CERN Document Server

Let $M$ be a complex manifold of complex dimension $n+k$. We say that the functions $u_1,...s,u_k$ and the vector fields $\\xi_1,...,\\xi_k$ on $M$ form a \\emph{complex gradient system} if $\\xi_1,...,\\xi_k,J\\xi_1,...,J\\xi_k$ are linearly independent at each point $p\\in M$ and generate an integrable distribution of $TM$ of dimension $2k$ and $du_\\alpha(\\xi_\\beta)=0$, $\\d^c\\u_\\alpha(\\xi_\\beta)=\\delta_{\\alpha\\beta}$ for $\\alpha,\\beta=1,...,k$. We prove a Cauchy theorem for such complex gradient systems with initial data along a $\\CR-$submanifold of type $(\\CRdim,\\CRcodim)$. We also give a complete local characterization for the complex gradient systems which are \\emph{holomorphic} and \\emph{abelian}, which means that the vector fields $\\xi_\\alpha^c=\\xi_\\alpha-J\\xi_\\beta$, $\\alpha=1,...,k$ are ...

CERN Document Server

Based on 58 million J/Psi events collected with the BESII detector at the BEPC, the baryon pair processes J/Psi to $\\Sigma^+ \\bar{\\Sigma}^-$ and J/Psi to $\\Xi^0 \\bar{\\Xi}^0$ are observed for the first time. The branching fractions are measured to be ${\\cal B}(J/Psi to \\Sigma^+ \\bar{\\Sigma}^-)=(1.50\\pm 0.10\\pm 0.22)\\times 10^{-3}$ and ${\\cal B}(J/Psi to \\Xi^0 \\bar{\\Xi}^0)=(1.20\\pm 0.12\\pm 0.21)\\times 10^{-3}$, where the first errors are statistical and the second ones are systematic.

Science.gov (United States)

This paper explores effects of differential diffusion in nonpremixed turbulent jet flames. Pulsed Raman scattering spectroscopy is used to measure temperature and species concentrations in chemically reacting jets of H{sub 2}/CO{sub 2} into air, over a range of jet Reynolds numbers from 1,000 to 30,000 based on cold jet fluid properties. Results show significant effects of differential diffusion at all jet Reynolds numbers considered. Differential diffusion between H{sub 2} and C0{sub 2} produces differences between the hydrogen element mixture fraction ({xi}{sub H}) and the carbon element mixture fraction ({xi}{sub c}). The greatest effects occur on the rich side of stoichiometric, where {xi}{sub H} is observed to be smaller than {xi}{sub C} at all Reynolds numbers. Differential diffusion between H{sub 2} and H{sub 2}O creates a net flux of hydrogen element toward the stoichiometric contour and causes ...

CERN Document Server

The mean-field pictures based on the standard time-dependent variational approach have widely been used in the study of nonlinear many-boson systems such as the Bose-Hubbard model. The mean-field schemes relevant to Gutzwiller-like trial states $|F>$, number-preserving states $|\\xi >$ and Glauber-like trial states $|Z>$ are compared to evidence the specific properties of such schemes. After deriving the Hamiltonian picture relevant to $|Z>$ from that based on $|F>$, the latter is shown to exhibit a Poisson algebra equipped with a Weyl-Heisenberg subalgebra which preludes to the $|Z>$-based picture. Then states $|Z>$ are shown to be a superposition of $\\cal N$-boson states $|\\xi>$ and the similarities/differences of the $|Z>$-based and $|\\xi>$-based pictures are discussed. Finally, after proving that the simple, symmetric state $|\\xi>$ indeed corresponds to a SU(M) ...

Energy Technology Data Exchange (ETDEWEB)

The Boiler and Pressure Vessel Code (BPVC) of the American Society of Mechanical Engineers (ASME) has introduced a risk based approach into Section XI that covers Rules for Inservice Inspection of Nuclear Power Plant Components. The risk based approach requires application of the probabilistic risk assessments (PRA). Because no industry consensus standard existed for PRAs, ASME has developed a standard to evaluate the quality level of an available PRA needed to support a given risk based application. The paper describes the PRA standard, Section XI application of PRAs, and plans for broader applications of PRAs to other ASME nuclear codes and standards. The paper addresses several specific topics of interest to Section XI. Important consideration are special methods (surrogate components) used to overcome the lack of PRA treatments of passive components in PRAs. The approach allows calculations of conditional core damage ...

International Nuclear Information System (INIS)

By 1970 the first edition of the ASME Code Section XI, Inservice Inspection of Nuclear Reactor Coolant Systems was published. From its inception, the Section XI inservice inspection scope was based on a fundamental risk-based selection process. In other words the inservice inspection scope included components where the consequences of a pressure boundary failure were high. Once the consequence significant system boundaries were established, inspections would then be performed at locations believed to be most susceptible service induced failure. Current Section XI requirements require that inspection locations be selected on the basis of peak stress and fatigue usage values contained in the Design Reports. These original stress calculations were designed to qualify a design and assure that the plant would provide reliable service throughout its design life. For the most part, the fatigue usage values in these reports do not ...

CERN Document Server

In a recent breakthrough work, Chatterjee proved a long standing conjecture that relates the transversal exponent \\xi and the fluctuation exponent \\chi in first-passage percolation on Z^d. The purpose of this paper is to introduce a new and intuitive idea that replaces Chatterjee's main argument and gives an alternative proof of this relation. Specifically, we show that under the assumption that exponents (as defined by Chatterjee) exist, one has the relation \\chi \\leq 2\\xi -1. One advantage of our argument is that it does not require a `nearly Gamma' assumption on the edge-weight distribution.

International Nuclear Information System (INIS)

In this work an analysis of the influence of the choice of the algorithm or planning system, on the calculus of the same treatment plan is introduced. For this purpose specific software has been developed for comparing plans of a series of IMRT cases of prostate and head and neck cancer calculated using the convolution, superposition and fast superposition algorithms implemented in the XiO 4.40 planning system (CMS). It has also been used for the comparison of the same treatment plan for lung pathology calculated in XiO with the mentioned algorithms, and calculated in the Plan 4.1 planning system (Brainlab) using its pencil beam algorithm. Differences in dose among the treatment plans have been quantified using a set of metrics. The recommendation for the dosimetrist of a careful choice of the algorithm has been numerically confirmed. (Author).

International Nuclear Information System (INIS)

A phenomenological analysis of lifetimes of bottom and charmed hadrons within the framework of the heavy quark expansion is performed. The baryon matrix element is evaluated using the bag model and the nonrelativistic quark model. We find that bottom-baryon lifetimes follow the pattern #tau#(#OMEGA#_b)#approx =##tau#(#XI#_b"-)>#tau#(#LAMBDA#_b)#approx =##tau#(#XI#_b"0). However, neither the lifetime ratio #tau#(#LAMBDA#_b)/#tau#(B_d) nor the absolute decay rates of the #LAMBDA#_b baryon and B mesons can be explained. One way of solving both difficulties is to allow the presence of linear 1/m_Q corrections by scaling the inclusive nonleptonic width with the fifth power of the hadron mass m_H__Q rather than the heavy quark mass m_Q. The hierarchy of bottom baryon lifetimes is dramatically modified to #tau#(#LAMBDA#_b)>#tau#(#XI#_b"-)>#tau#(#XI#_b"0)>#tau#(#OMEGA#_b): The longest-lived #OMEGA#_b among bottom ...

CERN Document Server

In this paper we first establish global pointwise time-space estimates for a class of oscillatory integrals. Then, we use them to establish $L^p-L^q$ estimates for a class of higher order wave-type equations of the form $\\partial_{tt}u+P(D_{x})u=0$, where the symbol $P(\\xi)$ is a real non-degenerate elliptic polynomial of ${\\bf R}^n$.

CERN Document Server

Given a Gibbs point process $\\P^{\\Psi}$ on $\\R^d$ having a weak enough potential $\\Psi$, we consider the random measures $\\mu_\\la := \\sum_{x \\in \\P^{\\Psi} \\cap Q_\\la} \\xi(x, \\P^{\\Psi} \\cap Q_\\la) \\delta_{x/\\la^{1/d}}$, where $Q_{\\la} := [-\\la^{1/d}/2,\\la^{1/d}/2]^d$ is the volume $\\la$ cube and where $\\xi(\\cdot,\\cdot)$ is a translation invariant stabilizing functional. Subject to $\\Psi$ satisfying a localization property and translation invariance, we establish weak laws of large numbers for $\\la^{-1} \\mu_\\la(f)$, $f$ a bounded test function on $\\R^d$, and weak convergence of $\\la^{-1/2} \\mu_\\la(f),$ suitably centered, to a Gaussian field acting on bounded test functions. The result yields limit laws for geometric functionals on Gibbs point processes including the Strauss and area interaction point processes as well as more general point processes defined by the Widom-Rowlinson and hard-core model. We provide ...

Energy Technology Data Exchange (ETDEWEB)

The design of a reaction cell which permits the investigation of the sorption kinetics of microcomponents without separation of the phases under automated condition has been described. The use of thin-layer inorganic sorbents obtained by depositing films of a sorbing substance from aqueous solutions on flat substrates of small thickness makes it possible to determine the extent of sorption even at small values in the case of /beta/ emitters with a low energy and /alpha/ emitters. Detailed observation of the kinetics of isotopic exchange in the CdS-/sup 115m/Cd-HNO/sub 3/ system has made it possible to reveal at least four stages in the process during the time of observation.

International Nuclear Information System (INIS)

Using the Laser-Fluorescence technique, an investigation was made, adopting the standard mix method, on trace uranium concentrations in hot spring water and geothermal water from Lishan region, and in tap water from some major cities in Shanxi province. Totally 40 samples from 27 sites were investigated. Measurement showed that the tap water contains around 10"-"6 g/L of uranium, whose concentrations in both hot spring water and geothermal water are 10"-"5 g/L. Most of samples are at normal radioactive background level, some higher contents were determined in a few samples

Energy Technology Data Exchange (ETDEWEB)

Dose-response studies of the radiosensitivity of spermatogonial stem cells in various epithelial stages after irradiation with graded doses of fission neutrons of 1 MeV mean energy were carried out in the Cpb-N mouse. These studies on the stem cell population in stages IX-XI yielded simple exponential lines characterized by an average D0 value of 0.76 +/- 0.02 Gy. In the subsequent epithelial stages XII-III, a significantly lower D0 value of 0.55 +/- 0.02 Gy was found. In contrast to the curves obtained for stem cells in stages IX-III, the curves obtained in stages IV-VIII indicated the presence of a mixture of radioresistant and radiosensitive stem cells. In stage VII, almost no radioresistant stem cells appeared to be present and a D0 value for the radiosensitive stem cells of 0.22 +/- 0.01 Gy was derived. Previously, data were obtained on the size of colonies (in number of spermatogonia) derived from surviving stem cells. Combining these data with data from the ...

Energy Technology Data Exchange (ETDEWEB)

The radiosensitivity of spermatogonial stem cells of C3H/HeHx101/H F[sub 1] hybrid mice was determined by counting undifferentiated spermatogonia at 10 days after X-irradiation. During the spermatogenic cycle, differences in radiosensitivity were found, which were correlated with the proliferative activity of the spermatogonial stem cells. In stage VIII[sub irr], during quiescence, the spermatogonial stem cells were most radiosensitive with a D[sub 0] of 1.4 Gy. In stages XI[sub irr]-V[sub irr], when the cells were proliferatively active, the D[sub 0] was about 2.6 Gy. Based on the D[sub 0] values for sensitive and resistant spermatogonia and on the D[sub 0] for the total population, a ratio of 45:55% of sensitive to resistant spermatogonial stem cells was estimated for cell killing. When the present data were compared with data on translocation induction obtained in mice of the same genotype, a close fit was obtained when the translocation yield (Y; in % abnormal ...

Energy Technology Data Exchange (ETDEWEB)

The overall objective of the study in this report was to gather data on waste management technologies to allow comparison of various alternatives for managing municipal solid waste (MSW). The specific objectives of the study were to: 1. Compile detailed data for existing waste management technologies on costs, environmental releases, energy requirements and production, and coproducts such as recycled materials and compost. Identify missing information necessary to make energy, economic, and environmental comparisons of various MSW management technologies, and define needed research that could enhance the usefulness of the technology. 3. Develop a data base that can be used to identify the technology that best meets specific criteria defined by a user of the data base. Volume I contains the report text. Volume II contains supporting exhibits. Volumes III through X are appendices, each addressing a specific MSW management technology. Volumes XI and XII contain ...

International Nuclear Information System (INIS)

The in-plane resistivity, in-plane absolute thermopower, and upper critical field measurements are reported for single-crystal samples of YNi_2B_2C and LuNi_2B_2C superconductors. The in-plane resistivity shows metallic behavior and varies approximately linearly with temperature near room temperature (RT) but shows nearly quadratic behavior in temperature at low temperatures. The YNi_2B_2C and LuNi_2B_2C single-crystal samples exhibit large transverse magnetoresistance (#approx#6 8% at 45 kOe) in the ab plane. The absolute thermopower S(T) is negative from RT to the superconducting transition temperature T_c. Its magnitude at RT is a few times of the value for a typical good metal. S(T) is approximately linear in temperature between #approx#150 K and RT. Extrapolation to T=0 gives large intercepts (few #mu#V/K) for both samples suggesting the presence of a much larger knee than would be expected from electron-phonon interaction renormalization effects. The upper critical fields for H ...

International Nuclear Information System (INIS)

This report summarizes work performed by Argonne National Laboratory (ANL) on fatigue and environmentally assisted cracking (EAC) in light water reactors (LWRs) during the six months from October 1993 to March 1994. EAC and fatigue of piping, pressure vessels, and core components in LWRs are important concerns in operating plants and as extended reactor lifetimes are envisaged. Topics that have been investigated include (a) fatigue of low-alloy steel used in piping, steam generators, and reactor pressure vessels, (b) EAC of wrought and cast austenitic stainless steels (SSs), and (c) radiation-induced segregation and irradiation-assisted stress corrosion cracking (IASCC) of Type 304 SS after accumulation of relatively high fluence. Fatigue tests have been conducted on A302-Gr B low-alloy steel to verify whether the current predictions of modest decreases of fatigue life in simulated pressurized water reactor water are valid for high-sulfur heats that show environmentally enhanced ...

Energy Technology Data Exchange (ETDEWEB)

The most relevant aspects of research and service experience with environmentally-assisted cracking (EAC) of carbon (C) and low-alloy steels (LAS) in high-temperature (HT) water are reviewed, with special emphasis on the primary pressure boundary components of boiling water reactors (BWRs). The main factors controlling the susceptibility to EAC under light water reactor (LWR) conditions are discussed with respect to crack initiation and crack growth. The adequacy and conservatism of the current BWRVIP-60 stress corrosion cracking (SCC) disposition lines (DLs), ASME III fatigue design curves, and ASME XI reference fatigue crack growth curves, as well as of the GE EAC crack growth model are evaluated in the context of recent research results. The operating experience is summarized and compared to the experimental/mechanistic background knowledge. Finally, open questions and possible topics for further research are identified. Laboratory investigations revealed ...

Energy Technology Data Exchange (ETDEWEB)

The CASTOC project addresses environmentally assisted cracking (EAC) phenomena in low alloy steels used for pressure boundary components in both Western type boiling water reactors (BWR) and Russian type pressurised water reactors (VVER). It comprises the four work packages (WP): inter-laboratory comparison test (WP1); EAC behaviour under static load (WP2), EAC behaviour under cyclic load and load transients (WP3); evaluation of the results with regard to their relevance for components in practice (WP4). The use of sophisticated test facilities and measurement techniques for the on-line detection of crack advances have provided a more detailed understanding of the mechanisms of environmentally assisted cracking and provided quantitative data of crack growth rates as a function of loading events and time, respectively. The effect of several major parameters controlling EAC was investigated with particular emphasis on the transferability of the results to components in service. The ...