نتایج جستجو برای: cesium ion
تعداد نتایج: 209601 فیلتر نتایج به سال:
We have studied the block of potassium channels in voltage-clamped squid giant axons by nine organic and alkali cations, in order to learn how the channel selects among entering ions. When added to the internal solution, all of the ions blocked the channels, with inside-positive voltages enhancing the block. Cesium blocked the channels from the outside as well, with inside-negative voltages fav...
We found that bacteria in a commercial soil conditioner sold in Ishinomaki, Miyagi, exhibited concentrative and saturable cesium ion (Cs(+)) uptake in the natural range of pH and temperature. The concentration of intracellular Cs(+) could be condensed at least a few times higher compared with the outside medium of the cells. This uptake appeared to be mediated by a K(+) transport system, since ...
A simple design for a cesium sputter ion source compatible with vacuum and ion-optical systems as well as with electronics of the commercially available Cameca IMS-4f instrument is reported. This ion source has been tested with the cluster primary ions of Si(n)(-) and Cu(n)(-). Our experiments with surface characterization and depth profiling conducted to date demonstrate improvements of the an...
Isolated and cleaned giant axons of Loligo pealii were internally perfused with solutions containing cesium sulfate and potassium fluoride. Membrane currents obtained as a function of clamped membrane potentials indicated a severe depression of the delayed outward current component normally attributed to potassium ion movement. Steady-state currents showed a negative slope in the potential rang...
qppg. 1961. -The permeability of the squid axon membrane to choline, guanidine, thiourea, urea, sucrose, starch, and cesium was investigated by use of radiotracers. In the resting state, the time constant for the loss of intracellular radioactive (free) choline, guanidine, and cesium was of the same order of magnitude as that for labeled sodium or potassium ions. Choline ion was found to bind r...
A theory for fast modulation effects in cesium frequency s tandards has been developed and expressions derived for frequency offsets pxodtlced by Rabi and cavit,y pulling wi th square-wave phase modulation. These are compared wi th equivalent expressions for sine-wave phase modulation. Ratios of the amplitudes of the fseqnerlcy offsets in t h e two modulation schemes a re calculated for a ruoxl...
For the past 50 years, atomic standards based on the frequency of the cesium ground-state hyperfine transition have been the most accurate time pieces in the world. We now report a comparison between the cesium fountain standard NIST-F1, which has been evaluated with an inaccuracy of about 4 x 10(-16), and an optical frequency standard based on an ultraviolet transition in a single, laser-coole...
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