Growth of InAs on GaAs(1 0 0) by low-pressure metalorganic chemical vapor deposition employing in situ generated arsine radicals

InAs was grown by low-pressure metalorganic chemical vapor deposition on vicinal GaAs(1 0 0) substrates misoriented by 2° toward [0 0 1]. We observed InAs crystal growth, at substrate temperatures down to 300°C, employing in situ plasma-generated arsine radicals as the arsenic source. The in situ generated arsine was produced by placing solid arsenic downstream of a microwave driven hydrogen plasma. Trimethylindium (TMIn) feedstock carried by hydrogen gas was used as the indium source. The Arrhenius plot of InAs growth rate vs. reciprocal substrate temperature displayed an activation energy of 46.1 kcal/mol in the temperature range of 300–350°C. This measured activation energy value is very close to the energy necessary to remove the first methyl radical from the TMIn molecule, which has never been reported in prior InAs growth to the best of authors’ knowledge. The film growth mechanism is discussed. The crystallinity, infrared spectrum, electrical properties and impurity levels of grown InAs are also presented.     

Thermodynamics of Shape Memory Alloy Wire: Modeling, Experiments, and Application

A thermomechanical model for a shape memory alloy (SMA) wire under uniaxial loading is implemented in a finite element framework, and simulation results are compared with mechanical and infrared experimental data. The constitutive model is a one–dimensional strain-gradient continuum model of an SMA wire element, including two internal field variables, possible unstable mechanical behavior, and the relevant thermomechanical couplings resulting from latent heat effects. The model is calibrated to recent and new experiments of typical commercially available polycrystalline NiTi wire. The shape memory effect and pseudoelastic behaviors are demonstrated numerically as a function of applied displacement rate and environmental parameters, and the results compare favorably to experimental data. The model is then used to simulate a simple SMA actuator device, and its performance is assessed for different thermal boundary conditions.     

Evaluating electronic workshops through analysing the ‘brainstormed’ ideas

This paper explores how participants work in a new format of brainstorm, called an ‘incubated gathering’. The paper explores brainstorm-type activities, where senior managers share occupational knowledge in the generation of a solution to a problem in which they have an embedded interest. The findings suggest that participants perceive great worth in the incubated gathering, and (compared to other formats of gathering) it allows participants to consider a significantly wider range of issues, and in more detail. They also suggest that an outcome from an incubated gathering will be informed by a more rich consideration of the pertinent issues than that from other formats of brainstorming. This paper substantiates these claims with evidence from a suite of new approaches to gauge the ability of participants to share knowledge during group brainstorming-type activities.     

An invariant manifold approach to nonlinear normal modes of oscillation

Summary A method for determining the amplitude-dependent mode shapes and the corresponding modal dynamics of weakly nonlinear vibratory systems is described. The method is a combination of a Galerkin projection and invariant manifold techniques and is applied to a class of distributed parameter vibratory systems. In this paper the general theory for a class of conservative systems is outlined and applied to determine the nonlinear mode shapes and modal dynamics of a linear Euler-Bernoulli team attached to a nonlinear elastic foundation.     

L 2 existence theorems for the\bar \partial _b - Neumann problem on strongly pseudoconvex CR manifoldsproblem on strongly pseudoconvex CR manifolds

LetM be the boundary of a strongly pseudoconvex domain in \(\mathbb{C}^n \) ,n≥4 and ω be an open subset inM such that ?ω is the intersection ofM with a flat hypersurface. We establish theL ² existence theorems of the \(\bar \partial _b - Neumann\) problem on ω. In particular, we prove that the \(\bar \partial _b - Laplacian\) \(\square _b = \bar \partial _b \bar \partial _b^* + \bar \partial _b^* \bar \partial _b \) equipped with a pair of natural boundary conditions, the so-called \(\bar \partial _b - Neumann\) boundary conditions, has closed range when it acts on (0,q) forms, 1≤q≤n?3. Thus there exists a bounded inverse operator for \(\square _b \) , the \(\bar \partial _b - Neumann\) operatorN _b, and we have the following Hodge decomposition theorem on ω for \(\bar \partial _b \bar \partial _b^* N_b \alpha + \bar \partial _b^* \bar \partial _b N_b \alpha \) , for any (0,q) form α withL ²(ω) coefficients. The proof depends on theL ^p regularity of the tangential Cauchy-Riemann operators \(\bar \partial _b u = \alpha \) on ω?M under the compatibility condition \(\bar \partial _b \alpha = 0\) , where α is a (p, q) form on ω, where 1≤q≤n?2. The interior regularity ofN _b follows from the fact that \(\square _b \) is subelliptic in the interior of ω. The operatorN _b induces natural questions on the regularity up to the boundary ?ω. Near the characteristic point of the boundary, certain compatibility conditions will be present. In fact, one can show thatN _b is not a compact operator onL ²(ω).