Localized surface plasmon resonance nanosensor: a high-resolution distance-dependence study using atomic layer deposition

Atomic layer deposition (ALD) is used to deposit 1-600 monolayers of Al(2)O(3) on Ag nanotriangles fabricated by nanosphere lithography (NSL). Each monolayer of Al(2)O(3) has a thickness of 1.1 A. It is demonstrated that the localized surface plasmon resonance (LSPR) nanosensor can detect Al(2)O(3) film growth with atomic spatial resolution normal to the nanoparticle surface. This is approximately 10 times greater spatial resolution than that in our previous long-range distance-dependence study using multilayer self-assembled monolayer shells. The use of ALD enables the study of both the long- and short-range distance dependence of the LSPR nanosensor in a single unified experiment. Ag nanoparticles with fixed in-plane widths and decreasing heights yield larger sensing distances. X-ray photoelectron spectroscopy, variable angle spectroscopic ellipsometry, and quartz crystal microbalance measurements are used to study the growth mechanism. It is proposed that the growth of Al(2)O(3) is initiated by the decomposition of trimethylaluminum on Ag. Semiquantitative theoretical calculations were compared with the experimental results and yield excellent agreement.     

A survey of knowledge-based systems research in decision sciences (1980–1995)

Research in knowledge-based systems (KBS) has become an important area of inquiry within decision sciences. In this paper, we present the results of an extensive survey of research papers published on this topic. We determined frequency counts of papers and we also performed a content analysis of the papers we surveyed. The results indicate that there are a large number of studies informing us of the design and development issues relating to KBS. However, there seems to be less research examining issues relating to the management and impact of KBS on individuals and organisations. We summarise our key findings and identify avenues for future research.     

An evaluation of mathematical programming and minicomputers

The availability of efficient mathematical software on minicomputers could greatly increase the use of operations research techniques in industry and government. The objective of this paper is to demonstrate the feasibility of implementing a particular class of mathematical programming algorithms, namely shortest path algorithms, on “typical” minicomputers. Two distinct shortest path algorithms were tested on four computer systems using a common set of test problems. Computational results are presented which verify the feasibility of implementing these algorithms in a minicomputer environment, and also show the relative efficiency of each algorithm to be the same when tested on a minicomputer as when tested on a large-scale computer system.     

The microcalorimeter X-ray detector: A true paradigm shift in X-ray spectroscopy

The microcalorimeter x-ray detector registers the heat deposited in an absorber from individual x-ray photons by means of a sensitive thermometer. It combines advantages of wavelength-dispersive and energy-dispersive detectors: relatively high energy resolution over a broad energy spectrum. Operating at very low temperatures reduces the noise, making the high energy resolution possible. The absorber can be tailored to any energy range, from soft x-rays to gamma rays. After many years of development, several designs have reached a level of performance and reliability that makes them competitive x-ray detectors for many kinds of experiment. We survey current microcalorimeter detectors using several different thermometers. Their applications already run from chemical analysis to plasma physics and x-ray astronomy. We describe two examples of how the microcalorimeter detector can enable novel determinations in x-ray physics.