Effect of trimethylsilane flow rate on the growth of SiC thin-films for fiber-optic temperature sensors

We have investigated the effect of trimethylsilane ([(CH/sub 3/)/sub 3/SiH] or 3MS) flow rate on the growth of SiC thin-film on single-crystal sapphire substrate for fiber-optic temperature sensor. The SiC film thickness was in the range of 2-3 /spl mu/m. The variation of the 3MS flow rate affected the structural properties of the SiC films. This, in turn, changed the optical properties and temperature sensing performance of the sensors. Optical reflection from the SiC thin-film Fabry-Pe/spl acute/rot interferometers showed one-way phase shifts in resonant minima on all measured samples. Linear fits to the resonant minima (at 660 to 710 nm) versus temperature provide the corresponding thermal expansion coefficient, /spl kappa//sub /spl phi//, of 1.7-1.9/spl times/10/sup -5///spl deg/C. With the optimized 3MS flow rate, the SiC temperature sensor exhibits a temperature accuracy of /spl plusmn/2.8/spl deg/C from 22 to 540/spl deg/C. The short-term SiC sensor stability at 532/spl deg/C for two weeks shows a very small standard deviation of 0.97/spl deg/C.     

Baseline levels of Hsp 70, a stress protein and biomarker, in halibut from the Cook Inlet region of Alaska

The levels of Hsp 70, a heat shock protein, was quantitatively determined in Pacific halibut, Hippoglossus stenolepis, from the Cook Inlet region in south central Alaska. A dot blot analysis using a monoclonal antibody for Hsp 70 was combined with a standard protein analysis to determine Hsp 70 levels in 26 samples from gills. The average Hsp 70 concentration was 4.6 micrograms/mg, with levels ranging from 2.2 to 14.5 micrograms/mg total protein. Mercury in gill tissue also was measured and, in the 26 samples, only three samples had concentrations of mercury (X = 0.10 mg/kg, range = 0.09-0.11) above the minimum detection level.     

Beyond fast mapping: Young children's extensions of novel words and novel facts.

L. Markson and P. Bloom (1997) concluded that there was evidence against a dedicated system for word learning on the basis of their finding that children remembered a novel word and a novel fact equally well. However, a word-learning system involves more than recognition memory; it must also provide a means to guide the extension of words to additional exemplars, and words and facts may differ with regard to extendibility. Two studies are reported in which 2–4-year-old children learned novel words and novel facts for unfamiliar objects and then were asked to extend the words and facts to additional exemplars of the training objects. In both studies, children extended the novel word to significantly more category members than they extended the novel fact. The results show that by 2 years of age, children honor the necessary extendibility of novel count nouns but are uncertain about the extendibility of arbitrary facts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

SiC thin-film Fabry-Perot interferometer for fiber-optic temperature sensor

Polycrystalline SiC grown on single-crystal sapphire substrates have been investigated as thin-film Fabry-Perot interferometers for fiber-optic temperature measurements in harsh temperatures. SiC-based temperature sensors are compact in size, robust, and stable at high temperatures, making them one of the best choices for high temperature applications. SiC films with thickness of about 0.5-2.0 /spl mu/m were grown at 1100/spl deg/C by chemical vapor deposition (CVD) with trimethylsilane. The effect of operating temperature on the shifts in resonance minima, /spl Delta//spl lambda//sub m/, of the SiC/sapphire substrate has been measured in the visible-infrared wavelength range. A temperature sensitivity of 1.9/spl times/10/sup -5///spl deg/C is calculated using the minimum at /spl sim/700 nm. Using a white, broadband light source, a temperature accuracy of /spl plusmn/3.5/spl deg/C is obtained over the temperature range of 22/spl deg/C to 540/spl deg/C.