[en] The results of an investigation of the finite self-consistent field theory of elementary matter applied earlier to the calculation of the Lamb shift in hydrogen, now applied to the problem of the Lamb shift in the low lying states of helium are presented. The covariant nonlinear field equations of this theory for helium are constructed from the Lagrangian formalism. In the linear approximation, the Hamiltonian associated with the theory for helium atom is set up. It is equivalent to the Breit Hamiltonian plus two extra terms. This generalization is a direct consequence of two-component spinor formalism of electromagnetism that is contained in this field theory. Thus, the energy spectrum predicted for the helium atom is the spectrum predicted by the Breit Hamiltonian, shifted by amounts in the different states due to the effects of these extra terms. The latter can be associated with the corrections to the helium spectrum that are conventionally attributed to the Lamb shift. The level shift for the ground state and first excited states is calculated using the Foldy-Wouthuysen transformation, with the generalization of Charplvy for the two-electron atom. The results are found to be in close agreement with the experimental values for the energy shifts not predicted by the Dirac theory, and with the theoretical values predicted by quantum electrodynamics. (U.S.)

[en] The objective of this project is to develop a method to predict the potential reliability of software to be used in a digital system instrumentation and control system. The reliability prediction is to make use of existing measures of software reliability such as those described in IEEE Std 982 and 982.2. This prediction must be of sufficient accuracy to provide a value for uncertainty that could be used in a nuclear power plant probabilistic risk assessment (PRA). For the purposes of the project, reliability was defined to be the probability that the digital system will successfully perform its intended safety function (for the distribution of conditions under which it is expected to respond) upon demand with no unintended functions that might affect system safety. The ultimate objective is to use the identified measures to develop a method for predicting the potential quantitative reliability of a digital system. The reliability prediction models proposed in this report are conceptual in nature. That is, possible prediction techniques are proposed and trial models are built, but in order to become a useful tool for predicting reliability, the models must be tested, modified according to the results, and validated. Using methods outlined by this project, models could be constructed to develop reliability estimates for elements of software systems. This would require careful review and refinement of the models, development of model parameters from actual experience data or expert elicitation, and careful validation. By combining these reliability estimates (generated from the validated models for the constituent parts) in structural software models, the reliability of the software system could then be predicted. Modeling digital system reliability will also require that methods be developed for combining reliability estimates for hardware and software. System structural models must also be developed in order to predict system reliability based upon the reliability of the individual hardware/software components. Existing modeling techniques--such as fault tree analyses or reliability block diagrams--can probably be adapted to bridge the gaps between the reliability of the hardware components, the individual software elements, and the overall digital system. This project builds upon previous work to survey and rank potential measurement methods which could be used to measure software product reliability 3. This survey and ranking identified candidate measures for use in predicting the reliability of digital computer-based control and protection systems for nuclear power plants. Additionally, information gleaned from the study can be used to supplement existing review methods during an assessment of software-based digital systems

[en] La_1-xSr_xCuO_2.5-δ (LSCu), which exhibit excellent electrical conductivity and oxygen vacancies were investigated as potential cathode materials for solid oxide fuel cell (SOFC) applications. The structure stability, electrical conductivity, cathodic overpotential, and the reactivity with yttria-stabilized zirconia (YSZ) were examined in this study. It was found that the LSCu perovskite was obtained only when the addition of strontium fell in the range between 15 and 30%. With more than 20% of strontium addition, this material showed excellent electrical property and immunity to the reaction with YSZ at 800 deg. C. The conductivities of LSCu were as high as 900 S/cm at 600 deg. C, and 800 S/cm at 800 deg. C. The cathodic overpotential of this material was approximately 3.8 and 10.6 mV at a current density of 100 mA/cm² at 850 and 750 deg. C, respectively. These properties are superior to Sr-doped lanthanum manganite (LSM), which is the state-of-the-art cathode material of SOFCs

[en] Laser vaporization of an appropriate target and recent developments in molecular beam technology have now made it possible to produce supersonic cluster beams of virtually any element in the periodic table. This paper describes the design and principles of a cluster source combined with a time of flight mass spectrometer built for reaction experiments and spectroscopic investigations at Stockholm University

[en] To continue their systematic study of odd-odd nuclei in the mass 160 region, and to further investigate the abnormal band-crossing frequencies observed in a number of odd-odd Tm and Lu isotopes, the authors studied ¹⁵⁸Ho and ¹⁵⁶Ho recently at the Lawrence Berkeley Laboratory. High spin states of ¹⁵⁸Ho and ¹⁵⁶Ho were populated using the ¹⁵⁰Nd(¹⁴N,6n) and ¹⁴⁸Nd(¹⁴N,6n) reactions at beam energies of 92 and 96 MeV, respectively. Gamma rays were detected by the 36 Ge detectors of the Gammasphere Phase I array. About 1 billion and 800 million triple- or higher-fold coincident events were collected for the ¹⁵⁸Ho and ¹⁵⁶Ho experiments, respectively. These data were sorted into cubes and analyzed by the computer code open-quotes LEVIT8Rclose quotes. The preliminary results have established multiple rotational bands in both nuclei. The band crossings, relative transition probabilities and other high spin properties especially concerning odd-odd nuclei will be discussed in comparison with either neighboring even-even, and odd-odd isotopes and isotones

[en] The important role of transition metal clusters for catalysis is obvious as well as the role of 'metcars' - metal-carbon clusters and 'metnits' -metal-nitrogen clusters - for technical applications. These new type of clusters can be generated by reactions of the metal atoms in the laser plasma. In this contribution we report on some of these reactions and show how different the results can be even with very similar metals. Our main interest is connected to reactivity and structure but also on the formation of thin films deposited from these exotic materials and there technical importance. (author)

[en] The relationship between redox potential of a solution containing 1.5M HNO₃-1.5M Al(NO₃)₃-xM FeSA and Fe³⁺/Fe²⁺ ratio has been studied. The formal potential of 777 m V vs SHE of Fe³⁺-Fe²⁺ couple in a given solution was obtained. Observed anomalous potential jump of Fe³⁺-Fe²⁺ couple depends on Fe³⁺/Fe²⁺ ratio, SA concentration and surface condition of platinum electrode. The potential measurement of radioactive solution is a promising method for estimation of Fe³⁺/Fe²⁺ ratio and Np, Pu valency change in the solution. (author)

[en] The importance and value of Mergers and Acquisitions (M&As) have increased with the expectancy to obtain key technology capabilities and rapid impact on innovation. This article develops an original analytical framework to elucidate the impact of the technology and product relatedness (similarity/complementarity) of the Technology-driven M&A’ partners on post-innovation performance. We present results drawing on a multiple case studies of Chinese High-Tech firms from three industries. (Author)

[en] The single domain size of BaFe₁₂O₁₉ powder with crystallite sizes less than 200 nm was produced using a citric acid precursor method. Fe³⁺ and Ba²⁺, in a molar ratio of 12, were chelated by COOH^- in an aqueous solution. After ethylene glycol additions, esterification, dehydration, and calcination led to the formation of ester-derived BaFe₁₂O₁₉ powder. High pH and/or high citric acid contents in the starting solution are required to complete chelate metallic ions in the solution and to form pure barium ferrite powder at 1073 K. Pure single magnetic domain BaFe₁₂O₁₉ particles of M(30 kOe)∼54 emu/g, M_r∼28 emu/g, and H_c∼3.7 kOe were produced using [citric acid]/[metallic ions]=1.5 and pH≥7

[en] The structural design of the large HTGR prismatic core fuel elements involve the interaction of four engineering disciplines: nuclear physics, thermo-hydraulics, structural and material science. Fuel element stress analysis techniques and the development of structural criteria are discussed in the context of an overview of the entire design process. The core of the proposed 2240 MW(t) HTGR is described as an example where the design process was used. Probabalistic stress analysis techniques coupled with probabalistic risk analysis (PRA) to develop structural criteria to account for uncertainty are described. The PRA provides a means for ensuring that the proposed structural criteria are consistent with plant investment and safety risk goals. The evaluation of cracked fuel elements removed from the Fort St. Vrain reactor in the USA is discussed in the context of stress analysis uncertainty and structural criteria development