Information in the form of sound waves is communicated as functions of frequency, intensity and time. In order to grasp these processes we must employ a three-dimensional representation. In a piece ...of orchestral music we regard the concerted playing and its changes from pianissimo to fortissimo as a pleasing sensation. The cumulative effect of machine and industrial noise, which may coincide with that of a piece of music, is found to be un-pleasant, annoying and damaging. The preceding papers have considered the damaging effects of noise which lead to deafness. The importance of frequency and its representation by the A weighted network and by limit curves, e.g. n.r. curves has also been treated.
The reception of a self-synchronized cathode ray television image in an airplane demonstrated this type of television under conditions of far greater rigor than are to be met in practice. Employing ...the ultra-high frequency of 44,500 kilocycles, or 6 3/4 meters, images were received from the Don Lee television station W6XAO while traveling at the speed of 120 miles per hour above the city of Los Angeles. Continuous variation of signal strength was observed, occasioned by changing shadows cast by the plane on its antenna, changing pick-up of the polarized wave because of variation of the receiver antenna angle with respect to the oncoming wave, and change of absolute field strength because of the speed of travel through the transmitter field strength pattern.
Vacuum-Tube Voltmeter Design Lubcke, H.R.
Proceedings of the Institute of Radio Engineers
17, Številka:
5
Journal Article
It is shown that for every input range and meter a set of optimum conditions exist, which insure maximum readability, economy, and minimum operating current. Equations are developed (and illustrated ...with several examples) for the rapid design of a meter for a predetermined range. Optimum conditions are imposed. The dependence of the range secured upon plate circuit impedance is shown and its variation with frequency explained. The procedure for eliminating frequency error up to and including radio frequencies is illustrated.
The transport of Na+, K+, Cl-, and HCO3(-) across the epithelium of the rat submaxillary salivary duct is postulated to be due to the coupling of the basolateral Na+-K+-ATPase with various ion ...transport systems in the luminal and basolateral membranes. Na+ reabsorption depends on the presence of a rheogenic (Na+ conductance) and an electroneutral (Na+:H exchange) pathway, both of which are sensitive to amiloride. K+ secretion is postulated to be mediated by a K+: H+ antiport, coupling between Na+ reabsorption and K+ secretion, thus depending on local H+ ion concentration. The ratio between electroneutral Na+ influx and K+ efflux, therefore, determines the rate of HCO3(-) secretion. In the absence of Na+ influx, although K+ efflux falls, HCO3(-) secretion rises to a value equal to that of K+ secretion. The maintenance of K+ secretion in the absence of luminal Na+ requires an additional Na+-entry step across the basolateral membrane, also postulated to be due to Na+:H+ exchange.
From L sub 3 absorption measurement, information on the valence and size of small matrix-isolated Sm clusters is obtained by analyzing the X-ray-absorption near-edge structure and the extended ...X-ray-absorption fine structure (EXAFS). Depending on the mean cluster size, which is a function of the atomic concentration (Sm to rare-gas atom ratio), every valence between 2.0-3.0 is reproducibly achievable. At very low Sm concentrations the samples have the atomic valence; at a critical concentration c approx 1:100 a steep rise of the valence up to upsilon = 2.6 is found. Then, with increasing metal concentration, the Sm-cluster valence approaches the valence of the solid. From EXAFS analysis, a mean cluster size of 13 atoms for clusters with upsilon = 2.6 follows. The mixed valence of the Sm atoms is explained by the pressure exerted on the Sm cluster by the distorted rare-gas lattice (the rare gas is Ne, Ar, or Kr). 37 ref.--AA
The L sub III absorption thresholds of Pr, Nd, and Sm clusters isolated in solid Ar are marked by prominent white lines. The lines ascribed to divalent and trivalent rare-earth metals are well ...separated in energy. From the relative intensities of these lines an average valence of the rare-earth atoms in the cluster has been determined. For dimers and trimers the average valence is close to two, the value for free atoms. For clusters consisting of > 20 atoms the average valence approaches three, the value for bulk metals. In between the valence changes abruptly, indicating the existence of a critical cluster size of approximately five atoms for Pr and Nd and of 13 atoms for Sm. 46 ref.--AA
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