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Laser spectroscopic studies of elements in the heavy actinide and transactinide region help understand the nuclear ground state properties of these heavy systems. Pioneering experiments at GSI, Darmstadt identified the first atomic transitions in the element nobelium. For the purpose of determining nuclear properties in nobelium isotopes with higher precision, a new apparatus for high-resolution laser spectroscopy in a gas-jet called JetRIS is under development. To determine the spectral resolution and the homogeneity of the gas-jet, the laser-induced fluorescence of 164Dy atoms seeded in the jet was studied. Different hypersonic nozzles were investigated for their performance in spectral resolution and efficiency. Under optimal conditions, a spectral linewidth of about 200–250 MHz full width at half maximum and a Mach number of about 7 was achieved, which was evaluated in context of the density profile of the atoms in the gas-jet. [ABSTRACT FROM AUTHOR]

We present a crossed molecular beam velocity-map ion imaging study of state-to-state rotational energy transfer of NO(A²Σ+, v = 0, N = 0, j = 0.5) in collisions with Ne atoms. From these measurements, we report differential cross sections and angle-resolved rotational angular momentum alignment moments for product states N' = 3 and 5-10 for collisions at an average energy of 523 cm-1, and N' = 3 and 5-14 for collisions at an average energy of 1309 cm-1, respectively. The experimental results are compared to the results of close-coupled quantum scattering calculations on two literature ab initio potential energy surfaces (PESs) [Pajón-Suárez et al., Chem. Phys. Lett. 429, 389 (2006) and Cybulski and Fernández, J. Phys. Chem. A 116, 7319 (2012)]. The differential cross sections from both experiment and theory show clear rotational rainbow structures at both collision energies, and comparison of the angles observed for the rainbow peaks leads to the conclusion that Cybulski and Fernández PES better represents the NO(A²Σ+)-Ne interaction at the collision energies used here. Sharp, forward scattered (<10?), peaks are observed in the experimental differential cross sections for a wide range of N' at both collision energies, which are not reproduced by theory on either PES. We identify these as L-type rainbows, characteristic of attractive interactions, and consistent with a shallow well in the collinear Ne-N-O geometry, similar to that calculated for the NO(A²Σ+)-Ar surface [Kłos et al., J. Chem. Phys. 129, 244303 (2008)], but absent from both of the NO(A²Σ+)-Ne surfaces tested here. The angle-resolved alignment moments calculated by quantum scattering theory are generally in good agreement with the experimental results, but both experiment and quantum scattering theories are dramatically different to the predictions of a classical rigid-shell, kinematic-apse conservation model. Strong oscillations are resolved in the experimental alignment moments as a function of scattering angle, confirming and extending the preliminary report of this behavior [Steill et al., J. Phys. Chem. A 117, 8163 (2013)]. These oscillations are correlated with structure in the differential cross section, suggesting an interference effect is responsible for their appearance. [ABSTRACT FROM AUTHOR]

We use static as well as time-dependent first-principles computations to study interaction of the CO, NO, and HCN molecules with the Ag8 nanocluster. The many-body based GW correction is applied for accurate description of the highest occupied (HOMO) and the lowest unoccupied (LUMO) molecular orbital levels. It is argued that the adsorption of these molecules changes the stable structure of Ag8 from Td to the more chemically active D2d symmetry. We discuss that the CO, NO, and HCN molecules prefer to adsorb on the atom of the cluster with significant contribution to both HOMO and LUMO, for the accomplishment of the required charge transfers in the systems. The charge back donation is found to leave an excess energy of about 110 meV on the NO molecular bond, evidencing potential application of silver clusters for NO reduction. It is argued that CO and specially NO exhibit strong physical interaction with the silver cluster and hence significantly modify the electronic and optical properties of the system, while HCN makes very week physical bonds with the cluster. The optical absorption spectra of the Ag8 cluster before and after molecule adsorption are computed and a nontrivial red shift is observed in the NO and HCN adsorbed clusters. [ABSTRACT FROM AUTHOR]

We use static as well as time-dependent first-principles computations to study interaction of the CO, NO, and HCN molecules with the Ag8 nanocluster. The many-body based GW correction is applied for accurate description of the highest occupied (HOMO) and the lowest unoccupied (LUMO) molecular orbital levels. It is argued that the adsorption of these molecules changes the stable structure of Ag8 from Td to the more chemically active D2d symmetry. We discuss that the CO, NO, and HCN molecules prefer to adsorb on the atom of the cluster with significant contribution to both HOMO and LUMO, for the accomplishment of the required charge transfers in the systems. The charge back donation is found to leave an excess energy of about 110 meV on the NO molecular bond, evidencing potential application of silver clusters for NO reduction. It is argued that CO and specially NO exhibit strong physical interaction with the silver cluster and hence significantly modify the electronic and optical properties of the system, while HCN makes very week physical bonds with the cluster. The optical absorption spectra of the Ag8 cluster before and after molecule adsorption are computed and a nontrivial red shift is observed in the NO and HCN adsorbed clusters. [ABSTRACT FROM AUTHOR]

Laser spectroscopic studies of elements in the heavy actinide and transactinide region help understand the nuclear ground state properties of these heavy systems. Pioneering experiments at GSI, Darmstadt identified the first atomic transitions in the element nobelium. For the purpose of determining nuclear properties in nobelium isotopes with higher precision, a new apparatus for high-resolution laser spectroscopy in a gas-jet called JetRIS is under development. To determine the spectral resolution and the homogeneity of the gas-jet, the laser-induced fluorescence of 164Dy atoms seeded in the jet was studied. Different hypersonic nozzles were investigated for their performance in spectral resolution and efficiency. Under optimal conditions, a spectral linewidth of about 200–250 MHz full width at half maximum and a Mach number of about 7 was achieved, which was evaluated in context of the density profile of the atoms in the gas-jet.

Laser spectroscopy enables the determination of fundamental atomic and nuclear properties with high precision. In view of the low production rates of the heaviest elements, a high total efficiency is a crucial requirement for any experimental setup to be used in on-line experiments. The setup requires the use of gas stopping techniques to slow down the radionuclides of interest. In previous studies laser spectroscopy was performed inside a gas-filled stopping cell with a limited spectral resolution of a few GHz. Collisional broadening inside stopping cells ultimately limits the precision of laser spectroscopic studies and hampers in particular hyperfine spectroscopy. The spectral linewidth is reduced by an order of magnitude when the laser spectroscopy is performed in a well-collimated gas jet formed by the exit nozzle of a gas stopping cell. In addition, the exposure of the jet to high-repetition rate laser light which saturates the optical transitions allows maintaining a high total efficiency. Here, we present a new setup dedicated to laser spectroscopy of the heaviest elements with an improved resolution, which is presently under construction. This setup combines the efficient filament neutralization demonstrated for nobelium with the improved resolution of in-gas-jet spectroscopy. [ABSTRACT FROM AUTHOR]

Direct high-precision mass spectrometry of the heaviest elements with SHIPTRAP, at GSI in Darmstadt, Germany, requires high efficiency to deal with the low production rates of such exotic nuclides. A second-generation gas stopping cell, operating at cryogenic temperatures, was developed and recently integrated into the relocated system to boost the overall efficiency. Offline measurements using 223Ra and 225Ac recoil-ion sources placed inside the gas volume were performed to characterize the gas stopping cell with respect to purity and extraction efficiency. In addition, a first online test using the fusion-evaporation residue 254No was performed, resulting in a combined stopping and extraction efficiency of 33(5)%. An extraction time of 55(44) ms was achieved. The overall efficiency of SHIPTRAP for fusion-evaporation reaction products was increased by an order of magnitude to 6(1)%. This will pave the way for direct mass spectrometry of heavier and more exotic nuclei, eventually in the region of superheavy elements with proton numbers Z ⩾ 104. [ABSTRACT FROM AUTHOR]

Highlights • The adsorption properties NO and H 2 O 2 on original and Ti-doped Fe 3 O 4 (1 1 1) surface were first studied by DFT calculations. • Ti doping plays a significant role of the catalytic oxidation of NO by H 2 O 2 over Ti-doped Fe 3 O 4 (1 1 1) surfaces. • Oxidation mechanism of NO over Ti-doped Fe 3 O 4 (1 1 1) surfaces by active oxygen was discussed. Abstract Magnetite is considered a promising catalyst for catalytic oxidation of nitrogen oxide (NOx) by vaporized H 2 O 2. The NO oxidation mechanisms on original and Ti-doped Fe 3 O 4 (1 1 1) catalyst surfaces were analyzed by density functional theory, and the individual and combined adsorption characteristics of H 2 O 2 and NO on the original and Ti-doped surfaces were investigated. Results revealed that H 2 O 2 disassociates on the original and Ti-doped surfaces with large adsorption energies. Ti doping significantly augmented the adsorption intensity of H 2 O 2 and promoted the decomposition of H 2 O 2 on the catalyst surface. NO was adsorbed on the original and Ti-doped surfaces in molecular form. The adsorption intensity of H 2 O 2 was greater than that of NO. HNO 2 was generated on the original and Ti-doped surfaces through NO and H 2 O 2 co-adsorption, thereby confirming that NO was oxidized. Analysis of electronic structures demonstrated that H 2 O 2 was decomposed according to the Haber-Weiss mechanism. The oxidation of NO by surface oxygen atoms over the original and Ti-doped surfaces was also calculated, and the low energy barrier obtained suggests that NO is easily oxidized by active O over catalyst surfaces. [ABSTRACT FROM AUTHOR]

The mass distributions of fragments resulting from the fission of the isotopes of Fm and No at excitation energies 0–50 MeV are studied with the statistical scission-point fission model. The available experimental mass distributions in the spontaneous and thermal-neutron-induced fission are well described and the origin of transition between asymmetric and symmetric fission modes with variations of neutron number and excitation energy is explored. [ABSTRACT FROM AUTHOR]

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The hydrogen like ion is the simplest structure of an atom, so the studying on it gives a change to test of methods using for determinating of atomic structures. It is also an occasion the studying on hydrogen like ions to understand atomic structure. For this reason, it is performed a study for hydrogen like nobelium (No101+, Z=102). It has been used both multiconfiguration Hartree-Fock, MCHF, and multiconfiguration Dirac-Fock method, MCDF, as calculating level structure of No101+. The calculations have contained some relativistic corrections and quantum electrodynamic effects. There are very few theoretical works in available literature and no experimental one for No101+. The calculated results have been interpreted in comparison with other theoretical results. [ABSTRACT FROM AUTHOR]

Oxy-H 2 O combustion is a novel oxy-fuel combustion technology, different from conventional and oxy-CO 2 combustion. NO and N 2 O emissions during devolatilization and char combustion of a single biomass particle in O 2 /N 2 and O 2 /H 2 O were investigated in a tube reactor under different temperatures (700 °C, 800 °C, and 900 °C) and oxygen concentrations (21%, 30%, 40%, and 50% by volume). Single biomass pellets of poplar wood, rice husk, and corn stalk were selected. The method of isothermal thermo-gravimetric analysis was applied to distinguish the two stages of biomass combustion based on its proximate analysis. The presence of H 2 O vapor can improve the free radicals, H 2 and CO concentrations, promoting NO and N 2 O reduction. The total conversions of fuel-N to NO and N 2 O in O 2 /N 2 are over 2 times higher than those in O 2 /H 2 O. In O 2 /N 2 , NO is formed as the sample heated up, while N 2 O is mainly formed during char combustion stage. However, NO is formed after N 2 O in O 2 /H 2 O. No matter in O 2 /N 2 or in O 2 /H 2 O, a higher fuel-N content in biomass results in higher NO and N 2 O yields during the two stages, whilst the conversions of fuel-N to NO and N 2 O during the two stages decrease with increasing fuel-N/ash content. In O 2 /N 2 , the total conversion of fuel-N to NO reaches the maximum value (14.35%) at T = 800 °C, whilst the total conversion of fuel-N to NO increases with increasing temperature in O 2 /H 2 O. The total conversions of fuel-N to N 2 O decrease with increasing temperature in O 2 /N 2 and O 2 /H 2 O. The influence of oxygen concentration on NO and N 2 O is similar to that of temperature. In O 2 /N 2 , there is a maximum value of the total conversion of fuel-N to NO (14.35%) at 〈O 2 〉 = 30%, whilst there is no obvious change of the total conversion of fuel-N to NO with increasing oxygen concentration in O 2 /H 2 O. The total conversions of fuel-N to N 2 O decrease with increasing oxygen concentration in O 2 /N 2 and O 2 /H 2 O. The results are beneficial to understand the NO and N 2 O emission mechanisms and favorable for the NO and N 2 O control in O 2 /H 2 O. [ABSTRACT FROM AUTHOR]

A copper complex, [CuI(tmpa)(MeCN)]+, effectively reductively couples NO(g) at RT in methanol (MeOH), giving a structurally characterized hyponitritodicopper(II) adduct. Hydrogen-bonding from MeOH is critical for the hyponitrite complex formation and stabilization. This complex exhibits the reverse redox process in aprotic solvents, giving CuI + NO(g), leading to CuI-mediated NO(g)-disproportionation. The relationship of this chemistry to biological iron and/or copper mediated NO(g) reductive coupling to give N2O(g) is discussed. [ABSTRACT FROM AUTHOR]

In this paper, activity of sol–gel synthesized LaB 0.5 B′ 0.5 O 3 (B = Fe, Mn, B′= Fe, Mn, Co, Cu) perovskite catalysts was evaluated in catalytic reduction of NO by CO. Perovskite catalysts were characterized by XRD, BET, H 2 -TPR and SEM analysis. LaMn 0.5 Cu 0.5 O 3 has the highest activity among LaB 0.5 B′ 0.5 O 3 perovskite catalysts (88% CO conversion and 93% NO conversion at 350 °C). The superior activity of LaMn 0.5 Cu 0.5 O 3 over other perovskite catalysts was associated to synergistic effect between Mn and Cu, higher reducibility at low temperature and more structural defects. The Langmuir–Hinshelwood mechanisms were used for Kinetic modeling of reduction of NO by CO. According to kinetic calculations, the most probable mechanism for this process was found to be the one based on dissociation of adsorbed NO (herein referred to as mechanism 1), according to which the experimental data was predicted at correlation coefficient of R 2 > 0.99. [ABSTRACT FROM AUTHOR]

Using the sensitive Radiation Detected Resonance Ionization Spectroscopy (RADRIS) technique an optical transition in neutral nobelium (No, Z = 102) was identified. A remnant signal when delaying the ionizing laser indicated the influence of a strong buffer gas induced de-excitation of the optically populated level. A subsequent investigation of the chemical homologue, ytterbium (Yb, Z = 70), enabled a detailed study of the atomic levels involved in this process, leading to the development of a rate equation model. This paves the way for characterizing resonance ionization spectroscopy (RIS) schemes used in the study of nobelium and beyond, where atomic properties are currently unknown. Graphical abstract: [ABSTRACT FROM AUTHOR]

MoFe/Beta@CeO 2 core−shell catalyst was designed with nano-size Beta supporting MoFe bimetallic oxides as the core and CeO 2 thin film as the shell. The structure and physico-chemical properties of the coated and uncoated CeO 2 catalysts were characterized by TEM, SEM, XRD, N 2 adsorption-desorption, XPS, XANES, ICP-AES, NH 3 -TPD, H 2 -TPR and in-situ DRIFTS. The catalytic activity tests for NH 3 -SCR of NO indicated that the catalyst coated by CeO 2 shell exhibits a remarkable improvement of deNO x activity, excellent tolerance to SO 2 and H 2 O, as well as high thermal stability. The both chemisorbed oxygen species (O 2 − , O − ) and specific surface area increased for the catalysts after the coating of CeO 2 shells. CeO 2 shells not only increase the acid amount but also improve its acid strength, which could be beneficial to improving NO oxidation to NO 2 during NH 3 -SCR. Furthermore, there is a strong interaction among the iron oxides, molybdenum oxides and CeO 2 shells. CeO 2 shells can serve as an effective barrier to inhibit the active metal oxides nanoparticles from aggregating at high temperature. As a result, the coated catalyst with CeO 2 thin film shows a better thermal stability than the uncoated one. What’s more, CeO 2 shells can not only suppress the formation of ammonium nitrate and sulfate species blocking the active iron sites but also restrain the generation of iron sulfate, leading to a higher SO 2 and H 2 O-tolerance. The above results demonstrate that the design of a core−shell structure catalyst is favorable for improving the performance of deNO x catalysts. [ABSTRACT FROM AUTHOR]

A grand challenge in photocatalysis is to seek chemically stable photcatalysts with minimized recombination of photoinduced charges in order to maximize the efficiency of the subsequent redox reactions. Because of the structural noncentrosymmetry, TiO2-based and lead-containing perovskite-type photocatalysts exhibit excellence in both stability and ferroelectricity to facilitate charge separation state. To extend their visible light activity, we use molten salts synthesis methodology to prepare Pb2Bi4Ti5O18 perovskites with various nanoscale morphologies and evaluated their visible light-driven photocatalytic activity for NO removal. The results show that perovskite Pb2Bi4Ti5O18 samples exhibit excellent stability as well as display over 50% NO removal efficiency under visible light in contrast to no more than 15% for commercial P25. A set of radical scavengers were used to probe the reaction mechanism. A bond-valence method was used to calculate the direction and magnitude of the dipole moments of the asymmetric unit in the structure. We revealed that the photocatalytic Pb2Bi4Ti5O18 possesses distorted units in which the dipole-induced internal fields promote the charge separation, leading to the enhanced photocatalytic activity. Because this novel photocatalytic NO removal is a solid-gas reaction in which the lead content is secured in solid phase, this work finds a suitable application for Pb-containing perovskite photocatalysts with great industrial interests and add a new fundamental coordination for better photocatalysts-by-designing. [ABSTRACT FROM AUTHOR]

The experimental determination of atomic levels and the first ionization potential of the heaviest elements ( Z ⩾ 100 ) is key to challenge theoretical predictions and to reveal changes in the atomic shell structure. These elements are only artificially produced in complete-fusion evaporation reactions at on-line facilities such as the GSI in Darmstadt at a rate of, at most, a few atoms per second. Hence, highly sensitive spectroscopic methods are required. Laser spectroscopy is one of the most powerful and valuable tools to investigate atomic properties. In combination with a buffer-gas filled stopping cell, the Radiation Detected Resonance Ionization Spectroscopy (RADRIS) technique provides the highest sensitivity for laser spectroscopy on the heaviest elements. The RADRIS setup, as well as the measurement procedure, have been optimized and characterized using the α -emitter 155 Yb in on-line conditions, resulting in an overall efficiency well above 1%. This paves the way for a successful search of excited atomic levels in nobelium and heavier elements. [ABSTRACT FROM AUTHOR]

We investigate the collinear ternary fission of the 260 No isotope. The calculations are performed in the framework of the three cluster model for all possible accompanied light particles of even mass numbers A = 4 − 52 . The folding nuclear and Coulomb interaction potentials are used, based on the M3Y-Reid nucleon–nucleon force for the nuclear part. The deformation of the involved fragments and their relative orientations with respect to each other inside the fissioning nuclei are considered. Among all possible fragmentation channels, the suggested most probable channels are indicated as the ones showing a peak in the Q-value and a local minimum in the fragmentation potential, with respect to the mass and charge asymmetries. The indicated favored fragmentation channels from the approximate spherical calculations and those obtained after considering the deformations of the produced fragments are discussed in detail. In addition to the preferred heavy fragments of closed shells, favored prolate ones of high deformations appear when the nuclear deformations are taken into account. Among indicated fifty six favored channels, a collinear ternary fission of the 260 No isotope is indicated to be most favored through the fragmentation channels of 150 58 Ce+ 4 10 Be+ 40 100 Zr, 60 152 Nd+ 4 12 Be+ 38 96 Sr, 58 150 Ce+ 6 14 C+ 38 96 Sr, 58 148 Ce+ 6 16 C+ 38 96 Sr, 54 140 Xe+ 8 22 O+ 40 98 Zr, 42 106 Mo+ 18 48 Ar+ 42 106 Mo and 41 104 Nb+ 20 52 Ca+ 41 104 Nb. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to seek a surfactant or template-free, simple and green method to fabricate NiO nanobelts and to find an effective technique to detect the ethanol vapor at room temperature.Design/methodology/approach NiO nanobelts with high aspect ratio and dispersive distribution have been synthesized by a template-free hydrothermal reaction at 160°C for 12 h. The products are studied by X-ray diffraction (XRD), energy dispersive spectroscopY, scanning electron microscopy, atomic force microscopy, high-resolution transmission electron microscopy, selective area electron diffractio and X-ray photoelectron spectroscopy. In particular, the room-temperature ethanol sensitivity of NiO nanobelts is investigated by the surface photo voltage (SPV) technique.Findings The prepared NiO nanobelts is single crystalline bunsenite structure with the length of approximately 10 μm and the diameter of approximately 30 nm. The atomic ratio of “Ni” to “O” is 0.92:1. When the concentration of ethanol vapor reaches 100 ppm, the sensitivity of NiO nanobelts is 7, which can meet the commercial demanding of ethanol gas sensor.Originality/value The NiO nanobelts can be obtained by a template-free, simple and green hydrothermal reaction at 160°C for 12 h. The NiO nanobelts-based gas sensor is a promising candidate for the application in ethanol monitoring at room temperature by SPV technique. [ABSTRACT FROM AUTHOR]

We calculate properties of the ground and excited states of nuclei in the nobelium region for proton and neutron numbers of 92 ≤ Z ≤ 104 and 144 ≤ N ≤ 156 , respectively. We use three different energy-density-functional (EDF) approaches, based on covariant, Skyrme, and Gogny functionals, each with two different parameter sets. A comparative analysis of the results obtained for quasiparticle spectra, odd–even and two-particle mass staggering, and moments of inertia allows us to identify single-particle and shell effects that are characteristic to these different models and to illustrate possible systematic uncertainties related to using the EDF modelling. [ABSTRACT FROM AUTHOR]

Pulsing 15N18O onto an annealed 1% Mn16Ox/Ce16O2 catalyst resulted in very fast oxygen isotope exchange and 15N2 formation at 295 K. In the 1st 15N18O pulse, due to the presence of large number of surface oxygen defects, extensive 15N218O and 15N2 formations were observed. In subsequent pulses oxygen isotope exchange dominated as a result of highly labile oxygen in the oxide. [ABSTRACT FROM AUTHOR]

Pulsing 15N18O onto an annealed 1% Mn16Ox/Ce16O2 catalyst resulted in very fast oxygen isotope exchange and 15N2 formation at 295 K. In the 1st 15N18O pulse, due to the presence of large number of surface oxygen defects, extensive 15N218O and 15N2 formations were observed. In subsequent pulses oxygen isotope exchange dominated as a result of highly labile oxygen in the oxide. [ABSTRACT FROM AUTHOR]

Forward-directed NO molecules with large translational energies are formed upon exposure of an O-covered Ru(0001) surface to a nitrogen (N+N2) beam. This is an unequivocal experimental demonstration of the Eley-Rideal reaction for a "heavy" (i.e., nonhydrogenated) neutral system. The time dependence of prompt NO formation exhibits an exceptionally fast decay as a consequence of shifting reaction pathways and probabilities over the course of the exposure. Prompt production shuts down as the O coverage decreases due to competition from more favorable Eley-Rideal production of N2. [ABSTRACT FROM AUTHOR]

Strong efforts are undertaken at GSI in Darmstadt preparing for laser spectroscopy of the synthetic element nobelium. Several excimer- and dye lasers will be used in the forthcoming search for the $^1$P$_1$-level in No. Based on the highly-efficient Radiation Detected Resonance Ionization Spectroscopy (RADRIS) technique, the identification of this excited state predicted around 3.8 eV becomes possible within a relatively short period of beam-time. This will form the basis for future studies of the atomic structure of the heaviest elements. [ABSTRACT FROM AUTHOR]

Chemical studies of the heaviest elements in liquid phases at Japan atomic energy agency (JAEA) are reviewed. From the systematic investigation of ion-exchange chromatographic behavior of element 104, rutherfordium (Rf), based on an atom-at-a-time scale, it has been found that the properties of Rf are quite similar to those of the group-4 homologs, Zr and Hf, in the formation of chloride, nitrate, and sulfate complexes, although there are some differences in complexation strength between Rf and the lighter homologues. On the contrary, fluoride complex formation of Rf is significantly different from that of the homologues. Anionic fluoride complexation of element 105, dubnium (Db), has also been studied. The result clearly demonstrates that the fluoride complex formation of Db is considerably different from that of the group-5 homologue Ta, while the behavior of Db is similar to that of the lighter homologue Nb. A new electrochemical approach to the heaviest elements has been successfully conducted by a flow electrolytic column chromatographic method; the oxidation state of element 102, nobelium (No), with single atoms can be controlled with the developed apparatus. Prospects for the future studies on chemical properties of the heaviest elements at JAEA will be briefly considered. [ABSTRACT FROM AUTHOR]

Background: Nuclei in the Z RS 100 mass region represent the heaviest systems where detailed spectroscopic information is experimentally available. Although microscopic-macroscopic and self-consistent models have achieved great success in describing the data in this mass region, a fully satisfying precise theoretical description is still missing. Purpose: By using fine-tuned parametrizations of the energy density functionals, the present work aims at an improved description of the single-particle properties and rotational bands in the nobelium region. Such locally optimized parametrizations may have better properties when extrapolating towards the superheavy region. Methods: Skyrme Hartree-Fock-Bogolyubov and Lipkin-Nogami methods were used to calculate the quasi-particle energies and rotational bands of nuclei in the nobelium region. Starting from the most recent Skyrme parametrization, UNEDF1, the spin-orbit coupling constants and pairing strengths have been tuned, so as to achieve a better agreement with the excitation spectra and odd-even mass differences in 25lCf and 249Bk. Results: The quasiparticle properties of 251Cf and 249Bk were very well reproduced. At the same time, crucial deformed neutron and proton shell gaps open up at N = 152 and Z = 100, respectively. Rotational bands in Fm, No, and Rf isotopes, where experimental data are available, were also fairly well described. To help future improvements towards a more precise description, small deficiencies of the approach were carefully identified. Conclusions: In the Z ≈ 100 mass region, larger spin-orbit strengths than those from global adjustments lead to improved agreement with data. Puzzling effects of particle-number restoration on the calculated moment of inertia, at odds with the experimental behavior, require further scrutiny. [ABSTRACT FROM AUTHOR]

Abstract: Cu-Fe/ZSM-5 catalyst prepared by subsequent ion-exchange showed higher NOx conversion compared with Fe/ZSM-5 or Cu/ZSM-5. Presence of small amount of copper in xCu-yFe/ZSM-5 catalysts was found to be enough to improve the low temperature NOx conversion without significantly affecting the high temperature performance. Co-presence of Cu increases the reducibility of Fe and also increased strong acid sites in Cu-Fe/ZSM-5. However, no correlation between acid site strength and NOx conversion is observed. Higher NOx conversion over Cu-Fe/ZSM-5 can be correlated to the facile reduction of metal species. Thus the redox properties and NOx conversion can be tuned by changing the composition of Cu-Fe/ZSM-5 catalyst. [Copyright &y& Elsevier]

Abstract: A novel amperometric-type NO2 sensor based on La10Si5NbO27.5 (LSNO) and nano-structured NiO sensing electrode was fabricated. The nano-structured NiO particles in the range of 20–50nm were synthesized in LSNO porous layer by the impregnating method. The sensor exhibited well response-recovery characteristics to NO2. The response current was almost linear to NO2 concentration in the range between 2 and 500ppm at 450–600°C. With increase of operating temperature, the sensitivity increased and reached 95nA/ppm at 600°C. The response current of the sensor was slightly affected by co-existant O2 and CO2 in concentration range of 0–10vol%. [Copyright &y& Elsevier]

Abstract: BER estimation method by Eb/No for CO-OFDM systems with QPSK mapping is studied in this paper. The relationships of BER vs. OSNR and Q factor vs. OSNR are firstly represented in detail. The comparisons between BER estimation by Eb/No and Monte-Carlo (MC) method with OSNR, chromatic dispersion (CD), laser linewidth and fiber nonlinearity impairments are also researched in this paper. Through simulation in 40Gb/s CO-OFDM systems with those impairments, BER based on Eb/No can estimate accurately 10−16 levels justly using 105 bits, while MC required at least 1018 bits in comparison. Eb/No is creditable and offers an alternative to the time-consuming MC method. [Copyright &y& Elsevier]

Two series of (0-4 wt%) potassium doped oxide catalysts based on iron and manganese spinel were prepared. The synthesized materials were characterized in terms of their structure (XRD, Raman spectroscopy) and surface electronic properties (work function measurements). The catalytic activity towards soot combustion was determined by temperature programmed oxidation of a physical mixture of soot and catalyst in tight contact in gas oxygen mixtures with and without NO addition. For iron spinel based materials, where potassium is localized at the surface, the catalytic activity correlates with the work function lowering upon K doping, while for manganese spinel based materials, where potassium is incorporated into the bulk (formation of KMnO or KMnO), the correlation was not found. The presence of NO in the gas mixture leads to a systematic decrease of soot ignition temperature for all samples. [ABSTRACT FROM AUTHOR]

Abstract: Monoclinic tungsten oxide nanorods with diameters of 50–150nm and lengths of 5–20μm have been grown directly onto porous silicon with no catalyst by thermal evaporation. The obtained products were investigated by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, energy dispersive spectroscopy, and transmission electron microscopy. The mechanisms which yield different distributions of nanorods onto porous silicon were studied. The sensitivity to NO2 of the porous silicon/WO3 nanorods was investigated. It was found that the sensor of tungsten oxide nanorods on a porous silicon had a good response and recovery characteristics to NO2 at room temperture. The lowest concentration of NO2 detected was 250ppb. The novel composite structure improved sensing properties which are significant for future applications. [Copyright &y& Elsevier]

The adsorption of CO and NO over VO-SBA-15 mesoporous materials with different vanadium content was investigated by FT-IR spectroscopy. Vanadium complexes were reduced in situ by hydrogen atmosphere at 450 °C for 3 h. Spectra of reduced samples show increasing in intensity of silanol groups, caused by dissociation of V-O(Si) bonds and formation of new H-O(Si) bonds. Reduction occurs with formation of water. The band corresponds to overtone of V=O stretching modes decreases in intensity because of oxygen withdrawing from V=O species. Presence of V and V species was observed. Inspection of CO adsorbed IR spectra evidenced existence at least two different type of V-CO complexes on the silica surface differing in both stretching frequencies and complex stabilities. We did not found principal difference between spectra of absorbed CO at −196 °C on the samples with different concentration of vanadium, probably because of relative low degree of reduction. As well as heterogeneity of surface V and V species was evidenced by adsorption of NO. Both V and V ions possess two effective coordinative vacancies and as a result can adsorb two NO molecules forming dinitrosyls. A part of V cations forms only mononitrosyls characterize by band at 1724 cm. Results obtained after NO adsorption reveal existence of three different kinds of vanadium species. Probably two of them are isolated and associated vanadium sites. The third type of vanadium has different surrounding than other two types. It was demonstrated that NO is a better probe than CO for testing the oxidation and coordination state of reduced vanadium species. [ABSTRACT FROM AUTHOR]

An impedimetric NOx dosimeter based on the NOx sorption material KMnO4 is proposed. In addition to its application as a low level NOx dosimeter, KMnO4 shows potential as a precious metal free lean NOx trap material (LNT) for NOx storage catalysts (NSC) enabling electrical in-situ diagnostics. With this dosimeter, low levels of NO and NO2 exposure can be detected electrically as instantaneous values at 380°C by progressive NOx accumulation in the KMnO4 based sensitive layer. The linear NOx sensing characteristicsare recovered periodically by heating to 650°C or switching to rich atmospheres. Further insight into the NOx sorption-dependent conductivity of the KMnO4-based material is obtained by the novel eTPD method that combines electrical characterization with classical temperature programmed desorption (TPD). The NOx loading amount increases proportionally to the NOx exposure time at sorption temperature. The cumulated NOx exposure, as well as the corresponding NOx loading state, can be detected linearly by electrical means in two modes: (1) time-continuously during the sorption interval including NOx concentration information from the signal derivative or (2) during the short-term thermal NOx release. [ABSTRACT FROM AUTHOR]

Abstract: Traditionally EfW (Energy from Waste) plants apply a reciprocating grate to combust waste fuel. An integrated steam generator recovers the heat of combustion and converts it to steam for use in a steam turbine/generator set. This is followed by an array of flue gas cleaning technologies to meet regulatory limitations. Modern combustion applies a two-step method using primary air to fuel the combustion process on the grate. This generates a complex mixture of pyrolysis gases, combustion gases and unused combustion air. The post-combustion step in the first pass of the boiler above the grate is intended to “clean up” this mixture by oxidizing unburned gases with secondary air. This paper describes modifications to the combustion process to minimize exhaust gas volumes and the generation of noxious gases and thus improving the overall thermal efficiency of the EfW plant. The resulting process can be coupled with an innovative SNCR (Selective Non-Catalytic Reduction) technology to form a clean and efficient solid waste combustion system. Measurements immediately above the grate show that gas compositions along the grate vary from 10% CO, 5% H2 and 0% O2 to essentially unused “pure” air, in good agreement with results from a mathematical model. Introducing these diverse gas compositions to the post combustion process will overwhelm its ability to process all these gas fractions in an optimal manner. Inserting an intermediate step aimed at homogenizing the mixture above the grate has shown to significantly improve the quality of combustion, allowing for optimized process parameters. These measures also resulted in reduced formation of NO x (nitrogenous oxides) due to a lower oxygen level at which the combustion process was run (2.6vol% O2, wet instead of 6.0vol% O2, wet). This reduction establishes optimal conditions for the DyNOR™ (Dynamic NO x Reduction) NO x reduction process. This innovative SNCR technology is adapted to situations typically encountered in solid fuel combustion. DyNOR™ measures temperature in small furnace segments and delivers the reducing reagent to the exact location where it is most effective. The DyNOR™ distributor reacts precisely and dynamically to rapid changes in combustion conditions, resulting in very low NO x emissions from the stack. [Copyright &y& Elsevier]

A low temperature, isothermal, gas-phase, recyclable process is described for the partial oxidation of methane to methanol over Cu-ZSM-5. Activation in NO at 150 °C followed by methane reaction and steam extraction (both at 150 °C) allowed direct observation of methanol at the reactor outlet. [ABSTRACT FROM AUTHOR]

One of the most important atomic properties governing an element's chemical behavior is the energy required to remove its least-bound electron, referred to as the first ionization potential. For the heaviest elements, this fundamental quantity is strongly influenced by relativistic effects which lead to unique chemical properties. Laser spectroscopy on an atom-at-a-time scale was developed and applied to probe the optical spectrum of neutral nobelium near the ionization threshold. The first ionization potential of nobelium is determined here with a very high precision from the convergence of measured Rydberg series to be 6.62621±0.00005 eV. This work provides a stringent benchmark for state-of-the-art many-body atomic modeling that considers relativistic and quantum electrodynamic effects and paves the way for high-precision measurements of atomic properties of elements only available from heavy-ion accelerator facilities. [ABSTRACT FROM AUTHOR]

Until recently, ground-state nuclear moments of the heaviest nuclei could only be inferred from nuclear spectroscopy, where model assumptions are required. Laser spectroscopy in combination with modern atomic structure calculations is now able to probe these moments directly, in a comprehensive and nuclear-model-independent way. Here we report on unique access to the differential mean-square charge radii of 252,253,254No, and therefore to changes in nuclear size and shape. State-of-the-art nuclear density functional calculations describe well the changes in nuclear charge radii in the region of the heavy actinides, indicating an appreciable central depression in the deformed proton density distribution in 252,254No isotopes. Finally, the hyperfine splitting of 253No was evaluated, enabling a complementary measure of its (quadrupole) deformation, as well as an insight into the neutron single-particle wave function via the nuclear spin and magnetic moment. [ABSTRACT FROM AUTHOR]

The fusion excitation functions of 249 - 263No are studied by using various reaction systems based on the dinuclear system model. The neutron-rich radioactive beam 22O is used to produce neutron-rich nobelium isotopes, and the new neutron-rich isotopes 261 - 263No are synthesized by 242Pu (22O, ³n) 261No, 244Pu (22O, 4n) 262No, and 244Pu (22O, 3n) 263No reactions, respectively. The corresponding maximum evaporation residue cross sections are 0.628, 4.649, and 1.638 μb, respectively. The effects of the three processes (capture, fusion, and survival) in the complete fusion reaction are also analyzed. From investigation, a neutron-rich radioactive beam as the projectile and neutron-rich actinide as the target could be a new selection of the projectile-target combination to produce a neutron-rich heavy nuclide. [ABSTRACT FROM AUTHOR]