Charged-particle pseudorapidity density distributions from Au+Au collisions at sqrt[s(NN)]=130 GeV

The charged-particle pseudorapidity density dN(ch)/d eta has been measured for Au+Au collisions at sqrt[s(NN)] = 130 GeV at RHIC, using the PHOBOS apparatus. The total number of charged particles produced for the 3% most-central Au+Au collisions for /eta/相似文献   

Chiral scale and conformal invariance in 2D quantum field theory

It is well known that a local, unitary Poincaré-invariant 2D quantum field theory with a global scaling symmetry and a discrete non-negative spectrum of scaling dimensions necessarily has both a left and a right local conformal symmetry. In this Letter, we consider a chiral situation beginning with only a left global scaling symmetry and do not assume Lorentz invariance. We find that a left conformal symmetry is still implied, while right translations are enhanced either to a right conformal symmetry or a left U(1) Kac-Moody symmetry.     

Analysis of enhanced oil recovery formulations

Summary Methods for the determination of low levels of surfactants in produced oil field brines have been developed. Alkylbenzene sulfonates (ABS) and alkylether sulfates can be quantified at very low levels by high-performance liquid chromatography (HPLC) and mobile-phase ion chromatography (MPIC), respectively. These methods proved to be rapid, selective, and gave results in excellent agreement with traditional low-phase titration techniques. Although this paper records the use of these methods for analysis of oil field produced fluids, they should be easily adaptable to other situations wherein the analysis of these two classes of surfactants is required.     

Application of TG-DTG analysis in the study of the ammoxidised carbon materials

The effect of ammoxidation on thermal stability of carbonaceous materials characterised by degree of coalification other than that of brown coal (Konin mine, Poland) or sub-bituminous coal (Sośnica mine, Poland) was studied by thermogravimetric (TG-DTG) method. Analysis of TG-DTG curves has shown that coal samples ammoxidised at the higher temperature show slightly lower thermal stability. It has been established the importance of the sequence in the processes of carbonisation and ammoxidation. Both the amount of nitrogen introduced on the surface of studied carbonaceous materials and the thermal stability of nitrogen groups were affected.     

Thermal processes in multilayer second-generation HTSC under swift heavy-ion irradiation

On the basis of the thermal spike model, the estimations with regard to tapes of the second-generation Ag/YBaCuO/MgO/Hastelloy HTSC under irradiation with Ar, Kr, and Xe ions of an energy of about 1.2 MeV/amu have been carried out. The results have been compared with the available experimental data. In addition, the possibility of processes such as melting, recrystallization, amorphization, and other phase transitions in multilayer structures under ion irradiation has been studied.     

Radial filtration in highly concentrated suspensions undergoing constant-force squeeze flow and its effect on the normal stress distribution

Liquid-phase migration and jamming of the suspended particles appear to be the cause of the previously reported drastic changes in the normal stress distribution in concentrated suspensions subjected to squeeze flow as the initial volume fraction is raised above a critical value. Liquid-phase migration was found to depend on the initial volume fraction of solids, the viscosity of the suspending fluid, and the size of the particles. Under some conditions, liquid-phase migration did not take place to any significant degree; however, under other conditions, the volume fraction of solids increased throughout the sample, but especially in the central region, as liquid was expelled from the test region in preference to the solids. Criteria for the occurrence of liquid-phase migration in suspensions undergoing squeeze flow are discussed in terms of dimensionless groups.     

Bayesian approach to network modularity

We present an efficient, principled, and interpretable technique for inferring module assignments and for identifying the optimal number of modules in a given network. We show how several existing methods for finding modules can be described as variant, special, or limiting cases of our work, and how the method overcomes the resolution limit problem, accurately recovering the true number of modules. Our approach is based on Bayesian methods for model selection which have been used with success for almost a century, implemented using a variational technique developed only in the past decade. We apply the technique to synthetic and real networks and outline how the method naturally allows selection among competing models.     

Pseudo-steady-state solutions for solidification in a wedge

Polubarinova-Kochina's analytical differential equation methodis used to determine the pseudo-steady-state solution to problemsinvolving the freezing (solidification) of wedges of liquidwhich are initially at their fusion temperature. In particular,we consider four distinct problems for wedges which are: freezingwith the same constant boundary temperature, freezing with thesame constant boundary heat fluxes, freezing with distinct constantboundary temperatures and freezing with distinct constant fluxesat the boundaries. For the last two problems, a Heun's differentialequation with an unknown singularity is derived, which in bothcases admits a particularly elegant simple solution for thespecial case when the wedge angle is . The moving boundariesobtained are shown pictorially.