Combination of electron energy-loss spectroscopy and energy dispersive x-ray spectroscopy to determine indium concentration in InGaN thin film structures

We demonstrate a method to determine the indium concentration, x, of In x Ga1-x N thin films by combining plasmon excitation studies in electron energy-loss spectroscopy (EELS) with a novel way of quantification of the intensity of x-ray lines in energy-dispersive x-ray spectroscopy (EDXS). The plasmon peak in EELS of InGaN is relatively broad. We fitted a Lorentz function to the main plasmon peak to suppress noise and the influence from the neighboring Ga 3d transition in the spectrum, which improves the precision in the evaluation of the plasmon peak position. As the indium concentration of InGaN is difficult to control during high temperature growth due to partial In desorption, the nominal indium concentrations provided by the growers were not considered reliable. The indium concentration obtained from EDXS quantification using Oxford Instrument ISIS 300 x-ray standard quantification software often did not agree with the nominal indium concentration, and quantification using K and L lines was inconsistent. We therefore developed a self-consistent iterative procedure to determine the In content from thickness-dependent k-factors, as described in recent work submitted to Journal of Microscopy. When the plasmon peak position is plotted versus the indium concentration from EDXS we obtain a linear relationship over the whole compositional range, and the standard error from linear least-squares fitting shows that the indium concentration can be determined from the plasmon peak position to within Δx = ± 0.037 standard deviation

“It’s Like Hating Puppies!” Employee Disengagement and Corporate Social Responsibility

Corporate social responsibility (CSR) has been linked with numerous organizational advantages, including recruitment, retention, productivity, and morale, which relate specifically to employees. However, despite specific benefits of CSR relating to employees and their importance as a stakeholder group, it is noteworthy that a lack of attention has been paid to the individual level of analysis with CSR primarily being studied at the organizational level. Both research and practice of CSR have largely treated the individual organization as a “black box,” failing to account for individual differences amongst employees and the resulting variations in antecedents to CSR engagement or disengagement. This is further exacerbated by the tendency in stakeholder theory to homogenize priorities within a single stakeholder group. In response, utilizing case study data drawn from three multinational tourism and hospitality organizations, combined with extensive interview data collected from CSR leaders, industry professionals, engaged, and disengaged employees, this exploratory research produces a finer-grained understanding of employees as a stakeholder group, identifying a number of opportunities and barriers for individual employee engagement in CSR interventions. This research proposes that employees are situated along a spectrum of engagement from actively engaged to actively disengaged. While there are some common drivers of engagement across the entire spectrum of employees, differences also exist depending on the degree to which employees, rather than senior management, support corporate responsibility within their organizations. Key antecedents to CSR engagement that vary depending on employees’ existing level of broader engagement include organizational culture, CSR intervention design, employee CSR perceptions, and the observed benefits of participation

Attribute-Based Refinement of Software Architectures

This paper aims to show the usefulness of attaching attributes to pieces of software architectures, in order to direct a transformation and refinement process. These attributes are properties that can be considered as abstract ways to express architectural structures, and characteristics that constrain the refinement process. Then we define a methodology that consists in refining and transforming an architecture on the basis of the attributes attached to it. The methodology will be illustrated on a case study

Attribute-Based Refinement of Software Architectures

This paper aims to show the usefulness of attaching attributes to pieces of software architectures, in order to direct a transformation and refinement process. These attributes ways to express architectural structures, and characteristics that constrain the refinement process. Then we define a methodology that consists in refining and transforming an architecture on the basis of the attributes attached to it. The methodology will be illustrated on a case study. 1. Introduction an

Recursive All Pass Realizations Subject to Tangential Constraints

Given d complex points i and associated directions (of C n ) z i , we develop a recursive algorithm for obtaining a " I 2 \Sigma # -unitary realization fA; B; C; Dg of a \Sigma-unitary transfer matrix U() (and of its inverse) which satisfies U( i )z i = 0; i = 1; :::; d: This algorithm is based on \Sigma-unitary transformations and has O(nd 2 ) complexity. Furthermore we introduce a modification to this algorithm that allows to work in real arithmetic in the case of self conjugate conditions

High Performance Algorithms for Toeplitz and block Toeplitz matrices

this paper we discuss several high performance variants of the classical Schur algorithm algorithms to factor symmetric block Toeplitz matrices. Specifically we discuss routines to factor symmetric positive definite, positive semidefinite and indefinite matrices. Algorithms to obtain the QR factorization of exactly and nearly rank deficient Toeplitz matrices are also discussed. In this paper the classical Schur algorithm for obtaining the Cholesky factorization of symmetric positive definite block Toeplitz matrices [9, 8] is generalized to the block Toeplitz matrix case using a block generalization of the hyperbolic Householder reflectors. The block generalization of the Schur algorithm and various blocking schemes differing in the amount of storage and computational primitives used are described in Section 2. Blocking the hyperbolic Householder transformations allows us to apply these transformations using BLAS 3 primitives rather than the BLAS 2 primitives which are required for plain hyperbolic Householder transformations. On machines with a memory hierarchy this provides us with a faster algorithm. For symmetric indefinite block Toeplitz matrices the Schur algorithm breaks down if the matrix has singular principal minors. A scheme to modify the block Schur algorithm by per

Study of the martensitic transformation in the Hafnium-Palladium system

High temperature shape memory alloys have received a large interest for many years but none of the systems studied so far has led to industrial applications. Those alloys are expected to develop an actuating role in high temperature environment as for example aircraft turbines. Lots of criteria are required in order to substitute or optimize heavy existing actuators. Here are presented a few results obtained with the system hafnium-palladium, not so documented for the moment, that develops a martensitic transformation at around 773 K. According to the characteristics of very well-known alloys such as NiTi, some compositions around the equiatomic are explored. The main ob jective of our work is to know the influence of a stoechiometry gap on the microstructure of the alloys and the martensitic transformation