Solid phase crystallization of amorphous silicon on glass by thin film heater for thin film transistor (TFT) application

A new process for solid phase crystallization (SPC) of amorphous silicon (a-Si) using thin film heater is reported. With this localized Ti silicide thin film heater, we successfully crystallized 500 Å-thick a-Si in a few minutes without any thermal deformation of glass substrate. The size of crystallized silicon grain was abnormally big (30-40 μm). Polycrystalline thin film transistors (TFT) fabricated using this unique thin film heater showed better mobility than those of conventional ones by furnace annealing.     

The BAGEL assembler generation library

This paper presents two coupled software packages which receive widespread use in the field of numerical simulations of Quantum Chromo-Dynamics. These consist of the BAGEL library and the BAGEL fermion sparse-matrix library, BFM.The Bagel library can generate assembly code for a number of architectures and is configurable – supporting several precision and memory pattern options to allow architecture specific optimisation. It provides high performance on the QCDOC, BlueGene/L and BlueGene/P parallel computer architectures that are popular in the field of lattice QCD. The code includes a complete conjugate gradient implementation for the Wilson and domain wall fermion actions, making it easy to use for third party codes including the Jefferson Laboratory's CHROMA, UKQCD's UKhadron, and the Riken–Brookhaven–Columbia Collaboration's CPS packages.

Program summary

Program title: BagelCatalogue identifier: AEFE_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFE_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: GNU Public License V2No. of lines in distributed program, including test data, etc.: 109 576No. of bytes in distributed program, including test data, etc.: 892 841Distribution format: tar.gzProgramming language: C++, assemblerComputer: Massively parallel message passing. BlueGene/QCDOC/others.Operating system: POSIX, Linux and compatible.Has the code been vectorised or parallelized?: Yes. 16 384 processors used.Classification: 11.5External routines: QMP, QDP++Nature of problem: Quantum Chromo-Dynamics sparse matrix inversion for Wilson and domain wall fermion formulations.Solution method: Optimised Krylov linear solver.Unusual features: Domain specific compiler generates optimised assembly code.Running time: 1 h per matrix inversion; multi-year simulations.     

Automated generation of lattice QCD Feynman rules

The derivation of the Feynman rules for lattice perturbation theory from actions and operators is complicated, especially for highly improved actions such as HISQ. This task is, however, both important and particularly suitable for automation. We describe a suite of software to generate and evaluate Feynman rules for a wide range of lattice field theories with gluons and (relativistic and/or heavy) quarks. Our programs are capable of dealing with actions as complicated as (m)NRQCD and HISQ. Automated differentiation methods are used to calculate also the derivatives of Feynman diagrams.

Program summary

Program title: HiPPY, HPsrcCatalogue identifier: AEDX_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDX_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: GPLv2 (see Additional comments below)No. of lines in distributed program, including test data, etc.: 513 426No. of bytes in distributed program, including test data, etc.: 4 893 707Distribution format: tar.gzProgramming language: Python, Fortran95Computer: HiPPy: Single-processor workstations. HPsrc: Single-processor workstations and MPI-enabled multi-processor systemsOperating system: HiPPy: Any for which Python v2.5.x is available. HPsrc: Any for which a standards-compliant Fortran95 compiler is availableHas the code been vectorised or parallelised?: YesRAM: Problem specific, typically less than 1 GB for either codeClassification: 4.4, 11.5Nature of problem: Derivation and use of perturbative Feynman rules for complicated lattice QCD actions.Solution method: An automated expansion method implemented in Python (HiPPy) and code to use expansions to generate Feynman rules in Fortran95 (HPsrc).Restrictions: No general restrictions. Specific restrictions are discussed in the text.Additional comments: The HiPPy and HPsrc codes are released under the second version of the GNU General Public Licence (GPL v2). Therefore anyone is free to use or modify the code for their own calculations. As part of the licensing, we ask that any publications including results from the use of this code or of modifications of it cite Refs. [1,2] as well as this paper. Finally, we also ask that details of these publications, as well as of any bugs or required or useful improvements of this core code, would be communicated to us.Running time: Very problem specific, depending on the complexity of the Feynman rules and the number of integration points. Typically between a few minutes and several weeks. The installation tests provided with the program code take only a few seconds to run.References:

• [1] 

  A. Hart, G.M. von Hippel, R.R. Horgan, L.C. Storoni, Automatically generating Feynman rules for improved lattice eld theories, J. Comput. Phys. 209 (2005) 340–353, doi:10.1016/j.jcp.2005.03.010, arXiv:hep-lat/0411026.

• [2] 

  M. Lüscher, P. Weisz, Efficient Numerical Techniques for Perturbative Lattice Gauge Theory Computations, Nucl. Phys. B 266 (1986) 309, doi:10.1016/0550-3213(86)90094-5.

     

Analysis of Polycyclic Aromatic Compounds Using Microbore Columns

The gas chromatographic analysis of polycyclic aromatic compounds can be completed faster and with increased chromatographic resolution using microbore columns (Fast GC). Microbore columns contain two to three times the number of theoretical plates per meter when compared to 0.25 mm internal diameter (i.d.) capillary columns. The increased chromatographic resolving power of microbore columns enables separations to be carried out with much shorter columns giving rise to faster analysis times. Analysis times of priority polycyclic aromatic hydrocarbons on 20 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) and 10 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) columns are reduced by about 45% and 60% respectively in comparison with 30 m columns, and data quality (precision and accuracy) is not affected. All areas/parameters of the chromatographic system must be adjusted and optimized to ensure proper chromatographic performance. Smaller injection volumes (0.2-0.5 w L) and injection liners (1-2 mm i.d.) are required to obtain optimum (and reproducible) chromatography on 0.1 mm i.d. columns.     

Selective detection of C by laser photodetachment mass spectrometry

In this paper, we demonstrate how laser photodetachment mass spectrometry (LPMS) can be used to selectively detect ¹³C⁻ ions in the presence of ¹²C⁻ ions in a low energy ion beam. An isotopically enriched beam of carbon ions consisting of equal amounts of ¹³C⁻ and ¹²C⁻ ions was extracted from an ion source. The ions interacted with a laser beam in a collinear geometry over a distance of 70 cm. Residual atoms produced in the photodetachment process were detected in a neutral particle detector placed downstream of the collinear interaction region. By making use of the Doppler effect we were able to selectively photodetach ¹³C⁻ ions. The number of detected ¹³C atoms was 13 times larger than the number of detected ¹²C atoms. The population of the excited, weakly bound ²D excited state of the C⁻ ion was depleted by the use of a second laser. This significantly reduced the background accompanying the signal arising from the photodetachment of the ⁴S ground state C⁻ ion. Different applications of the LPMS method will be discussed in the paper.     

气相色谱—热能分析法测定啤酒中N—亚硝基二甲胺

本文采用硅藻土柱层析分离、气相色谱——热能分析法测定啤酒中N—亚硝基二甲胺的含量,并对方法的灵敏度、准确度及各种影响因素进行探讨。用于样品测定取得较为满意的结果。     

Optical and morphological characterization of photocatalytic TiO2 thin films doped with silver

Silver-doped titanium dioxide thin films were deposited on glass substrates by the sol-gel process. Undoped films and films doped with 1 and 3 mol% Ag were annealed at 100 or 500 °C. The optical and morphological properties of the films were analyzed by optical absorption spectroscopy and scanning electron microscopy. Additionally, the films were evaluated for their ability to degrade methylene blue. It was found that the photocatalytic activity is barely sensitive to silver doping for films annealed at 100 °C, whereas the effect of silver resulted in enhanced photocatalytic activity for films annealed at 500 °C. For the latter annealing temperature, the photocatalytic activity increased with increasing Ag doping concentration.     

Lateral SbTeN based multi-layer phase change memory for multi-state storage

X-ray diffraction patterns and resistivity measurement indicate that as-deposited N-doped Sb₂Te₃ (STN) films become amorphous while the as-deposited Sb₂Te₃ film is crystalline. A lateral as-deposited STN-based multi-layer phase change memory was proposed for multi-state storage. The active region of the device consists of a top 30-nm TiN/180-nm STN/20-nm TiN/bottom 120-nm STN stacked multi-layer. Static switching properties of the device with STN initially starting from the amorphous state exhibit two apparent S-shaped switchings, which correspond to two marked device resistance drops by a factor of 2-5. The first and second threshold voltages are around 2.8-3.2 and 4.3-5.4 V, respectively. Finite element analysis of the device shows that the two switchings could sequentially occur at the electrode steps from the bottom 120-nm STN layer to the top thick 180-nm STN layer.     

Cross section calculations in Glauber model: I. Core plus one-nucleon case

This paper presents a Fortran program to calculate cross sections for various reactions between composite particles in the framework of Glauber theory. The projectile nucleus is described as a core plus one valence-nucleon system. The input data needed for the calculation are the core and target densities and the nucleon-nucleon profile function. The single-particle wave function of the valence nucleon may be provided by a user or generated by the code if appropriate quantum numbers of the wave function are specified. Multiple integrations involving the valence-nucleon wave function are performed by a Monte Carlo technique with Metropolis algorithm. The program gives the total reaction cross section, the one-nucleon removal cross section, the elastic differential cross section, and the longitudinal momentum distribution of the core fragment. Sample calculations include the reactions of ^13,19C+¹²C, ¹¹Be+¹²C, ¹¹Be+⁹Be, and ⁸B+¹²C systems.     

Low-lying Wilson Dirac operator eigenvector mixing in dynamical overlap hybrid Monte Carlo

Current dynamical overlap fermion hybrid Monte Carlo simulations encounter large fermionic forces when there is mixing between eigenvectors of the kernel operator with near zero-eigenvalues. This leads to low acceptance rates when there is a large density of near zero eigenvalues. I present a method where these large forces are eliminated and the large action jumps seen when two eigenvalues approach zero are significantly reduced. This significantly increases the stability of the algorithm, and allows the use of larger integration time steps.