Einfluß des Phosphors auf die Korrosionsgeschwindigkeit weicher,unlegierter Stähle in verdünnter Schwefelsäure

Einfluß von Phosphor auf den zeitlichen Verlauf der Korrosionsgeschwindigkeit am Ruhepotential beim Beizen in verdünnter Schwefelsäure. Unstetigkeit der Stromdichte-Potential-Kurve bei Stählen mit hohen Phosphorgehalten durch Deckschichtbildung. Untersuchungen zum Aufbau und zur chemischen Zusammensetzung der Deckschicht.     

Monolithic demodulator for 40-gb/s DQPSK using a star coupler

A novel device that demodulates both quadratures of the optical differential quadrature phase-shift keying (DQPSK) format in a single interferometer by using a 4 /spl times/ 4 star coupler was demonstrated. Simultaneous measurements of both DQPSK quadratures at 42.7 Gb/s are also presented.     

One-third terabit/s transmission through 150 km ofdispersion-managed fiber

340 Gb/s (seventeen 20-Gb/s 2³¹-1 PRBS NRZ channels) were transmitted through 150 km of fiber with 50 km amplifier spacing. Chromatic dispersion penalties and four-photon mixing effects were minimized by dispersion management     

Buried stacked insulator: new SOI-structure formed by ion beam synthesis

The formation of a new SOI-structure is proposed and the first experimental results are presented. Using high dose implantation of nitrogen and oxygen, a buried stacked layer consisting of silicon dioxide (upper part), silicon oxynitride (medium part) and silicon nitride (lower part) was formed in single crystalline silicon.<>     

Origin of nondisjunction in trisomy 8 and trisomy 8 mosaicism

OBJECTIVES: This study explores reactions to low-level chemical challenge, aiming at the development of test procedures for assessing individual sensitivity to smells and chemicals. METHODS: Subjects with symptoms and neuropsychological test results compatible with toxic encephalopathy type 2A (TE-2A) and 2B (TE-2B) and unexposed referents (N=12 in each group) were challenged in an exposure chamber. Toluene exposure was started at 11 mg/m3, and it followed a geometric progression scale with a ratio of 2, until reaching 180 mg/m3. In a counterbalanced design, the subjects were similarly exposed to n-butyl acetate starting at a concentration of 14 mg/m3 and increasing to 228 mg/m3. At each exposure level, smell intensity was measured on a 7-step category scale. Mucous membrane irritation and annoyance reactions were rated on visual analogue scales. RESULTS: Both TE groups showed high sensitivity to the low-level solvent challenge, which provoked immediate annoyance and fatigue reactions. In particular the TE-2B group related smell intensity to various annoyance dimensions during exposure to n-butyl acetate, a pattern not observed during toluene exposure. The reference group clearly separated smell intensity and annoyance reactions in both exposure conditions. CONCLUSIONS: The reaction of the TE cases suggests that chemical sensitivity can be distinguished from normal annoyance reactions by the inability to differentiate between smell intensity and an experience of irritation from mucous membranes in air concentrations well below the trigeminal irritation threshold level. Fatigue coreactivity in challenges to single substances below the neurotoxic level may also be important.     

Clinical relevance of lithium determination in RBC: results of a catamnestic study (author's transl)]

In 34 out-patients Li+- and K+-concentrations were determined in plasma and RBC during 15 months of clinical routine observations. Average frequency of check-ups was 9/patient. Psychopathological state and side effects were documented by the AMP-system. The mean intra-extracellular lithium concentration ratio (LiQ) was 34%. The ratio and the absolute lithium RBC concentration showed a wide intraindividual variability between 5 and 53%. Patients under 50 years old had the same absolute concentration values as the older ones but required a 50% higher average dose. Side effects such as tremor and thirst correlated well the intra-extracellular ratio. No difference was found between unipolar and bipolar depressions. LiQ was slightly reduced and KQ increased in patients with severe relapses or additional psychotropic medication.     

The role of microstructure in hydrogen-assisted fracture of 7075 aluminum

Underaged, peak strength (T6), and overaged (T73) microstructures were studied in 7075 plate material. Hydrogen charged and uncharged tensile specimens of longitudinal orientation were tested between −196°C and room temperature. The results confirm a hydrogen embrittlement effect, manifested mainly in the temperature dependence of the reduction of area loss; a classical behavior of hydrogen embrittlement. The maximum embrittlement shifted to lower temperatures with further aging. The effect of hydrogen was largest for the underaged condition and smallest for the overaged, thus following the pattern found for the sensitivity to stress-corrosion cracking in high strength aluminum alloys. The fracture path was predominantly transgranular, with minor amounts of intergranular fracture. J. ALBRECHT, formerly with the Department of Metallurgy and Materials Science, Carnegie-Mellon University     

The detection of sodium vapor bubble collapse in a liquid metal fast breeder reactor

Sodium boiling detection utilizing the sound pressure emanated during the collapse of a sodium vapor bubble in a subcooled media is discussed in terms of the sound characteristic, the reactor ambient noise background, transmission loss considerations and performance criteria. Data obtained in several loss of flow experiments on Fast Test Reactor Fuel Elements indicate that the collapse of the sodium vapor bubble depends on the presence of a subcooled structure or sodium. The collapse pressure pulse was observed in all cases to be on the order of a kPa, indicating a soft type of cavitational collapse. Spectral examination of the pulses indicates the response function of the test structure and geometry is important. The sodium boiling observed in these experiments was observed to occur at a low (<50°C) liquid superheat with the rate of occurrence of sodium vapor bubble collapse in the 3 to 30 Hz range. Reactor ambient noise data were found to be due to machinery induced vibrations, flow induced vibrations, and flow noise. These data were further found to be weakly stationary enhancing the possibility of acoustic surveillance of an operating Liquid Metal Fast Breeder Reactor. Based on these noise characteristics and extrapolating the noise measurements from the Fast Flux Test Facility Pump (FFTP), one would expect a signal to noise ratio of up to 20 dB in the absence of transmission loss. The requirement of a low false alarm probability is shown to necessitate post detection analysis of the collapse event sequence and the cross correlation with the second derivative of the neutronic boiling detection signal. Sodium boiling detection using the sounds emitted during sodium vapor bubble collapse are shown to be feasible but a need for in-reactor demonstration is necessary.