Maximum a posteriori estimation of activation energies that control silicon self-diffusion

Self-diffusion in crystalline silicon is controlled by a network of elementary steps whose activation energies are important to know in a variety of applications in microelectronic fabrication. The present work employs maximum a posteriori (MAP) estimation to improve existing values for these activation energies, based on self-diffusion data collected at different values of the loss rates for interstitial atoms to the surface. Parameter sensitivity analysis shows that for high surface loss fluxes, the energy for exchange between an interstitial and the lattice plays the leading role in determining the shape of diffusion profiles. At low surface loss fluxes, the dissociation energy of large-atom clusters plays a more important role. Subsequent MAP analysis provides significantly improved values for these parameters.     

Assessing the validity of landscape evaluations

This paper was first presented at LRG's OASES conference, (Observing Australia) at Exeter in 1987. It examines the history of the tree lined avenue in Australia, especially New South Wales and discovers that its stylistic origins are varied and complex, from India and the United States as well as from Europe.     

Surface Treatment of Polypropylene Films Using Homogeneous DBD Plasma at Atmospheric Pressure in Air

The homogeneous dielectric barrier discharge （DBD） in atmospheric air is most favorable for polymer sur- face modification due to the low cost of operation and the ability of ambient on-line continuous...     

Impact sensitivity of nitroglycerin

Abstract

The impact sensitivity of liquid nitroglycerin, 50% initiation level, was observed to be near 1.8 kg?cm or 3.3 × 10³ j/m². The impact sensitivity of solid nitroglycerin, 50% initiation level, was observed by extrapolation to be near 200 kg?cm or 4.4 × 10⁵ j/m². The impact sensitivity of a mixture of solid and liquid NG was observed to be comparable to solid NG at the two stimulus levels tested. Thus, the presence of solid nitroglycerin reduces the impact sensitivity of liquid nitroglycerin.

The 50% initiation level for Class A cyclo-tetra-methylenetetranitramine was observed to be near 150 kg?cm or 3.3 × 10⁵ j/m² using the same instrument.     

Landscape evaluation in practice: a survey of local authorities

The paper reports the continuing use of landscape evaluation techniques by local planning departments in England and Scotland. A survey of 165 authorities, with a 67% response rate, shows that 22% percent have used such techniques in the last 5 years, yet their research base remains inadequate. The main reason reported for others not using these methods is lack of need, not antipathy towards the landscape evaluation approach.     

The ‘Manchester’ landscape evaluation method: a critical appraisal

The discovery of ozone holes and the potential warming of the planet will create a situation to which landscape architects must be prepared to respond. Suggestions as to possible actions are given.