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Semiconducting organometallic films such as copper tetracyanoquinodimethane (CuTCNQ) have been observed to switch between two stable states when exposed to optical radiation. Observations of switching between two states in these films have been made by Raman spectroscopic methods and direct observation of electrical resistance changes. Line or pattern generation is observed for exposure above certain threshold levels. These effects are observed in a wide range of Cu and Ag organometallic compounds.

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mi of the concept of aromaticity, which is itself somewhat an artifact of inadequate structural description, suggest that such designations are not presently justifiable.Consideration of tropone as formally related to benzene by carbonyl insertion of 2-and 4-pyrone as similarly related to furan shows that insertion of a carbonyl group into these aromatic rings drastically suppresses the contribution of nonlocal effects to the molecular magnetic susceptibility.Extrapolation of these results beyond the present studies raises the questions of whether formal carbonyl insertion into other aromatic compounds will lead to a large suppression of aromatic character as judged by magnetic criteria and whether this suppression will be manifest in other criteria of aromatic character. Qualitative correlation between the magnetic, thermodynamic, spectroscopic, and calculational criteria of aromatic character is usually observed, but the interrelationships are sufficiently vague that it is not clear to what extent the present demonstration of a low degree of aromatic character for 1, 2, and 3 by magnetic criteria should be reflected in other criteria. For example, in considering the relationship between a suggested nmr-based quantitative criterion for aromaticity and the thermodynamic criterion for aromaticity, it was shown that in a thermo-dynamic comparison of the stabilization energy of Nmethyl-2-pyridone with 2-methoxypyridine the latter was found to be favored by only about 6 kcal/mol, while the nmr criterion suggested a much greater difference.2425 This lack of agreement could reflect failure (24) P.

After hafnium carbide has been oxidized at temperatures in the range of 1400" to 2060°C, three distinct layers are present in the film cross section: (a) a residual carbide layer with dissolved oxygen in the lattice, (b) a dense-appearing oxide interlayer containing carbon, and (c) a porous outer layer of hafnium oxide. Experimental measurements of layer thicknesses and oxygen concentrations are combined with an extended formulation of moving-boundary diffusion theory to obtain the diffusion constants of oxygen in each of the three layers. The results indicate that the oxide interlayer is a better diffusion barrier for oxygen than either of the other layers. Based on X-ray microanalysis, X-ray diffraction, and resistance measurements, the interlayer is an oxygendeficient oxide of hafnium with a carbon impurity. The interlayer hardness equals that of the residual carbide layer.

Abstract-Every surgical item used during surgery (e.g., sponges) must be accounted for after surgery to ensure that none of these items is left inside the patient. Despite the numerous precautions in place, in approximately 1 in 1500 cases, something gets left behind inside the patient's body. This paper presents ASSIST, an automated system for surgical instrument and sponge tracking that increases the safety of surgical procedures. ASSIST utilizes RFID (Radio Frequency Identification) technology to aid in accounting for all items used during surgery. The design takes into account safety, simplicity, ease of deployment, and ease of use. An initial evaluation utilizing RFID-tagged sponges demonstrates that ASSIST can reliably track surgical sponges with minimal impact to current operating room procedures. Sources of error that can impact the reliability of the system are also discussed.

This paper contains a preliminary report of the composition of the gases evolved during the pitting corrosion of aluminum in aqueous electrolytes containing respectively KCI, KSCN, or NaNO.. We believe the rather surprising resul~s will bear positively on understanding pitting mechanisms and reactions. First, each electrolyte has a unique set of gases. Second, using a light microscope (I, 2), it was observed in each system that the gas evolution begins when the potential is increased above the pitting potential, E_, and ceases when the potential is decreased b~low ~il E has been determined to be about -0.8 V pBtentials are referred to the saturated calomel electrode) for 1M CI-electrolytes by many investigators (e.g., 3-5). Galvele, et al have published pitting potentials of about 1.46 V and 0.96 V for 1M NaNO 3 and 1M KSCN, respectively (6, 7). Kaesche has observed that gas evolution occurs only above EQ for chloride electrolyte (8). Bargeron and Givens have observed blister formation, which requires gas production at the oxide-metal interface, as a step in the breakdown of the passivating oxide in chloride solutions (I, 2). As will be shown, the gases evolved from the NO~ and SCN-electrolytes can only be expJained by direct reaction of the anion with the metal. These results may also imply that CI-reacts directly with the metal.The aluminum used for observations under the light microscope was 0.25 mm thick discs of purity 99.999 percent. The discs were placed in an electrode holder as described previously (I, 2). For the gas collection, aluminum of purity 99.99 percent was machined into a cylinder about 1 cm high and 1 cm in diameter. Samples were degreased in acetone and pickled briefly in 1N NaOH. The samples used in the gas analysis experiments were screwed onto a Teflon holder which sealed the electrical connections from the electrolyte. Deionized water of resistivity 18 M~-cm and A.C.S. reagents (highest purity available) were used to prepare electrolytes. The electrolytes were deaerated with high purity argon before gas collection. The gas collection apparatus (a glass tube with a bellshaped piece on the end) was evacuated and filled with electrolyte. The evolved gases displaced the electrolyte in the tube, and I-2 cm 3 of gas was collected. Before entering the gas analyzer (VEECO Model SPI-IO), the gases passed through a trap at -50~ (alcohol and dry ice) to remove water. After an experiment the trap was warmed to room temperature, and gases from it were analyzed. Only water was detected from the trap.The sample potential was potentiostatically controlled. The reference electrode was a saturated calomel electrode connected by a bridge of the electrolyte through a Luggin capillary placed about 1 mm from the sample surface (the O.D. of the capillary was also about 1 mm).The mass spectrum of the gas collected from pitting aluminum at a potential of 1.5 V in 1M KCI is shown in Figure la. The spectrum shows the presence of H^ and the deaera-, . Z t tion gas Ar whlch is always present (Ar at m/e = 40 and Ar ++...