Waveguide Panel Display Using Electromechanical Spatial Modulators

A novel micro‐electro‐mechanical system (MEMS) approach in waveguide panel displays (WPD) is described. High efficiency electromechanical spatial modulators, based on the use of frustrated total internal reflection, were demonstrated. Potential applications of the new display in HDTV using solid‐state light emitting diode (LED) as a light source are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92009/1/1.1833659.pd

Hot filament enhanced chemical vapor deposition of AlN thin films

Hot filament enhanced chemical vapor deposition of aluminum nitride thin films from trimethylaluminum and ammonia has been investigated for deposition temperatures ranging from 584 to 732 K. The use of a hot filament resulted in an approximate two orders of magnitude increase in the deposition rate compared to a similar, uncatalyzed growth. The film deposition rate and refractive index did not depend on the substrate temperature. X‐ray photoelectron spectroscopy and Fourier‐transform infrared spectroscopy indicated that the films were high purity aluminum nitride, with negligible carbon and oxygen contamination.  Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69855/2/APPLAB-59-5-549-1.pd

Synthesis of Fe-MCM-41 from silatrane and FeCl 3 via sol–gel process and its epoxidation acivity

An iron-containing mesoporous molecular sieve, or Fe-MCM-41, was successfully synthesized the via sol–gel technique using silatrane and FeCl 3 as the silicon and iron sources, and was characterized using various techniques. Many factors were investigated, namely, reaction temperature and time, calcination rate, and iron amount in the reaction mixture. It was found that the optimum conditions in which to synthesize Fe-MCM-41 was to carry out the reaction at 60 °C for 7 h using a 1 °C min −1 calcination rate and a 550 °C calcination temperature. The catalytic activity and selectivity of styrene epoxidation using hydrogen peroxide showed that the selectivity of the styrene oxide reached 65% at a styrene conversion of 22% over the 1%wt catalyst. Copyright © 2008 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58025/1/1356_ftp.pd

Selective deposition of polycrystalline silicon thin films at low temperature by hot‐wire chemical vapor deposition

Polycrystalline silicon thin films have been selectively deposited at a substrate temperature of 300 °C on molybdenum or silicon over silicon dioxide, silicon nitride or Corning 7059 glass substrates in a continuous hot‐wire chemical vapor deposition (HWCVD) process involving hydrogen and disilane. Excellent selectivity is achieved on features as small as 1 μm spaced molybdenum lines. The deposition rate on molybdenum is 60–100 Å/min which is higher than that obtained by a pulsed gas plasma‐enhanced chemical vapor deposition (PECVD) or a very high‐frequency PECVD (VHF‐PECVD). The selective deposition rate obtained in our system is attributed to the high concentration of atomic hydrogen generated when molecular hydrogen passes over a heated tungsten filament. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69983/2/APPLAB-68-19-2681-1.pd

A novel catalytic reactor system for transient response and its use in CO oxidation on Pd/Al2O3

In this paper we describe a computer-controlled reactor system capable of imposing any concentration-forcing function on the input. Combination of a monolithic support with a fast-scan Fourier Transform Infrared (FTIR) results in a system capable of detecting all the IR-active species inside the reactor simultaneously, with a time resolution of 0.17 s. Flow characteristics and typical results obtained from oxidation of CO over [gamma]-alumina-supported palladium demonstrate the capabilities of this reactor system in detecting fast phenomena that could not be observed by analysis of the effluent stream.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25610/1/0000158.pd

A dynamic study of CO oxidation on supported platinum

Catalytic oxidation of CO on alumina-supported platinum was studied in a tubular isothermal reactor with applied concentration transients. A completely automated reactor system capable of switching frequencies as high as 0.2 Hz was constructed. Concentration cycling resulted in reaction rates that were much higher than the maximum rate achievable at steady-state operation. Mapping of the time-averaged carbon dioxide production rate in the time-period duty-fraction plane, resulted in a unique global maximum. We find that the maximum in rate occurs when the switching times are comparable to the characteristic time of the surface reaction. Results of our experiments also rule out significant contribution from the Eley-Rideal mechanism at the temperature range of this work (below 120°C).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37391/1/690310415_ftp.pd

Dynamics of growth of silica particles from ammonia-catalyzed hydrolysis of tetra-ethyl-orthosilicate

The NH3-catalyzed formation of colloidal silica particles from tetra-ethyl-orthosilicate (TEOS) in methanol and ethanol is studied by means of light scattering and Raman spectroscopy. We find that the growth is characterized by an incubation period after which no significant nucleation takes place. The particles have uniform, non-fractal structure and show low polydispersity. In the presence of excess water, the rate-limiting step is the hydrolysis, which is a first-order process in the orthosilicate concentration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27243/1/0000250.pd

Linewidth and viscosity of isobutyric acid—deuterium oxide mixtures of critical composition above and below the phase separation temperature

Linewidth and visocity measurement covering the single phase and two phase region were made. Comparison of the data with the mode–mode coupling results of Kawasaki show good agreement with no adjustable parameters. In the one phase region measurements of autocorrelation functions indicate small deviations from a single exponential when ‖T −Tc‖?0.05 °C. The shear viscosity exponent ϕ was found to be 0.077±0.002, somewhat larger than the theoretical estimates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70414/2/JCPSA6-74-10-5842-1.pd

Extraction of aminoglycoside antibiotics with reverse micelles

The reverse micelle system of sodium di-2-ethylhexyl phosphate was used to extract aminoglycoside antibiotics, neomycin and gentamicin. The aminoglycosides can be efficiently extracted into a reverse micelle solution, and the antibiotics extracted into the micelle phase can readily be recovered back to a divalent cation aqueous solution, such as Ca 2+ . The transfer efficiency, % E , is heavily dependent on pH and salt concentration in the aqueous feed solution. % E decreases drastically with pH in the pH range 8·5–11, and declines with increasing (NH 4 ) 2 SO 4 concentration. A simple transfer mechanism was proposed which suggests that the antibiotic molecules were extracted into the inner water cores of reverse micelles through attractive electrostatic interaction during forward transfer. In backward transfer, the antibiotics loaded in the micelle phase are released back to an aqueous phase through breaking up of the reverse micelles by using divalent cation solutions. The model is supported by the results of dynamic light scattering and infra-red spectroscopy study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38295/1/390_ftp.pd

Boundary effects in a surface reaction model for CO oxidation

The surface reaction model of Ziff, Gulari, and Barshad (ZGB) is investigated on finite systems with ‘‘hard’’ oxygen boundary conditions. The rate of production of CO2 is calculated as a function of y and system size. When the rate of CO adsorption y is above the first‐order transition value y2, the reactive region is found to extend into the system a distance ξ which scales as (y−y2)−0.40 when y→y2.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70742/2/JCPSA6-98-1-674-1.pd