Structure and strength properties of brazed joints of JS26NK cast nickel alloy. Part 2

Materials science problems of formation of brazed joints in the JS26NK cast nickel alloy are considered. Physical-chemical properties of brazed joints, produced with application of standard boron-containing brazing alloy and brazing alloy containing silicon as second depressant, and different binders are presented. It is shown that application of a binder in the form of solution of acrylic acid in acetone is efficient in case of application of complex brazing alloys containing 20 % of the Ni--12 % Si (NS12) commercial brazing alloy powder. Achieved at room temperature strength and fracture toughness of a brazed joint from the JS26NK alloy exceed similar characteristics of the JS26VI alloy. Connection of mechanical properties of brazed joints with direction of dendrite growth in the metal being brazed is shown.Рассмотрены материаловедческие особенности формирования паяных соединений в литейном никелевом сплаве ЖС26НК. Приведены физико-механические свойства паяных соединений, полученных с использованием стандартного бор- и кремнийсодержащего припоя и припоя, имеющего в качестве второго депрессанта кремний, а также различных связующих. Показано, что использование связующего в виде раствора акриловой кислоты в ацетоне является эффективным в случае применения комплексных припоев, содержащих 20 % порошка промышленного припоя Ni-12 % Si (НС12). Достигнутые при комнатной температуре прочность и вязкость разрушения паяного соединения из сплава ЖС26НК превышают аналогичные характеристики сплава ЖС26ВИ. Показана связь механических свойств паяных соединений с направлением преимущественного роста дендритов в паяемом металле

Covert Waking Brain Activity Reveals Instantaneous Sleep Depth

The neural correlates of the wake-sleep continuum remain incompletely understood, limiting the development of adaptive drug delivery systems for promoting sleep maintenance. The most useful measure for resolving early positions along this continuum is the alpha oscillation, an 8–13 Hz electroencephalographic rhythm prominent over posterior scalp locations. The brain activation signature of wakefulness, alpha expression discloses immediate levels of alertness and dissipates in concert with fading awareness as sleep begins. This brain activity pattern, however, is largely ignored once sleep begins. Here we show that the intensity of spectral power in the alpha band actually continues to disclose instantaneous responsiveness to noise—a measure of sleep depth—throughout a night of sleep. By systematically challenging sleep with realistic and varied acoustic disruption, we found that sleepers exhibited markedly greater sensitivity to sounds during moments of elevated alpha expression. This result demonstrates that alpha power is not a binary marker of the transition between sleep and wakefulness, but carries rich information about immediate sleep stability. Further, it shows that an empirical and ecologically relevant form of sleep depth is revealed in real-time by EEG spectral content in the alpha band, a measure that affords prediction on the order of minutes. This signal, which transcends the boundaries of classical sleep stages, could potentially be used for real-time feedback to novel, adaptive drug delivery systems for inducing sleep

Flocculation of influenza virus by specific anti-neuraminidase antibody

1. Flocculation of purified preparations of influenza virus has been demonstrated to occur in the presence of low dilutions of specific anti-neuraminidase sera. High dilutions of the sera caused microscopic aggregation of virions. It is suggested that the effects of anti-neuraminidase antibody on the replication of influenza virus observed in vitro could be caused by antibody binding virions to infected cells, rather than by inhibition of neuraminidase enzymic activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41680/1/705_2005_Article_BF01253756.pd

On skewness and kurtosis in multivariate analysis

SIGLEAvailable from British Library Document Supply Centre- DSC:D38231/81 / BLDSC - British Library Document Supply CentreGBUnited Kingdo