Different Species Of Ions Research Articles

Resistivity Phenomena in Multi-Ion Plasma with Ion Acoustic Turbulence

The effect of different species of ions on the resistivity of a plasma in the presence of ion acoustic turbulence has been studied. Results have been applied to the case of hydrogen-helium plasma mixture. The variation of drift velocity with Te/Ti for quasi stationary fluctuation levels for different percentages of light and heavy ions available in the plasma is also investigated. It is found that the variation is quite significant even for small percentages of light ion contamination.

Telescoping Beams for Heavy Ion Fusion

In addition to the strong longitudinal compression and multiple beams now used in all designs for heavy ion fusion drivers, attaining the required beam power could be helped by telescoping bunches of different ion species. Telescoping is here defined as the overtaking and interpenetration of bunches consisting of ions of different species but whose velocity, mass, and charge state have been selected so that the typical ions in the various bunches have the same ratio of momentum to charge, or magnetic rigidity, and, therefore, the same single particle dynamics in transport and focussing lines. With velocities differing by 10% or more, the highest powers would only arise close to the end of the transport lines. Telescoping also increases the total available phase space of the different species. This can be translated to a smaller final momentum spread or a means to accommodate greater phase space dilution.

Energy dependence of collisionless multiphoton ionization of D2O molecules by a TEA-CO2 laser

Time-resolved ion spectra of the collisionless ionization of D2O was measured. The ionization was energy density dependent with different thresholds for different species of ions.

Amorphization of germanium crystals during ion bombardment

Abstract Germanium single crystal amorphization doses Da , during bombardment with 30 keV ions of different species (5⩽Zi;⩽83)are determined by a high energy electron diffraction method. The experimental dependence of the amorphization dose on ion atomic number is compared with the theoretical one, obtained on the assumption that the amorphous layer is formed as a result of an increase in the number and dimensions of microscopic amorphous zones produced by the bombarding ions. The character changes of the diffraction patterns for the lightest ions with dose differs from that for heavier ions. The temperature dependence of the amorphization dose for phosphorous ion bombardment in the range 10 °C ⩽ T ⩽ 250 °C is measured and compared with existing theories.

Effective Force Constant and Impurity Mode in the Low- and High-Frequency Limits

By employing an effective force constant introduced earlier in the framework of a rigid-ion model for the lattice dynamics we have discussed the asymptotic behavior of the high-frequency localized modes and the low-frequency resonance modes due to substitutional impurities in realistic cubic lattices. Simple expressions for the frequencies of these impurity modes and the linewidths of the resonance modes have been obtained. In the asymptotic description the motion of an impurity may be simulated by an Einstein oscillator which is vibrating in the rest of the host crystal assumed to be static. However, the dynamical correlation of the impurity with the other ions of the host lattice is found to be significant especially in the case of an impurity strongly coupled to the lattice. Numerical calculations have been made for CsI crystals doped with impurity ions of different species in the breathing-shell model. A good agreement between the theoretical and experimental results is observed. The values of the frequencies of the impurity modes and the linewidths of the resonant modes calculated in the asymptotic limits compare well with the experimental values. The discrepancy between the calculated and the experimental values in the majority of cases lie within 20%. In both the low- and high-frequency regions, the value of the effective force constant is seen to be independent of frequency. However, the value of the effective force constant in the high-frequency region is smaller in magnitude than that in the low-frequency region. Further, the value of the effective force constant does not depend on the kind of the ion in a unit cell in ionic crystal, i.e., the value is found to be practically the same whether we consider a positively charged impurity ion or a negatively charged impurity ion. The implication of these results is that one may employ a simple rigid-ion model for a realistic crystal lattice with central interactions for understanding the defect properties of solids in the low- and the very high-frequency regions.

Freezability of Bovine Spermatozoa in Tris-Buffered Yolk Extenders Containing Different Levels of Tris, Sodium, Potassium and Calcium Ions

This study was designed to investigate the effect of different species of ions and osmotic pressure on survival of bull spermatozoa during freezing to − 196 C. Replacing 20 to 80% of the Tris-buffered 20% yolk extender with isosmotic NaCl, KCl, or CaCl2 solutions was found to be harmful. Potassium was more harmful than Na or Ca at the highest level of replacement. When either 10 or 20% by volume of a 0.25 m Tris-buffered 1% yolk extender was replaced with isosmotic Na and K chloride and citrate salt solutions, survival of spermatozoa during freezing was not affected. Replacement of 50% or more of the Na citrate with K citrate in 1 and 20% yolk-citrate extenders reduced sperm cell survival before and after freezing. These results indicate that the optimum levels of Na and K in extenders for freezing spermatozoa are less than the normal intracellular concentrations of these ions.Osmotic pressure of a 0.25 m Tris-buffered 20% egg yolk extender (freezing point depression, 0.55C) was increased by adding NaCl, KC1, and CaCl2 singly and in all combinations. As the osmotic pressure increased, motility of the spermatozoa after freezing declined in a linear manner, regardless of the tonicity contributed by each cation.

The mode of the change in internal potassium of the frog sartorius muscle produced by the change in external potassium or calcium ion concentration.

Using isolated frog sartorius muscles, tracer experiments and chemical analysis for K+ and Na+ were performed to evaluate the mode that the removal of external K+ or Ca++ affects on the change in internal K concentration.1. During the continuous depolarization of the muscle membrane, K42 efflux was increased continuously while Ca45 efflux was increased transiently. Although the changes in K or Ca efflux showed a parallelism with the change in membrane potential it is reasonable to suppose that the vacancy of the Ca++ or K+ sites of the membrane due to the withdrawal of external Ca++ or K+ is the first step of the change in internal K under these conditions.2. The exchange between ions of the same species takes place, at the membrane, more preferentially than the interchange between an ion and ions of different species. The K+-K+ exchange in Ringer is not qualitatively different from the K+-Na+ interchange in K free Ringer, because these two processes are capable of translating from each other by the condition which is determined by the ionic composition on both sides of the membrane.3. By repetitive stimulation, Na increase within the muscle occurred at the cost of K release in Ringer. This efflux of K+ is different in nature from the net efflux of K+ in K free Ringer. Accordingly, the K ions movable outwards are the adjuster for maintaining the constancy of internal milieu.4. The influence of the removal of external K+ or Ca++ upon the internal K loss takes place by different means. Detail of each process has been interpreted by the change in the pattern of association/dissociation of K or Ca ions with/from the membrane anionic sites.5. Removal of external K or Ca ions first produces the change in the membrane molecular configuration. Then, external K+ influences upon internal K energetically through homogeneous K pool while Ca+ does informationally through heterogeneous pools of K, Ca or both.

Linear waves in weakly ionized multicomponent plasmas

The dispersion relations developed in a previous paper 1) are used to investigate a weakly ionized plasma, consisting of N different species of ions (being indifferently positively or negatively charged) and N' kinds of neutral particles. An external magnetic field parallel to the wave vector is applied. These assumptions allow the recasting of the dispersion equations into short formulas, yielding resonance frequencies.

Magnetic relaxation studies of low symmetry defects in quenched nickel

Using a sensitive silicon paddle oscillator technique, we measured the internal friction of single-crystalline silicon substrate implanted with As+, Si+, B+, and H+ ions with a dose of ∼1019 m−2. A distinct internal friction peak at about 48 K is observed in all cases. The overall internal friction from 0.4 K to room temperature is also similar for the different species of ions used. The peak shifts to lower temperature at a reduced resonance frequency, characteristic of a thermally activated relaxation. The insensitivity of the peak to the ion species indicates that it is caused by a vacancy-type defect. Isochronal annealing study shows that the peak anneals away at a temperature between 200 and 300 ° C, and that is consistent with divacancy defects. By plasma etching the substrate layer by layer, we have identified that the defects are concentrated at a damaged crystalline layer right underneath the top amorphized layer in the Si+ implanted sample. The exact mechanism that caused the relaxation peak is still not clear, although our quantitative analysis points to an electronic origin.

Conversion of Ion Types in Nitrogen

A single-shutter drift tube, together with a hot-filament-type ion source, was used to investigate the conversion and drift properties of ions in nitrogen. Three different species of ions, namely N+, N2+, and N3+, were detected, and their drift velocities in nitrogen were measured over a range of E/p0 (ratio of electric field strength to pressure) from 10 to 200 V/(cm·mm Hg). N2+ was found to undergo time-rate-controlled conversion to N3+. Theoretical solutions of such a drift transient have been obtained and were compared with experiment. The attachment frequency α was deduced from the transient form, and its dependence on pressure and E/p0 measured. It was found that α∝p02 exp[A (−E/p0) ].

Theory of Protein Solutions. II

The formal theory of the first paper of this series is extended here to include the binding of several different species of ions or molecules on a protein, aggregation in a protein solution, and solutions containing more than one type of protein molecule.