PEO protective coatings on inner surface of tubes

Plasma electrolytic oxidation (PEO), also called micro-arc oxidation (MAO) or anode spark deposition (ASD), is a novel technique to produce hard ceramic coatings on metals, such as aluminum, titanium, magnesium (called valve metals) and their alloys. Up to now, many researchers focused on the PEO process for workpieces of regular shapes such as cube, cake or stick samples, etc. But no one paid attention to the irregular samples such as tubular materials. This research emphasized the PEO process of long tubes, especially the way to obtain uniform thickness of ceramic coatings on inner surface of tubes. Furthermore, the PEO kinetic behaviors of aluminum tubes were also investigated. The potential difference between the electrodes indicated a linear relationship with the coating thickness. A central accessory electrode was axially used to eliminate the shielding effect of electric field and was effective to obtain axially uniform coating on the inner surface of the tubes. The combination of hot-dipping aluminum and PEO process to obtain ceramic coating on 45# steel tubes was also performed in this work.     

Characteristics of copper oxide films deposited by PBII&D

Copper oxide films were deposited by plasma based ion implantation and deposition using a copper antenna as rf sputtering ion source. A gas mixture of Ar + O₂ was used as working gas. During the process, copper that was sputtered from the rf antenna reacted with oxygen and was deposited on a silicon substrate. The composition and the chemical state of the deposited films were analyzed by XPS. The structure of the films was detected by XRD. It is observed that Cu₂O film has been prepared on the Si substrate. It is found that the microstructure of the deposited film is amorphous for the applied voltage of − 5 kV. The surface layer of the deposited films is CuO. This is because the surface layer absorbs the oxygen from ambient air after the treated sample was removed from the vacuum chamber. An appropriate applied voltage, 2 kV under the present conditions, brings the lowest resistance. It is also seen that the maximum absorbance of the deposited films moves to a lower wavelength with increased applied voltage.     

Resolution of singularities for multi-loop integrals

We report on a program for the numerical evaluation of divergent multi-loop integrals. The program is based on iterated sector decomposition. We improve the original algorithm of Binoth and Heinrich such that the program is guaranteed to terminate. The program can be used to compute numerically the Laurent expansion of divergent multi-loop integrals regulated by dimensional regularisation. The symbolic and the numerical steps of the algorithm are combined into one program.

Program summary

Program title: sector_decompositionCatalogue identifier: AEAG_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAG_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 47 506No. of bytes in distributed program, including test data, etc.: 328 485Distribution format: tar.gzProgramming language: C++Computer: allOperating system: UnixRAM: Depending on the complexity of the problemClassification: 4.4External routines: GiNaC, available from http://www.ginac.de, GNU scientific library, available from http://www.gnu.org/software/gslNature of problem: Computation of divergent multi-loop integrals.Solution method: Sector decomposition.Restrictions: Only limited by the available memory and CPU time.Running time: Depending on the complexity of the problem.     

Reduction of the self-forces in Monte Carlo simulations of semiconductor devices on unstructured meshes

When using an unstructured mesh for device geometry, the ensemble Monte Carlo simulations of semiconductor devices may be affected by unwanted self-forces resulting from the particle-mesh coupling. We report on the progress in minimisation of the self-forces on arbitrary meshes by showing that they can be greatly reduced on a finite element mesh with proper interpolation functions. The developed methodology is included into a self-consistent finite element 3D Monte Carlo device simulator. Minimising of the self-forces using the proper interpolation functions is tested by simulating the electron transport in a 10 nm gate length, 6.1 nm body thick, double gate metal-oxide-semiconductor field-effect transistor (MOSFET). We demonstrate the reduction in the self-force and illustrate the practical distinction by showing I-V characteristics for the device.     

LanHEP—a package for the automatic generation of Feynman rules in field theory. Version 3.0

The LanHEP program version 3.0 for Feynman rules generation from the Lagrangian is described. It reads the Lagrangian written in a compact form, close to the one used in publications. It means that Lagrangian terms can be written with summation over indices of broken symmetries and using special symbols for complicated expressions, such as covariant derivative and strength tensor for gauge fields. Supersymmetric theories can be described using the superpotential formalism and the 2-component fermion notation. The output is Feynman rules in terms of physical fields and independent parameters in the form of CompHEP model files, which allows one to start calculations of processes in the new physical model. Alternatively, Feynman rules can be generated in FeynArts format or as LaTeX table. One-loop counterterms can be generated in FeynArts format.

Program summary

Program title: LanHEPCatalogue identifier: ADZV_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECH_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 83 041No. of bytes in distributed program, including test data, etc.: 1 090 931Distribution format: tar.gzProgramming language: CComputer: PCOperating system: LinuxRAM: 2 MB (SM), 12 MB (MSSM), 120 MB (MSSM with counterterms)Classification: 4.4Nature of problem: Deriving Feynman rules from the LagrangianSolution method: The program reads the Lagrangian written in a compact form, close to the one used in publications. It means that Lagrangian terms can be written with summation over indices of broken symmetries and using special symbols for complicated expressions, such as covariant derivative and strength tensor for gauge fields. Tools for checking the correctness of the model, and for simplifying the output expressions are provided. The output is Feynman rules in terms of physical fields and independent parameters in the form of CompHEP model files, which allows one to start calculations of processes in the new physical model. Alternatively, Feynman rules can be generated in FeynArts format or as a LaTeX table.Running time: 1 sec (SM), 8 sec (MSSM), 8 min (MSSM with counterterms)     

NearFar: A computer program for nearside-farside decomposition of heavy-ion elastic scattering amplitude

The NearFar program is a package for carrying out an interactive nearside-farside decomposition of heavy-ion elastic scattering amplitude. The program is implemented in Java to perform numerical operations on the nearside and farside angular distributions. It contains a graphical display interface for the numerical results. A test run has been applied to the elastic scattering at Elab=1503 MeV.

Program summary

Title of program: NearFarCatalogue identifier: ADYP_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYP_v1_0Program obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandLicensing provisions: noneComputers: designed for any machine capable of running Java, developed on PC-Pentium-4Operating systems under which the program has been tested: Microsoft Windows XP (Home Edition)Program language used: JavaNumber of bits in a word: 64Memory required to execute with typical data: case dependentNo. of lines in distributed program, including test data, etc.: 3484Number of bytes distributed program, including test data, etc.: 142 051Distribution format: tar.gzOther software required: A Java runtime interpreter, or the Java Development Kit, version 5.0Nature of physical problem: Interactive nearside-farside decomposition of heavy-ion elastic scattering amplitude.Method of solution: The user must supply a external data file or PPSM parameters which calculates theoretical values of the quantities to be decomposed.Typical running time: Problem dependent. In a test run, it is about 35 s on a 2.40 GHz Intel P4-processor machine.     

Growth of silicon nitride films by bombarding amorphous silicon with N ions: MD simulation

In this study, the molecular dynamics simulation method was employed to investigate the growth of silicon nitride films by using N⁺ ions, with energies of 50, 100, 150 and 200 eV, to bombard an amorphous silicon surface at 300 K. After an initial period of N⁺ bombardment, saturation of the number of N atoms deposited on the surface is observed, which is in agreement with experiments. During subsequent steady state deposition, a balance between uptake of N by the surface and sputtering of previously deposited N is established. The Si(N_x) (x = 1-4) and N(Si_y) (y = 1-3) bond configurations in the grown films are analyzed.     

D0C: A code to calculate scalar one-loop four-point integrals with complex masses

We present a new Fortran code to calculate the scalar one-loop four-point integral with complex internal masses, based on the method of 't Hooft and Veltman. The code is applicable when the external momenta fulfill a certain physical condition. In particular it holds if one of the external momenta or a sum of them is timelike or lightlike and therefore covers all physical processes at colliders. All the special cases related to massless external particles are treated separately. Some technical issues related to numerical evaluation and Landau singularities are discussed.     

A transport simulation code for inertial confinement fusion relevant laser-plasma interaction

We present a code for the simulation of laser-plasma interaction processes relevant for applications in inertial confinement fusion. The code consists of a fully nonlinear hydrodynamics in two spatial dimensions using a Lagrangian, discontinuous Galerkin-type approach, a paraxial treatment of the laser field and a spectral treatment of the dominant non-local transport terms. The code is fully parallelized using MPI in order to be able to simulate macroscopic plasmas.One example of a fully nonlinear evolution of a laser beam in an underdense plasma is presented for the conditions previewed for the future MegaJoule laser project.     

Heat Capacity of Adsorbed Helium-3 at Ultra-Low Temperatures

We report on direct measurements of the heat capacity of monolayers of ³He adsorbed on the surface of a copper cell filled with superfluid ³He. We found that at ultra low temperatures the surface ³He heat capacity dominates over the heat capacity of the bulk liquid ³He. The replacement of adsorbed ³He by ⁴He changes the heat capacity of the sample by an order of magnitude. These investigations were made in the framework of the “ULTIMA” project, a dark matter detector based on superfluid ³He in the limit of ultra low temperatures.