In this paper, lead chalcogenide based thermoelectric nanolaminate structures were fabricated by alternately depositing PbTe and PbSe ALD layers on regular planar silicon wafers and on microporous silicon templates. Lead bis(2,2,6,6-tetramethyl-3,5-heptanedionato) (Pb (C 11 H 19 O 2 ) 2 ), plus (trimethylsilyl) telluride ((Me 3 Si) 2 Te) and (trimethylsilyl) selenide ((Me 3 Si) 2 Se) were used as the chemical ALD precursors for lead, tellurium and selenium, respectively. The Seebeck coefficient in horizontal direction (parallel direction to the surface) to the multiple layered PbTe/PbSe nanolaminate structures was measured by an MMR Seebeck system, and benchmarked against the Seebeck coefficient in the vertical direction to the sample surface. The results of the Seebeck measurements clearly indicate that the multiple layered PbTe/PbSe nanolaminate structures synthesized by ALD on microporous silicon templates exhibit significantly increased Seebeck coefficients in both horizontal and vertical directions, in stark contrast to the case when the same ALD thermoelectric nanolaminates are grown on regular planar bulk Si substrates. As a green renewable technology, thermoelectrics (TE) can play an important role in recovering energy from waste heat due to its potential in converting heat into electricity, and consequently this effect could be applied in TE power generators or TE refrigerators. The challenge for current state-of-the-art TE devices is the low conversion efficiency. The efficiency of a thermoelectric device is expressed as:where T C and T H indicates the temperature of the cold and hot side. The conversion efficiency η is determined by the dimensionless thermoelectric figure of merit ZT,where S is the Seebeck coefficient, σ is the electrical conductivity, T is the temperature in Kelvin, κ e is the thermal conductivity due to electrons, and κ L is lattice thermal conductivity due to phonons. 1 Figure 1 shows the simulation result for the dependence of the conversion efficiency η on ZT and temperature difference. This graph demonstrates a clear trend: the higher the figure of merit ZT, the higher the conversion efficiency η would be. For current state-of-the-art TE devices, the figure of merit ZT value is usually around one, which translates into a conversion efficiency that is usually no higher than 5%. For large-scale practical applications, it is critical to synthesize better TE materials with a figure of merit ZT higher than 2 in order to promote attractive conversion efficiencies for TE devices. Much of the previous work demonstrated that alloying can be used to decrease the lattice thermal conductivity and thus to increase ZT due to mass difference enhanced phonon scattering.2 In order to further progress in the development and commercialization of the next generation of thermoelectric devices it is necessary to enhance significantly the figure of merit ZT value. Most recently novel innovative research approaches focused on low dimensional nanostructures, 3 including quantum wells, 4 quantum dots, 5...

Some more electric aircraft concepts require soft magnetic FeCo materials to be stable at temperatures as high as 773 K for long periods of time. At this high operating temperature, aging related processes may occur that result in changes in material properties. The material supplier typically specifies only room-temperature properties, and only limited reports are available on properties at elevated temperatures. The change in properties as a function of time at 773 K will give information on the lifetime of the material to assist designers when selecting materials for high-temperature applications. We have conducted a study on the effects of long-term aging on the magnetic, mechanical, and electrical properties of Hiperco® 27, Hiperco® 50, and Hiperco® 50 HS FeCo soft magnetic alloys. Samples of each material were aged in argon for 100, 1000, 2000, and 5000 h at 773 K. Here, we report the changes in electrical resistivity after aging. Of the three alloys, high-temperature aging has the greatest effect on the resistivity of Hiperco® 50. The electrical resistivities for each sample are compared and conclusions are drawn on the relative thermal stability of each alloy. The changes in electrical resistivities for each alloy are also related to changes in other properties, such as total power loss and coercivity, that were observed during this study on aging.

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Electrical properties of electrostatic self-assembled (ESA) films were investigated using a conductive polymer and metal bar. These nanostructured polymeric films were fabricated on gold-coated glass slides using the ESA method. The thicknesses of the films were in the range 120-630 nm, and the films were obtained by depositing numbers of bilayers of negatively charged Poly s-119 (PS-119) or heparin and positively charged Poly(diallyldimethylammonium chloride) (PDDA). Measurement electrodes were fabricated on the ESA films using conductive silver grease and a brass bar. Capacitance measurements were conducted to determine the dielectric constant of the ESA films over various temperature and frequency ranges at 1 mV and 15% relative humidity, while electric field breakdown tests were performed at 1000 Hz, 15% relative humidity and varying temperatures and voltages. The test results showed that dielectric constant values were between 1.8 and 2.4 and breakdown field values were approximately 9 kV mm −1 . Based on the test results, it is concluded that this is a technique that might prove useful in estimating the capacitance, dielectric constant and breakdown field values of nanostructured ESA films.

A cost-effective optical cancer screening and monitoring technique was demonstrated in a pilot study of canine serum samples and was patented for commercialization. Compared to conventional blood chemistry analysis methods, more accurate estimations of the concentrations of albumin, globulins, and hemoglobin in serum were obtained by fitting the near UV absorbance and photoluminescence spectra of diluted serum as a linear combination of component reference spectra. Tracking these serum proteins over the course of treatment helped to monitor patient immune response to carcinoma and therapy. For cancer screening, 70% of dogs with clinical presentation of cancer displayed suppressed serum hemoglobin levels (below 20 mg͞dL) in combination with atypical serum protein compositions, that is, albumin levels outside of a safe range (from 4 to 8 g͞dL) and globulin levels above or below a more normal range (from 1.7 to 3.7 g͞dL). Of the dogs that met these criteria, only 20% were given a false positive label by this cancer screening test.