries, and sensors. This paper presents the results of scale up studies to determine the feasibility of extending the nitridation approach to thin 0.1 mm stainless steel alloy foils for proton exchange membrane fuel cell (PEMFC) bipolar plates. A major emphasis was placed on selection of alloy foil composition and nitidation conditions potentially capable of meeting the stringent cost goals for automotive PEMFC applications. Developmental Fe-20Cr-4V alloy and type 2205 stainless steel foils were treated by pre-oxidation and nitridation to form low-ICR, corrosion-resistant surfaces. Promising behavior was observed under simulated aggressive anode- and cathode- side bipolar plate conditions for both materials. ...

2010-09-01

1 2 3 4 5

Magnetic moments of "1"7"7Ta apd sup(181,182,187)Re states

We have applied photofragment ion imaging to investigate the dissociation dynamics of low-lying, doubly excited states of molecular hydrogen. A doubly excited electronic state is one in which both of the hydrogen electrons reside in excited molecular orbitals. Two-step, two-color multiphoton excitation of H_2, first via 201.8 nm, two-photon excitation into the E, F "1#SIGMA#"+_g(v_E=0, J=1) state, followed by #approx#563 nm, 1+m (m=1, 2) excitation through the B double-prime "1#SIGMA#"+_u(v=0, J=0, 2), D "1#PI#_u(v=2, J=1, 2), and B' "1#SIGMA#"+_u(v=4, J=0, 2) states provides a ready means of populating several low-lying doubly excited states of H_2 at increasing internuclear separations. From these doubly excited repulsive states, both dissociation and autoionization processes are possible. Because the excitation energy remains relatively constant as each intermediate state is accessed, differences in the photodissociation dynamics via each ...

Isobaric analog resonances in "8"9Y

The magnetic moments of "1"7"7Ta and sup(181,182,187)Re levels decaying via the K-forbidden transitions are measured. The nuclei studied are produced via the "1"7"7W and sup(181,182)Os and "1"8"7W #beta#-decay respectively. The magnetic moments have been measured using the method of the differential #gamma##gamma# angular correlations, perturbed by an external magnetic field. The following magnetic moments and lifetimes are obtained: for the 5/2"-1/2"-[541] "1"8"1Re level with excitation energy of 357 keV #mu#/#mu#sub(n)=2.00+-0.10, Tsub(1/2)=(76+-8)x10sup(-8) s; for the 186.4 keV 5/2"-1/2"-[541] "1"7"7Ta level #mu#/#mu#sub(n)=2.02+-0.13, Tsub(1/2)=(2.78+-0.09)x10sup(-6) s; for the 236 keV 2"- "1"8"2Re level #mu#/#mu#sub(n)=2.12+-0.08; for the 203 keV 9/2"- [514] "1"8"7Re level #mu#/#mu#sub(n)=5.04+-0.09.

1978-03-01

Reduced boron diffusion under interstitial injection in fluorine implanted silicon

Three resonances at the proton energies 7.0, 7.08, and 7.53 MeV on the target "8"8Sr were chosen to investigate the possibility of determining the amplitudes of the weak coupling experimentally. The corresponding "8"9Sr levels under investigation were 1.93 MeV ("5/_2"+), 2.00 MeV ("3/_2"+), and 2.46 MeV ("3/_2"+). Angular distributions were measured on resonance at 7.0, 7.08, and 7.53 MeV from proton inelastic scattering to the 1.84 MeV (2"+) state of "8"8Sr for differential cross section, analyzing power, spin-flip probability, and spin-flip asymmetry. A polarized beam of protons was used to obtain the analyzing power. The spin-flip probability was obtained from the coincidence of the prompt gamma rays from the (p,p'#gamma#) reaction with the scattered protons. With the polarized beam, the gamma coincidence technique was further used to obtain a spin-flip asymmetry measurement. From these measurements, the polarization was calculated, and the ...

ZZ MCJEF22NEA.BOLIB, MCNP Cross Section Library Based on JEF-2.2

Point defect injection studies are performed to investigate how fluorine implantation influences the diffusion of boron marker layers in both the vacancy-rich and interstitial-rich regions of the fluorine damage profile. A 185 keV, 2.3x10"1"5 cm"-"2 F"+ implant is made into silicon samples containing multiple boron marker layers and rapid thermal annealing is performed at 1000 deg. C for times of 15-120 s. The boron and fluorine profiles are characterized by secondary ion mass spectroscopy and the defect structures by transmission electron microscopy (TEM). Fluorine implanted samples surprisingly show less boron diffusion under interstitial injection than those under inert anneal. This effect is particularly noticeable for boron marker layers located in the interstitial-rich region of the fluorine damage profile and for short anneal times (15 s). TEM images show a band of dislocation loops around the range of the fluorine implant and the ...

2007-12-01

Accuracy of patient dose calculation for lung IMRT: A comparison of Monte Carlo, convolution/superposition, and pencil beam computations

1 - Description or function: Continuous energy cross-section data library for the Monte Carlo program MCNP based on the JEF-2.2 evaluated nuclear data library (ACE Format). Format: ACE Number of groups: Continuous energy Nuclides (107): H-1, H-2, He-4, Li-6, Li-7, Be-9, B-10, B-11, C-nat, N-14, N-15, O-16, O-17, F-19, Na-23, Mg-nat, Al-27, Si-nat, Cl-nat, Ti-nat, Cr-50, Cr-52, Cr-53, Cr-54, Mn-55, Fe-54, Fe-56, Fe-57, Fe-58, Co-59, Ni-58, Ni-60, Ni-61, Ni-62, Ni-64, Zr-90, Zr-91, Zr-92, Zr-94, Zr-96, Zr-nat, Nb-93, Mo-92, Mo-94, Mo-95, Mo-96, Mo-97, Mo-98, Mo-100, Mo-nat, Tc-99, Ru-101, Ru-102, Ru-104, Rh-103, Pd-105, Pd-107, Ag-109, I-129, Xe-131, Cs-133, Pr-141, Nd-143, Nd-145, Pm-147, Sm-147, Sm-149, Sm-150, Sm-151, Sm-152, Eu-153, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, Hf-174, Hf-176, Hf-177, Hf-178, Hf-179, Hf-180, Pb-nat, Bi-209, Th-232, U-234, U-235, U-236, U-238, Np-237, Pu-238, Pu-239, Pu-239bis, Pu-240, Pu-241, Pu-242, Am-241, Am-242, Am-242m, Am-243, Cm-242, Cm-243, ...