Performance Of Such Structures Research Articles

Chromium diffusion in lithium niobate for active optical waveguides

A method to fabricate chromium-doped lithium niobate substrates in which the active ions are introduced by thermal diffusion from a film is reported. Chromium concentration depth profiles have been obtained by secondary-ion-mass spectrometry and the relevant diffusion parameters have been derived. Fluorescence spectrum and upper laser level lifetime of chromium diffused proton-exchanged and chromium/titanium-diffused lithium niobate waveguides have been measured. A simple model has been used to estimate the performance of such structures as waveguide optical amplifiers and lasers.

Polarization dependence of optoelectronic properties in quantum dots and quantum wires-consequences of valence-band mixing

The electronic bandstructure in quantum dots and quantum wires is studied, including the valence-band mixing effects. Based on the bandstructure, results for the polarization dependence of absorption and gain (at room temperature) are examined. The related differential gain and the /spl alpha/-parameter is also studied. Our results show that it is extremely important to include valence-band mixing effects in predicting the laser performance of such structures.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

High heat flux performance of actively cooled divertor mock-ups

Abstract For the divertor of NET, actively cooled brazed CC/refractory metal mock-ups with an active length of 320 mm have been manufactured by Metallwerk Plansee, Austria, in order to evaluate the high heat flux performance of such structures. Seven tiles of CC material, 26 × 44.5 × 9 mm 3 , are brazed to an “interlayer” of TZM with a Zr braze. Subsequently this interlayer is brazed to a TZM body with a CuPd alloy. Inside the TZM body a tube of MoRe provides active cooling. In the ion beam test facility at KFA Julich two test series were performed. In order to determine the maximum tolerable heat load, the applied power density was increased stepwise at constant pulse lengths of 30 s in screening tests. The thermal fatigue behaviour of the divertor components was investigated by thermal cycling.

Parallel multi-layer classifier architectures of increasing hierarchical order

Multi-level classifier architectures provide a means of improving error-rate performance in many classification tasks such as machine printed or handwritten character recognition. It is argued that appropriate multi-level structures are well suited to parallel implementation, and results are presented to characterise the performance of such structures in a practical character recognition environment for a range of configurations and, in particular, for hierarchies of increasing order.

Detailed structural calculation and mechanical measurement of the insertion device support structure for ELETTRA

Structural calculations made during the design and testing of the insertion device (ID) carriage for ELETTRA are presented pointing out the differences obtained between different modeling approaches. The calculations are compared with a set of measurements that prove the validity and need of a detailed numerical model in order to predict the performance of such structures. The effects of thermal gradients are also considered. The results of a series of measurements made in order to assess the mechanical performances of the insertion device carriage are also presented.

Finite element consolidation analysis of embankments

Abstract The construction of earth embankments may lead to the development of excess pore pressures in foundation and embankment soils. The ability to predict the development and dissipation of these pore pressures is important in assessing the performance of such structures. This paper describes a finite element analysis method that allows the prediction of the behaviour of embankments including stress-deformation and consolidation behaviour. The application of the method is demonstrated through application to a reinforced embankment on peat and clay and to a high rockfill dam.

Properties of AlxGa1−xAs (xAl≂0.3) grown by molecular-beam epitaxy on misoriented substrates

The effects of substrate misorientation on the morphological and optical properties of AlxGa1−xAs (xAl≂0.3) grown by molecular-beam epitaxy (MBE) have been studied. The substrate temperatures and V/III beam-flux ratios used were such that layers grown on nominally (100) substrates typically exhibited rough morphologies and poor 4.2 K PL characteristics. By intentionally misorienting the substrate slightly from (100), smooth layers can be grown at 620 and 650 °C at typical MBE growth rates (≂1 μm/h). These smooth layers also exhibited sharp, exciton-related emission peaks at 4.2 K with half-widths as narrow as 5 meV. Since rough surfaces may lead to poor interfaces between GaAs and (Al,Ga)As and in turn to degraded performance in heterojunction devices, the present results may have significant implications for the performance of such structures grown by MBE.

A Review On Partial Infilled Frames Under Lateral Loads

Masonry infilled walls are provided within the reinforced concrete structures without being analyzed as a combination of concrete and brick elements, though in reality they act as a single unit during earthquakes. The performance of such structures during earthquakes has proved to be superior in comparison to the bare frames in terms of stiffness, strength and energy dissipation. There are plenty of researches done so far for infilled frames, however partially infilled frames are still the topic of interest. Though it has been understood that the infills play significant role in enhancing the lateral stiffness of complete structure, the past experience in various earthquakes have proved that the partially infilled framed structures somehow are affected adversely. This paper intends to highlight the need of knowledge on partially infilled frames and the composite action. It also summarizes the findings till date done by various researchers on the behavior of partial infilled frames under lateral loads. DOI: http://dx.doi.org/10.3126/kuset.v8i1.6054 KUSET 2012; 8(1): 142-152