Search Results - (Author, Cooperation:M. H. Lim)

2011-10-28

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Aldehydes/metabolism ; Crystallography, X-Ray ; Enzymes/chemistry/metabolism ; Hydrogen Peroxide/*chemistry/metabolism ; Iron/*chemistry/metabolism ; Ligands ; Models, Molecular ; Nonheme Iron Proteins/chemistry/metabolism ; Oxygen/chemistry/metabolism

1077-3118

AIP Digital Archive

Physics

The ability to preserve a grating profile during epitaxial overgrowth is vital to the design and operation of devices such as planar waveguide-coupled Bragg-resonant filters. Intentional preservation of rectangular-patterned InP gratings during gas source molecular beam epitaxial overgrowth has been accomplished. The use of a low temperature atomic hydrogen-assisted oxide removal technique alleviates the dependence on elevated temperatures for desorption of the native oxide, and is crucial to the preservation of the patterned profile. Confirmation of the overgrown grating fidelity is demonstrated via scanning electron microscopy and triple axis x-ray diffractometry. © 1997 American Institute of Physics.

Electronic Resource

1572-8145

Process control ; fuzzy logic ; neural network ; frequency trimming ; crystal resonator

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

In the development of a process diagnostic system to monitor the condition of the frequency-trimming process in the production of crystal resonators, fuzzy logic can be applied in the recognition of unnatural statistical patterns in the control charts. The heuristics for reasoning are based on the principles behind statistical process control. Using expert experience and knowledge to troubleshoot the causes of problems, one can associate a characteristic chart pattern with a set of known physical causes. As these causes related to the unnatural statistical patterns are not independent of each other, it is difficult to precisely associate the chart distribution patterns with the known causes. Furthermore, as the trimming process is dynamic, the causes of problems dealt with will vary with time. Hence, by means of neural networks, it is possible to associate fuzzily deduced chart patterns with plausible causes to achieve optimum operating conditions.

Electronic Resource

1573-2894

Springer Online Journal Archives 1860-2000

Computer Science

Abstract Most existing placement algorithms were designed to handle blocks that are rectangular in shape. In this paper, we show how a genetic algorithm (GA) is used to construct an optimal arrangement of two-dimensional rectilinear blocks. Our approach does not require the orientation of each block to be fixed. To transform the placement problem to a GA problem, we devised a decoding technique known as circular placement. The novelty of the circular placement technique is that it configures the rectilinear blocks by building up potentially good groupings of blocks starting from the corners of the placement area. To complement the circular placement approach, we present a methodology for deriving a suitable objective function. We confirm the performance of our GA-based placement algorithm by presenting simulation results of some problems on tiling with up to 128 polyominoes. The algorithm described in this paper has great potential for applications in packing, compacting and general component placement in the various disciplines of engineering.

Electronic Resource