Effects of copper ions on the characteristics of egg white gel induced by strong alkali.

Science.gov (United States)

Shao, Yaoyao; Zhao, Yan; Xu, Mingsheng; Chen, Zhangyi; Wang, Shuzhen; Tu, Yonggang

2017-09-01

This study investigated the effects of copper ions on egg white (EW) gel induced by strong alkali. Changes in gel characteristics were examined through texture profile analysis, scanning electron microscopy (SEM), and chemical methods. The value of gel strength reached its maximum when 0.1% copper ions was added. However, the lowest cohesiveness values were observed at 0.1%. The springiness of gel without copper ions was significantly greater than the gel with copper ions added. SEM results illustrated that the low concentration of copper ions contributes to a dense and uniform gel network, and an open matrix was formed at 0.4%. The free and total sulphhydryl group content in the egg white protein gel significantly decreased with the increased copper. The increase of copper ions left the contents of ionic and hydrogen bonds basically unchanged, hydrophobic interaction presented an increasing trend, and the disulfide bond exhibited a completely opposite change. The change of surface hydrophobicity proved that the main binding force of copper induced gel was hydrophobic interaction. However, copper ions had no effect on the protein component of the gels. Generally, a low level of copper ions facilitates protein-protein association, which is involved in the characteristics of gels. Instead, high ionic strength had a negative effect on gels induced by strong alkali. © 2017 Poultry Science Association Inc.

Relativistic quantum dynamics in strong fields: Photon emission from heavy, few-electron ions

International Nuclear Information System (INIS)

Fritzsche, S.; Stoehlker, T.

2005-03-01

Recent progress in the study of the photon emission from highly-charged heavy ions is reviewed. These investigations show that high-Z ions provide a unique tool for improving the understanding of the electron-electron and electron-photon interaction in the presence of strong fields. Apart from the bound-state transitions, which are accurately described in the framework of quantum electrodynamics, much information has been obtained also from the radiative capture of (quasi-) free electrons by high-Z ions. Many features in the observed spectra hereby confirm the inherently relativistic behavior of even the simplest compound quantum systems in nature. (orig.)

He2+ molecular ion and the He- atomic ion in strong magnetic fields

Science.gov (United States)

Vieyra, J. C. Lopez; Turbiner, A. V.

2017-08-01

We study the question of existence, i.e., stability with respect to dissociation of the spin-quartet permutation- and reflection-symmetric 4(-3) +g (Sz=-3 /2 ,M =-3 ) state of the (α α e e e ) Coulomb system: the He2 + molecular ion, placed in a magnetic field 0 ≤B ≤10 000 a.u. We assume that the α particles are infinitely massive (Born-Oppenheimer approximation of zero order) and adopt the parallel configuration, when the molecular axis and the magnetic field direction coincide, as the optimal configuration. The study of the stability is performed variationally with a physically adequate trial function. To achieve this goal, we explore several helium-containing compounds in strong magnetic fields, in particular; we study the spin-quartet ground state of the He- ion and the ground (spin-triplet) state of the helium atom, both for a magnetic field in 100 ≤B ≤10 000 a.u. The main result is that the He2 + molecular ion in the state 4(-3) +g is stable towards all possible decay modes for magnetic fields B ≳120 a .u . and with the magnetic field increase the ion becomes more tightly bound and compact with a cigar-type form of electronic cloud. At B =1000 a .u . , the dissociation energy of He2 + into He-+α is ˜702 eV and the dissociation energy for the decay channel to He +α +e is ˜729 eV , and both energies are in the energy window for one of the observed absorption features of the isolated neutron star 1E1207.4-5209.

Sequential nonadiabatic excitation of large molecules and ions driven by strong laser fields

International Nuclear Information System (INIS)

Markevitch, Alexei N.; Levis, Robert J.; Romanov, Dmitri A.; Smith, Stanley M.; Schlegel, H. Bernhard; Ivanov, Misha Yu.

2004-01-01

Electronic processes leading to dissociative ionization of polyatomic molecules in strong laser fields are investigated experimentally, theoretically, and numerically. Using time-of-flight ion mass spectroscopy, we study the dependence of fragmentation on laser intensity for a series of related molecules and report regular trends in this dependence on the size, symmetry, and electronic structure of a molecule. Based on these data, we develop a model of dissociative ionization of polyatomic molecules in intense laser fields. The model is built on three elements: (i) nonadiabatic population transfer from the ground electronic state to the excited-state manifold via a doorway (charge-transfer) transition; (ii) exponential enhancement of this transition by collective dynamic polarization of all electrons, and (iii) sequential energy deposition in both neutral molecules and resulting molecular ions. The sequential nonadiabatic excitation is accelerated by a counterintuitive increase of a large molecule's polarizability following its ionization. The generic theory of sequential nonadiabatic excitation forms a basis for quantitative description of various nonlinear processes in polyatomic molecules and ions in strong laser fields

Metabolic Acidosis and Strong Ion Gap in Critically Ill Patients with Acute Kidney Injury

Directory of Open Access Journals (Sweden)

Cai-Mei Zheng

2014-01-01

Full Text Available Purpose. To determine the influence of physicochemical parameters on survival in metabolic acidosis (MA and acute kidney injury (AKI patients. Materials and Methods. Seventy-eight MA patients were collected and assigned to AKI or non-AKI group. We analyzed the physiochemical parameters on survival at 24 h, 72 h, 1 week, 1 month, and 3 months after AKI. Results. Mortality rate was higher in the AKI group. AKI group had higher anion gap (AG, strong ion gap (SIG, and apparent strong ion difference (SIDa values than non-AKI group. SIG value was higher in the AKI survivors than nonsurvivors and this value was correlated serum creatinine, phosphate, albumin, and chloride levels. SIG and serum albumin are negatively correlated with Acute Physiology and Chronic Health Evaluation IV scores. AG was associated with mortality at 1 and 3 months post-AKI, whereas SIG value was associated with mortality at 24 h, 72 h, 1 week, 1 month, and 3 months post-AKI. Conclusions. Whether high or low SIG values correlate with mortality in MA patients with AKI depends on its correlation with serum creatinine, chloride, albumin, and phosphate (P levels. AG predicts short-term mortality and SIG value predicts both short- and long-term mortality among MA patients with AKI.

Bifurcation analysis for ion acoustic waves in a strongly coupled plasma including trapped electrons

Science.gov (United States)

El-Labany, S. K.; El-Taibany, W. F.; Atteya, A.

2018-02-01

The nonlinear ion acoustic wave propagation in a strongly coupled plasma composed of ions and trapped electrons has been investigated. The reductive perturbation method is employed to derive a modified Korteweg-de Vries-Burgers (mKdV-Burgers) equation. To solve this equation in case of dissipative system, the tangent hyperbolic method is used, and a shock wave solution is obtained. Numerical investigations show that, the ion acoustic waves are significantly modified by the effect of polarization force, the trapped electrons and the viscosity coefficients. Applying the bifurcation theory to the dynamical system of the derived mKdV-Burgers equation, the phase portraits of the traveling wave solutions of both of dissipative and non-dissipative systems are analyzed. The present results could be helpful for a better understanding of the waves nonlinear propagation in a strongly coupled plasma, which can be produced by photoionizing laser-cooled and trapped electrons [1], and also in neutron stars or white dwarfs interior.

Irradiation effect of different heavy ions and track section on the silkworm Bombyx mori

Energy Technology Data Exchange (ETDEWEB)

Tu Zhenli E-mail: tu514@yahoo.co.jp; Kobayashi, Yasuhiko; Kiguchi, Kenji; Watanabe, Hiroshi

2003-05-01

In order to compare the irradiation effects of different ions, wandering larvae were whole-body exposed or locally irradiated with 50-MeV {sup 4}He{sup 2+}, 220-MeV {sup 12}C{sup 5+}, and 350-MeV {sup 20}Ne{sup 8+} ions, respectively. For the whole-body-exposed individuals, the survival rates at the cocooning, pupation, and emergence stages all decreased as dose increased, and a range-dependent difference was clearly observed. For local irradiation of ovaries, irradiation effects depend very strongly on the projectile range. In the case of local irradiation of dermal cells by different track sections of heavy ions, the closer the target was to the high-LET section of the track, the more pronounced were the radiation effects. These results indicated that by selectively using ion species and adjusting the irradiation depth to the target, heavy-ion radiosurgery on particular tissues or organs of small experimental animals can be performed more accurately.

Irradiation effect of different heavy ions and track section on the silkworm Bombyx mori

International Nuclear Information System (INIS)

Tu Zhenli; Kobayashi, Yasuhiko; Kiguchi, Kenji; Watanabe, Hiroshi

2003-01-01

In order to compare the irradiation effects of different ions, wandering larvae were whole-body exposed or locally irradiated with 50-MeV 4 He 2+ , 220-MeV 12 C 5+ , and 350-MeV 20 Ne 8+ ions, respectively. For the whole-body-exposed individuals, the survival rates at the cocooning, pupation, and emergence stages all decreased as dose increased, and a range-dependent difference was clearly observed. For local irradiation of ovaries, irradiation effects depend very strongly on the projectile range. In the case of local irradiation of dermal cells by different track sections of heavy ions, the closer the target was to the high-LET section of the track, the more pronounced were the radiation effects. These results indicated that by selectively using ion species and adjusting the irradiation depth to the target, heavy-ion radiosurgery on particular tissues or organs of small experimental animals can be performed more accurately

Truncated exponential-rigid-rotor model for strong electron and ion rings

International Nuclear Information System (INIS)

Larrabee, D.A.; Lovelace, R.V.; Fleischmann, H.H.

1979-01-01

A comprehensive study of exponential-rigid-rotor equilibria for strong electron and ion rings indicates the presence of a sizeable percentage of untrapped particles in all equilibria with aspect-ratios R/a approximately <4. Such aspect-ratios are required in fusion-relevant rings. Significant changes in the equilibria are observed when untrapped particles are excluded by the use of a truncated exponential-rigid-rotor distribution function. (author)

Calculation of the total plasma concentration of nonvolatile weak acids and the effective dissociation constant of nonvolatile buffers in plasma for use in the strong ion approach to acid-base balance in cats.

Science.gov (United States)

McCullough, Sheila M; Constable, Peter D

2003-08-01

To determine values for the total concentration of nonvolatile weak acids (Atot) and effective dissociation constant of nonvolatile weak acids (Ka) in plasma of cats. Convenience plasma samples of 5 male and 5 female healthy adult cats. Cats were sedated, and 20 mL of blood was obtained from the jugular vein. Plasma was tonometered at 37 degrees C to systematically vary PCO2 from 8 to 156 mm Hg, thereby altering plasma pH from 6.90 to 7.97. Plasma pH, PCO2, and concentrations of quantitatively important strong cations (Na+, K+, and Ca2+), strong anions (Cl-, lactate), and buffer ions (total protein, albumin, and phosphate) were determined. Strong ion difference was estimated from the measured strong ion concentrations and nonlinear regression used to calculate Atot and Ka from the measured pH and PCO2 and estimated strong ion difference. Mean (+/- SD) values were as follows: Atot = 24.3 +/- 4.6 mmol/L (equivalent to 0.35 mmol/g of protein or 0.76 mmol/g of albumin); Ka = 0.67 +/- 0.40 x 10(-7); and the negative logarithm (base 10) of Ka (pKa) = 7.17. At 37 degrees C, pH of 7.35, and a partial pressure of CO2 (PCO2) of 30 mm Hg, the calculated venous strong ion difference was 30 mEq/L. These results indicate that at a plasma pH of 7.35, a 1 mEq/L decrease in strong ion difference will decrease pH by 0.020, a 1 mm Hg decrease in PCO2 will increase plasma pH by 0.011, and a 1 g/dL decrease in albumin concentration will increase plasma pH by 0.093.

Ion channels versus ion pumps: the principal difference, in principle.

Science.gov (United States)

Gadsby, David C

2009-05-01

The incessant traffic of ions across cell membranes is controlled by two kinds of border guards: ion channels and ion pumps. Open channels let selected ions diffuse rapidly down electrical and concentration gradients, whereas ion pumps labour tirelessly to maintain the gradients by consuming energy to slowly move ions thermodynamically uphill. Because of the diametrically opposed tasks and the divergent speeds of channels and pumps, they have traditionally been viewed as completely different entities, as alike as chalk and cheese. But new structural and mechanistic information about both of these classes of molecular machines challenges this comfortable separation and forces its re-evaluation.

Strong-field physics using lasers and relativistic heavy ions at the high-energy storage ring HESR at FAIR

International Nuclear Information System (INIS)

Kuehl, T; Bagnoud, V; Stoehlker, T; Litvinov, Y; Winters, D F A; Zielbauer, B; Backe, H; Spielmann, Ch; Seres, J; Tünnermann, A; Neumayer, P; Aurand, B; Namba, S; Zhao, H Y

2014-01-01

The HESR high-energy ion storage ring at FAIR will provide unprecedented possibilities for strong-field physics using novel laser sources on relativistic heavy ions. An overview on the planning will be given.

Magnetic field fluctuations analysis for the ion trap implementation of the quantum Rabi model in the deep strong coupling regime

Science.gov (United States)

Puebla, Ricardo; Casanova, Jorge; Plenio, Martin B.

2018-03-01

The dynamics of the quantum Rabi model (QRM) in the deep strong coupling regime is theoretically analyzed in a trapped-ion set-up. Recognizably, the main hallmark of this regime is the emergence of collapses and revivals, whose faithful observation is hindered under realistic magnetic dephasing noise. Here, we discuss how to attain a faithful implementation of the QRM in the deep strong coupling regime which is robust against magnetic field fluctuations and at the same time provides a large tunability of the simulated parameters. This is achieved by combining standing wave laser configuration with continuous dynamical decoupling. In addition, we study the role that amplitude fluctuations play to correctly attain the QRM using the proposed method. In this manner, the present work further supports the suitability of continuous dynamical decoupling techniques in trapped-ion settings to faithfully realize different interacting dynamics.

Exchange interaction of strongly anisotropic tripodal erbium single-ion magnets with metallic surfaces

DEFF Research Database (Denmark)

Dreiser, Jan; Wäckerlin, Christian; Ali, Md. Ehesan

2014-01-01

We present a comprehensive study of Er(trensal) single-ion magnets deposited in ultrahigh vacuum onto metallic surfaces. X-ray photoelectron spectroscopy reveals that the molecular structure is preserved after sublimation, and that the molecules are physisorbed on Au(111) while they are chemisorbed...... on a Ni thin film on Cu(100) single-crystalline surfaces. X-ray magnetic circular dichroism (XMCD) measurements performed on Au(111) samples covered with molecular monolayers held at temperatures down to 4 K suggest that the easy axes of the strongly anisotropic molecules are randomly oriented...... pathways toward optical addressing of surface-deposited single-ion magnets....

The exotic molecular ion H43+ in a strong magnetic field

International Nuclear Information System (INIS)

Olivares P, H.

2006-01-01

Using the variational method, a detailed study of the lowest m = 0, -1 electronic states of the exotic molecular ion H3+ 4 in a strong magnetic field, in the linear symmetric configuration parallel to the direction of the magnetic field is carried out. A extended study of the 1σg ground state (J.C. Lopez and A.Turbiner, Phys. Rev A 62, 022510, 2000) was performed obtaining that the potential energy curve displays a sufficiently deep minimum for finite internuclear distances, indicating the possible existence of the molecular ion H 4 3+ , for magnetic fields of strength B > ∼ 3 x 10 13 G. It is demonstrated that the excited state 1π u , can exist for a magnetic field B = 4.414 x 10 13 G corresponding to the limit of applicability of the non-relativistic theory. (Author)

Correlation potential of a test ion near a strongly charged plate.

Science.gov (United States)

Lu, Bing-Sui; Xing, Xiangjun

2014-03-01

We analytically calculate the correlation potential of a test ion near a strongly charged plate inside a dilute m:-n electrolyte. We do this by calculating the electrostatic Green's function in the presence of a nonlinear background potential, the latter having been obtained using the nonlinear Poisson-Boltzmann theory. We consider the general case where the dielectric constants of the plate and the electrolyte are distinct. The following generic results emerge from our analyses: (1) If the distance to the plate Δz is much larger than a Gouy-Chapman length, the plate surface will behave effectively as an infinitely charged surface, and the dielectric constant of the plate effectively plays no role. (2) If Δz is larger than a Gouy-Chapman length but shorter than a Debye length, the correlation potential can be interpreted in terms of an image charge that is three times larger than the source charge. This behavior is independent of the valences of the ions. (3) The Green's function vanishes inside the plate if the surface charge density is infinitely large; hence the electrostatic potential is constant there. In this respect, a strongly charged plate behaves like a conductor plate. (4) If Δz is smaller than a Gouy-Chapman length, the correlation potential is dominated by the conventional image charge due to the dielectric discontinuity at the interface. (5) If Δz is larger than a Debye length, the leading order behavior of the correlation potential will depend on the valences of the ions in the electrolyte. Furthermore, inside an asymmetric electrolyte, the correlation potential is singly screened, i.e., it undergoes exponential decay with a decay width equal to the Debye length.

Strong coupling between a single nitrogen-vacancy spin and the rotational mode of diamonds levitating in an ion trap

Science.gov (United States)

Delord, T.; Nicolas, L.; Chassagneux, Y.; Hétet, G.

2017-12-01

A scheme for strong coupling between a single atomic spin and the rotational mode of levitating nanoparticles is proposed. The idea is based on spin readout of nitrogen-vacancy centers embedded in aspherical nanodiamonds levitating in an ion trap. We show that the asymmetry of the diamond induces a rotational confinement in the ion trap. Using a weak homogeneous magnetic field and a strong microwave driving we then demonstrate that the spin of the nitrogen-vacancy center can be strongly coupled to the rotational mode of the diamond.

Spin dynamics in relativistic ionization with highly charged ions in super-strong laser fields

International Nuclear Information System (INIS)

Klaiber, Michael; Yakaboylu, Enderalp; Bauke, Heiko; Hatsagortsyan, Karen Z; Müller, Carsten; Paulus, Gerhard G

2014-01-01

Spin dynamics and induced spin effects in above-threshold ionization of hydrogenlike highly charged ions in super-strong laser fields are investigated. Spin-resolved ionization rates in the tunnelling regime are calculated by employing two versions of a relativistic Coulomb-corrected strong-field approximation (SFA). An intuitive simpleman model is developed which explains the derived scaling laws for spin flip and spin asymmetry effects. The intuitive model as well as our ab initio numerical simulations support the analytical results for the spin effects obtained in the dressed SFA where the impact of the laser field on the electron spin evolution in the bound state is taken into account. In contrast, the standard SFA is shown to fail in reproducing spin effects in ionization even at a qualitative level. The anticipated spin-effects are expected to be measurable with modern laser techniques combined with an ion storage facility. (paper)

Energy deposition of heavy ions in the regime of strong beam-plasma correlations.

Science.gov (United States)

Gericke, D O; Schlanges, M

2003-03-01

The energy loss of highly charged ions in dense plasmas is investigated. The applied model includes strong beam-plasma correlation via a quantum T-matrix treatment of the cross sections. Dynamic screening effects are modeled by using a Debye-like potential with a velocity dependent screening length that guarantees the known low and high beam velocity limits. It is shown that this phenomenological model is in good agreement with simulation data up to very high beam-plasma coupling. An analysis of the stopping process shows considerably longer ranges and a less localized energy deposition if strong coupling is treated properly.

EISCAT measurements of ion temperatures which indicate non-isotropic ion velocity distributions

International Nuclear Information System (INIS)

Perraut, S.; Brekke, A.; Hubert, D.

1984-01-01

Substantial increases of the ion temperature can be observed at high latitudes as a consequence of strong convection electric fields. We have measured, with EISCAT, three independent components of the ion velocity vector and temperature in the same scattering volume, at about 300 km. During periods of strong variations in ion velocity (consequently of the E-field), the ion temperatures derived at the 3 sites are different. This difference, which appears to be systematic for the two experiments studied, can be interpreted in terms of different ion temperature perpendicular and parallel to the magnetic field, i.e. Tsub(i perpendicular) greater than Tsub(i parallel). Assuming that a bi-Maxwellian distribution is present for convection electric field strengths as large as 50 mV m -1 , one obtains an anisotropy factor of approximately 1.5. It also appears that resonant charge exchange is the dominant collision process. During the evening sector events studied, the electron density was decreasing, whereas the electron temperature was generally increasing. Such events are strongly related to variations in the magnetic H component detected on the ground. (author)

Ion-sound oscillations in strongly non-isotherm weakly ionized nonuniform hydrogen plasma

International Nuclear Information System (INIS)

Leleko, Ya.F.; Stepanov, K.N.

2010-01-01

A stationary distribution of strongly non-isotherm weakly ionized hydrogen plasma parameters is obtained in the hydrodynamic approximation in a quasi neutrality region in the transient layer between the plasma and dielectric taking the ionization, charge exchange, diffusion, viscosity, and a self-consistent field potential distribution. The ion-sound oscillation frequency and the collisional damping decrement as functions of the wave vector in the plasma with the obtained parameters are found in the local approximation.

Quantitative accuracy of the simplified strong ion equation to predict serum pH in dogs.

Science.gov (United States)

Cave, N J; Koo, S T

2015-01-01

Electrochemical approach to the assessment of acid-base states should provide a better mechanistic explanation of the metabolic component than methods that consider only pH and carbon dioxide. Simplified strong ion equation (SSIE), using published dog-specific values, would predict the measured serum pH of diseased dogs. Ten dogs, hospitalized for various reasons. Prospective study of a convenience sample of a consecutive series of dogs admitted to the Massey University Veterinary Teaching Hospital (MUVTH), from which serum biochemistry and blood gas analyses were performed at the same time. Serum pH was calculated (Hcal+) using the SSIE, and published values for the concentration and dissociation constant for the nonvolatile weak acids (Atot and Ka ), and subsequently Hcal+ was compared with the dog's actual pH (Hmeasured+). To determine the source of discordance between Hcal+ and Hmeasured+, the calculations were repeated using a series of substituted values for Atot and Ka . The Hcal+ did not approximate the Hmeasured+ for any dog (P = 0.499, r(2) = 0.068), and was consistently more basic. Substituted values Atot and Ka did not significantly improve the accuracy (r(2) = 0.169 to <0.001). Substituting the effective SID (Atot-[HCO3-]) produced a strong association between Hcal+ and Hmeasured+ (r(2) = 0.977). Using the simplified strong ion equation and the published values for Atot and Ka does not appear to provide a quantitative explanation for the acid-base status of dogs. Efficacy of substituting the effective SID in the simplified strong ion equation suggests the error lies in calculating the SID. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Quantum screening effects on the electron-ion occurrence scattering time advance in strongly coupled semiclassical plasmas

International Nuclear Information System (INIS)

Song, Mi-Young; Jung, Young-Dae

2003-01-01

Quantum screening effects on the occurrence scattering time advance for elastic electron-ion collisions in strongly coupled semiclassical plasmas are investigated using the second-order eikonal analysis. The electron-ion interaction in strongly coupled semiclassical plasmas is obtained by the pseudopotential model taking into account the plasma screening and quantum effects. It is found that the quantum-mechanical effects significantly reduce the occurrence scattering time advance. It is also found that the occurrence scattering time advance increases with increasing Debye length. It is quite interesting to note that the domain of the maximum occurrence time advance is localized for the forward scattering case. The region of the scaled thermal de Broglie wave length (λ-bar) for the maximum occurrence time advance is found to be 0.4≤λ-bar≤1.4

Integrated fiber-mirror ion trap for strong ion-cavity coupling

International Nuclear Information System (INIS)

Brandstätter, B.; Schüppert, K.; Casabone, B.; Friebe, K.; Stute, A.; Northup, T. E.; McClung, A.; Schmidt, P. O.; Deutsch, C.; Reichel, J.; Blatt, R.

2013-01-01

We present and characterize fiber mirrors and a miniaturized ion-trap design developed to integrate a fiber-based Fabry-Perot cavity (FFPC) with a linear Paul trap for use in cavity-QED experiments with trapped ions. Our fiber-mirror fabrication process not only enables the construction of FFPCs with small mode volumes, but also allows us to minimize the influence of the dielectric fiber mirrors on the trapped-ion pseudopotential. We discuss the effect of clipping losses for long FFPCs and the effect of angular and lateral displacements on the coupling efficiencies between cavity and fiber. Optical profilometry allows us to determine the radii of curvature and ellipticities of the fiber mirrors. From finesse measurements, we infer a single-atom cooperativity of up to 12 for FFPCs longer than 200 μm in length; comparison to cavities constructed with reference substrate mirrors produced in the same coating run indicates that our FFPCs have similar scattering losses. We characterize the birefringence of our fiber mirrors, finding that careful fiber-mirror selection enables us to construct FFPCs with degenerate polarization modes. As FFPCs are novel devices, we describe procedures developed for handling, aligning, and cleaning them. We discuss experiments to anneal fiber mirrors and explore the influence of the atmosphere under which annealing occurs on coating losses, finding that annealing under vacuum increases the losses for our reference substrate mirrors. X-ray photoelectron spectroscopy measurements indicate that these losses may be attributable to oxygen depletion in the mirror coating. Special design considerations enable us to introduce a FFPC into a trapped ion setup. Our unique linear Paul trap design provides clearance for such a cavity and is miniaturized to shield trapped ions from the dielectric fiber mirrors. We numerically calculate the trap potential in the absence of fibers. In the experiment additional electrodes can be used to compensate

Blood gas analysis, anion gap, and strong ion difference in horses treated with polyethylene glycol balanced solution (PEG 3350 or enteral and parenteral electrolyte solutions

Directory of Open Access Journals (Sweden)

Cláudio Luís Nina Gomes

2014-06-01

Full Text Available Large volumes of different electrolytes solutions are commonly used for ingesta hydration in horses with large colon impaction, but little is known about their consequences to blood acid-base balance. To evaluate the effects of PEG 3350 or enteral and parenteral electrolyte solutions on the blood gas analysis, anion gap and strong ion difference, five adult female horses were used in a 5x5 latin square design. The animals were divided in five groups and distributed to each of the following treatments: NaCl (0.9% sodium chloride solution; EES (enteral electrolyte solution, EES+LR (EES plus lactated Ringer's solution; PEG (balanced solution with PEG 3350 and PEG+LR (PEG plus lactated Ringer's solution. Treatments PEG or PEG + LR did not change or promoted minimal changes, while the EES caused a slight decrease in pH, but its association with lactated Ringer's solution induced increase in AG and SID values, as well as caused hypernatremia. In turn, the treatment NaCl generated metabolic acidosis. PEG 3350 did not alter the acid-base balance. Despite it's slight acidifying effect, the enteral electrolyte solution (EES did not cause clinically relevant changes.

Realization of collective strong coupling with ion Coulomb crystals in an optical cavity

DEFF Research Database (Denmark)

Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan

2009-01-01

Cavity quantum electrodynamics (CQED) focuses on understanding the interactions between matter and the electromagnetic field in cavities at the quantum level 1, 2 . In the past years, CQED has attracted attention 3, 4, 5, 6, 7, 8, 9 especially owing to its importance for the field of quantum...... information 10 . At present, photons are the best carriers of quantum information between physically separated sites 11, 12 and quantum-information processing using stationary qubits 10 is most promising, with the furthest advances having been made with trapped ions 13, 14, 15 . The implementation of complex...... quantum-information-processing networks 11, 12 hence requires devices to efficiently couple photons and stationary qubits. Here, we present the first CQED experiments demonstrating that the collective strong-coupling regime 2 can be reached in the interaction between a solid in the form of an ion Coulomb...

Strongly \\'etale difference algebras and Babbitt's decomposition

OpenAIRE

Tomašić, Ivan; Wibmer, Michael

2015-01-01

We introduce a class of strongly \\'{e}tale difference algebras, whose role in the study of difference equations is analogous to the role of \\'{e}tale algebras in the study of algebraic equations. We deduce an improved version of Babbitt's decomposition theorem and we present applications to difference algebraic groups and the compatibility problem.

Particle Production in Strong Electromagnetic Fields in Relativistic Heavy-Ion Collisions

Directory of Open Access Journals (Sweden)

Kirill Tuchin

2013-01-01

Full Text Available I review the origin and properties of electromagnetic fields produced in heavy-ion collisions. The field strength immediately after a collision is proportional to the collision energy and reaches ~mπ2 at RHIC and ~10mπ2 at LHC. I demonstrate by explicit analytical calculation that after dropping by about one-two orders of magnitude during the first fm/c of plasma expansion, it freezes out and lasts for as long as quark-gluon plasma lives as a consequence of finite electrical conductivity of the plasma. Magnetic field breaks spherical symmetry in the direction perpendicular to the reaction plane, and therefore all kinetic coefficients are anisotropic. I examine viscosity of QGP and show that magnetic field induces azimuthal anisotropy on plasma flow even in spherically symmetric geometry. Very strong electromagnetic field has an important impact on particle production. I discuss the problem of energy loss and polarization of fast fermions due to synchrotron radiation, consider photon decay induced by magnetic field, elucidate J/ψ dissociation via Lorentz ionization mechanism, and examine electromagnetic radiation by plasma. I conclude that all processes in QGP are affected by strong electromagnetic field and call for experimental investigation.

Influence of strong single-ion anisotropy on phase states of 3D and 2D frustrated magnets

International Nuclear Information System (INIS)

Fridman, Yu.A.; Kosmachev, O.A.; Matunin, D.A.; Gorelikov, G.A.; Klevets, Ph.N.

2010-01-01

We investigated the influence of strong single-ion anisotropy, exceeding exchange interaction, and frustrated exchange interaction on spin-wave excitation spectra and phase states using the Hubbard operators' technique, allowing the exact account of single-ion anisotropy. The results show that both the homogeneous phases (ferromagnetic and quadrupolar) and the spatially inhomogeneous phase (spiral structure) are possible in the 3D magnetic crystal. The region of existence of the spiral structure is considerably smaller than that in the analogues system, but with weak single-ion anisotropy. The situation is more complex in the 2D system; another spatially inhomogeneous state (the domain structure) can be realized in addition to the spiral magnetic structure. The phase diagrams for both the 3D and 2D systems were plotted.

Evidence for strong Breit interaction in dielectronic recombination of highly charged heavy ions.

Science.gov (United States)

Nakamura, Nobuyuki; Kavanagh, Anthony P; Watanabe, Hirofumi; Sakaue, Hiroyuki A; Li, Yueming; Kato, Daiji; Currell, Fred J; Ohtani, Shunsuke

2008-02-22

Resonant strengths have been measured for dielectronic recombination of Li-like iodine, holmium, and bismuth using an electron beam ion trap. By observing the atomic number dependence of the state-resolved resonant strength, clear experimental evidence has been obtained that the importance of the generalized Breit interaction (GBI) effect on dielectronic recombination increases as the atomic number increases. In particular, it has been shown that the GBI effect is exceptionally strong for the recombination through the resonant state [1s2s(2)2p(1/2)](1).

Strong-field non-sequential ionization: The vector momentum distribution of multiply charged Ne ions

International Nuclear Information System (INIS)

Rottke, H.; Trump, C.; Wittmann, M.; Korn, G.; Becker, W.; Hoffmann, K.; Sandner, W.; Moshammer, R.; Feuerstein, B.; Dorn, A.; Schroeter, C.D.; Ullrich, J.; Schmitt, W.

2000-01-01

COLTRIMS (COLd Target Recoil-Ion Momentum Spectroscopy) was used to measure the vector momentum distribution of Ne n+ (n=1,2,3) ions formed in ultrashort (30 fsec) high-intensity (≅10 15 W/cm 2 ) laser pulses with center wavelength at 795 nm. To a high degree of accuracy the length of the Ne n+ ion momentum vector is equal to the length of the total momentum vector of the n photoelectrons released, with both vectors pointing into opposite directions. At a light intensity where non-sequential ionization of the atom dominates the Ne 2+ and Ne 3+ momentum distributions show distinct maxima at 4.0 a.u. and 7.5 a.u. along the polarization axis of the linearly polarized light beam. First, this is a clear signature of non-sequential multiple ionization. Second, it indicates that instantaneous emission of two (or more) electrons at electric field strength maxima of the light wave can be ruled out as main mechanism of non-sequential strong-field multiple ionization. In contrast, this experimental result is in accordance with the kinematical constraints of the 'rescattering model'

Effects of intravenous hyperosmotic sodium bicarbonate on arterial and cerebrospinal fluid acid-base status and cardiovascular function in calves with experimentally induced respiratory and strong ion acidosis.

Science.gov (United States)

Berchtold, Joachim F; Constable, Peter D; Smith, Geoffrey W; Mathur, Sheerin M; Morin, Dawn E; Tranquilli, William J

2005-01-01

The objectives of this study were to determine the effects of hyperosmotic sodium bicarbonate (HSB) administration on arterial and cerebrospinal fluid (CSF) acid-base balance and cardiovascular function in calves with experimentally induced respiratory and strong ion (metabolic) acidosis. Ten healthy male Holstein calves (30-47 kg body weight) were instrumented under halothane anesthesia to permit cardiovascular monitoring and collection of blood samples and CSE Respiratory acidosis was induced by allowing the calves to spontaneously ventilate, and strong ion acidosis was subsequently induced by i.v. administration of L-lactic acid. Calves were then randomly assigned to receive either HSB (8.4% NaHCO3; 5 ml/kg over 5 minutes, i.v.; n=5) or no treatment (controls, n=5) and monitored for 1 hour. Mixed respiratory and strong ion acidosis was accompanied by increased heart rate, cardiac index, mean arterial pressure, cardiac contractility (maximal rate of change of left ventricular pressure), and mean pulmonary artery pressure. Rapid administration of HSB immediately corrected the strong ion acidosis, transiently increased arterial partial pressure of carbon dioxide (P(CO2)), and expanded the plasma volume. The transient increase in arterial P(CO2) did not alter CSF P(CO2) or induce paradoxical CSF acidosis. Compared to untreated control calves, HSB-treated calves had higher cardiac index and contractility and a faster rate of left ventricular relaxation for 1 hour after treatment, indicating that HSB administration improved myocardial systolic function. We conclude that rapid i.v. administration of HSB provided an effective and safe method for treating strong ion acidosis in normovolemic halothane-anesthetized calves with experimentally induced respiratory and strong ion acidosis. Fear of inducing paradoxical CSF acidosis is not a valid reason for withholding HSB administration in calves with mixed respiratory and strong ion acidosis.

Preliminary results of spatially resolved ECR ion beam profile investigations

International Nuclear Information System (INIS)

Panitzsch, L.; Stalder, M.; Wimmer-Schweingruber, R.F.

2012-01-01

The profile of an ion beam produced in an Electron Cyclotron Resonance Ion Source (ECRIS) can vary greatly depending on the source settings and the ion-optical tuning. Strongly focussed ion beams form circular structures (hollow beams) as predicted by simulations and observed in experiments. Each of the rings is predicted to be dominated by ions with same or at least similar m/q-ratios due to ion-optical effects. To check this we performed a series of preliminary investigations to test the required tuning capabilities of our ion source. This includes beam focussing (A) and beam steering (B) using a 3D-movable extraction. Having tuned the source to deliver a beam of strongly focussed ions of different ion species and having steered this beam to match the transmittance area of the sector magnet we also recorded the ion charge state distribution of the strongly focussed beam profile at different, spatially limited positions (C). The preliminary results will be introduced within this paper: it appears that our 3D-movable extraction is very efficient to steer and to focus the beam strongly. The paper is followed by the slides of the presentation. (authors)

Spin Wave Theory of Strongly Anisotropic Magnets

DEFF Research Database (Denmark)

Lindgård, Per-Anker

1977-01-01

A strong anisotropy gives rise to a non-spherical precession of the spins with different amplitudes in the x and y directions. The highly anharmonic exchange interaction thereby becomes effectively anisotropic. The possibility of detecting a genuine two-ion anisotropy is discussed, and comments...

Simulation study on ion extraction from electron cyclotron resonance ion sources

Science.gov (United States)

Fu, S.; Kitagawa, A.; Yamada, S.

1994-04-01

In order to study beam optics of NIRS-ECR ion source used in the HIMAC project, the EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1D and 2D sheath theories are used, respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source are presented in this paper, exhibiting an agreement with the experiment results.

Simulation study on ion extraction from ECR ion sources

International Nuclear Information System (INIS)

Fu, S.; Kitagawa, A.; Yamada, S.

1993-07-01

In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author)

Simulation study on ion extraction from ECR ion sources

Energy Technology Data Exchange (ETDEWEB)

Fu, S.; Kitagawa, A.; Yamada, S.

1993-07-01

In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author).

SOLVENT EFFECTS IN THE LIQUID-PHASE HYDRATION OF CYCLOHEXENE CATALYZED BY A MACROPOROUS STRONG ACID ION-EXCHANGE RESIN

NARCIS (Netherlands)

PANNEMAN, HJ; BEENACKERS, AACM

1992-01-01

The liquid-phase hydration of cyclohexene, a pseudo first order reversible reaction catalyzed by a strong acid ion exchange resin, macroporous Amberlite XE 307, was investigated in solvent mixtures of water and sulfolane. A decrease by a factor of 3 and 6 is observed in the experimentally measured

Heavy ion fusion reactions: comparison among different models

Energy Technology Data Exchange (ETDEWEB)

Canto, L F; Carlson, B V; Hussein, M S

1988-03-01

A comparison among different ion fusion models is presented. In particular, the multistep aspects of the recently proposed Dinucleus Doorway Model are made explicit and the model is confronted with other compound nucleus limitation models. It is suggested that the latter models provide effective one-step descriptions of heavy ion fusion.

Strong out-of-plane magnetic anisotropy in ion irradiated anatase TiO2 thin films

Directory of Open Access Journals (Sweden)

M. Stiller

2016-12-01

Full Text Available The temperature and field dependence of the magnetization of epitaxial, undoped anatase TiO2 thin films on SrTiO3 substrates was investigated. Low-energy ion irradiation was used to modify the surface of the films within a few nanometers, yet with high enough energy to produce oxygen and titanium vacancies. The as-prepared thin film shows ferromagnetism which increases after irradiation with low-energy ions. An optimal and clear magnetic anisotropy was observed after the first irradiation, opposite to the expected form anisotropy. Taking into account the experimental parameters, titanium vacancies as di-Frenkel pairs appear to be responsible for the enhanced ferromagnetism and the strong anisotropy observed in our films. The magnetic impurities concentrations was measured by particle-induced X-ray emission with ppm resolution. They are ruled out as a source of the observed ferromagnetism before and after irradiation.

Air ion concentrations in various urban outdoor environments

Science.gov (United States)

Ling, Xuan; Jayaratne, Rohan; Morawska, Lidia

2010-06-01

Atmospheric ions are produced by many natural and anthropogenic sources and their concentrations vary widely between different environments. There is very little information on their concentrations in different types of urban environments, how they compare across these environments and their dominant sources. In this study, we measured airborne concentrations of small ions, particles and net particle charge at 32 different outdoor sites in and around a major city in Australia and identified the main ion sources. Sites were classified into seven groups as follows: park, woodland, city centre, residential, freeway, power lines and power substation. Generally, parks were situated away from ion sources and represented the urban background value of about 270 ions cm -3. Median concentrations at all other groups were significantly higher than in the parks. We show that motor vehicles and power transmission systems are two major ion sources in urban areas. Power lines and substations constituted strong unipolar sources, while motor vehicle exhaust constituted strong bipolar sources. The small ion concentration in urban residential areas was about 960 cm -3. At sites where ion sources were co-located with particle sources, ion concentrations were inhibited due to the ion-particle attachment process. These results improved our understanding on air ion distribution and its interaction with particles in the urban outdoor environment.

H- ion production from different converter materials

International Nuclear Information System (INIS)

Leung, K.N.; Ehlers, K.W.

1984-10-01

For heating plasmas and for current drive in some fusion reactors, high energy neutral beams may be required. The high neutralization efficiency of H - or D - ions makes them favorable to form neutral atoms with energies in excess of 160 keV. It has been shown that a steady-state H - ion beam with current greater than 1 A can be generated by a surface conversion type source with Mo being used as the converter material. In order to achieve the proper cesium coverage and thereby increasing the H - ion yield, the application of porous cesium-dispensing converters is being investigated. It is also possible to optimize the H - production by choosing the proper converter material. In this paper, we compare the negative ion yield generated by different materials (such as Mo, Ti, V, Nb, Pt, Pd, Rh, Cu, Ta, Al, Au, LaB 6 and stainless-steel) in the pure hydrogen and cesium-hydrogen modes of operation

Laser cooled ion beams and strongly coupled plasmas for precision experiments

International Nuclear Information System (INIS)

Bussmann, Michael

2008-01-01

This cumulative thesis summarizes experimental and theoretical results on cooling of ion beams using single-frequency, single-mode tabletop laser systems. It consists of two parts. One deals with experiments on laser-cooling of ion beams at relativistic energies, the other with simulations of stopping and sympathetic cooling of ions for precision in-trap experiments. In the first part, experimental results are presented on laser-cooling of relativistic C 3+ ion beams at a beam energy of 122 MeV/u, performed at the Experimental Storage Ring (ESR) at GSI. The main results presented in this thesis include the first attainment of longitudinally space-charge dominated relativistic ion beams using pure laser-cooling. The second part lists theoretical results on stopping and sympathetic cooling of ions in a laser-cooled one-component plasma of singly charged 24 Mg ions, which are confined in a three-dimensional harmonic trap potential. (orig.)

Photochemical decomposition of perfluorooctanoic acid mediated by iron in strongly acidic conditions

Energy Technology Data Exchange (ETDEWEB)

Ohno, Masaki, E-mail: mohno@hiroshima-u.ac.jp [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Ito, Masataka; Ohkura, Ryouichi [Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Mino A, Esteban R. [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Kose, Tomohiro [Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Okuda, Tetsuji [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Nakai, Satoshi [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan); Kawata, Kuniaki [Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Nishijima, Wataru [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan)

2014-03-01

Highlights: • Perfluorooctanoic acid (PFOA) was decomposed based on ferric ion performance. • Complete decomposition of PFOA was confirmed in strongly acidic conditions. • Fe{sup 2+} changed to Fe{sup 3+} to restore chemical equilibrium in this condition. • Fe{sup 3+} was only produced from Fe{sup 2+} by hydroxyl radical in weakly acidic conditions. • The Fe{sup 3+} regeneration mechanisms resulted in the performance of Fe{sup 3+} for PFOA. - Abstract: The performance of a ferric ion mediated photochemical process for perfluorooctanoic acid (PFOA) decomposition in strongly acidic conditions of pH 2.0 was evaluated in comparison with those in weakly acidic conditions, pH 3.7 or pH 5.0, based on iron species composition and ferric ion regeneration. Complete decomposition of PFOA under UV irradiation was confirmed at pH 2.0, whereas perfluoroheptanoic acid (PFHpA) and other intermediates were accumulated in weakly acidic conditions. Iron states at each pH were evaluated using a chemical equilibrium model, Visual MINTEQ. The main iron species at pH 2.0 is Fe{sup 3+} ion. Although Fe{sup 3+} ion is consumed and is transformed to Fe{sup 2+} ion by photochemical decomposition of PFOA and its intermediates, the produced Fe{sup 2+} ion will change to Fe{sup 3+} ion to restore chemical equilibrium. Continuous decomposition will occur at pH 2.0. However, half of the iron cannot be dissolved at pH 3.7. The main species of dissolved iron is Fe(OH){sup 2+}. At pH 3.7 or higher pH, Fe{sup 3+} ion will only be produced from the oxidation of Fe{sup 2+} ion by hydroxyl radical produced by Fe(OH){sup 2+} under UV irradiation. These different mechanisms of Fe{sup 3+} regeneration that prevail in strongly and weakly acidic conditions will engender different performances of the ferric ion.

Higher Order QED Contributions to the Atomic Structure at Strong Central Fields

International Nuclear Information System (INIS)

Mokler, P H

2007-01-01

An accurate determination of the precise structure of highly charged, very heavy ions is crucial for understanding QED at strong fields. The experimental advances in the spectroscopy of very heavy, highly charged ions-in particular H-, He- and Li-like species-are reviewed: Presently the ground state Lamb shift for H-like U ions is measured on a 1% level of accuracy; the screening terms in two-electron QED have just been touched by experiments for He-like U; and two-loop QED terms have been determined with ultimate accuracy for Li-like heavy species. The different approaches on QED measurements in strong fields will be discussed and the results compared to theory

Laser cooled ion beams and strongly coupled plasmas for precision experiments

Energy Technology Data Exchange (ETDEWEB)

Bussmann, Michael

2008-03-17

This cumulative thesis summarizes experimental and theoretical results on cooling of ion beams using single-frequency, single-mode tabletop laser systems. It consists of two parts. One deals with experiments on laser-cooling of ion beams at relativistic energies, the other with simulations of stopping and sympathetic cooling of ions for precision in-trap experiments. In the first part, experimental results are presented on laser-cooling of relativistic C{sup 3+} ion beams at a beam energy of 122 MeV/u, performed at the Experimental Storage Ring (ESR) at GSI. The main results presented in this thesis include the first attainment of longitudinally space-charge dominated relativistic ion beams using pure laser-cooling. The second part lists theoretical results on stopping and sympathetic cooling of ions in a laser-cooled one-component plasma of singly charged {sup 24}Mg ions, which are confined in a three-dimensional harmonic trap potential. (orig.)

Strong activation of bile acid-sensitive ion channel (BASIC) by ursodeoxycholic acid

Science.gov (United States)

Wiemuth, Dominik; Sahin, Hacer; Lefèvre, Cathérine M.T.; Wasmuth, Hermann E.; Gründer, Stefan

2013-01-01

Bile acid-sensitive ion channel (BASIC) is a member of the DEG/ENaC gene family of unknown function. Rat BASIC (rBASIC) is inactive at rest. We have recently shown that cholangiocytes, the epithelial cells lining the bile ducts, are the main site of BASIC expression in the liver and identified bile acids, in particular hyo- and chenodeoxycholic acid, as agonists of rBASIC. Moreover, it seems that extracellular divalent cations stabilize the resting state of rBASIC, because removal of extracellular divalent cations opens the channel. In this addendum, we demonstrate that removal of extracellular divalent cations potentiates the activation of rBASIC by bile acids, suggesting an allosteric mechanism. Furthermore, we show that rBASIC is strongly activated by the anticholestatic bile acid ursodeoxycholic acid (UDCA), suggesting that BASIC might mediate part of the therapeutic effects of UDCA. PMID:23064163

Application of the nuclear liquid drop model to a negative hydrogen ion in the strong electric field of a laser

Energy Technology Data Exchange (ETDEWEB)

Amusia, M.Ya.; Kornyushin, Y. [Racah Institute of Physics, Hebrew University, Jerusalem (Israel)]. E-mail: yurik@vms.huji.ac.il

2000-09-01

The nuclear liquid drop model is applied to describe some basic properties of a negative hydrogen ion in the strong electric field of a laser. The equilibrium ionic size, energy and polarizability of the ion are calculated. Collective modes of the dipole oscillations are considered. A barrier which arises in a strong electric field is studied. The barrier vanishes at some large value of the electric field, which is defined as a critical value. The dependence of the critical field on frequency is studied. At frequencies {omega}{>=}({omega}{sub d}/2{sup 1/2}) ({omega}{sub d} is the frequency of the dipole oscillations of the electronic cloud relative to the nucleus) the barrier remains for any field. At high frequencies a 'stripping' mechanism for instability arises. At the resonant frequency a rather low amplitude of the electric field causes the 'stripping' instability. (author)

Properties of plasma sheath with ion temperature in magnetic fusion devices

International Nuclear Information System (INIS)

Liu Jinyuan; Wang Feng; Sun Jizhong

2011-01-01

The plasma sheath properties in a strong magnetic field are investigated in this work using a steady state two-fluid model. The motion of ions is affected heavily by the strong magnetic field in fusion devices; meanwhile, the effect of ion temperature cannot be neglected for the plasma in such devices. A criterion for the plasma sheath in a strong magnetic field, which differs from the well-known Bohm criterion for low temperature plasma sheath, is established theoretically with a fluid model. The fluid model is then solved numerically to obtain detailed sheath information under different ion temperatures, plasma densities, and magnetic field strengths.

Bacterial growth on ion exchange resin - investigations with a strong cationic exchanger. Pt. 3. Disinfection with peracetic acid

Energy Technology Data Exchange (ETDEWEB)

Flemming, H.C.

1984-12-01

The suitability of peracetic acid (PAA) for the disinfection of ion exchangers was investigated. 0.02% PAA is suitable for satisfactory disinfection. In this way corrosive effects are strongly reduced. Ca/sup 2+/-ions seem to protect the bacteria, therefore the disinfection should be done with the Na/sup +/-form. The disinfection has no remanent effect and therefore is not suitable for preventing bacterial aftergrowth during off-periods. A combination of silver and disinfectant can accomplish this, until a new, silver-tolerant microflora has evolved. In this case the use of 0.02% PAA is imperative, because higher concentrations will dissolve the silver. As a principle the effectiveness of disinfection procedure should be monitored bacteriologically.

Modeling and simulation of protein elution in linear pH and salt gradients on weak, strong and mixed cation exchange resins applying an extended Donnan ion exchange model.

Science.gov (United States)

Wittkopp, Felix; Peeck, Lars; Hafner, Mathias; Frech, Christian

2018-04-13

Process development and characterization based on mathematic modeling provides several advantages and has been applied more frequently over the last few years. In this work, a Donnan equilibrium ion exchange (DIX) model is applied for modelling and simulation of ion exchange chromatography of a monoclonal antibody in linear chromatography. Four different cation exchange resin prototypes consisting of weak, strong and mixed ligands are characterized using pH and salt gradient elution experiments applying the extended DIX model. The modelling results are compared with the results using a classic stoichiometric displacement model. The Donnan equilibrium model is able to describe all four prototype resins while the stoichiometric displacement model fails for the weak and mixed weak/strong ligands. Finally, in silico chromatogram simulations of pH and pH/salt dual gradients are performed to verify the results and to show the consistency of the developed model. Copyright © 2018 Elsevier B.V. All rights reserved.

On the interpretation of different flow vectors of different ion species in the magnetospheric boundary layer

International Nuclear Information System (INIS)

Lundin, R.; Stasiewicz, K.; Hultqvist, B.

1986-05-01

Recent measurements of the ion composition in the magnetospheric boundary layer indicate that the boundary layer may contain clouds of magnetosheath plasma which are gradually becoming mixed with the magnetospheric plasma. A significant difference between flow vectors of different ion species (ca50-100 km/s) implies that an ideal MHD equation E+VxB=0, does not describe the macroscopic plasma flow inside such inhomogeneities. An analysis based on the first order drift theory indicates that gradients of the partial ion pressure and of the magnetic field could induce differential ion drifts comparable in magnitude to the electric drift velocity. We discuss some implications of these results on the physics of solar wind-magnetosphere interactions. (authors)

Adsorption of heavy metal ions on different clays

International Nuclear Information System (INIS)

Kruse, K.

1992-01-01

The aim of the present dissertation is to study the adsorption of heavy metal ions (Cd 2+ , Cu 2+ , Pb 2+ , Zn 2+ ) and their mixtures on clays. Different clays and bentonites (Ca 2+ -bentonite, activated Na + -bentonite, special heavy metal adsorber bentonite, two organophilic bentonites and a mixed layer clay) were used. The adsorbed metal ions were desorbed by appropriate solutions of HCl, EDTA and dioctadecyl dimethylammonium bromide. High concentrations of the heavy metal ions in the solutions can be reached. The desorption guarantees economical recycling. After desorption the clays were used (up to three times) for purification of contaminated water. The best experimental conditions, i.e. the highest adsorption of heavy metal ions from aqueous solutions was found for the greatest ratio of adsorbent/adsorbate. The adsorption was very fast. Calcium, sodium bentonites and the heavy metal adsorber bentonite attained the highest adsorption and desorption for Cu 2+, Zn 2+ and Pb 2+ ions. Cd 2+ ions were only absorbed by Silitonit, a special heavy metal absorber bentonite. The mixed layer clay (Opalit) ranges in adsorption and desorption properties below the unmodified Ca 2+ -bentonite (Montigel) or the activated Na + -bentonite. Only Tixosorb and Tixogel (organophilic bentonites) reach the lowest value of heavy metal adsorption. Only lead cations which are characterised by good polarizability were adsorbed at higher rates, therefore the organophilic bentonites are not appropriate for adsorption of heavy metal ions from aqueous solutions. Mixing of the metal ions generally decreases the adsorption of Pb 2+ and increases the adsorption of Cd 2+ . From mixtures if heavy metal ions adsorption and desorption of Cu 2+ ions reached a maximum for all clays. (author) figs., tabs., 56 refs

Deactivation kinetics of acid-sensing ion channel 1a are strongly pH-sensitive.

Science.gov (United States)

MacLean, David M; Jayaraman, Vasanthi

2017-03-21

Acid-sensing ion channels (ASICs) are trimeric cation-selective ion channels activated by protons in the physiological range. Recent reports have revealed that postsynaptically localized ASICs contribute to the excitatory postsynaptic current by responding to the transient acidification of the synaptic cleft that accompanies neurotransmission. In response to such brief acidic transients, both recombinant and native ASICs show extremely rapid deactivation in outside-out patches when jumping from a pH 5 stimulus to a single resting pH of 8. Given that the resting pH of the synaptic cleft is highly dynamic and depends on recent synaptic activity, we explored the kinetics of ASIC1a and 1a/2a heteromers to such brief pH transients over a wider [H + ] range to approximate neuronal conditions better. Surprisingly, the deactivation of ASICs was steeply dependent on the pH, spanning nearly three orders of magnitude from extremely fast (pH 8 to very slow (>300 ms) at pH 7. This study provides an example of a ligand-gated ion channel whose deactivation is sensitive to agonist concentrations that do not directly activate the receptor. Kinetic simulations and further mutagenesis provide evidence that ASICs show such steeply agonist-dependent deactivation because of strong cooperativity in proton binding. This capacity to signal across such a large synaptically relevant bandwidth enhances the response to small-amplitude acidifications likely to occur at the cleft and may provide ASICs with the ability to shape activity in response to the recent history of the synapse.

Mathematical simulation and calculation of the continuous countercurrent process of ion-exchange extraction of strontium from strongly mineralized solutions

International Nuclear Information System (INIS)

Nikashina, V.A.; Guryanova, L.N.; Baturova, L.L.; Venetsianov, E.V.; Ivanov, V.A.; Nikolaev, N.P.

1993-01-01

The program open-quotes Countercurrentclose quotes is developed for the simulation of a continuous ion-exchange extraction of strontium from strongly mineralized NaCl and CaCl 2 solutions using a KB-4 carboxylic cation-exchanger in the countercurrent columns. The program allows one to Calculate the conditions of Ca and Sr separation depending on the mode of operation at the sorption and regeneration stages, the residual Sr content on the overloaded sorbent, and the Sr separation on incompletely regenerated KB-4. It also makes it possible to find the optimal separation conditions. The program open-quotes Countercurrentclose quotes can be also used to simulate other ion-exchange processes

Dose verification with different ion chambers for SRT/SBRT plans

Science.gov (United States)

Durmus, I. F.; Tas, B.; Okumus, A.; Uzel, O. E.

2017-02-01

Verification of patient plan is very important in stereotactic treatments. VMAT plans were prepared with 6MV-FFF or 10MV-FFF energies for 25 intracranial and extracranial stereotactic patients. Absolute dose was measured for dose verification in each plans. Iba® CC01, Iba® CC04, Iba® CC13 ion chambers placed at a depth of 5cm in solid phantom (RW3). Also we scanned this phantom with ion chambers by Siemens® Biograph mCT. QA plans were prepared by transferring twenty five patient plans to phantom assemblies for three ion chambers. All plans were performed separately for three ion chambers at Elekta® Versa HD linear accelerator. Statistical analysis of results were made by Wilcoxon signed-rank test. Difference between dose values were determined %1.84±3.4 (p: 0.001) with Iba CC13 ion chamber, %1.80±3.4 (p: 0.002) with Iba CC04 ion chamber and %0.29±4.6 (p: 0.667) with Iba CC01 ion chamber. In stereotactic treatments, dosimetric uncertainty increases in small areas. We determined more accurate results with small sized detectors. Difference between TPS calculations and all measurements were founded lower than %2.

Ion exchange removal of chromium (iii) from tannery wastes by using a strong acid cation exchange resin amberlite ir-120 h+ and its hybrids

International Nuclear Information System (INIS)

Ahmad, T.

2014-01-01

A strong acid cation exchange resin Amberlite IR-120 H+ and its hybrids with Mn(OH)/sub 2/, Cu(OH)/sub 2/ and Fe(OH)/sub 3/ are used for the removal of chromium (III) from spent tannery bath. The experimental data give good fits with the Langmuir sorption model. The thermodynamic parameters entropy (delta S), enthalpy (delta H) and free energy (delta G) changes are computed, which reveal that the chromium removal from tannery wastes by ion exchangers is an endothermic, physical sorption and entropically driven process. The rate of sorption is found to increase with the increase of resin dosage, stirring speed and temperature. Different kinetic models such as film diffusion, particle diffusion and Lagergren pseudo first order are used to evaluate the mechanism of the process. It is found that the hybrid ion exchange resins have better removal capacity as compared to the parent ion exchanger. The increase in the removal capacity is found to be in the order of the corresponding PZC values of the hybrid ion exchangers. Further, it is suggested that the higher exchange capacity is the result of Donnan effect and specific adsorption of chromium by the oxides / hydroxides present inside the matrix of the organic cation exchanger. (author)

Energy distributions of plume ions from silver at different angles ablated in vacuum

DEFF Research Database (Denmark)

Christensen, Bo Toftmann; Schou, Jørgen; Canulescu, Stela

A typical pulsed laser deposition (PLD) is carried out for a fluence between 0.5 and 2.5 J/cm2. The ablated particles are largely neutrals at the lowest fluence, but the fraction of ions increases strongly with fluence and accounts for more 0.5 of the particles at 2.5 J/cm2 [1,2]. Since it may...... be comparatively difficult to measure the energy and angular distribution of neutrals, measurements of the ionic fraction will be valuable for any modeling of PLD. We have irradiated silver in a vacuum chamber (~ 10-7 mbar) with a Nd:YAG laser at a wavelength of 355 nm and made detailed measurements of the time......-resolved angular distribution. The ion flow in different directions has been measured with a hemispherical array of Langmuir probes, by which the time-of-flight spectra the in all directions can be recorded [1,2]. In contrast to earlier work the beam spot was circular such that any flip-over effect of the plume...

Precipitation characteristics of uranyl ions at different pHs depending on the presence of carbonate ions and hydrogen peroxide.

Science.gov (United States)

Kim, Kwang-Wook; Kim, Yeon-Hwa; Lee, Se-yoon; Lee, Jae-Won; Joe, Kih-Soo; Lee, Eil-Hee; Kim, Jong-Seung; Song, Kyuseok; Song, Kee-Chan

2009-04-01

This work studied the dissolution of uranium dioxide and precipitation characteristics of uranyl ions in alkaline and acidic solutions depending on the presence of carbonate ions and H2O2 in the solutions at different pHs controlled by adding HNO3 or NaOH in the solution. The chemical structures of the precipitates generated in different conditions were evaluated and compared by using XRD, SEM, TG-DT, and IR analyses together. The sizes and forms of the precipitates in the solutions were evaluated, as well. The uranyl ions were precipitated in the various forms, depending on the solution pH and the presences of hydrogen peroxide and carbonate ions in the solution. In a 0.5 M Na2CO3 solution with H2O2, where the uranyl ions formed mixed uranyl peroxy-carbonato complexes, the uranyl ions were precipitated as a uranium peroxide of UO4(H20)4 at pH 3-4, and precipitated as a clarkeite of Na2U2Ox(OH)y(H2O)z above pH 13. In the same carbonate solution without H2O2, where the uranyl ions formed uranyl tris-carbonato complex, the uranyl ions were observed to be precipitated as a different form of clarkeite above pH 13. The precipitate of uranyl ions in a nitrate solution without carbonate ions and H2O2 at a high pH were studied together to compare the precipitate forms in the carbonate solutions.

Strong electron dissipation by a mode converted ion hybrid (Bernstein) wave

International Nuclear Information System (INIS)

Lashmore-Davies, C.N.; Ram, A.K.

1996-01-01

The fast wave approximation, extended to include the effects of electron dissipation, is used to calculate the power mode converted to the ion hybrid (Bernstein) wave in the vicinity of the ion hybrid resonance. The power absorbed from the fast wave by ion cyclotron damping and by electron Landau and transit time damping (including cross terms) is also calculated. The fast wave equation is solved for either the Budden configuration of a cut-off-resonance pair or the triplet configuration of cut-off-resonance-cut-off. The fraction mode converted is compared for the triplet case and the Budden multi-pass situation. The electron damping rate of the ion hybrid wave is obtained from the local dispersion relation and a ray tracing code is used to calculate the damping of the mode converted ion hybrid wave by the electrons as it propagates away from the resonance. Quantitative results for a range of conditions relevant to JET, TFTR and ITER are given. copyright 1996 American Institute of Physics

Ion transfer from an atmospheric pressure ion funnel into a mass spectrometer with different interface options: Simulation-based optimization of ion transmission efficiency.

Science.gov (United States)

Mayer, Thomas; Borsdorf, Helko

2016-02-15

We optimized an atmospheric pressure ion funnel (APIF) including different interface options (pinhole, capillary, and nozzle) regarding a maximal ion transmission. Previous computer simulations consider the ion funnel itself and do not include the geometry of the following components which can considerably influence the ion transmission into the vacuum stage. Initially, a three-dimensional computer-aided design (CAD) model of our setup was created using Autodesk Inventor. This model was imported to the Autodesk Simulation CFD program where the computational fluid dynamics (CFD) were calculated. The flow field was transferred to SIMION 8.1. Investigations of ion trajectories were carried out using the SDS (statistical diffusion simulation) tool of SIMION, which allowed us to evaluate the flow regime, pressure, and temperature values that we obtained. The simulation-based optimization of different interfaces between an atmospheric pressure ion funnel and the first vacuum stage of a mass spectrometer require the consideration of fluid dynamics. The use of a Venturi nozzle ensures the highest level of transmission efficiency in comparison to capillaries or pinholes. However, the application of radiofrequency (RF) voltage and an appropriate direct current (DC) field leads to process optimization and maximum ion transfer. The nozzle does not hinder the transfer of small ions. Our high-resolution SIMION model (0.01 mm grid unit(-1) ) under consideration of fluid dynamics is generally suitable for predicting the ion transmission through an atmospheric-vacuum system for mass spectrometry and enables the optimization of operational parameters. A Venturi nozzle inserted between the ion funnel and the mass spectrometer permits maximal ion transmission. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Heating tokamaks via the ion-cyclotron and ion-ion hybrid resonances

International Nuclear Information System (INIS)

Perkins, F.W.

1977-04-01

For the ion-ion hybrid resonance it is shown that: (1) the energy absorption occurs via a sequence of mode conversions; (2) a poloidal field component normal to the ion-ion hybrid mode conversion surface strongly influences the mode conversion process so that roughly equal electron and ion heating occurs in the present proton-deuterium experiments, while solely electron heating is predicted to prevail in deuterium-tritium reactors; (3) the ion-ion hybrid resonance suppresses toroidal eigenmodes; and (4) wave absorption in minority fundamental ion-cyclotron heating experiments will be dominated by ion-ion hybrid mode conversion absorption for minority concentrations exceeding roughly 1 percent. For the ion-cyclotron resonance, it is shown that: (1) ion-cyclotron mode conversion leads to surface electron heating; and (2) ion-cyclotron mode conversion absorption dominates fundamental ion-cyclotron absorption thereby preventing efficient ion heating

Negative Ion Density Fronts

International Nuclear Information System (INIS)

Igor Kaganovich

2000-01-01

Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas

Electron screening and kinetic-energy oscillations in a strongly coupled plasma

International Nuclear Information System (INIS)

Chen, Y.C.; Simien, C.E.; Laha, S.; Gupta, P.; Martinez, Y.N.; Mickelson, P.G.; Nagel, S.B.; Killian, T.C.

2004-01-01

We study equilibration of strongly coupled ions in an ultracold neutral plasma produced by photoionizing laser-cooled and trapped atoms. By varying the electron temperature, we show that electron screening modifies the equilibrium ion temperature. Even with few electrons in a Debye sphere, the screening is well described by a model using a Yukawa ion-ion potential. We also observe damped oscillations of the ion kinetic energy that are a unique feature of equilibration of a strongly coupled plasma

Comparative study on bromide and iodide ion-isotopic exchange reactions using strongly basic anion exchange resin Duolite A-113

International Nuclear Information System (INIS)

Lokhande, R.S.; Dole, M.H.; Singare, P.U.

2006-01-01

Kinetics of ion-isotopic exchange reaction was studied using industrial grade ion exchange resin Duolite A-113. The radioactive isotopes 131 I and 82 Br were used to trace the ion-isotopic exchange reaction. The experiments were performed in the temperature range of 26.0degC to 43.0degC and the concentration of external ionic solution varying from 0.005 M to 0.100 M. For bromide ion-isotopic exchange reaction, the calculated values of specific reaction rate, initial rate of bromide ion exchange, and amount of bromide ions exchanged were obtained higher than that for iodide ion-isotopic exchange reaction under identical experimental conditions. The observed variation in the results for two ion-isotopic exchange reactions was due to the difference in the ionic size of bromide and iodide ions. (author)

Interaction of energetic ions with high-density plasmas

International Nuclear Information System (INIS)

Gericke, D.O.; Edie, D.; Grinenko, A.; Vorberger, J.

2010-01-01

Complete text of publication follows. The talk will review the importance of energetic ions in different inertial confinement fusion scenarios: i) heavy ion beams are very efficient drivers that can deliver the energy for compression in indirect as well as direct drive approaches; ii) the interaction of α-particles, that are created in a burning plasma, with the surrounding cold plasma is essential for creating a burn wave; iii) laser-produced ion beams are also a strong candidate to create the hot spot needed for fast ignition. In all applications the ions interact with dense matter that is characterized by strongly coupled ions and (possibly) partially degenerate electrons. Moreover, the coupling between beam ions and target electrons can be strong as well. Under these conditions, standard approaches for the beam-plasma interactions process are known to fail. The presentation will demonstrate how advanced models for the energy loss of ions in dense plasmas can resolve the issues mentioned above. These models are largely built on quantum kinetic theory that is able to describe degeneracy and strong coupling in a systematic way. In particular, strong interactions require a quantum description for electron-ion collisions in dense plasma environments, which is done by direct solutions of the Schroedinger equation. Degeneracy and collective excitations can be included via the Lenard-Balescu description where strong interactions may be included via a pseudo-potential approach. Finally, results are shown for all three fusion applications described above. The effects related to strong coupling and degeneracy mainly concern the end of the stopping range where the beam ion dose not have enough energy to excite all possible degrees of freedom and, thus, certain processes are frozen out. However, we also find a significant reduction of the range for swift heavy ions in the GeV-range when stopping in dense matter is considered. The stopping range of α-particles in the

The effect of cation source and dietary cation-anion difference on rumen ion concentrations in lactating dairy cows.

Science.gov (United States)

Catterton, T L; Erdman, R A

2016-08-01

Many studies have focused on the influence of dietary cation-anion difference (DCAD) on animal performance but few have examined the effect of DCAD on the rumen ionic environment. The objective of this study was to examine the effects of DCAD, cation source (Na vs. K), and anion source (Cl vs. bicarbonate or carbonate) on rumen environment and fermentation. The study used 5 rumen-fistulated dairy cows and 5 dietary treatments that were applied using a 5×5 Latin square design with 2-wk experimental periods. Treatments consisted of (1) the basal total mixed ration (TMR); (2) the basal TMR plus 340mEq/kg of Na (dry matter basis) using NaCl; (3) the basal TMR plus 340mEq/kg of K using KCl; (4) the basal TMR plus 340mEq/kg of Na using NaHCO3; and (5) the basal TMR plus 340mEq/kg of K using K2CO3. On the last day of each experimental period, rumen samples were collected and pooled from 5 different locations at 0, 1.5, 3, 4.5, 6, 9, and 12h postfeeding for measurement of rumen pH and concentrations of strong ions and volatile fatty acids (VFA). Dietary supplementation of individual strong ions increased the corresponding rumen ion concentration. Rumen Na was decreased by 24mEq/L when K was substituted for Na in the diet, but added dietary Na had no effect on rumen K. Rumen Cl was increased by 10mEq/L in diets supplemented with Cl. Cation source had no effect on rumen pH or total VFA concentration. Increased DCAD increased rumen pH by 0.10 pH units and increased rumen acetate by 4mEq/L but did not increase total VFA. This study demonstrated that rumen ion concentrations can be manipulated by dietary ion concentrations. If production and feed efficiency responses to DCAD and ionophores in the diet are affected by rumen Na and K concentrations, then manipulating dietary Na and K could be used either to enhance or diminish those responses. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

LATTICE SIMULATIONS OF THE THERMODYNAMICS OF STRONGLY INTERACTING ELEMENTARY PARTICLES AND THE EXPLORATION OF NEW PHASES OF MATTER IN RELATIVISTIC HEAVY ION COLLISIONS

International Nuclear Information System (INIS)

KARSCH, F.

2006-01-01

At high temperatures or densities matter formed by strongly interacting elementary particles (hadronic matter) is expected to undergo a transition to a new form of matter--the quark gluon plasma--in which elementary particles (quarks and gluons) are no longer confined inside hadrons but are free to propagate in a thermal medium much larger in extent than the typical size of a hadron. The transition to this new form of matter as well as properties of the plasma phase are studied in large scale numerical calculations based on the theory of strong interactions--Quantum Chromo Dynamics (QCD). Experimentally properties of hot and dense elementary particle matter are studied in relativistic heavy ion collisions such as those currently performed at the relativistic heavy ion collider (RHIC) at BNL. We review here recent results from studies of thermodynamic properties of strongly interacting elementary particle matter performed on Teraflops-Computer. We present results on the QCD equation of state and discuss the status of studies of the phase diagram at non-vanishing baryon number density

Strong beam production for some elements

International Nuclear Information System (INIS)

Camplan, J.; Chaumont, J.; Meunier, R.

1974-01-01

Three electromagnetic isotope separators are installed in Rene Bernas Laboratory, one being especially adapted to ion implantation. The three apparatus use the same type of ion source and system of beam extraction. The special ion source is distinguishable from the others only by its smaller dimensions. These sources allow strong currents to be obtained for almost every element. The source and its extraction system are briefly described, examples of beams obtained are given [fr

Improved theoretical approximation for the ion drag force in collisionless plasma with strong ion-grain coupling

International Nuclear Information System (INIS)

Khrapak, S. A.; Nosenko, V.; Morfill, G. E.; Merlino, R.

2009-01-01

We point out a deficiency in our previous analytic calculation of the ion drag force for conditions of the experiment by Nosenko et al. [Phys. Plasmas 14, 103702 (2007)]. An inaccurate approximation is corrected and the ion drag force is recalculated. The improved model yields better overall agreement with the experimental results as compared to the original calculation.

Separation of boron isotopes by ion exchange chromatography: studies on regeneration of strong base anion exchange resins

International Nuclear Information System (INIS)

Sharma, B.K.; Subramanian, R.; Mathur, P.K.

1994-01-01

The optimum conditions for the regeneration of strong base anion exchange resins of type-I and type-II were determined for cost-effective separation of isotopes of boron by ion exchange chromatography where the hydroxyl form of an anion exchange resin is equilibrated with boric acid solution containing mannitol as a complexing reagent. The possibility of using unspent alkali content of the effluent was also exploited. Removal of carbonate impurity from Rayon grade caustic lye (used as regenerant after dilution) and recycling of Ba(OH) 2 was studied to avoid waste disposal problems. (author)

Non-uniform 3He polarization formed by multiple collisions of a fast 3He+ ion with polarized Rb vapor in a strong magnetic field

International Nuclear Information System (INIS)

Arimoto, Y.; Yonehara, K.; Yamagata, T.; Tanaka, M.

2001-01-01

We investigated the spatial distribution of a polarization in 3 He beam expected from a novel polarized 3 He ion source based on electron pumping, i.e., multiple electron capture and stripping collisions of an incident fast 3 He + ion with a polarized Rb vapor in a strong axial magnetic field. For this purpose, a Monte Carlo simulation was carried out for 19 keV 3 He + ions with varying Rb vapor thickness, magnetic field, and beam emittance. The calculated results showed a distribution of the 3 He polarization that we call a 'polarization hole', which has a low polarization area around the beam axis. The parameters characterizing the polarization hole, i.e., the polarization and radius of the hole, were found to depend on the Rb vapor thickness, the magnetic field, the beam size, and the angular divergence of the initial beam. These parameters were successfully reproduced with analytical functions deduced from a probability density function prescription. This provides a powerful tool to treat complex phenomena of multiple collisions in strong magnetic fields without performing time-consuming Monte Carlo calculations

Negative secondary ion emission from oxidized surfaces

International Nuclear Information System (INIS)

Gnaser, H.; Kernforschungsanlage Juelich G.m.b.H.

1984-01-01

The emission of negative secondary ions from 23 elements was studied for 10 keV O 2 + and 10 keV In + impact at an angle of incidence of 45 0 . Partial oxidation of the sample surfaces was achieved by oxygen bombardment and/or by working at a high oxygen partial pressure. It was found that the emission of oxide ions shows an element-characteristic pattern. For the majority of the elements investigated these features are largely invariant against changes of the surface concentration of oxygen. For the others admission of oxygen strongly changes the relative intensities of oxide ions: a strong increase of MO 3 - signals (M stands for the respective element) is accompanied by a decrease of MO - and M - intensities. Different primary species frequently induce changes of both the relative and the absolute negative ion intensities. Carbon - in contrast to all other elements - does not show any detectable oxide ion emission but rather intense cluster ions Csub(n) - (detected up to n=12) whose intensities oscillate in dependence on n. (orig./RK)

Application of lanthanide ions doped in different glasses

International Nuclear Information System (INIS)

Dhondiyal, Charu Chandra

2015-01-01

. The optical absorption spectrum of the RE ions from the UV to the mid infrared originates from transition between electronic states in the partially filled 4f orbital shielded by filled 5s and 5p shells. These partially filled shells of f electron give rise narrow localized electronic transitions that occurs not only in visible parts of the electromagnetic spectrum but also in IR and ultraviolet region. Rare earth ions are unique in that transitions within the 4f n core are substantially screened from outside influence and sharp spectroscopic lines having high peak cross sections result. When these ions are doped in crystalline lattices, glass or polymers. Phosphate glasses were chosen because they possess a large glass formation region, are good host for fluorescent ions, and shows good thermo-mechanical and chemical properties. Different rare earths, their optical properties and application of lanthanide ions will be key thrust area of paper. (author)

Selective recovery of gold and other metal ions from an algal biomass

Energy Technology Data Exchange (ETDEWEB)

Darnall, D.W.; Greene, B.; Henzl, M.T.; Hosea, J.M.; McPherson, R.A.; Sneddon, J.; Alexander, M.D.

1986-02-01

The authors observed that the pH dependence of the binding of Au/sup 3 +/, Ag/sup +/, and Hg/sup 2 +/ to the algae Chlorella vulgaris is different than the binding of other metal ions. Between pH 5 and 7, a variety of metal ions bind strongly to the cell surface. Most of these algal-bound metal ions can be selectively desorbed by lowering the pH to 2; however, Au/sup 3 +/, Hg/sup 2 +/, and Ag/sup +/ are all bound strongly at pH 2. Addition of a strong ligand at different pHs is required to elute these ions from the algal surface. Algal-bound gold and mercury can be selectively eluted by using mercaptoethanol. An elution scheme is demonstrated for the binding and selective recovery of Cu/sup 2 +/, Zn/sup 2 +/, Au/sup 3 +/, and Hg/sup 2 +/ from an equimolar mixture. 20 references, 2 figures.

SOLVENT EFFECTS ON THE HYDRATION OF CYCLOHEXENE CATALYZED BY A STRONG ACID ION-EXCHANGE RESIN .3. EFFECT OF SULFOLANE ON THE EQUILIBRIUM CONVERSION

NARCIS (Netherlands)

PANNEMAN, HJ; BEENACKERS, AACM

The liquid-phase hydration of cyclohexene, a pseudo-first-order reversible reaction catalyzed by a strong acid ion-exchange resin, was investigated in solvent mixtures of water and sulfolane. Macroporous Amberlite XE 307 was used because of its superior catalytic activity. Chemical equilibrium

Mechanically induced strong red emission in samarium ions doped piezoelectric semiconductor CaZnOS for dynamic pressure sensing and imaging

Science.gov (United States)

Wang, Wei; Peng, Dengfeng; Zhang, Hanlu; Yang, Xiaohong; Pan, Caofeng

2017-07-01

Piezoelectric semiconductor with optical, electrical and mechanical multifunctions has great potential applications in future optoelectronic devices. The rich properties and applications mainly encompass the intrinsic structures and their coupling effects. Here, we report that lanthanide ions doped piezoelectric semiconductor CaZnOS:Sm3+ showing strong red emission induced by dynamic mechanical stress. Under moderate mechanical load, the doped piezoelectric semiconductor exhibits strong visible red emission to the naked eyes even under the day light. A flexible dynamic pressure sensor device is fabricated based on the prepared CaZnOS:Sm3+ powders. The mechanical-induced emission properties of the device are investigated by the optical fiber spectrometer. The linear characteristic emissions are attributed to the 4G5/2→6H5/2 (566 nm), 4G5/2→6H7/2 (580-632 nm), 4G5/2→6H9/2 (653-673 nm) and 4G5/2→6H11/2 (712-735 nm) f-f transitions of Sm3+ ions. The integral emission intensity is proportional to the value of applied pressure. By using the linear relationship between integrated emission intensity and the dynamic pressure, the real-time pressure distribution is visualized and recorded. Our results highlight that the incorporation of lanthanide luminescent ions into piezoelectric semiconductors as smart materials could be applied into the flexible mechanical-optical sensor device without additional auxiliary power, which has great potential for promising applications such as mapping of personalized handwriting, smart display, and human machine interface.

Plasma immersion ion implantation (and deposition) inside metallic tubes of different dimensions and configurations

Science.gov (United States)

Ueda, M.; Silva, C.; Santos, N. M.; Souza, G. B.

2017-10-01

There is a strong need for developing methods to coat or implant ions inside metallic tubes for many practical contemporary applications, both for industry and science. Therefore, stainless steel tubes with practical diameters of 4, 11 and 16 cm, but short lengths of 20 cm, were internally treated by nitrogen plasma immersion ion implantation (PIII). Different configurations as tube with lid in one of the ends or both sides open were tested for better PIII performance, in the case of smallest diameter tube. Among these PIII tests in tubes, using the 4 cm diameter one with a lid, it was possible to achieve tube temperatures of more than 700 °C in 15 min and maintain it during the whole treatment time (typically 2 h). Samples made of different materials were placed at the interior of the tube, as the monitors for posterior analysis, and the tube was solely pulsed by high voltage pulser producing high voltage glow discharge and hollow cathode discharge both driven by a moderate power source. In this experiment, samples of SS 304, pure Ti, Ti6Al4V and Si were used for the tests of the above methods. Results on the analysis of the surface of these nitrogen PIII treated materials, as well as on their processing methods, are presented and discussed in the paper.

Low-Frequency Loudspeaker-Room Simulation Using Finite Differences in the Time Domain-Part 1: Analysis<strong> strong>

DEFF Research Database (Denmark)

Celestinos, Adrian; Nielsen, Sofus Birkedal

2008-01-01

Small- and medium-size rectangular rooms have a strong influence on the low-frequency performance of loudspeakers. A simulation program based on the finite-difference time-domain (FDTD) method is introduced to analyze the sound field produced by loudspeakers in rectangular rooms at low frequencies...

A small electron beam ion trap/source facility for electron/neutral–ion collisional spectroscopy in astrophysical plasmas

Science.gov (United States)

Liang, Gui-Yun; Wei, Hui-Gang; Yuan, Da-Wei; Wang, Fei-Lu; Peng, Ji-Min; Zhong, Jia-Yong; Zhu, Xiao-Long; Schmidt, Mike; Zschornack, Günter; Ma, Xin-Wen; Zhao, Gang

2018-01-01

Spectra are fundamental observation data used for astronomical research, but understanding them strongly depends on theoretical models with many fundamental parameters from theoretical calculations. Different models give different insights for understanding a specific object. Hence, laboratory benchmarks for these theoretical models become necessary. An electron beam ion trap is an ideal facility for spectroscopic benchmarks due to its similar conditions of electron density and temperature compared to astrophysical plasmas in stellar coronae, supernova remnants and so on. In this paper, we will describe the performance of a small electron beam ion trap/source facility installed at National Astronomical Observatories, Chinese Academy of Sciences.We present some preliminary experimental results on X-ray emission, ion production, the ionization process of trapped ions as well as the effects of charge exchange on the ionization.

Instabilities in strongly coupled plasmas

CERN Document Server

Kalman, G J

2003-01-01

The conventional Vlasov treatment of beam-plasma instabilities is inappropriate when the plasma is strongly coupled. In the strongly coupled liquid state, the strong correlations between the dust grains fundamentally affect the conditions for instability. In the crystalline state, the inherent anisotropy couples the longitudinal and transverse polarizations, and results in unstable excitations in both polarizations. We summarize analyses of resonant and non-resonant, as well as resistive instabilities. We consider both ion-dust streaming and dust beam-plasma instabilities. Strong coupling, in general, leads to an enhancement of the growth rates. In the crystalline phase, a resonant transverse instability can be excited.

Estimate of electrical potential difference between plasmas with different degrees of ionization

Energy Technology Data Exchange (ETDEWEB)

Chang, Chong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-01-12

The electrical potential difference has been estimated across the mixing region of two plasmas with different degrees of ionization. The estimation has been carried out in two different contexts of a charge neutral mixing region and a charge non-neutral sheath. Ion energy gained due to the potential difference has also been estimated. In both analyses, ion energy gain is proportional to the degree of ionization, and a fairly large ionization appears to be needed for overcoming the potential energy barrier of strongly coupled plasmas.

Differences between Doppler velocities of ions and neutral atoms in a solar prominence

Science.gov (United States)

Anan, T.; Ichimoto, K.; Hillier, A.

2017-05-01

Context. In astrophysical systems with partially ionized plasma, the motion of ions is governed by the magnetic field while the neutral particles can only feel the magnetic field's Lorentz force indirectly through collisions with ions. The drift in the velocity between ionized and neutral species plays a key role in modifying important physical processes such as magnetic reconnection, damping of magnetohydrodynamic waves, transport of angular momentum in plasma through the magnetic field, and heating. Aims: This paper aims to investigate the differences between Doppler velocities of calcium ions and neutral hydrogen in a solar prominence to look for velocity differences between the neutral and ionized species. Methods: We simultaneously observed spectra of a prominence over an active region in H I 397 nm, H I 434 nm, Ca II 397 nm, and Ca II 854 nm using a high dispersion spectrograph of the Domeless Solar Telescope at Hida observatory. We compared the Doppler velocities, derived from the shift of the peak of the spectral lines presumably emitted from optically-thin plasma. Results: There are instances when the difference in velocities between neutral atoms and ions is significant, for example 1433 events ( 3% of sets of compared profiles) with a difference in velocity between neutral hydrogen atoms and calcium ions greater than 3σ of the measurement error. However, we also found significant differences between the Doppler velocities of two spectral lines emitted from the same species, and the probability density functions of velocity difference between the same species is not significantly different from those between neutral atoms and ions. Conclusions: We interpreted the difference of Doppler velocities as being a result of the motions of different components in the prominence along the line of sight, rather than the decoupling of neutral atoms from plasma. The movie attached to Fig. 1 is available at http://www.aanda.org

Nonlinear Excitations in Strongly-Coupled Fermi-Dirac Plasmas

OpenAIRE

Akbari-Moghanjoughi, M.

2012-01-01

In this paper we use the conventional quantum hydrodynamics (QHD) model in combination with the Sagdeev pseudopotential method to explore the effects of Thomas-Fermi nonuniform electron distribution, Coulomb interactions, electron exchange and ion correlation on the large-amplitude nonlinear soliton dynamics in Fermi-Dirac plasmas. It is found that in the presence of strong interactions significant differences in nonlinear wave dynamics of Fermi-Dirac plasmas in the two distinct regimes of no...

Mathematical simulation and calculation of continuous countercurrent process of ion-exchange extraction of strontium from strongly mineralized solutions

International Nuclear Information System (INIS)

Nikashina, V.A.; Venitsianov, E.V.; Ivanov, V.A.; Gur'yanova, L.N.; Nikolaev, N.P.; Baturova, L.L.; Moskovskij Gosudarstvennyj Univ., Moscow

1993-01-01

A program 'Countercurrent' is developed for the simulation of a continuous ion-exchange extraction of strontium from the strongly mineralized solutions containing NaCl and CaCl 2 using carboxylic cation exchanger KB-4 in countercurrent columns. The use of the program allows one to calculate the consitions of Ca and Sr separation depending on the modes of operation at the stage of sorption as well as regeneration, to calculate a residual Sr content on an overloaded sorbent and Sr separation on an incompletely regenerated KB-4, and to find the optimal separation conditions

The creation of strongly coupled plasmas using an intense heavy ion beam: low-entropy compression of hydrogen and the problem of hydrogen metallization

CERN Document Server

Tahir, N A; Shutov, A; Varentsov, D; Udrea, S; Hoffmann, Dieter H H; Juranek, H; Redmer, R; Portugues, R F; Lomonosov, I V; Fortov, V E

2003-01-01

Intense heavy ion beams deposit energy very efficiently over extended volumes of solid density targets, thereby creating large samples of strongly coupled plasmas. Intense beams of energetic heavy ions are therefore an ideal tool to research this interesting field. It is also possible to design experiments using special beam-target geometries to achieve low-entropy compression of samples of matter. This type of experiments is of particular interest for studying the problem of hydrogen metallization. In this paper we present a design study of such a proposed experiment that will be carried out at the future heavy ion synchrotron facility SIS100, at the Gesellschaft fuer Schwerionenforschung, Darmstadt. This study has been done using a two-dimensional hydrodynamic computer code. The target consists of a solid hydrogen cylinder that is enclosed in a thick shell of lead whose one face is irradiated with an ion beam which has an annular (ring shaped) focal spot. The beam intensity and other parameters are consider...

Effects of ion beam treatment on atomic and macroscopic adhesion of copper to different polymer materials

International Nuclear Information System (INIS)

Zaporojtchenko, V.; Zekonyte, J.; Faupel, F.

2007-01-01

Low-energy ion irradiation of polymer induces different phenomena in the near surface layer, which effect strongly the metal-polymer interface formation and promotes adhesion of polymers to metals. Low-energy argon and oxygen ion beams were used to alter the chemical and physical properties of different polymers (PS (polystyrene), PαMS (poly(α-methylstyrene), BPA-PC (bisphenol-A-polycarbonate) and PMMA (poly(methyl methacrylate)), in order to understand the adhesion phenomena between a deposited Cu layer and the polymers. The resulting changes were investigated by various techniques including X-ray photoelectron spectroscopy, measurements of the metal condensation coefficient and a new technique to measure cross-linking at the polymer surface. Two types of practical adhesion strengths of Cu-polymer systems, measured using 90 o peel tests, were observed: (i) peel strength increased at low ion fluences, reached a maximum and then decreased after prolonged treatment and (ii) no improvement in the peel strength on treated polymer surfaces was recorded. The improvement in the metal-polymer adhesion in the ion fluence range of 10 13 -10 15 cm -2 is attributed to the creation of a large density of new adsorption sites resulting in a larger contact area and incorporation of chemically active groups that lead to increased interaction between metal and polymer by metal-oxygen-polymer species formation. XPS analysis of peeled-off surfaces showed that in most cases the failure location changed from interfacial for untreated polymers to cohesive failure in the polymer for treated surfaces. These observations and measurements of the metal condensation coefficients suggest that bonding is improved at the metal-polymer interface for all metal-polymer systems. However, the decrease in the peel strength at high ion fluences is attributed to the formation of a weak boundary layer in polymers. The correlation between sputter rate of polymers and altering in the peel strength for

A comparison of prognostic significance of strong ion gap (SIG) with other acid-base markers in the critically ill: a cohort study.

Science.gov (United States)

Ho, Kwok M; Lan, Norris S H; Williams, Teresa A; Harahsheh, Yusra; Chapman, Andrew R; Dobb, Geoffrey J; Magder, Sheldon

2016-01-01

This cohort study compared the prognostic significance of strong ion gap (SIG) with other acid-base markers in the critically ill. The relationships between SIG, lactate, anion gap (AG), anion gap albumin-corrected (AG-corrected), base excess or strong ion difference-effective (SIDe), all obtained within the first hour of intensive care unit (ICU) admission, and the hospital mortality of 6878 patients were analysed. The prognostic significance of each acid-base marker, both alone and in combination with the Admission Mortality Prediction Model (MPM0 III) predicted mortality, were assessed by the area under the receiver operating characteristic curve (AUROC). Of the 6878 patients included in the study, 924 patients (13.4 %) died after ICU admission. Except for plasma chloride concentrations, all acid-base markers were significantly different between the survivors and non-survivors. SIG (with lactate: AUROC 0.631, confidence interval [CI] 0.611-0.652; without lactate: AUROC 0.521, 95 % CI 0.500-0.542) only had a modest ability to predict hospital mortality, and this was no better than using lactate concentration alone (AUROC 0.701, 95 % 0.682-0.721). Adding AG-corrected or SIG to a combination of lactate and MPM0 III predicted risks also did not substantially improve the latter's ability to differentiate between survivors and non-survivors. Arterial lactate concentrations explained about 11 % of the variability in the observed mortality, and it was more important than SIG (0.6 %) and SIDe (0.9 %) in predicting hospital mortality after adjusting for MPM0 III predicted risks. Lactate remained as the strongest predictor for mortality in a sensitivity multivariate analysis, allowing for non-linearity of all acid-base markers. The prognostic significance of SIG was modest and inferior to arterial lactate concentration for the critically ill. Lactate concentration should always be considered regardless whether physiological, base excess or physical-chemical approach

Enhanced ion acoustic fluctuations and ion outflows

Directory of Open Access Journals (Sweden)

F. R. E. Forme

1999-02-01

Full Text Available A number of observations showing enhanced ion acoustic echoes observed by means of incoherent scatter radars have been reported in the literature. The received power is extremely enhanced by up to 1 or 2 orders of magnitude above usual values, and it is mostly contained in one of the two ion acoustic lines. This spectral asymmetry and the intensity of the received signal cannot be resolved by the standard analysis procedure and often causes its failure. As a result, and in spite of a very clear spectral signature, the analysis is unable to fit the plasma parameters inside the regions of ion acoustic turbulence. We present European Incoherent Scatter radar (EISCAT observations of large ion outflows associated with the simultaneous occurrence of enhanced ion acoustic echoes. The ion fluxes can reach 1014 m-2 s-1 at 800 km altitude. From the very clear spectral signatures of these echoes, a method is presented to extract estimates of the electron temperature and the ion drift within the turbulent regions. It is shown that the electron gas is strongly heated up to 11 000 K. Also electron temperature gradients of about 0.02 K/m exist. Finally, the estimates of the electron temperature and of the ion drift are used to study the possible implications for the plasma transport inside turbulent regions. It is shown that strong electron temperature gradients cause enhancement of the ambipolar electric field and can account for the observed ion outflows.Key words. Ionosphere (auroral ionosphere; ionosphere · magnetosphere interactions; plasma waves and instabilities.

Nectar sugars and amino acids in day- and night-flowering Nicotiana species are more strongly shaped by pollinators' preferences than organic acids and inorganic ions.

Science.gov (United States)

Tiedge, Kira; Lohaus, Gertrud

2017-01-01

Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats) to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences. Glucose, fructose and sucrose were the only sugars found in the nectar of all examined species. Sugar concentration of the nectar of day-flowering species was 20% higher and amino acid concentration was 2-3-fold higher compared to the nectar of night-flowering species. The sucrose-to-hexose ratio was significantly higher in night-flowering species and the relative share of sucrose based on the total sugar correlated with the flower tube length in the nocturnal species. Flowers of different tobacco species contained varying volumes of nectar which led to about 150-fold higher amounts of total sugar per flower in bat- or sunbird-pollinated species than in bee-pollinated or autogamous species. This difference was even higher for total amino acids per flower (up to 1000-fold). As a consequence, some Nicotiana species invest large amounts of organic nitrogen for certain pollinators. Higher concentrations of inorganic ions, predominantly anions, were found in nectar of night-flowering species. Therefore, higher anion concentrations were also associated with pollinator types active at night. Malate, the main organic acid, was present in all nectar samples but the concentration was not correlated with pollinator type. In conclusion, statistical analyses revealed that pollinator types have a stronger effect on nectar composition than phylogenetic relations. In this context, nectar sugars and amino

Nectar sugars and amino acids in day- and night-flowering Nicotiana species are more strongly shaped by pollinators’ preferences than organic acids and inorganic ions

Science.gov (United States)

Tiedge, Kira; Lohaus, Gertrud

2017-01-01

Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats) to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences. Glucose, fructose and sucrose were the only sugars found in the nectar of all examined species. Sugar concentration of the nectar of day-flowering species was 20% higher and amino acid concentration was 2-3-fold higher compared to the nectar of night-flowering species. The sucrose-to-hexose ratio was significantly higher in night-flowering species and the relative share of sucrose based on the total sugar correlated with the flower tube length in the nocturnal species. Flowers of different tobacco species contained varying volumes of nectar which led to about 150-fold higher amounts of total sugar per flower in bat- or sunbird-pollinated species than in bee-pollinated or autogamous species. This difference was even higher for total amino acids per flower (up to 1000-fold). As a consequence, some Nicotiana species invest large amounts of organic nitrogen for certain pollinators. Higher concentrations of inorganic ions, predominantly anions, were found in nectar of night-flowering species. Therefore, higher anion concentrations were also associated with pollinator types active at night. Malate, the main organic acid, was present in all nectar samples but the concentration was not correlated with pollinator type. In conclusion, statistical analyses revealed that pollinator types have a stronger effect on nectar composition than phylogenetic relations. In this context, nectar sugars and amino

Nectar sugars and amino acids in day- and night-flowering Nicotiana species are more strongly shaped by pollinators' preferences than organic acids and inorganic ions.

Directory of Open Access Journals (Sweden)

Kira Tiedge

Full Text Available Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences. Glucose, fructose and sucrose were the only sugars found in the nectar of all examined species. Sugar concentration of the nectar of day-flowering species was 20% higher and amino acid concentration was 2-3-fold higher compared to the nectar of night-flowering species. The sucrose-to-hexose ratio was significantly higher in night-flowering species and the relative share of sucrose based on the total sugar correlated with the flower tube length in the nocturnal species. Flowers of different tobacco species contained varying volumes of nectar which led to about 150-fold higher amounts of total sugar per flower in bat- or sunbird-pollinated species than in bee-pollinated or autogamous species. This difference was even higher for total amino acids per flower (up to 1000-fold. As a consequence, some Nicotiana species invest large amounts of organic nitrogen for certain pollinators. Higher concentrations of inorganic ions, predominantly anions, were found in nectar of night-flowering species. Therefore, higher anion concentrations were also associated with pollinator types active at night. Malate, the main organic acid, was present in all nectar samples but the concentration was not correlated with pollinator type. In conclusion, statistical analyses revealed that pollinator types have a stronger effect on nectar composition than phylogenetic relations. In this context

Simulated orbits of heavy planetary ions at Mars for different IMF configurations

Science.gov (United States)

Curry, Shannon; Luhmann, Janet; Livi, Roberto; Hara, Takuya; Dong, Chuanfei; Ma, Yingjuan; McFadden, James; Bougher, Stephen

2014-11-01

We present simulated detections of O+, O2+ and CO2+ ions at Mars along a virtual orbit in the Mars space environment. Planetary pick-up ions are formed through the direct interaction of the solar wind with the neutral upper atmosphere, causing the newly created ions to be picked up and accelerated by the background convective electric field. Because previous missions such as Mars Global Surveyor (MGS) and Mars Express (MEX) have not been able to measure the interplanetary magnetic field (IMF) components simultaneously with plasma measurements, the response of heavy planetary pick-up ions to changes in the IMF has not been well characterized. Using a steady-state multi-species MHD model to provide the background electric and magnetic fields, the Mars Test Particle (MTP) simulation can trace each of these particles along field lines in near-Mars space and construct virtual ion detections from a spacecraft orbit. Specifically, we will present energy-time spectrograms and velocity space distributions (VSDs) for a selection of orbits during different IMF configurations and solar cycle conditions. These simulated orbits have broader implications for how to measure ion escape. Using individual particle traces, the origin and trajectories of different ion populations can be analyzed in order to assess how and where they contribute to the total atmospheric escape rate, which is a major objective of the upcoming MAVEN mission.

Strong Interaction Studies with PANDA at FAIR

Science.gov (United States)

Schönning, Karin

2016-10-01

The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme.

Strong Interaction Studies with PANDA at FAIR

International Nuclear Information System (INIS)

Schönning, Karin

2016-01-01

The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme

3.5 Radiation stability of ion exchangers

International Nuclear Information System (INIS)

Marhol, M.

1976-01-01

The main knowledge is summed up of the radiation stability of ion exchangers. No basic changes occur in inorganic ion exchangers with the exception of the exchange capacity at doses of up to 10 9 rad. This also applies to coal-based ion exchangers. Tables are given showing the changes in specific volume, exchange capacity and weight of different types of organic ion exchangers in dependence on the radiation dose. The effects are discussed of the structure of organic cation and anion exchangers, polymeric strong basic anion exchangers, polycondensate anion exchangers and ion exchange membranes on their radiation stability. General experimental procedures are given for laboratory tests of the radiation stability of exchangers. (L.K.)

Strong dopant dependence of electric transport in ion-gated MoS2

NARCIS (Netherlands)

Piatti, Erik; Chen, Qihong; Ye, Jianting

2017-01-01

We report modifications of the temperature-dependent transport properties of MoS2 thin flakes via field-driven ion intercalation in an electric double layer transistor. We find that intercalation with Li+ ions induces the onset of an inhomogeneous superconducting state. Intercalation with K+ leads

A strong shock tube problem calculated by different numerical schemes

Science.gov (United States)

Lee, Wen Ho; Clancy, Sean P.

1996-05-01

Calculated results are presented for the solution of a very strong shock tube problem on a coarse mesh using (1) MESA code, (2) UNICORN code, (3) Schulz hydro, and (4) modified TVD scheme. The first two codes are written in Eulerian coordinates, whereas methods (3) and (4) are in Lagrangian coordinates. MESA and UNICORN codes are both of second order and use different monotonic advection method to avoid the Gibbs phenomena. Code (3) uses typical artificial viscosity for inviscid flow, whereas code (4) uses a modified TVD scheme. The test problem is a strong shock tube problem with a pressure ratio of 109 and density ratio of 103 in an ideal gas. For no mass-matching case, Schulz hydro is better than TVD scheme. In the case of mass-matching, there is no difference between them. MESA and UNICORN results are nearly the same. However, the computed positions such as the contact discontinuity (i.e. the material interface) are not as accurate as the Lagrangian methods.

Evidence for a glassy state in strongly driven carbon

International Nuclear Information System (INIS)

Brown, C.R.D.; Gericke, D.O.; Wunsch, K.; Cammarata, M.; Fritz, D.; Glenzer, S.H.; Heimann, P.; Lee, H.J.; Lemke, H.; Nagler, B.; Zhu, D.; Galtier, E.; Moinard, A.; Rosmej, F.B.

2014-01-01

Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen close to their original positions in the fluid. (authors)

The exotic molecular ion H{sub 4}{sup 3+} in a strong magnetic field; El ion molecular exotico H{sub 4}{sup 3+} en un campo magnetico intenso

Energy Technology Data Exchange (ETDEWEB)

Olivares P, H. [ICN-UNAM, A.P. 70-543, 04510 Mexico D.F. (Mexico)]. e-mail: horop@nucleares.unam.mx

2006-07-01

Using the variational method, a detailed study of the lowest m = 0, -1 electronic states of the exotic molecular ion H3+{sub 4} in a strong magnetic field, in the linear symmetric configuration parallel to the direction of the magnetic field is carried out. A extended study of the 1{sigma}g ground state (J.C. Lopez and A.Turbiner, Phys. Rev A 62, 022510, 2000) was performed obtaining that the potential energy curve displays a sufficiently deep minimum for finite internuclear distances, indicating the possible existence of the molecular ion H{sub 4}{sup 3+}, for magnetic fields of strength B > {approx} 3 x 10{sup 13} G. It is demonstrated that the excited state 1{pi}{sub u}, can exist for a magnetic field B = 4.414 x 10{sup 13} G corresponding to the limit of applicability of the non-relativistic theory. (Author)

Simple area determination of strongly overlapping ion mobility peaks

Czech Academy of Sciences Publication Activity Database

Borovcová, L.; Hermannová, M.; Pauk, V.; Šimek, M.; Havlíček, Vladimír; Lemr, Karel

2017-01-01

Roč. 981, AUG 15 (2017), s. 71-79 ISSN 0003-2670 Grant - others:GA MŠk(CZ) LO1305 Institutional support: RVO:61388971 Keywords : Ion mobility-mass spectrometry * Fitting of mobility peaks * Analysis of isomers Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 4.950, year: 2016

Ion cyclotron resonance heating

International Nuclear Information System (INIS)

Tajima, T.

1982-01-01

Ion cyclotron resonance heating of plasmas in tokamak and EBT configurations has been studied using 1-2/2 and 2-1/2 dimensional fully self-consistent electromagnetic particle codes. We have tested two major antenna configurations; we have also compared heating efficiencies for one and two ion species plasmas. We model a tokamak plasma with a uniform poloidal field and 1/R toroidal field on a particular q surface. Ion cyclotron waves are excited on the low field side by antennas parallel either to the poloidal direction or to the toroidal direction with different phase velocities. In 2D, minority ion heating (vsub(perpendicular)) and electron heating (vsub(parallel),vsub(perpendicular)) are observed. The exponential electron heating seems due to the decay instability. The minority heating is consistent with mode conversion of fast Alfven waves and heating by electrostatic ion cyclotron modes. Minority heating is stronger with a poloidal antenna. The strong electron heating is accompanied by toroidal current generation. In 1D, no thermal instability was observed and only strong minority heating resulted. For an EBT plasma we model it by a multiple mirror. We have tested heating efficiency with various minority concentrations, temperatures, mirror ratios, and phase velocities. In this geometry we have beach or inverse beach heating associated with the mode conversion layer perpendicular to the toroidal field. No appreciable electron heating is observed. Heating of ions is linear in time. For both tokamak and EBT slight majority heating above the collisional rate is observed due to the second harmonic heating. (author)

Radial Distribution Functions of Strongly Coupled Two-Temperature Plasmas

Science.gov (United States)

Shaffer, Nathaniel R.; Tiwari, Sanat Kumar; Baalrud, Scott D.

2017-10-01

We present tests of three theoretical models for the radial distribution functions (RDFs) in two-temperature strongly coupled plasmas. RDFs are useful in extending plasma thermodynamics and kinetic theory to strong coupling, but they are usually known only for thermal equilibrium or for approximate one-component model plasmas. Accurate two-component modeling is necessary to understand the impact of strong coupling on inter-species transport, e.g., ambipolar diffusion and electron-ion temperature relaxation. We demonstrate that the Seuferling-Vogel-Toeppfer (SVT) extension of the hypernetted chain equations not only gives accurate RDFs (as compared with classical molecular dynamics simulations), but also has a simple connection with the Yukawa OCP model. This connection gives a practical means to recover the structure of the electron background from knowledge of the ion-ion RDF alone. Using the model RDFs in Effective Potential Theory, we report the first predictions of inter-species transport coefficients of strongly coupled plasmas far from equilibrium. This work is supported by NSF Grant No. PHY-1453736, AFSOR Award No. FA9550-16-1-0221, and used XSEDE computational resources.

Single ion induced surface nanostructures: a comparison between slow highly charged and swift heavy ions.

Science.gov (United States)

Aumayr, Friedrich; Facsko, Stefan; El-Said, Ayman S; Trautmann, Christina; Schleberger, Marika

2011-10-05

This topical review focuses on recent advances in the understanding of the formation of surface nanostructures, an intriguing phenomenon in ion-surface interaction due to the impact of individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by the formation of a surface nanostructure. More recently, a similar nanometric surface effect has been revealed for the impact of individual, very slow but highly charged ions. While swift ions transfer their large kinetic energy to the target via ionization and electronic excitation processes (electronic stopping), slow highly charged ions produce surface structures due to potential energy deposited at the top surface layers. Despite the differences in primary excitation, the similarity between the nanostructures is striking and strongly points to a common mechanism related to the energy transfer from the electronic to the lattice system of the target. A comparison of surface structures induced by swift heavy ions and slow highly charged ions provides a valuable insight to better understand the formation mechanisms. © 2011 IOP Publishing Ltd

Spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources. Experimental results

International Nuclear Information System (INIS)

Panitzsch, Lauri

2013-01-01

The experimental determination of the spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources (ECRIS) defines the focus of this thesis. The spatial distributions of different ion species were obtained in the object plane of the bending magnet (∼45 cm downstream from the plasma electrode) and in the plane of the plasma electrode itself, both in high spatial resolution. The results show that each of the different ion species forms a bloated, triangular structure in the aperture of the plasma electrode. The geometry and the orientation of these structures are defined by the superposition of the radial and axial magnetic fields. The radial extent of each structure is defined by the charge of the ion. Higher charge states occupy smaller, more concentrated structures. The total current density increases towards the center of the plasma electrode. The circular and star-like structures that can be observed in the beam profiles of strongly focused, extracted ion beams are each dominated by ions of a single charge state. In addition, the spatially resolved current density distribution of charged particles in the plasma chamber that impinge on the plasma electrode was determined, differentiating between ions and electrons. The experimental results of this work show that the electrons of the plasma are strongly connected to the magnetic field lines in the source and thus spatially well confined in a triangular-like structure. The intensity of the electrons increases towards the center of the plasma electrode and the plasma chamber, as well. These electrons are surrounded by a spatially far less confined and less intense ion population. All the findings mentioned above were already predicted in parts by simulations of different groups. However, the results presented within this thesis represent the first (and by now only) direct experimental verification of those predictions and are qualitatively transferable to other

Spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources. Experimental results

Energy Technology Data Exchange (ETDEWEB)

Panitzsch, Lauri

2013-02-08

The experimental determination of the spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources (ECRIS) defines the focus of this thesis. The spatial distributions of different ion species were obtained in the object plane of the bending magnet ({approx}45 cm downstream from the plasma electrode) and in the plane of the plasma electrode itself, both in high spatial resolution. The results show that each of the different ion species forms a bloated, triangular structure in the aperture of the plasma electrode. The geometry and the orientation of these structures are defined by the superposition of the radial and axial magnetic fields. The radial extent of each structure is defined by the charge of the ion. Higher charge states occupy smaller, more concentrated structures. The total current density increases towards the center of the plasma electrode. The circular and star-like structures that can be observed in the beam profiles of strongly focused, extracted ion beams are each dominated by ions of a single charge state. In addition, the spatially resolved current density distribution of charged particles in the plasma chamber that impinge on the plasma electrode was determined, differentiating between ions and electrons. The experimental results of this work show that the electrons of the plasma are strongly connected to the magnetic field lines in the source and thus spatially well confined in a triangular-like structure. The intensity of the electrons increases towards the center of the plasma electrode and the plasma chamber, as well. These electrons are surrounded by a spatially far less confined and less intense ion population. All the findings mentioned above were already predicted in parts by simulations of different groups. However, the results presented within this thesis represent the first (and by now only) direct experimental verification of those predictions and are qualitatively transferable to

SOLVENT EFFECTS ON THE HYDRATION OF CYCLOHEXENE CATALYZED BY A STRONG ACID ION-EXCHANGE RESIN .2. EFFECT OF SULFOLANE ON THE REACTION-KINETICS

NARCIS (Netherlands)

PANNEMAN, HJ; BEENACKERS, AACM

The kinetics of the' hydration of cyclohexene, catalyzed by a strong acid ion-exchange resin, have been studied in a packed bed reactor at temperatures between 353 and 413 K and a pressure of 20 bar. The kinetic rate constants were measured as a function of temperature and solvent composition (0-90

Spin dependence in the neutralization of He+ ions in metals: An analysis of different contributions

International Nuclear Information System (INIS)

Alducin, M.

2005-01-01

We study the spin polarization of the Auger electrons produced during the neutralization of He + ions in a free electron gas. In this process, one metal electron decays to the unoccupied state and a second electron is promoted to a continuum excited state. Although the spin of the decaying electron is fixed, both spins are allowed for the excited one. The states of the electrons involved in this Auger capture process are described by the spin-dependent Kohn-Sham orbitals obtained from density functional theory and the local spin approximation. The Auger capture rates indicate a strong polarization of the excited electron. In a paramagnetic free electron gas, there are two mechanisms accounting for this effect, the spin-dependent screening and the interference between indistinguishable processes when the involved electrons are in the same spin state. In a spin-polarized medium, the difference in the density of spin-up and spin-down electrons is a new ingredient to be considered. As a result, the excited electrons preferably come from the majority band, even in the case of He + ions with spin opposite to that of the majority band embedded in a low spin-polarized free electron gas

Quantum entanglement in strong-field ionization

Science.gov (United States)

Majorosi, Szilárd; Benedict, Mihály G.; Czirják, Attila

2017-10-01

We investigate the time evolution of quantum entanglement between an electron, liberated by a strong few-cycle laser pulse, and its parent ion core. Since the standard procedure is numerically prohibitive in this case, we propose a method to quantify the quantum correlation in such a system: we use the reduced density matrices of the directional subspaces along the polarization of the laser pulse and along the transverse directions as building blocks for an approximate entanglement entropy. We present our results, based on accurate numerical simulations, in terms of several of these entropies, for selected values of the peak electric-field strength and the carrier-envelope phase difference of the laser pulse. The time evolution of the mutual entropy of the electron and the ion-core motion along the direction of the laser polarization is similar to our earlier results based on a simple one-dimensional model. However, taking into account also the dynamics perpendicular to the laser polarization reveals a surprisingly different entanglement dynamics above the laser intensity range corresponding to pure tunneling: the quantum entanglement decreases with time in the over-the-barrier ionization regime.

Study of the ionization of H+2 ions in strong laser fields

International Nuclear Information System (INIS)

Odenweller, Matthias

2010-01-01

In the framework of this thesis it has been succeeded to develop a worldwide unique measurement apparatur, by which hydrogen-molecule ions can be ionized by means of short laser pulses and the reaction product kinematically completely measured. For this a detection method following the Coltrims technique, in which both protons and electrons can be detected over the complete spatial angle. The H + 2 ions origin from a high-frequency ion source and are accelerated to 400 keV. This ion beam is overlapped with a 780-nm laser pulse othe pulse length 40 fs. After the reaction the molecule ions fragments either via the dissociation channel H + 2 +nhν→H+H + or via an ionization followed by a Coulomb explosion: H + 2 +nhν→H + +H + +e - . The projectiles are detected after a drift path of about 3 m on an ion detector. For the detection of the electrons a special spectrometer was concipated. In the reaction it comes by the comparatively long pulse length already at low intensities to dissociation processes. The dissociating molecule reaches still during the increasing side of the laser pulse in this way distances, in which the charge-resonance-enhanced-ionization (CREI) can take place. Also the angular distribution of the measured protons lying in a very small angular range around the polarization direction of the laser suggests that CREI is the dominant ionization process. At circular polarization however a netto-acceleration of the electrons perpendicularly to the direction of the electric field at the ionization time takes place, so that the measurement of the electron momenta represents a suited measurement quantity for the study of the ionization process. By this way angular distributions of the electrons relatively to the internuclear axis within the polarization plane could be measured.

Different structural requirements for functional ion pore transplantation suggest different gating mechanisms of NMDA and kainate receptors.

Science.gov (United States)

Villmann, Carmen; Hoffmann, Jutta; Werner, Markus; Kott, Sabine; Strutz-Seebohm, Nathalie; Nilsson, Tanja; Hollmann, Michael

2008-10-01

Although considerable progress has been made in characterizing the physiological function of the high-affinity kainate (KA) receptor subunits KA1 and KA2, no homomeric ion channel function has been shown. An ion channel transplantation approach was employed in this study to directly test if homomerically expressed KA1 and KA2 pore domains are capable of conducting currents. Transplantation of the ion pore of KA1 or KA2 into GluR6 generated perfectly functional ion channels that allowed characterization of those electrophysiological and pharmacological properties that are determined exclusively by the ion pore of KA1 or KA2. This demonstrates for the first time that KA1 and KA2 ion pore domains are intrinsically capable of conducting ions even in homomeric pore assemblies. NMDA receptors, similar to KA1- or KA2-containing receptors, function only as heteromeric complexes. They are composed of NR1 and NR2 subunits, which both are non-functional when expressed homomerically. In contrast to NR1, the homomeric NR2B ion pore failed to translate ligand binding into pore opening when transplanted into GluR6. Similarly, heteromeric coexpression of the ion channel domains of both NR1 and NR2 inserted into GluR6 failed to produce functional channels. Therefore, we conclude that the mechanism underlying the ion channel opening in the obligatorily heterotetrameric NMDA receptors differs significantly from that in the facultatively heterotetrameric alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate and KA receptors.

Using different drift gases to change separation factors (alpha) in ion mobility spectrometry

Science.gov (United States)

Asbury; Hill

2000-02-01

The use of different drift gases to alter separation factors (alpha) in ion mobility spectrometry has been demonstrated. The mobility of a series of low molecular weight compounds and three small peptides was determined in four different drift gases. The drift gases chosen were helium, argon, nitrogen, and carbon dioxide. These drift gases provide a range of polarizabilities and molecular weights. In all instances, the compounds showed the greatest mobility in helium and the lowest mobility in carbon dioxide; however the percentage change of mobility for each compound was different, effectively changing the alpha value. The alpha value changes were primarily due to differences in drift gas polarizability but were also influenced by the mass of the drift gas. In addition, gas-phase ion radii were calculated in each of the different drift gases. These radii were then plotted against drift gas polarizability producing linear plots with r2 values greater than 0.99. The intercept of these plots provides the gas-phase radius of an ion in a nonpolarizing environment, whereas the slope is indicative of the magnitude of the ion's mobility change related to polarizability. It therefore, should be possible to separate any two compounds that have different slopes with the appropriate drift gas.

Space and velocity distributions of fast ions in magnetically confined plasmas

International Nuclear Information System (INIS)

Kolesnichenko, Ya.I.; Lutsenko, V.V.; Lisak, M.; Wising, F.

1994-01-01

General expressions in terms of the orbit averaged distribution function are obtained for local characteristic quantities of fast ions, such as the velocity distribution, energy density and power deposition. The resulting expressions are applied to the case of a very peaked production profile of fast ions, characterized by particularly strong orbital effects. It is shown that in this case the radial profiles of the fast ions can be qualitatively different from the source profile, being e.g. strongly non-monotonic. The analysis is carried out for a straight as well as for a tokamak magnetic field. It is predicted that marginally co-passing and semi-trapped particles (i.e. particles that are trapped in only one azimuthal direction) can be transformed to trapped and circulating particles due to electron drag. This leads to e.g. different distribution functions of fast ions in the cases of co- or counter-injection. Collisional constants of motion are obtained

Intermittency in Hall-magnetohydrodynamics with a strong guide field

OpenAIRE

Imazio, P. Rodriguez; Martin, L. N.; Dmitruk, P.; Mininni, P. D.

2013-01-01

We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure funct...

Enhanced electron/fuel-ion equilibration through impurity ions: Studies applicable to NIF and Omega

Science.gov (United States)

Petrasso, R. D.; Sio, H.; Kabadi, N.; Lahmann, B.; Simpson, R.; Parker, C.; Frenje, J.; Gatu Johnson, M.; Li, C. K.; Seguin, F. H.; Rinderknecht, H.; Casey, D.; Grabowski, P.; Graziani, F.; Taitano, W.; Le, A.; Chacon, L.; Hoffman, N.; Kagan, G.; Simakov, A.; Zylstra, A.; Rosenberg, M.; Betti, R.; Srinivasan, B.; Mancini, R.

2017-10-01

In shock-driven exploding-pushers, a platform used extensively to study multi-species and kinetic effects, electrons and fuel ions are far out of equilibrium, as reflected by very different temperatures. However, impurity ions, even in small quantities, can couple effectively to the electrons, because of a Z2 dependence, and in turn, impurity ions can then strongly couple to the fuel ions. Through this mechanism, electrons and fuel-ions can equilibrate much faster than they otherwise would. This is a quantitative issue, depending upon the amount and Z of the impurity. For NIF and Omega, we consider the role of this process. Coupled non-linear equations, reflecting the temperatures of the three species, are solved for a range of conditions. Consideration is also given to ablatively driven implosions, since impurities can similarly affect the equilibration. This work was supported in part by DOE/NNSA DE-NA0002949 and DE-NA0002726.

A strong shock tube problem calculated by different numerical schemes

International Nuclear Information System (INIS)

Lee, W.H.; Clancy, S.P.

1996-01-01

Calculated results are presented for the solution of a very strong shock tube problem on a coarse mesh using (1) MESA code, (2) UNICORN code, (3) Schulz hydro, and (4) modified TVD scheme. The first two codes are written in Eulerian coordinates, whereas methods (3) and (4) are in Lagrangian coordinates. MESA and UNICORN codes are both of second order and use different monotonic advection method to avoid the Gibbs phenomena. Code (3) uses typical artificial viscosity for inviscid flow, whereas code (4) uses a modified TVD scheme. The test problem is a strong shock tube problem with a pressure ratio of 10 9 and density ratio of 10 3 in an ideal gas. For no mass-matching case, Schulz hydro is better than TVD scheme. In the case of mass-matching, there is no difference between them. MESA and UNICORN results are nearly the same. However, the computed positions such as the contact discontinuity (i.e. the material interface) are not as accurate as the Lagrangian methods. copyright 1996 American Institute of Physics

Anisotropic flow studies with identified particles with ALICE: a tool to probe different stages of a heavy-ion collision

CERN Multimedia

CERN. Geneva

2017-01-01

Anisotropic flow studies play a crucial role in the characterization of the nature of the quark gluon plasma (QGP) created in collisions of heavy ions at ultra-relativistic energies. These studies rely on measuring the coefficients vn of the Fourier expansion of the azimuthal particle distribution. They have been essential in establishing that the QGP is a strongly coupled, almost perfect fluid. In this seminar, I review the latest results from measurements of elliptic (v2), triangular (v3), quadrangular (v4) and pentagonal (v5) flow of identified particles at the LHC measured with ALICE. I will discuss how these results allow us to gain insight into the transport properties of the QGP and the initial conditions of a heavy-ion collision. In addition, they reveal the role of different hadronisation mechanisms as well as the highly dissipative hadronic rescattering phase to the development of vn.

Cation–Anion Interactions within the Nucleic Acid Ion Atmosphere Revealed by Ion Counting

Science.gov (United States)

Gebala, Magdalena; Giambasu, George M.; Lipfert, Jan; Bisaria, Namita; Bonilla, Steve; Li, Guangchao; York, Darrin M.; Herschlag, Daniel

2016-01-01

The ion atmosphere is a critical structural, dynamic, and energetic component of nucleic acids that profoundly affects their interactions with proteins and ligands. Experimental methods that “count” the number of ions thermodynamically associated with the ion atmosphere allow dissection of energetic properties of the ion atmosphere, and thus provide direct comparison to theoretical results. Previous experiments have focused primarily on the cations that are attracted to nucleic acid polyanions, but have also showed that anions are excluded from the ion atmosphere. Herein, we have systematically explored the properties of anion exclusion, testing the zeroth-order model that anions of different identity are equally excluded due to electrostatic repulsion. Using a series of monovalent salts, we find, surprisingly, that the extent of anion exclusion and cation inclusion significantly depends on salt identity. The differences are prominent at higher concentrations and mirror trends in mean activity coefficients of the electrolyte solutions. Salts with lower activity coefficients exhibit greater accumulation of both cations and anions within the ion atmosphere, strongly suggesting that cation–anion correlation effects are present in the ion atmosphere and need to be accounted for to understand electrostatic interactions of nucleic acids. To test whether the effects of cation–anion correlations extend to nucleic acid kinetics and thermodynamics, we followed the folding of P4–P6, a domain of the Tetrahymena group I ribozyme, via single-molecule fluorescence resonance energy transfer in solutions with different salts. Solutions of identical concentration but lower activity gave slower and less favorable folding. Our results reveal hitherto unknown properties of the ion atmosphere and suggest possible roles of oriented ion pairs or anion-bridged cations in the ion atmosphere for electrolyte solutions of salts with reduced activity. Consideration of these new

Quantum Electrodynamical Shifts in Multivalent Heavy Ions.

Science.gov (United States)

Tupitsyn, I I; Kozlov, M G; Safronova, M S; Shabaev, V M; Dzuba, V A

2016-12-16

The quantum electrodynamics (QED) corrections are directly incorporated into the most accurate treatment of the correlation corrections for ions with complex electronic structure of interest to metrology and tests of fundamental physics. We compared the performance of four different QED potentials for various systems to access the accuracy of QED calculations and to make a prediction of highly charged ion properties urgently needed for planning future experiments. We find that all four potentials give consistent and reliable results for ions of interest. For the strongly bound electrons, the nonlocal potentials are more accurate than the local potential.

Electron beam induced strong organic/inorganic grafting for thermally stable lithium-ion battery separators

Science.gov (United States)

Choi, Yunah; Kim, Jin Il; Moon, Jungjin; Jeong, Jongyeob; Park, Jong Hyeok

2018-06-01

A tailored interface between organic and inorganic materials is of great importance to maximize the synergistic effects from hybridization. Polyethylene separators over-coated with inorganic thin films are the state-of-the art technology for preparing various secondary batteries with high safety. Unfortunately, the organic/inorganic hybrid separators have the drawback of a non-ideal interface, thus causing poor thermal/dimensional stability. Here, we report a straightforward method to resolve the drawback of the non-ideal interface between vapor deposited SiO2 and polyethylene separators, to produce a highly stable lithium-ion battery separator through strong chemical linking generated by direct electron beam irradiation. The simple treatment with an electron beam with an optimized dose generates thermally stable polymer separators, which may enhance battery safety under high-temperature conditions. Additionally, the newly formed Si-O-C or Si-CH3 chemical bonding enhances electrolyte-separator compatibility and thus may provide a better environment for ionic transport between the cathode and anode, thereby leading to better charge/discharge behaviors.

Swift Heavy Ions in Matter

Science.gov (United States)

Rothard, Hermann; Severin, Daniel; Trautmann, Christina

2015-12-01

The present volume contains the proceedings of the Ninth International Symposium on Swift Heavy Ions in Matter (SHIM). This conference was held in Darmstadt, from 18 to 21 May 2015. SHIM is a triennial series, which started about 25 years ago by a joint initiative of CIRIL - Caen and GSI - Darmstadt, with the aim of promoting fundamental and applied interdisciplinary research in the field of high-energy, heavy-ion interaction processes with matter. SHIM was successively organized in Caen (1989), Bensheim (1992), Caen (1995), Berlin (1998), Catania (2002), Aschaffenburg (2005), Lyon (2008), and Kyoto (2012). The conference attracts scientists from many different fields using high-energy heavy ions delivered by large accelerator facilities and characterized by strong and short electronic excitations.

Modification of high density polyethylene by gold implantation using different ion energies

Energy Technology Data Exchange (ETDEWEB)

Nenadović, M.; Potočnik, J. [INS Vinca, Laboratory of Atomic Physics, University of Belgrade, Mike Alasa 12–14, 11001 Belgrade (Serbia); Mitrić, M. [INS Vinca, Condensed Matter Physics Laboratory, University of Belgrade, Mike Alasa 12–14, 11001 Belgrade (Serbia); Štrbac, S. [ICTM Institute of Electrochemistry, University of Belgrade, Njegoseva 12, 11001 Belgrade (Serbia); Rakočević, Z., E-mail: zlatkora@vinca.rs [INS Vinca, Laboratory of Atomic Physics, University of Belgrade, Mike Alasa 12–14, 11001 Belgrade (Serbia)

2013-11-01

High density polyethylene (HDPE) samples were modified by Au{sup +} ion implantation at a dose of 5 × 10{sup 15} ions cm{sup −2}, using energies of 50, 100, 150 and 200 keV. The existence of implanted gold in the near-surface region of HDPE samples was confirmed by X-ray diffraction analysis. Surface roughness and Power Spectral Density analyses based on Atomic Force Microscopy (AFM) images of the surface topography revealed that the mechanism of HDPE modification during gold ion implantation depended on the energy of gold ions. Histograms obtained from phase AFM images indicated a qualitative change in the chemical composition of the surface during implantation with gold ions with different energies. Depth profiles obtained experimentally from cross-sectional Force Modulation Microscopy images and ones obtained from a theoretical simulation are in agreement for gold ions energies lower than 100 keV. The deviation that was observed for higher energies of the gold ions is explained by carbon precipitation in the near surface region of the HDPE, which prevented the penetration of gold ions further into the depth of the sample. - Highlights: • HDPE was implanted by Au{sup +} ions using energies of 50, 100, 150 and 200 keV. • Surface composition was analyzed from phase AFM images. • FMM depth profiles are in agreement with theoretical ones for energies up to 100 keV. • A deviation is observed for higher gold ion energies.

Modification of high density polyethylene by gold implantation using different ion energies

International Nuclear Information System (INIS)

Nenadović, M.; Potočnik, J.; Mitrić, M.; Štrbac, S.; Rakočević, Z.

2013-01-01

High density polyethylene (HDPE) samples were modified by Au + ion implantation at a dose of 5 × 10 15 ions cm −2 , using energies of 50, 100, 150 and 200 keV. The existence of implanted gold in the near-surface region of HDPE samples was confirmed by X-ray diffraction analysis. Surface roughness and Power Spectral Density analyses based on Atomic Force Microscopy (AFM) images of the surface topography revealed that the mechanism of HDPE modification during gold ion implantation depended on the energy of gold ions. Histograms obtained from phase AFM images indicated a qualitative change in the chemical composition of the surface during implantation with gold ions with different energies. Depth profiles obtained experimentally from cross-sectional Force Modulation Microscopy images and ones obtained from a theoretical simulation are in agreement for gold ions energies lower than 100 keV. The deviation that was observed for higher energies of the gold ions is explained by carbon precipitation in the near surface region of the HDPE, which prevented the penetration of gold ions further into the depth of the sample. - Highlights: • HDPE was implanted by Au + ions using energies of 50, 100, 150 and 200 keV. • Surface composition was analyzed from phase AFM images. • FMM depth profiles are in agreement with theoretical ones for energies up to 100 keV. • A deviation is observed for higher gold ion energies

Performance of Electrocoagulation Process for Removal of Sulphate Ion from Aqueous Environments Using Plate Aluminum Electrodes

Directory of Open Access Journals (Sweden)

a.h Mahvi

2012-05-01

Full Text Available

<strong>Background and Objectives:strong> Sulphate ion is one of the main ions available in natural and waste water. The high rate of sulphate in drinking water causes health problems such as irritation and digestive problems and makes water taste bitter. The purpose of this study was to assess the efficiency of sulphate ion removal from drinking water through Electrocogualation process (EC using plate aluminum electrodes. <strong>Methods:> This study was conducted as a pilot plant using one glass tank in the volume of 1.3liter containing 6 plate aluminum electrodes. These electrodes were attached to a power supply in a mono-polar and parallel arrangement in order to switch the alternating current to the direct one. That is, each electrode was attached to positive and negative poles directly and alternately. The tank was filled with synthetic water containing sulphate ion with the concentration of 350 & 700mg/L. Percentage of sulphate ion removal in potential range of 10, 20 and 30 V, reaction times of 40, 20 and 60min and pH 7.0, 3.0 & 11.0 were measured. <strong>Results: strong>In this study the maximum efficiency of sulphate ion removal was in the electrical potential of 30 V, reaction time of 60min and pH 11.0. With increase of ion concentration, the time needed to achieve a suitable efficiency of removal increased, that is, it indicated the direct effect of pH and difference of electrical potential on removal of sulphate ion through EC process. <strong>Conclusion:> The results of this research show that Electrocogualation technology can be introduced as a suitable and promising technique to remove sulphate ion from aqueous environments using plate aluminum electrodes.

Ion-ion coincidence imaging at high event rate using an in-vacuum pixel detector

Science.gov (United States)

Long, Jingming; Furch, Federico J.; Durá, Judith; Tremsin, Anton S.; Vallerga, John; Schulz, Claus Peter; Rouzée, Arnaud; Vrakking, Marc J. J.

2017-07-01

A new ion-ion coincidence imaging spectrometer based on a pixelated complementary metal-oxide-semiconductor detector has been developed for the investigation of molecular ionization and fragmentation processes in strong laser fields. Used as a part of a velocity map imaging spectrometer, the detection system is comprised of a set of microchannel plates and a Timepix detector. A fast time-to-digital converter (TDC) is used to enhance the ion time-of-flight resolution by correlating timestamps registered separately by the Timepix detector and the TDC. In addition, sub-pixel spatial resolution (principle experiment on strong field dissociative double ionization of carbon dioxide molecules (CO2), using a 400 kHz repetition rate laser system. The experimental results demonstrate that the spectrometer can detect multiple ions in coincidence, making it a valuable tool for studying the fragmentation dynamics of molecules in strong laser fields.

Influence of hot beam ions on MHD ballooning modes in tokamaks

International Nuclear Information System (INIS)

Rewoldt, G.; Tang, W.M.

1984-01-01

It has recently been proposed that the presence of high-energy ions from neutral-beam injection can have a strong stabilizing effect on kinetically modified ideal-MHD ballooning modes in tokamaks. To assess realistically the importance of such effects, a comprehensive kinetic stability analysis, which takes into account the integral equation nature of the basic problem, has been applied to this investigation. In the collisionless limit, the effect of adding small fractions of hot beam ions is indeed found to be strongly stabilizing. On the other hand, for somewhat larger fractions of hot ions, a different, beam-driven root of the mode equations is found to occur with a growth rate comparable in magnitude to the growth rate of the usual MHD ballooning mode in the absence of hot ions. This implies that there should be an optimal density of hot particles which minimizes the strength of the relevant instabilities. Employing non-Maxwellian equilibrium distribution functions to model the beam species makes a quantitative, but not qualitative, difference in the results. Adding collisions to the calculation tends to reduce considerably the stabilizing effect of the hot ions. (author)

Investigation of the source size and strong interaction with the femtoscopic correlations of baryons and antibaryons in heavy-ion collisions registered by ALICE

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00508100

The strong interaction is one of the four fundamental forces of nature. It binds together quarks inside protons and neutrons (which are example of baryons - particles composed of three quarks) and assures the stability of the atomic nucleus. Parameters describing the strong potential are also crucial for the neutron stars models used in astrophysics. What is more, a precise study of strongly interacting particles may help to better understand the process of baryon annihilation. The current knowledge of the strong interactions between baryons other than nucle- ons is limited - there exist only a few measurements of the cross sections for pairs of (anti)baryons. The reason is that in many cases it is not possible to perform scattering experiments with beams of particles and antiparticles, as the exotic matter (such as Λ, Ξ or Σ baryons) is very shot-living. This issue can be solved thanks to the recent particle colliders like the Large Hadron Collider and experiments dedicated to study the heavy-ion collisio...

Kinetic theory for strongly coupled Coulomb systems

Science.gov (United States)

Dufty, James; Wrighton, Jeffrey

2018-01-01

The calculation of dynamical properties for matter under extreme conditions is a challenging task. The popular Kubo-Greenwood model exploits elements from equilibrium density-functional theory (DFT) that allow a detailed treatment of electron correlations, but its origin is largely phenomenological; traditional kinetic theories have a more secure foundation but are limited to weak ion-electron interactions. The objective here is to show how a combination of the two evolves naturally from the short-time limit for the generator of the effective single-electron dynamics governing time correlation functions without such limitations. This provides a theoretical context for the current DFT-related approach, the Kubo-Greenwood model, while showing the nature of its corrections. The method is to calculate the short-time dynamics in the single-electron subspace for a given configuration of the ions. This differs from the usual kinetic theory approach in which an average over the ions is performed as well. In this way the effective ion-electron interaction includes strong Coulomb coupling and is shown to be determined from DFT. The correlation functions have the form of the random-phase approximation for an inhomogeneous system but with renormalized ion-electron and electron-electron potentials. The dynamic structure function, density response function, and electrical conductivity are calculated as examples. The static local field corrections in the dielectric function are identified in this way. The current analysis is limited to semiclassical electrons (quantum statistical potentials), so important quantum conditions are excluded. However, a quantization of the kinetic theory is identified for broader application while awaiting its detailed derivation.

Intermittency in Hall-magnetohydrodynamics with a strong guide field

International Nuclear Information System (INIS)

Rodriguez Imazio, P.; Martin, L. N.; Dmitruk, P.; Mininni, P. D.

2013-01-01

We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure functions and probability density functions. In the magnetohydrodynamic limit, we recover the usual results with the magnetic field being more intermittent than the velocity field. In the presence of the Hall effect, field fluctuations at scales smaller than the ion skin depth show a substantial decrease in the level of intermittency, with close to monofractal scaling

Ion transport in turbulent edge plasmas

International Nuclear Information System (INIS)

Helander, P.; Massachusetts Inst. of Tech., Cambridge, MA; Hazeltine, R.D.; Catto, P.J.

1996-02-01

Edge plasmas, such as the tokamak scrape-off layer, exist as a consequence of a balance between cross-field diffusion and parallel losses. The former is usually anomalous, and is widely thought to be driven by strong electrostatic turbulence. It is shown that the anomalous diffusion affects the parallel ion transport by giving rise to a new type of thermal force between different ion species. This force is parallel to the magnetic field, but arises entirely because of perpendicular gradients, and could be important for impurity retention in the tokamak divertor. (author)

OBSERVATION OF STRONG - STRONG AND OTHER BEAM - BEAM EFFECTS IN RHIC

International Nuclear Information System (INIS)

FISCHER, W.; BLASKIEWICZ, M.; BRENNAN, J.M.; CAMERON, P.; CONNOLLY, R.; MONTAG, C.; PEGGS, S.; PILAT, F.; PTITSYN, V.; TEPIKIAN, S.; TRBOJEVIC, D.; VAN ZEIJTS, J.

2003-01-01

RHIC is currently the only hadron collider in which strong-strong beam-beam effects can be seen. For the first time, coherent beam-beam modes were observed in a bunched beam hadron collider. Other beam-beam effects in RHIC were observed in operation and in dedicated experiments with gold ions, deuterons and protons. Observations include measurements of beam-beam induced tune shifts, lifetime and emittance growth measurements with and without beam-beam interaction, and background rates as a function of tunes. During ramps unequal radio frequencies in the two rings cause the crossing points to move longitudinally. Thus bunches experience beam-beam interactions only in intervals and the tunes are modulated. In this article we summarize the most important beam-beam observations made so far

Strong-field dissociation dynamics

International Nuclear Information System (INIS)

DiMauro, L.F.; Yang, Baorui.

1993-01-01

The strong-field dissociation behavior of diatomic molecules is examined under two distinctive physical scenarios. In the first scenario, the dissociation of the isolated hydrogen and deuterium molecular ions is discussed. The dynamics of above-threshold dissociation (ATD) are investigated over a wide range of green and infrared intensities and compared to a dressed-state model. The second situation arises when strong-field neutral dissociation is followed by ionization of the atomic fragments. The study results in a direct measure of the atomic fragment's ac-Stark shift by observing the intensity-dependent shifts in the electron or nuclear fragment kinetic energy. 8 figs., 14 refs

Study on rare earths complexes separation by means of different type of ion exchangers

International Nuclear Information System (INIS)

Hubicka, H.

1990-01-01

The applicability of different types of ion exchangers for purification and separation of rare earths complexes has been examined. The experimental work has been carried out on 14 chelating ion exchangers. The investigation results proved the great usefulness chelating ion exchangers especially of amino acid and phosphorus-type. Application of that type ion exchangers in column chromatographic process gave the excellent rare earths separation as well as enabled to obtain their preparates of high purity. 218 refs, 21 figs, 27 tabs

Ion Release and Galvanic Corrosion of Different Orthodontic Brackets and Wires in Artificial Saliva.

Science.gov (United States)

Tahmasbi, Soodeh; Sheikh, Tahereh; Hemmati, Yasamin B

2017-03-01

To investigate the galvanic corrosion of brackets manufactured by four different companies coupled with stainless steel (SS) or nickel-titanium (NiTi) wires in an artificial saliva solution. A total of 24 mandibular central incisor Roth brackets of four different manufacturers (American Orthodontics, Dentaurum, Shinye, ORJ) were used in this experimental study. These brackets were immersed in artificial saliva along with SS or NiTi orthodontic wires (0.016'', round) for 28 days. The electric potential difference of each bracket/ wire coupled with a saturated calomel reference electrode was measured via a voltmeter and recorded constantly. Corrosion rate (CR) was calculated, and release of ions was measured with an atomic absorption spectrometer. Stereomicroscope was used to evaluate all samples. Then, samples with corrosion were further assessed by scanning electron microscope and energy-dispersive X-ray spectroscopy. Two-way analysis of variance was used to analyze data. Among ions evaluated, release of nickel ions from Shinye brackets was significantly higher than that of other brackets. The mean potential difference was significantly lower in specimens containing a couple of Shinye brackets and SS wire compared with other specimens. No significant difference was observed in the mean CR of various groups (p > 0.05). Microscopic evaluation showed corrosion in two samples only: Shinye bracket coupled with SS wire and American Orthodontics bracket coupled with NiTi wire. Shinye brackets coupled with SS wire showed more susceptibility to galvanic corrosion. There were no significant differences among specimens in terms of the CR or released ions except the release of Ni ions, which was higher in Shinye brackets.

Ion energy/momentum effects during ion assisted growth of niobium nitride films

Science.gov (United States)

Klingenberg, Melissa L.

The research described herein was performed to better understand and discern ion energy vs. ion momentum effects during ion beam assisted (IBAD) film growth and their effects on residual stress, crystalline structure, morphology, and composition, which influence film tribological properties. NbxN y was chosen for this research because it is a refractory material that can possess a large number of crystalline structures, and it has been found to have good tribological properties. To separate the effects of momentum transfer per arriving atom (p/a), which considers bombarding species mass, energy, and ion-to-atom transport ratio, from those of energy deposition per arriving atom (E/a), a mass independent parameter, different inert ion beams (krypton, argon, and neon) were used to create a matrix of coatings formed using similar energy deposition, but different momentum transfer and vice versa. Deposition was conducted in a research-scale IBAD system using electron beam evaporation, a radio frequency ion source, and a neutral nitrogen gas backfill. Films were characterized using x-ray diffraction, atomic force microscopy, Rutherford backscattering spectrometry, and residual stress analysis. Direct and quantifiable effects of bombardment were observed; however, energy deposition and momentum transfer effects could not be completely separated, confirming that thin film processes are complex. Complexities arose from ion-specific interactions (ion size, recoil energy, per cent reflected neutrals, Penning ionization, etc.) and chemistry effects that are not considered by the simple models. Overall, it can be stated that bombardment promoted nitride formation, nanocrystallinity, and compressive stress formation; influenced morphology (which influenced post-deposition oxygen uptake) and stress evolution; increased lattice parameter; modified crystalline phase and texture; and led to inert gas incorporation. High stress levels correlated strongly with material disorder and

The Activation Mechanism of Bi3+ Ions to Rutile Flotation in a Strong Acidic Environment

Directory of Open Access Journals (Sweden)

Wei Xiao

2017-07-01

Full Text Available Lead hydroxyl compounds are known as rutile flotation of the traditional activated component, but the optimum pH range for flotation is 2–3 using styryl phosphoric acid (SPA as collector, without lead hydroxyl compounds in slurry solution. In this study, Bi3+ ions as a novel activator was investigated. The results revealed that the presence of Bi3+ ions increased the surface potential, due to the specific adsorption of hydroxyl compounds, which greatly increases the adsorption capacity of SPA on the rutile surface. Bi3+ ions increased the activation sites through the form of hydroxyl species adsorbing on the rutile surface and occupying the steric position of the original Ca2+ ions. The proton substitution reaction occurred between the hydroxyl species of Bi3+ ions (Bi(OHn+(3−n and the hydroxylated rutile surface, producing the compounds of Ti-O-Bi2+. The micro-flotation tests results suggested that Bi3+ ions could improve the flotation recovery of rutile from 61% to 90%, and from 61% to 64% for Pb2+ ions.

Status of ion beam data analysis and simulation software

Energy Technology Data Exchange (ETDEWEB)

Rauhala, E. [Accelerator Laboratory, Department of Physics, University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland)]. E-mail: eero.rauhala@helsinki.fi; Barradas, N.P. [Instituto Tecnologico e Nuclear, Estrada Nacional No. 10, Apartado 21, 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Fazinic, S. [Rudjer Boskovic Institute, Bijenicka c.54, 10000 Zagreb (Croatia); Mayer, M. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Thompson, M. [Department of MS and E/Bard Hall 328, Cornell University, Ithaca, NY 14853 (United States)

2006-03-15

The status of ion beam data analysis codes dedicated to Rutherford backscattering, elastic recoil detection analysis and non-resonant nuclear reaction analysis, is reviewed. The most important methods and approaches employed are discussed. The stopping power and scattering cross-section databases used, the ion-target interaction physics, the experimental and detection system characteristics and the structure of samples all have a strong impact on the analytical results. The models and algorithms used by different codes are reviewed and discussed in detail. Limitations in existing codes and perspectives for further developments are presented. The importance of ascertaining the correctness and accuracy of different methods and codes used in ion beam data analysis is stressed.

Effects of the Charge Ions Strength on the Swelling of Organic-Inorganic Nanogels

Energy Technology Data Exchange (ETDEWEB)

Yu, Qin; Lu, Xiangguo; Wang, Jing; Guo, Qi; Niu, Liwei [Northeast Petroleum University, Daqing (China)

2016-07-15

The swelling behavior and swelling mechanism of hydrogels can be greatly affected by the charge strength of ions in them. To investigate such effects, we prepared two gels: a carboxylic acid gel (CAG) and a poly (2-acrylamide–methyl propane sulfonic acid) gel (SAG) based on starchy polyacrylamide (PAM) nanocomposite gels, both with montmorillonite, which underwent in situ intercalation, and used them as probes in swelling experiments. The equilibrium swelling rates (ESRs) of the hydrogels in both salt water and acidic water strongly depended on the charge strength of the ions in the chains. SAG had a higher ESR than CAG at the same mole ratio of polymer/water, which is attributed to the greater electrostatic repulsion between the strong electrolyte ions of SAG. Both water salinity and hydrogen ion contact of the hydrogels weakened ESR with the enhancement of charge ionic strength. The downward trend of ESR with increasing concentration of salt or hydrogen ions became weaker in SAG compared to CAG, which is attributed to the shielding and deprotonation effects of the strong electrolyte ions. Regarding the swelling mechanism, the chain relaxation occurred in neutral and acidic solutions for SAG and in neutral and weak acidic solutions for CAG, but water diffusion dominated in strong acidic solutions for CAG, leading to different swelling behaviors.

High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED.

Science.gov (United States)

Ullmann, Johannes; Andelkovic, Zoran; Brandau, Carsten; Dax, Andreas; Geithner, Wolfgang; Geppert, Christopher; Gorges, Christian; Hammen, Michael; Hannen, Volker; Kaufmann, Simon; König, Kristian; Litvinov, Yuri A; Lochmann, Matthias; Maaß, Bernhard; Meisner, Johann; Murböck, Tobias; Sánchez, Rodolfo; Schmidt, Matthias; Schmidt, Stefan; Steck, Markus; Stöhlker, Thomas; Thompson, Richard C; Trageser, Christian; Vollbrecht, Jonas; Weinheimer, Christian; Nörtershäuser, Wilfried

2017-05-16

Electrons bound in highly charged heavy ions such as hydrogen-like bismuth 209 Bi 82+ experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron-nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth 209 Bi 82+,80+ with a precision that is improved by more than an order of magnitude. Even though this quantity is believed to be largely insensitive to nuclear structure and therefore the most decisive test of QED in the strong magnetic field regime, we find a 7-σ discrepancy compared with the theoretical prediction.

The difference between the metal ion extracted from the R.F. ion source by applying plasma chemistry reaction and by non-plasma range chemistry reaction

International Nuclear Information System (INIS)

Bai Gui Bin

1987-01-01

The paper introduced the difference between using plasma chemistry reaction draw metal ion and non-plasma range chemistry reaction in the R.F. ion source. By using of the plasma chemistry reaction draw metal ion higher percentage than non-plasma range chemistry reaction in the R.F. ion source. The authors plasma chemistry reaction to R.F. ion source and implanter successfully. The effect is very well, it has its own characteristic

Copper ion fluxes through the floating water bridge under strong electric potential.

Science.gov (United States)

Giuliani, Livio; D'Emilia, Enrico; Lisi, Antonella; Grimaldi, Settimio; Brizhik, Larissa; Del Giudice, Emilio

2015-01-01

We have performed a series of experiments applying high voltage between two electrodes, immersed in two beakers containing bidistilled water in a way similar to experiments conducted by Fuchs and collaborators, which showed that a water bridge can be formed between the two containers. We also observed the formation of water bridge. Moreover, choosing different pairs of electrodes depending on the material they are made up of, we observed that copper ions flow can pass along the bridge if the negative electrode is made up of copper. We show that the direction of the flux not only depends on the applied electrostatic field but on the relative electronegativity of the electrodes too. These results open new perspectives in understanding the properties of water. We suggest a possible explanation of the obtained results.

Specific Ion Effects in Cholesterol Monolayers

Directory of Open Access Journals (Sweden)

Teresa Del Castillo-Santaella

2016-05-01

Full Text Available The interaction of ions with interfaces and, in particular, the high specificity of these interactions to the particular ions considered, are central questions in the field of surface forces. Here we study the effect of different salts (NaI, NaCl, CaCl2 and MgCl2 on monolayers made of cholesterol molecules, both experimentally (surface area vs. lateral pressure isotherms measured by a Langmuir Film Balance and theoretically (molecular dynamics (MD all-atomic simulations. We found that surface isotherms depend, both quantitatively and qualitatively, on the nature of the ions by altering the shape and features of the isotherm. In line with the experiments, MD simulations show clear evidences of specific ionic effects and also provide molecular level details on ion specific interactions with cholesterol. More importantly, MD simulations show that the interaction of a particular ion with the surface depends strongly on its counterion, a feature ignored so far in most theories of specific ionic effects in surface forces.

Atom-Pair Kinetics with Strong Electric-Dipole Interactions.

Science.gov (United States)

Thaicharoen, N; Gonçalves, L F; Raithel, G

2016-05-27

Rydberg-atom ensembles are switched from a weakly to a strongly interacting regime via adiabatic transformation of the atoms from an approximately nonpolar into a highly dipolar quantum state. The resultant electric dipole-dipole forces are probed using a device akin to a field ion microscope. Ion imaging and pair-correlation analysis reveal the kinetics of the interacting atoms. Dumbbell-shaped pair-correlation images demonstrate the anisotropy of the binary dipolar force. The dipolar C_{3} coefficient, derived from the time dependence of the images, agrees with the value calculated from the permanent electric-dipole moment of the atoms. The results indicate many-body dynamics akin to disorder-induced heating in strongly coupled particle systems.

Tumour control in ion beam radiotherapy with different ions in the presence of hypoxia: an oxygen enhancement ratio model based on the microdosimetric kinetic model

Science.gov (United States)

Strigari, L.; Torriani, F.; Manganaro, L.; Inaniwa, T.; Dalmasso, F.; Cirio, R.; Attili, A.

2018-03-01

Few attempts have been made to include the oxygen enhancement ratio (OER) in treatment planning for ion beam therapy, and systematic studies to evaluate the impact of hypoxia in treatment with the beam of different ion species are sorely needed. The radiobiological models used to quantify the OER in such studies are mainly based on the dose-averaged LET estimates, and do not explicitly distinguish between the ion species and fractionation schemes. In this study, a new type of OER modelling, based on the microdosimetric kinetic model, taking into account the specificity of the different ions, LET spectra, tissues and fractionation schemes, has been developed. The model has been benchmarked with published in vitro data, HSG, V79 and CHO cells in aerobic and hypoxic conditions, for different ion irradiation. The model has been included in the simulation of treatments for a clinical case (brain tumour) using proton, lithium, helium, carbon and oxygen ion beams. A study of the tumour control probability (TCP) as a function of oxygen partial pressure, dose per fraction and primary ion type has been performed. The modelled OER depends on both the LET and ion type, also showing a decrease for an increased dose per fraction with a slope that depends on the LET and ion type, in good agreement with the experimental data. In the investigated clinical case, a significant increase in TCP has been found upon increasing the ion charge. Higher OER variations as a function of dose per fraction have also been found for low-LET ions (up to 15% varying from 2 to 8 Gy(RBE) for protons). This model could be exploited in the identification of treatment condition optimality in the presence of hypoxia, including fractionation and primary particle selection.

Determination of gas phase protein ion densities via ion mobility analysis with charge reduction.

Science.gov (United States)

Maisser, Anne; Premnath, Vinay; Ghosh, Abhimanyu; Nguyen, Tuan Anh; Attoui, Michel; Hogan, Christopher J

2011-12-28

measurements to be correlated to biomolecular structures in solution, low charge state ions should be analyzed. Further, to determine if different solution conditions give rise to ions of different structure, ions of similar charge state should be compared. Non-denatured protein ion densities are found to be in excellent agreement with non-denatured protein ion densities inferred from prior DMA and drift tube measurements made without charge reduction (all ions with densities in the 0.85-1.10 g cm(-3) range), showing that these ions are not strongly influenced by Coulombic stretching nor by analysis method.

Studies on biological effects of nitrogen ion implantation in different genotype rice

International Nuclear Information System (INIS)

Xie Jiahua; Xia Yingwu; Shu Qingyao

1994-01-01

The biological effects of nitrogen ion implantation on different genotype rice (Oryza sativa L) were studied. The results showed that there were obvious differences in physiological damages for the M 1 generation, mutation frequencies and mutagenic efficiencies of chlorophyll, heading date and plant height for M 2 generation of different genotypes. Treated by nitrogen ions, the varieties with high mutation frequency and mutagenic efficiency of chlorophyll in the M 2 generation were not necessarily high in those of heading date and plant height. Moreover, the radiation sensitivity of Fu8530 and Fuxian No.6 which were bred by using early maturing and semidwarf mutants as maternal plant was low. The early maturing and high stature mutation were not induced with these two varieties

The influence of the poisoning ions on the residual uranium water treatment

International Nuclear Information System (INIS)

Aurelian, F.; Jinescu, G.

1997-01-01

This paper studies uranium adsorption from pond waters on an anionic resin, strongly basic - AM type - under conditions of different concentrations of the noxions ions - the nitric, chlorine, carbonate, bicarbonate, sulfate ions - and also various organic substances content under the form of humates. The order in which these ions hinder uranium adsorption on resin and the variation of the loading capacity of the resin, when the concentration of these increase, were established

Ultrasonic velocimetry studies on different salts of chitosan: Effect of ion size.

Science.gov (United States)

Mohan, C Raja; Sathya, R; Nithiananthi, P; Jayakumar, K

2017-11-01

In the present investigation, the effect of ion size on the thermodynamical properties such as ultrasonic velocity (U), adiabatic compressibility (β), acoustic impedance (Z), adiabatic bulk modulus (K s ), relaxation strength (r s ) have been obtained for the different salts of chitosan viz., formate (3.5Å), acetate (4.5Å), Succinate (5Å) and Adipate (6Å). To find the effect of ion size, the effect due to water has been removed by calculating the change in ultrasonic velocity (dU), change in adiabatic compressibility (dβ), in acoustic impedance (dZ), in adiabatic bulk modulus (dK s ), and in relaxation strength (dr s ). Space filling factor and polarizability has been obtained from the refractive index data through Lorentz-Lorentz relation. FTIR studies confirm the formation of different quaternary salts of chitosan and their size (mass) effects which has been verified with Hooke's law. All the said properties vary both with ion size and concentration of different salts of chitosan. This investigation may throw some light on better usage of chitosan in biomedical applications. The detailed results are presented and discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Non-exponential dynamic relaxation in strongly nonequilibrium nonideal plasmas

International Nuclear Information System (INIS)

Morozov, I V; Norman, G E

2003-01-01

Relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics method for nonideal two-component non-degenerate plasmas. Three limiting examples of initial states of strongly nonequilibrium plasma are considered: zero electron velocities, zero ion velocities and zero velocities of both electrons and ions. The initial non-exponential stage, its duration τ nB and subsequent exponential stages of the relaxation process are studied for a wide range of the nonideality parameter and the ion mass

Ion beam application for improved polymer surface properties

International Nuclear Information System (INIS)

Lee, E.H.; Rao, G.R.; Lewis, M.B.; Mansur, L.K.

1992-01-01

Various polymeric materials were subjected to bombardment by different energetic ions with energies ranging from 200 to 1000 keV. Tests showed substantial improvements in hardness, wear resistance, oxidation resistance, resistance to chemicals, and electrical conductivity. The magnitude of property changes was strongly dependent upon ion species, energy, dose, and polymer structure. Both hardness and electrical conductivity increased with ion energy and dose. These properties were apparently related to the effectiveness of cross-linking. Ion species with a large electronic stopping cross-section are expected to produce more crosslinking. It is believed that the polymer property improvements are commensurate with the extent of crosslinking, which is responsible for the formation of three-dimensionally-connected, carbon-rich, rigid networks. 22 refs, 5 figs

Radiation blistering of niobium in sequence irradiated by helium ions with different energy

International Nuclear Information System (INIS)

Das, S.K.; Kaminskij, M.S.; Guseva, M.I.; Gusev, V.M.; Krasulin, Yu.L.; Martynenko, Yu.V.; Rozina, I.A.

1977-01-01

The results of the investigation of the blistering of the surface of polycrystalline niobium foils subjected to successive irradiation by helium ions of energies of 3 to 50 keV are reported. The critical doses of irradiation, the types of blisters and the rate of erosion were determined. A comparative analysis of the formation of blisters on cold-rolled and annealed niobium has been made. On cold-rolled niobium the blistering is mainly due to ions with energies of 3 to 80 keV, on annealed niobium of 100 to 500 keV. The erosion of cold-rolled niobium takes place through blisters formed by the action of helium ions with energies of the order of 45 keV, and that of annealed niobium, through helium ions with energies of 100 to 500 keV. The observed differences in the formation of blisters on niobium irradiated with helium ions of a wide range of energies are explained by the change in the diffusion kinetics of implanted ions having a uniform distribution across the thickness of the target

Effects of ion beam irradiation on the microstructures and strengths of different carbon fibers

International Nuclear Information System (INIS)

Oku, Tatsuo; Kurumada, Akira; Kawamata, Kiyohiro; Inagaki, Michio

1998-01-01

The high energy argon ion was irradiated to different carbon fibers with various microstructures. The cross-sectional structures and strengths properties have been evaluated before and after ion irradiation. As a result, the diameter of fibers decreased due to ion irradiation, except for the fiber with dual structure. The tensile strength also decreased due to ion irradiation, except for fibers which were not heat-treated. This suggests that it is necessary to consider not only the defects in the vertical cross-section but also changes in defect structures in the axial direction. The results of computer simulation indicated that argon ion with 175MeV/1μA produced homogeneous defects in the carbon fibers with the diameter of about 20 μm. (author)

Simulation of weak and strong Langmuir collapse regimes

International Nuclear Information System (INIS)

Hadzievski, L.R.; Skoric, M.M.; Kono, M.; Sato, T.

1998-01-01

In order to check the validity of the self-similar solutions and the existence of weak and strong collapse regimes, direct two dimensional simulation of the time evolution of a Langmuir soliton instability is performed. Simulation is based on the Zakharov model of strong Langmuir turbulence in a weakly magnetized plasma accounting for the full ion dynamics. For parameters considered, agreement with self-similar dynamics of the weak collapse type is found with no evidence of the strong Langmuir collapse. (author)

Diffuse ions produced by electromagnetic ion beam instabilities

International Nuclear Information System (INIS)

Winske, D.; Leroy, M.M.

1984-01-01

The evolution of the electromagnetic ions beam instability driven by the reflected ion component backstreaming away from the earth's how shock into the foreshock region is studied by means computer simulation. The linear the quasi-linear states of the instability are found to be in good agreement with known results for the resonant model propagating parallel to the beam along the magnetic field and with theory developed in this paper for the nonresonant mode, which propagates antiparallel to the beam direction. The quasi-linear stage, which produces large amplitude 8Bapprox.B, sinusoidal transverse waves and ''intermediate'' ion distribution, is terminated by a nonlinear phase in which strongly nonlinear, compressive waves and ''diffuse'' ion distributions are produced. Additional processes by which the diffuse ions are accelerated to observed high energies are not addressed. The results are discussed in terms of the ion distributions and hydromagnetic waves observed in the foreshock of the earth's bow shock and of interplanetary shocks

Fe(III) and Fe(II) ions different effects on Enterococcus hirae cell growth and membrane-associated ATPase activity

Energy Technology Data Exchange (ETDEWEB)

Vardanyan, Zaruhi [Department of Biophysics of the Biology Faculty, Yerevan State University, 1 A. Manoukian Str., 0025 Yerevan (Armenia); Trchounian, Armen, E-mail: trchounian@ysu.am [Department of Biophysics of the Biology Faculty, Yerevan State University, 1 A. Manoukian Str., 0025 Yerevan (Armenia)

2012-01-06

interaction of these ions with F{sub 0}F{sub 1} or there might be a Fe{sup 3+}-dependent ATPase different from F{sub 0}F{sub 1} in these bacteria that is active even in the presence of DCCD. Fe{sup 2+} inhibits E. hirae cell growth probably by strong effect on E{sub h} leading to changes in F{sub 0}F{sub 1} and decreasing its activity.

The synthesis of Ag/polypyrrole coaxial nanocables via ion adsorption method using different oxidants

Science.gov (United States)

Qiu, Teng; Xie, Huxiao; Zhang, Jiangru; Zahoor, Amad; Li, Xiaoyu

2011-03-01

Ag/polypyrrole (PPy) coaxial nanocables (NCs) were synthesized by an ion adsorption method. In this method, the pre-made Ag nanowires (NWs) were dispersed in the aqueous solution of copper acetate (Cu(Ac)2), and the Cu2+ ions adsorbed onto the surface of Ag NWs can oxidize pyrrole monomers to polymerize into uniform PPy sheath outside Ag NWs after the Cu(Ac)2-treated Ag NWs were re-dispersed in the aqueous solution of pyrrole. The morphology of NCs was characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). The relationship between the thickness of polymer sheath and the concentration of Cu(Ac)2 was established. As Cu(Ac)2 which served as the oxidant can also be replaced by AgNO3 in this synthesis, the differences on the structure of polymer sheath caused by different oxidants were studied by surface-enhanced Raman scattering (SERS), high-resolution transmission electron microscope (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Comparing with the characterization results of Ag/PPy NCs synthesized using AgNO3 as the oxidant which indicates the random arrangement of PPy chains at the interface between polymer sheath and Ag NWs, PPy chain oxidized by Cu2+ tends to show a relatively ordered conformation at the interface with the pyrrole rings identically taking the plane vertical to the surface of Ag NWs. In addition, although the main part of the polymer sheath was composed of PPy whatever kind of oxidant was used, the sheath of the NCs oxidized by Cu2+ is typical for the existence of Cu(I)-pyrrole coordinate structures with strong Cu(I)-N bond signal shown in XPS characterization.

The synthesis of Ag/polypyrrole coaxial nanocables via ion adsorption method using different oxidants

International Nuclear Information System (INIS)

Qiu Teng; Xie Huxiao; Zhang Jiangru; Zahoor, Amad; Li Xiaoyu

2011-01-01

Ag/polypyrrole (PPy) coaxial nanocables (NCs) were synthesized by an ion adsorption method. In this method, the pre-made Ag nanowires (NWs) were dispersed in the aqueous solution of copper acetate (Cu(Ac) 2 ), and the Cu 2+ ions adsorbed onto the surface of Ag NWs can oxidize pyrrole monomers to polymerize into uniform PPy sheath outside Ag NWs after the Cu(Ac) 2 -treated Ag NWs were re-dispersed in the aqueous solution of pyrrole. The morphology of NCs was characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). The relationship between the thickness of polymer sheath and the concentration of Cu(Ac) 2 was established. As Cu(Ac) 2 which served as the oxidant can also be replaced by AgNO 3 in this synthesis, the differences on the structure of polymer sheath caused by different oxidants were studied by surface-enhanced Raman scattering (SERS), high-resolution transmission electron microscope (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Comparing with the characterization results of Ag/PPy NCs synthesized using AgNO 3 as the oxidant which indicates the random arrangement of PPy chains at the interface between polymer sheath and Ag NWs, PPy chain oxidized by Cu 2+ tends to show a relatively ordered conformation at the interface with the pyrrole rings identically taking the plane vertical to the surface of Ag NWs. In addition, although the main part of the polymer sheath was composed of PPy whatever kind of oxidant was used, the sheath of the NCs oxidized by Cu 2+ is typical for the existence of Cu(I)–pyrrole coordinate structures with strong Cu(I)–N bond signal shown in XPS characterization.

Nonlinear response and bistability of driven ion acoustic waves

Science.gov (United States)

Akbari-Moghanjoughi, M.

2017-08-01

The hydrodynamic model is used to obtain a generalized pseudoforce equation through which the nonlinear response of periodically driven ion acoustic waves is studied in an electron-ion plasma with isothermal and adiabatic ion fluids. The pseudotime series, corresponding to different driving frequencies, indicates that nonlinearity effects appear more strongly for smaller frequency values. The existence of extra harmonic resonances in the nonlinear amplitude spectrum is a clear indication of the interaction of an external force with harmonic components of the nonlinear ion acoustic waves. It is shown that many plasma parameters significantly and differently affect the nonlinear resonance spectrum of ion acoustic excitations. A heuristic but accurate model for the foldover effect is used which quite satisfactorily predicts the bistability of driven plasma oscillations. It is remarked that the characteristic resonance peak of isothermal ion plasma oscillations appears at lower frequencies but is stronger compared to that of adiabatic ions. Comparison of the exact numerical results for fully nonlinear and approximate (weakly nonlinear) models indicates that a weakly nonlinear model exaggerates the hysteresis and jump phenomenon for higher values of the external force amplitude.

The Effect of Solar Wind Variations on the Escape of Oxygen Ions From Mars Through Different Channels: MAVEN Observations

Science.gov (United States)

Dubinin, E.; Fraenz, M.; Pätzold, M.; McFadden, J.; Halekas, J. S.; DiBraccio, G. A.; Connerney, J. E. P.; Eparvier, F.; Brain, D.; Jakosky, B. M.; Vaisberg, O.; Zelenyi, L.

2017-11-01

We present multi-instrument observations of the effects of solar wind on ion escape fluxes on Mars based on the Mars Atmosphere and Volatile EvolutioN (MAVEN) data from 1 November 2014 to 15 May 2016. Losses of oxygen ions through different channels (plasma sheet, magnetic lobes, boundary layer, and ion plume) as a function of the solar wind and the interplanetary magnetic field variations were studied. We have utilized the modified Mars Solar Electric (MSE) coordinate system for separation of the different escape routes. Fluxes of the low-energy (≤30 eV) and high-energy (≥30 eV) ions reveal different trends with changes in the solar wind dynamic pressure, the solar wind flux, and the motional electric field. Major oxygen fluxes occur through the tail of the induced magnetosphere. The solar wind motional electric field produces an asymmetry in the ion fluxes and leads to different relations between ion fluxes supplying the tail from the different hemispheres and the solar wind dynamic pressure (or flux) and the motional electric field. The main driver for escape of the high-energy oxygen ions is the solar wind flux (or dynamic pressure). On the other hand, the low-energy ion component shows the opposite trend: ion flux decreases with increasing solar wind flux. As a result, the averaged total oxygen ion fluxes reveal a low variability with the solar wind strength. The large standard deviations from the averages values of the escape fluxes indicate the existence of mechanisms which can enhance or suppress the efficiency of the ion escape. It is shown that the Martian magnetosphere possesses the properties of a combined magnetosphere which contains different classes of field lines. The existence of the closed magnetic field lines in the near-Mars tail might be responsible for suppression of the ion escape fluxes.

Monitoring of trace chloride ions at different stages of the gas production process

Directory of Open Access Journals (Sweden)

A.Y. El Naggar

2015-01-01

Full Text Available Fifty gas and liquid samples at different stages of Obaiyed gas plant in Egypt were selected and subjected for determining chloride ion and hydrocarbon compositions. The trace levels of chloride in the water extracted from natural gas, condensate, Benfield and glycol samples were achieved using ion chromatograph (IC, electrical, conductivity and potentiometric methods, respectively. The hydrocarbon compositions were analyzed and evaluated using capillary gas chromatography. The chloride ions in natural gas and condensate are a function of water content and their concentration mainly depends on the separation efficiency. Variability in natural gas and condensate compositions seasonally is not an uncommon occurrence. Our aim is monitoring of chloride ion to select and optimize the conditions of sweetening and dehydration regenerators in order to follow and prevent their gradient in gas plant.

Laser-plasma booster for ion post acceleration

Directory of Open Access Journals (Sweden)

Satoh D.

2013-11-01

Full Text Available A remarkable ion energy increase is demonstrated for post acceleration by a laser-plasma booster. An intense short-pulse laser generates a strong current by high-energy electrons accelerated, when this intense short-pulse laser illuminates a plasma target. The strong electric current creates a strong magnetic field along the high-energy electron current in plasma. During the increase phase in the magnetic field, a longitudinal inductive electric field is induced for the forward ion acceleration by the Faraday law. Our 2.5-dimensional particle-in-cell simulations demonstrate a remarkable increase in ion energy by several tens of MeV.

Application of strong phosphoric acid to radiochemistry

International Nuclear Information System (INIS)

Terada, Kikuo

1977-01-01

Not only inorganic and organic compounds but also natural substrances, such as accumulations in soil, are completely decomposed and distilled by heating with strong phosphoric acid for 30 to 50 minutes. As applications of strong phosphoric acid to radiochemistry, determination of uranium and boron by use of solubilization effect of this substance, titration of uranyl ion by use of sulfuric iron (II) contained in this substance, application to tracer experiment, and determination of radioactive ruthenium in environmental samples are reviewed. Strong phosphoric acid is also applied to activation analysis, for example, determination of N in pyrographite with iodate potassium-strong phosphoric acid method, separation of Os and Ru with sulfuric cerium (IV) - strong phosphoric acid method or potassium dechromate-strong phosphoric acid method, analysis of Se, As and Sb rocks and accumulations with ammonium bromide, sodium chloride and sodium bromide-strong phosphoric acid method. (Kanao, N.)

Ion-exchange equilibrium of N-acetyl-D-neuraminic acid on a strong anionic exchanger.

Science.gov (United States)

Wu, Jinglan; Ke, Xu; Zhang, Xudong; Zhuang, Wei; Zhou, Jingwei; Ying, Hanjie

2015-09-15

N-acetyl-D-neuraminic acid (Neu5Ac) is a high value-added product widely applied in the food industry. A suitable equilibrium model is required for purification of Neu5Ac based on ion-exchange chromatography. Hence, the equilibrium uptake of Neu5Ac on a strong anion exchanger, AD-1 was investigated experimentally and theoretically. The uptake of Neu5Ac by the hydroxyl form of the resin occurred primarily by a stoichiometric exchange of Neu5Ac(-) and OH(-). The experimental data showed that the selectivity coefficient for the exchange of Neu5Ac(-) with OH(-) was a non-constant quantity. Subsequently, the Saunders' model, which took into account the dissociation reactions of Neu5Ac and the condition of electroneutrality, was used to correlate the Neu5Ac sorption isotherms at various solution pHs and Neu5Ac concentrations. The model provided an excellent fit to the binary exchange data for Cl(-)/OH(-) and Neu5Ac(-)/OH(-), and an approximate prediction of equilibrium in the ternary system Cl(-)/Neu5Ac(-)/OH(-). This basic information combined with the general mass transfer model could lay the foundation for the prediction of dynamic behavior of fixed bed separation process afterwards. Copyright © 2015 Elsevier Ltd. All rights reserved.

Strong-coupling diffusion in relativistic systems

Indian Academy of Sciences (India)

hanced values needed to interpret the data at higher energies point towards the importance of strong-coupling effects. ... when all secondary particles have been created. For short times in the initial phase ... It is decisive for a proper representation of the available data for relativistic heavy-ion collisions at and beyond SPS.

The survival effects of V79 cells irradiated with carbon ions in different let

International Nuclear Information System (INIS)

Wang Jufang; Zhou Guangming; He Jing; Li Wenjian; Li Qiang; Dang Bingrong; Li Xinglin; Weng Xiaoqiong; Xie Hongmei; Wei Zengquan; Gao Qingxiang

2001-01-01

The survival of cultured Chinese V79 hamster cells irradiated with carbon ions with different LETs were investigated. Irradiation was performed at the heavy Ion Research Facility in Lanzhou (HIRFL). Results were compared with those obtained from the experiments with γ rats and could be concluded as follows: The survival curves for carbon ions showed as straight lines and were fitted to the one-target one-hit model, but for γ rays the curves with shoulders were fitted to the multi-target one-hit model. As the LETs were 125, 200 and 700 keV/μm for carbon ions, the inactivation cross section 35, 12 and 8 μm 2 , respectively, which suggested that under the experimental conditions, the lower the LET of carbon ions, the more seriously the irradiation killed cells. In the case of 125 keV/μm, the RBEs of carbon ions at the 0.1 and 0.37 survival levels were 1.47 and 2.19 respectively

Quartz gauge response in ion radiation

International Nuclear Information System (INIS)

Taylor, P.E.; Gilbert, P.H.; Kernthaler, C.; Anderson, M.U.

1995-01-01

This paper describes recent work to make high quality quartz gauge (temporal and spatial) shock wave measurements in a pulsed ion beam environment. Intense ion beam radiation, nominally 1 MeV protons, was deposited into material samples instrumented with shunted quartz gauges adjacent to the ion deposition zone. Fluence levels were chosen to excite three fundamentally different material response modes (1) strong vapor, (2) combined vapor and melt phase and (3) thermoelastic material response. A unique quartz gauge design was utilized that employed printed circuit board (PCB) technology to facilitate electrical shielding, ruggedness, and fabrication at sign e meeting the essential one dimensional requirements of the characterized Sandia shunted quartz gauge. Shock loading and unloading experiments were conducted to evaluate the piezoelectric response of the coupled quartz gauge/PCB transducer. High fidelity shock wave profiles were recorded at the three ion fluence levels providing dynamic material response data for vapor, melt and solid material phases

Polyvinylpyrrolidone as a New Fluorescent Sensor for Nitrate Ion

International Nuclear Information System (INIS)

Tang, I.H.; Lintang, H.O.; Leny Yuliati

2016-01-01

In this study, non-conjugated polyvinylpyrrolidone (PVP) was investigated for the first time as the potential polymeric material to sense nitrate ions by fluorescence spectroscopy. The PVP was diluted into various concentrations (3-10 %) and they were used to sense the nitrate ions in different concentrations (0.1-100 mM). The PVP showed two excitation peaks at 285 and 330 nm due to the presence of C=O and N-C groups, respectively. One strong emission at 400 or 408 nm was observed with the excitation at 285 or 330 nm. The higher value of quenching constant at excitation wavelength of 285 nm indicated that C=O site was more favored for NO 3 - ions sensing than the N-C site. The PVP 7 % gave the highest quenching constant; where the KSV value was 9.89 x 10 -3 mM -1 and 2.44 x 10 -3 mM -1 for excitation at 285 and 330 nm, respectively. The sensing capability was evaluated in the presence of interference ions (SO 4 2- , HCO 3 - , Cl - , and OH - ). It was observed that the interference ions interacted strongly with the C=O, but weakly with the N-C. Therefore, in the presence of the interference ions, the PVP would be a potential fluorescent sensor when it is excited at 330 nm. (author)

Observations of Heavy Ions in the Magnetosphere

Science.gov (United States)

Kistler, L. M.

2017-12-01

There are two sources for the hot ions in the magnetosphere: the solar wind and the ionosphere. The solar wind is predominantly protons, with about 4% He++ and less than 1% other high charge state heavy ions. The ionospheric outflow is also predominantly H+, but can contain a significant fraction of heavy ions including O+, N+, He+, O++, and molecular ions (NO+, N2+, O2+). The ionospheric outflow composition varies significantly both with geomagnetic activity and with solar EUV. The variability in the contribution of the two sources, the variability in the ionospheric source itself, and the transport paths of the different species are all important in determining the ion composition at a given location in the magnetosphere. In addition to the source variations, loss processes within the magnetosphere can be mass dependent, changing the composition. In particular, charge exchange is strongly species dependent, and can lead to heavy ion dominance at some energies in the inner magnetosphere. In this talk we will review the current state of our understanding of the composition of the magnetosphere and the processes that determine it.

Comparative transcriptome analysis of rice seedlings induced by different doses of heavy ion radiation

Science.gov (United States)

Zhao, Qian; Sun, Yeqing; Wang, Wei

2016-07-01

Highly ionizing radiation (HZE) in space is considered as a main factor causing biological effects on plant seeds. To investigate the different effects on genome-wide gene expression of low-dose and high-dose ion radiation, we carried out ground-base carbon particle HZE experiments with different cumulative doses (0Gy, 0.2Gy, 2Gy) to rice seeds and then performed comparative transcriptome analysis of the rice seedlings. We identified a total of 2551 and 1464 differentially expressed genes (DEGs) in low-dose and high-dose radiation groups, respectively. Gene ontology analyses indicated that low-dose and high-dose ion radiation both led to multiple physiological and biochemical activities changes in rice. By Gene Ontology analyses, the results showed that only one process-oxidation reduction process was enriched in the biological process category after high-dose ion radiation, while more processes such as response to biotic stimulus, heme binding, tetrapyrrole binding, oxidoreductase activity, catalytic activity and oxidoreductase activity were significantly enriched after low-dose ion radiation. The results indicated that the rice plants only focused on the process of oxidation reduction to response to high-dose ion radiation, whereas it was a coordination of multiple biological processes to response to low-dose ion radiation. To elucidate the transcriptional regulation of radiation stress-responsive genes, we identified several DEGs-encoding TFs. AP2/EREBP, bHLH, C2H2, MYB and WRKY TF families were altered significantly in response to ion radiation. Mapman analysis speculated that the biological effects on rice seedlings caused by the radiation stress might share similar mechanisms with the biotic stress. Our findings highlight important alterations in the expression of radiation response genes, metabolic pathways, and TF-encoding genes in rice seedlings exposed to low-dose and high-dose ion radiation.

Atmospheric pressure chemical ionization studies of non-polar isomeric hydrocarbons using ion mobility spectrometry and mass spectrometry with different ionization techniques

Science.gov (United States)

Borsdorf, H.; Nazarov, E. G.; Eiceman, G. A.

2002-01-01

The ionization pathways were determined for sets of isomeric non-polar hydrocarbons (structural isomers, cis/trans isomers) using ion mobility spectrometry and mass spectrometry with different techniques of atmospheric pressure chemical ionization to assess the influence of structural features on ion formation. Depending on the structural features, different ions were observed using mass spectrometry. Unsaturated hydrocarbons formed mostly [M - 1]+ and [(M - 1)2H]+ ions while mainly [M - 3]+ and [(M - 3)H2O]+ ions were found for saturated cis/trans isomers using photoionization and 63Ni ionization. These ionization methods and corona discharge ionization were used for ion mobility measurements of these compounds. Different ions were detected for compounds with different structural features. 63Ni ionization and photoionization provide comparable ions for every set of isomers. The product ions formed can be clearly attributed to the structures identified. However, differences in relative abundance of product ions were found. Although corona discharge ionization permits the most sensitive detection of non-polar hydrocarbons, the spectra detected are complex and differ from those obtained with 63Ni ionization and photoionization. c. 2002 American Society for Mass Spectrometry.

A novel strong tracking finite-difference extended Kalman filter for nonlinear eye tracking

Institute of Scientific and Technical Information of China (English)

ZHANG ZuTao; ZHANG JiaShu

2009-01-01

Non-Intrusive methods for eye tracking are Important for many applications of vision-based human computer interaction. However, due to the high nonlinearity of eye motion, how to ensure the robust-ness of external interference and accuracy of eye tracking poses the primary obstacle to the integration of eye movements into today's interfaces. In this paper, we present a strong tracking finite-difference extended Kalman filter algorithm, aiming to overcome the difficulty In modeling nonlinear eye tracking. In filtering calculation, strong tracking factor is introduced to modify a priori covariance matrix and im-prove the accuracy of the filter. The filter uses finite-difference method to calculate partial derivatives of nonlinear functions for eye tracking. The latest experimental results show the validity of our method for eye tracking under realistic conditions.

A review on various electrochemical techniques for heavy metal ions detection with different sensing platforms.

Science.gov (United States)

Bansod, BabanKumar; Kumar, Tejinder; Thakur, Ritula; Rana, Shakshi; Singh, Inderbir

2017-08-15

Heavy metal ions are non-biodegradable and contaminate most of the natural resources occurring in the environment including water. Some of the heavy metals including Lead (Pb), Mercury (Hg), Arsenic (As), Chromium (Cr) and Cadmium (Cd) are considered to be highly toxic and hazardous to human health even at trace levels. This leads to the requirement of fast, accurate and reliable techniques for the detection of heavy metal ions. This review presents various electrochemical detection techniques for heavy metal ions those are user friendly, low cost, provides on-site and real time monitoring as compared to other spectroscopic and optical techniques. The categorization of different electrochemical techniques is done on the basis of different types of detection signals generated due to presence of heavy metal ions in the solution matrix like current, potential, conductivity, electrochemical impedance, and electrochemiluminescence. Also, the recent trends in electrochemical detection of heavy metal ions with various types of sensing platforms including metals, metal films, metal oxides, nanomaterials, carbon nano tubes, polymers, microspheres and biomaterials have been evoked. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced loss of fast ions during mode conversion ion Bernstein wave heating in TFTR

International Nuclear Information System (INIS)

Darrow, D.S.; Majeski, R.; Fisch, N.J.; Heeter, R.F.; Herrmann, H.W.; Herrmann, M.C.; Zarnstorff, M.C.; Zweben, S.J.

1995-12-01

A strong interaction of fast ions with ion Bernstein waves has been observed in TFTR. It results in a large increase in the fast ion loss rate, and heats the lost particles to several MeV. The lost ions are observed at the passing/trapped boundary and appear to be either DD fusion produced tritons or accelerated D neutral beam ions. Under some conditions, enhanced loss of DT alpha particles is also seen. The losses provide experimental support for some of the elements required for alpha energy channeling

Electromagnetic modes in cold magnetized strongly coupled plasmas

OpenAIRE

Tkachenko, I. M.; Ortner, J.; Rylyuk, V. M.

1999-01-01

The spectrum of electromagnetic waves propagating in a strongly coupled magnetized fully ionized hydrogen plasma is found. The ion motion and damping being neglected, the influence of the Coulomb coupling on the electromagnetic spectrum is analyzed.

Modification of SRIM-calculated dose and injected ion profiles due to sputtering, injected ion buildup and void swelling

Energy Technology Data Exchange (ETDEWEB)

Wang, Jing, E-mail: jing.wang@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Texas A& M University, College Station, TX 77843 (United States); Toloczko, Mychailo B. [Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Bailey, Nathan [University of California, Berkeley, CA 94720 (United States); Garner, Frank A.; Gigax, Jonathan; Shao, Lin [Texas A& M University, College Station, TX 77843 (United States)

2016-11-15

In radiation effects on materials utilizing self-ion irradiations, it is necessary to calculate the local displacement damage level and ion injection profile because of the short distance that self-ions travel in a material and because of the strong variation of displacement rate with depth in a specimen. The most frequently used tool for this is the software package called Stopping and Range of Ions in Matter (SRIM). A SRIM-calculated depth-dependent dose level is usually determined under the implicit assumption that the target does not undergo any significant changes in volume during the process, in particular SRIM ignores the effect of sputtering, injected ions, and void swelling on the redistribution of the dose and injected ion profiles. This approach become increasingly invalid as the ion fluence reaches ever higher levels, especially for low energy ion irradiations. The original surface is not maintained due to sputter-induced erosion, while within the irradiated region of the specimen, injected ions are adding material, and if void swelling is occurring, it is creating empty space. An iterative mathematical treatment of SRIM outputs to produce corrected dose and injected ion profiles based on these phenomenon and without regard to diffusion is presented along with examples of differences between SRIM-calculated values and corrected values over a range of typical ion energies. The intent is to provide the reader with a convenient tool for more accurately calculating dose and injected ion profiles for heavy-ion irradiations.

Strong factor in the SO(2,3) S matrix

International Nuclear Information System (INIS)

Amado, R.D.; Sparrow, D.A.

1986-01-01

The group theoretic S matrix of Alhassid, Iachello, and Wu is factorable into a product of Coulomb and strong factors. The strong factor is examined with a view to relating it to more fa- miliar potential and phase shift descriptions. We find simple approximate expressions for the phase shifts which are very accurate for heavy-ion-type applications. For peripheral scattering it is possible to obtain simple expressions relating the strong factor to an effective potential

Caviton dynamics in strong Langmuir turbulence

International Nuclear Information System (INIS)

DuBois, D.; Rose, H.A.; Russell, D.

1989-01-01

Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound samping the turbulent energy is dominantly in nonlinear ''caviton'' excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful hf waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that ''free'' Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed. 40 refs., 19 figs

Caviton dynamics in strong Langmuir turbulence

Science.gov (United States)

DuBois, Don; Rose, Harvey A.; Russell, David

1990-01-01

Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound damping the turbulent energy is dominantly in non-linear "caviton" excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful HF waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that "free" Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed.

Caviton dynamics in strong Langmuir turbulence

International Nuclear Information System (INIS)

DuBois, D.; Rose, H.A.; Russell, D.

1990-01-01

Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound damping the turbulent energy is dominantly in non-linear ''caviton'' excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful HF waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that ''free'' Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed. (orig.)

Understanding Molecular Ion-Neutral Atom Collisions for the Production of Ultracold Molecular Ions

Science.gov (United States)

2016-06-06

2012): 0. doi: 10.1103/PhysRevLett.109.223002 Kuang Chen, Scott T. Sullivan, Wade G. Rellergert, Eric R. Hudson. Measurement of the Coulomb Logarithm...or fellowships for further studies in science, mathematics, engineering or technology fields: Student Metrics This section only applies to graduating...clouds of Ba+ ions and Ca atoms. Due to the strong Coulomb interaction, the Ba+ ions quickly cool the molecular ion translation motion, while the

Strong ion and weak acid analysis in severe preeclampsia: potential clinical significance.

Science.gov (United States)

Ortner, C M; Combrinck, B; Allie, S; Story, D; Landau, R; Cain, K; Dyer, R A

2015-08-01

The influence of common disturbances seen in preeclampsia, such as changes in strong ions and weak acids (particularly albumin) on acid-base status, has not been fully elucidated. The aims of this study were to provide a comprehensive acid-base analysis in severe preeclampsia and to identify potential new biological predictors of disease severity. Fifty women with severe preeclampsia, 25 healthy non-pregnant- and 46 healthy pregnant controls (26-40 weeks' gestation), were enrolled in this prospective case-control study. Acid-base analysis was performed by applying the physicochemical approach of Stewart and Gilfix. Mean [sd] base excess was similar in preeclamptic- and healthy pregnant women (-3.3 [2.3], and -2.8 [1.5] mEq/L respectively). In preeclampsia, there were greater offsetting contributions to the base excess, in the form of hyperchloraemia (BE(Cl) -2 [2.3] vs -0.4 [2.3] mEq/L, Palkalosis was associated with a non-reassuring/abnormal fetal heart tracing (Prespiratory and hypoalbuminaemic alkalosis that was metabolically offset by acidosis, secondary to unmeasured anions and dilution. While the overall base excess in severe preeclampsia is similar to that in healthy pregnancy, preeclampsia is associated with a greater imbalance offsetting hypoalbuminaemic alkalosis and hyperchloraemic acidosis. Rather than the absolute value of base excess, the magnitude of these opposing contributors may be a better indicator of the severity of this disease. Hypoalbuminaemic alkalosis may also be a predictor of fetal compromise. clinicaltrials.gov: NCT 02164370. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Strong-field Photoionization of Sputtered Neutral Molecules for Molecular Depth Profiling

Science.gov (United States)

Willingham, D; Brenes, D. A.; Wucher, A

2009-01-01

Molecular depth profiles of an organic thin film of guanine vapor deposited onto a Ag substrate are obtained using a 40 keV C60 cluster ion beam in conjunction with time-of-flight secondary ion mass spectrometric (ToF-SIMS) detection. Strong-field, femtosecond photoionization of intact guanine molecules is used to probe the neutral component of the profile for direct comparison with the secondary ion component. The ability to simultaneously acquire secondary ions and photoionized neutral molecules reveals new fundamental information about the factors that influence the properties of the depth profile. Results show that there is an increased ionization probability for protonated molecular ions within the first 10 nm due to the generation of free protons within the sample. Moreover, there is a 50% increase in fragment ion signal relative to steady state values 25 nm before reaching the guanine/Ag interface as a result of interfacial chemical damage accumulation. An altered layer thickness of 20 nm is observed as a consequence of ion beam induced chemical mixing. In general, we show that the neutral component of a molecular depth profile using the strong-field photoionization technique can be used to elucidate the effects of variations in ionization probability on the yield of molecular ions as well as to aid in obtaining accurate information about depth dependent chemical composition that cannot be extracted from TOF-SIMS data alone. PMID:20495665

Magnesium aluminate planar waveguides fabricated by C-ion implantation with different energies and fluences

Energy Technology Data Exchange (ETDEWEB)

Song, Hong-Lian; Yu, Xiao-Fei; Zhang, Lian; Wang, Tie-Jun; Qiao, Mei; Zhang, Jing; Liu, Peng; Wang, Xue-Lin, E-mail: xuelinwang@sdu.edu.cn

2015-11-01

We report on MgAl{sub 2}O{sub 4} planar waveguides produced using different energies and fluences of C-ion implantation at room temperature. Based on the prism coupling method and end-face coupling measurements, light could propagate in the C-ion-implanted samples. The Raman spectra results indicate that the MgAl{sub 2}O{sub 4} crystal lattice was damaged during the multi-energy C implantation process, whereas the absorption spectra were hardly affected by the C-ion implantation in the visible and infrared bands.

Forward electron production in heavy ion-atom and ion-solid collisions

International Nuclear Information System (INIS)

Sellin, I.A.

1984-01-01

A sharp cusp in the velocity spectrum of electrons, ejected in ion-atom and ion-solid collisions, is observed when the ejected electron velocity vector v/sub e/ matches that of the emergent ion vector v/sub p/ in both speed and direction. In ion-atom collisions, the electrons originate from capture to low-lying, projectile-centered continuum states (ECC) for fast bare or nearly bare projectiles, and from loss to those low-lying continuum states (ELC) when loosely bound projectile electrons are available. Most investigators now agree that ECC cusps are strongly skewed toward lower velocities, and exhibit full widths half maxima roughly proportional to v/sub p/ (neglecting target-shell effects, which are sometimes strong). A close examination of recent ELC data shows that ELC cusps are instead nearly symmetric, with widths nearly independent on v/sub p/ in the velocity range 6 to 18 a.u., a result only recently predicted by theory. Convoy electron cusps produced in heavy ion-solid collisions at MeV/u energies exhibit approximately velocity-independent widths very similar to ELC cusp widths. While the shape of the convoy peaks is approximately independent of projectile Z, velocity, and of target material, it is found that the yields in polycrystalline targets exhibit a strong dependence on projectile Z and velocity. While attempts have been made to link convoy electron production to binary ECC or ELC processes, sometimes at the last layer, or alternatively to a solid-state wake-riding model, our measured dependences of cusp shape and yield on projectile charge state and energy are inconsistent with the predictions of available theories. 10 references, 8 figures, 1 table

Laser cooling and ion beam diagnosis of relativistic ions in a storage ring

International Nuclear Information System (INIS)

Schroeder, S.

1990-08-01

Particle accelerator and storage ring technology has reached an advanced state, so that different heavy ion storage rings are coming into operation by now, capable of storing even fully stripped ions up to U 92+ . The main purpose of these machines are the accumulation of ions and the ability of improving the beam quality, that is the phase space density of the stored beams. This beam cooling is done successfully by the well established stochastic and electron cooling techniques. A new cooling method, the laser cooling, is taken over from atomic beam and ion trap experiments, where it has yielded extremely low temperatures of atomic samples. As a canditate at storage rings 7 Li + ions are stored in the Heidelberg TSR at 13.3 MeV. The ion beam properties of the metastable fraction like momentum spread, storage time and the influence of residual gas scattering are investigated by colinear laser spectroscopy in the experimental section of the TSR. An optical pumping experiment using two dye laser systems yields information about ion kinematics and velocity mixing processes in the ring. Lifetimes in the order of 100 ms for velocity classes marked in this way show that laser cooling can be applied to the stored 7 Li + beam. In an experimental situation of two strong counterpropagating laser beams, both tuned near resonance, a dramatic reduction of the ion beam momentum spread is observed. With a special geometrical control of laser and ion beam the longitudinal beam temperature is reduced from 260 K to at least 3 K with very high collection efficiency. (orig./HSI) [de

Theory of 'strong' turbulence - Application to the ion acoustic instability

International Nuclear Information System (INIS)

Abdel-Gawad, Hamdy Ibrahim

1984-01-01

In this thesis, we apply the techniques recently developed in the theory of turbulence to study the evolution of the current-driven ion acoustic instability. We present a method allow to describe analytically and with a self-coherent manner the dynamic of the deformation of the distribution function of particles in the same time as the evolution of the turbulent energy. We have also discerned the saturation mechanisms of the instability as well as their domain of validity. (author) [fr

Microvillar ion channels: cytoskeletal modulation of ion fluxes.

Science.gov (United States)

Lange, K

2000-10-21

movement of the system (electro-mechanical coupling). Because ionic transmission through linear polyelectrolytes is very slow compared with electronic conduction, only low-frequency electromagnetic fields can interact with the condensed counterion systems of linear polyelectrolytes. The delineated characteristics of microvillar ion conduction are strongly supported by the phenomenon of electro-mechanical coupling (reverse transduction) in microvilli of the audioreceptor (hair) cells and the recently reported dynamics of Ca(2+)signaling in microvilli of audio- and photoreceptor cells. Due to the cell-specific expression of different types and combinations of ion channels and transporters in the microvillar tip membrane of differentiated cells, the functional properties of this cell surface organelle are highly variable serving a multitude of different cellular functions including receptor-mediated effects such as Ca(2+)signaling, regulation of glucose and amino acid transport, as well as modulation of membrane potential. Even mechanical channel activation involved in cell volume regulation can be deduced from the systematic properties of the microvillar channel concept. In addition, the specific ion conduction properties of microfilaments combined with their proposed role in Ca(2+)signaling make microvilli the most likely cellular site for the interaction with external electric and magnetic fields. Copyright 2000 Academic Press.

The influence of polarizability and charge transfer on specific ion effects in the dynamics of aqueous salt solutions

Science.gov (United States)

Nguyen, Mary; Rick, Steven W.

2018-06-01

The diffusion rates for water molecules in salt solutions depend on the identity of the ions, as well as their concentration. Among the alkali metal ions, cesium and potassium increase and sodium strongly decreases the diffusion constant of water. The origin of the difference can be understood by examining the simulation results using different potential models. In this work, aqueous solutions of salts are simulated with a variety of models. Commonly used non-polarizable models, which otherwise reproduce many experimental properties, do not capture the trend in the diffusion constant, while models which include polarization and/or charge transfer interactions do. For the non-polarizable models, the diffusion constant decreases too strongly with salt concentration. The changes in the water diffusion constant with increasing salt concentration match the diffusion constant of the ion. The ion diffusion constant is dependent on the residence time for water in the ion solvation shell. The non-polarizable models over-estimate the residence time, relative to the translational diffusion constant and so tend to under-estimate the ion and water diffusion constants.

Electrochemical evidences and consequences of significant differences in ions diffusion rate in polyacrylate-based ion-selective membranes.

Science.gov (United States)

Woźnica, Emilia; Mieczkowski, Józef; Michalska, Agata

2011-11-21

The origin and effect of surface accumulation of primary ions within the ion-selective poly(n-butyl acrylate)-based membrane, obtained by thermal polymerization, is discussed. Using a new method, based on the relation between the shape of a potentiometric plot and preconditioning time, the diffusion of copper ions in the membrane was found to be slow (the diffusion coefficient estimated to be close to 10(-11) cm(2) s(-1)), especially when compared to ion-exchanger counter ions--sodium cations diffusion (a diffusion coefficient above 10(-9) cm(2) s(-1)). The higher mobility of sodium ions than those of the copper-ionophore complex results in exposed ion-exchanger role leading to undesirably exposed sensitivity to sodium or potassium ions.

Equilibration and hydrodynamics at strong and weak coupling

Science.gov (United States)

van der Schee, Wilke

2017-11-01

We give an updated overview of both weak and strong coupling methods to describe the approach to a plasma described by viscous hydrodynamics, a process now called hydrodynamisation. At weak coupling the very first moments after a heavy ion collision is described by the colour-glass condensate framework, but quickly thereafter the mean free path is long enough for kinetic theory to become applicable. Recent simulations indicate thermalization in a time t ∼ 40(η / s) 4 / 3 / T [L. Keegan, A. Kurkela, P. Romatschke, W. van der Schee, Y. Zhu, Weak and strong coupling equilibration in nonabelian gauge theories, JHEP 04 (2016) 031. arxiv:arXiv:1512.05347, doi:10.1007/JHEP04(2016)031], with T the temperature at that time and η / s the shear viscosity divided by the entropy density. At (infinitely) strong coupling it is possible to mimic heavy ion collisions by using holography, which leads to a dual description of colliding gravitational shock waves. The plasma formed hydrodynamises within a time of 0.41/T recent extension found corrections to this result for finite values of the coupling, when η / s is bigger than the canonical value of 1/4π, which leads to t ∼ (0.41 + 1.6 (η / s - 1 / 4 π)) / T [S. Grozdanov, W. van der Schee, Coupling constant corrections in holographic heavy ion collisions, arxiv:arXiv:1610.08976]. Future improvements include the inclusion of the effects of the running coupling constant in QCD.

Strong ion accelerating by collisionless magnetosonic shock wave propagating perpendicular to a magnetic field

International Nuclear Information System (INIS)

Ohsawa, Yukiharu.

1984-12-01

A 2-1/2 dimensional fully relativistic, fully electromagnetic particle code is used to study a time evolution of nonlinear magnetosonic pulse propagating in the direction perpendicular to a magnetic field. The pulse is excited by an instantaneous piston acceleration, and evolves totally self-consistently. Large amplitude pulse traps some ions and accelerates them parallel to the wave front. They are detrapped when their velocities become of the order of the sum of the ExB drift velocity and the wave phase velocity, where E is the electric field in the direction of wave propagation. The pulse develops into a quasi-shock wave in a collisionless plasma by a dissipation due to the resonant ion acceleration. Simple nonlinear wave theory for a cold plasma well describes the shock properties observed in the simulation except for the effects of resonant ions. In particular, magnitude of an electric potential across the shock region is derived analytically and is found to be in good agreement with our simulations. The potential jump is proportional to B 2 , and hence the ExB drift velocity of the trapped ions is proportional to B. (author)

Highly sensitive colour change system within slight differences in metal ion concentrations based on homo-binuclear complex formation equilibrium for visual threshold detection of trace metal ions

International Nuclear Information System (INIS)

Mizuguchi, Hitoshi; Atsumi, Hiroshi; Hashimoto, Keigo; Shimada, Yasuhiro; Kudo, Yuki; Endo, Masatoshi; Yokota, Fumihiko; Shida, Junichi; Yotsuyanagi, Takao

2004-01-01

A new technique of expressing slight differences in metal ion concentrations by clear difference in colour was established for visual threshold detection of trace metal ions. The proposed method is based on rapid change of the mole fraction of the homo-binuclear complex (M 2 L) about a ligand in a narrow range of the total metal ion concentration (M T ) in a small excess, in case the second metal ion is bound to the reagent molecule which can bind two metal ions. Theoretical simulations showed that the highly sensitive colour change within slight differences in metal ion concentrations would be realized under the following conditions: (i) both of the stepwise formation constants of complex species are sufficiently large; (ii) the stepwise formation constant of the 1:1 complex (ML) is larger than that of M 2 L; and (iii) the absorption spectrum of M 2 L is far apart from the other species in the visible region. Furthermore, the boundary of the colour region in M T would be readily controlled by the total ligand concentration (L T ). Based on this theory, the proposed model was verified with the 3,3'-bis[bis(carboxymethyl)amino]methyl derivatives of sulphonephthalein dyes such as xylenol orange (XO), methylthymol blue (MTB), and methylxylenol blue (MXB), which can bind two metal ions at both ends of a π-electron conjugated system. The above-mentioned model was proved with the iron(III)-XO system at pH 2. In addition, MTB and MXB were suitable reagents for the visual threshold detection of trivalent metal ions such as iron(III), aluminium(III), gallium(III) and indium(III) ion in slightly acidic media. The proposed method has been applied successfully as a screening test for aluminium(III) ion in river water sampled at the downstream area of an old mine

Delta-electron emission in fast heavy ion atom collisions

International Nuclear Information System (INIS)

Schmidt-Boecking, H.; Ramm, U.; Berg, H.; Kelbch, C.; Feng Jiazhen; Hagmann, S.; Kraft, G.; Ullrich, J.

1991-01-01

The δ-electron emission processes occuring in fast heavy ion atom collisons are explained qualitatively. The different spectral structures of electron emission arising from either the target or the projectile are explained in terms of simple models of the kinetics of momentum transfer induced by the COULOMB forces. In collisions of very heavy ions with matter, high nuclear COULOMB forces are created. These forces lead to a strong polarization of the electronic states of the participated electrons. The effects of this polarization are discussed. (orig.)

A sensitive fluorescent sensor of lanthanide ions

CERN Document Server

Bekiari, V; Lianos, P

2003-01-01

A fluorescent probe bearing a diazostilbene chromophore and a benzo-15-crown-5 ether moiety is a very efficient sensor of lanthanide ions. The ligand emits strong fluorescence only in the presence of specific ions, namely lanthanide ions, while the emission wavelength is associated with a particular ion providing high sensitivity and resolution.

Laser propagation and soliton generation in strongly magnetized plasmas

Energy Technology Data Exchange (ETDEWEB)

Feng, W.; Li, J. Q.; Kishimoto, Y. [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

2016-03-15

The propagation characteristics of various laser modes with different polarization, as well as the soliton generation in strongly magnetized plasmas are studied numerically through one-dimensional (1D) particle-in-cell (PIC) simulations and analytically by solving the laser wave equation. PIC simulations show that the laser heating efficiency substantially depends on the magnetic field strength, the propagation modes of the laser pulse and their intensities. Generally, large amplitude laser can efficiently heat the plasma with strong magnetic field. Theoretical analyses on the linear propagation of the laser pulse in both under-dense and over-dense magnetized plasmas are well confirmed by the numerical observations. Most interestingly, it is found that a standing or moving soliton with frequency lower than the laser frequency is generated in certain magnetic field strength and laser intensity range, which can greatly enhance the laser heating efficiency. The range of magnetic field strength for the right-hand circularly polarized (RCP) soliton formation with high and low frequencies is identified by solving the soliton equations including the contribution of ion's motion and the finite temperature effects under the quasi-neutral approximation. In the limit of immobile ions, the RCP soliton tends to be peaked and stronger as the magnetic field increases, while the enhanced soliton becomes broader as the temperature increases. These findings in 1D model are well validated by 2D simulations.

Influence of hot beam ions on MHD ballooning modes in tokamaks

International Nuclear Information System (INIS)

Rewoldt, G.; Tang, W.M.

1984-07-01

It has recently been proposed that the presence of high energy ions from neutral beam injection can have a strong stabilizing effect on kinetically-modified ideal MHD ballooning modes in tokamaks. In order to assess realistically the importance of such effects, a comprehensive kinetic stability analysis, which takes into account the integral equation nature of the basic problem, has been applied to this investigation. In the collisionless limit, the effect of adding small fractions of hot beam ions is indeed found to be strongly stabilizing. On the other hand, for somewhat larger fractions of hot ions, a new beam-driven mode is found to occur with a growth rate comparable in magnitude to the growth rate of the MHD ballooning mode in the absence of hot ions. This implies that there should be an optimal density of hot particles which minimizes the strength of the relevant instabilities. Employing non-Maxwellian equilibrium distribution functions to model the beam species makes a quantitative, but not qualitative, difference in the results. Adding collisions to the calculation tends to reduce considerably the stabilizing effect of the hot ions

Investigation of the lithium ion mobility in cyclic model compounds and their ion conduction properties

Energy Technology Data Exchange (ETDEWEB)

Thielen, Joerg

2011-07-27

In view of both, energy density and energy drain, rechargeable lithium ion batteries outperform other present accumulator systems. However, despite great efforts over the last decades, the ideal electrolyte in terms of key characteristics such as capacity, cycle life, and most important reliable safety, has not yet been identified. Steps ahead in lithium ion battery technology require a fundamental understanding of lithium ion transport, salt association, and ion solvation within the electrolyte. Indeed, well defined model compounds allow for systematic studies of molecular ion transport. Thus, in the present work, based on the concept of immobilizing ion solvents, three main series with a cyclotriphosphazene (CTP), hexaphenylbenzene (HBP), and tetramethylcyclotetrasiloxane (TMS) scaffold were prepared. Lithium ion solvents, among others ethylene carbonate (EC), which has proven to fulfill together with propylene carbonate safety and market concerns in commercial lithium ion batteries, were attached to the different cores via alkyl spacers of variable length. All model compounds were fully characterized, pure and thermally stable up to at least 235 C, covering the requested broad range of glass transition temperatures from -78.1 C up to +6.2 C. While the CTP models tend to rearrange at elevated temperatures over time, which questions the general stability of alkoxide related (poly)phosphazenes, both, the HPB and CTP based models show no evidence of core stacking. In particular the CTP derivatives represent good solvents for various lithium salts, exhibiting no significant differences in the ionic conductivity {sigma}{sub dc} and thus indicating comparable salt dissociation and rather independent motion of cations and ions. In general, temperature-dependent bulk ionic conductivities investigated via impedance spectroscopy follow a William-Landel-Ferry (WLF) type behavior. Modifications of the alkyl spacer length were shown to influence ionic conductivities only in

Nonlinear Electron Waves in Strongly Magnetized Plasmas

DEFF Research Database (Denmark)

Pécseli, Hans; Juul Rasmussen, Jens

1980-01-01

Weakly nonlinear dispersive electron waves in strongly magnetized plasma are considered. A modified nonlinear Schrodinger equation is derived taking into account the effect of particles resonating with the group velocity of the waves (nonlinear Landau damping). The possibility of including the ion...... dynamics in the analysis is also demonstrated. As a particular case the authors investigate nonlinear waves in a strongly magnetized plasma filled wave-guide, where the effects of finite geometry are important. The relevance of this problem to laboratory experiments is discussed....

Discovery of iron group impurity ion spin states in single crystal Y{sub 2}SiO{sub 5} with strong coupling to whispering gallery photons

Energy Technology Data Exchange (ETDEWEB)

Goryachev, Maxim; Farr, Warrick G.; Carmo Carvalho, Natalia do; Creedon, Daniel L.; Le Floch, Jean-Michel [ARC Centre of Excellence for Engineered Quantum Systems, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia); Probst, Sebastian [Physikalisches Institut, Karlsruhe Institute of Technology, D-76128 Karlsruhe (Germany); Bushev, Pavel [Experimentalphysik, Universität des Saarlandes, D-66123 Saarbrücken (Germany); Tobar, Michael E., E-mail: michael.tobar@uwa.edu.au [ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Western Australia, Crawley 6009 (Australia)

2015-06-08

Interaction of Whispering Gallery Modes (WGMs) with dilute spin ensembles in solids is an interesting paradigm of Hybrid Quantum Systems potentially beneficial for Quantum Signal Processing applications. Unexpected ion transitions are measured in single crystal Y{sub 2}SiO{sub 5} using WGM spectroscopy with large Zero Field Splittings at 14.7 GHz, 18.4 GHz, and 25.4 GHz, which also feature considerable anisotropy of the g-tensors as well as two inequivalent lattice sites, indicating spins from Iron Group Ion (IGI) impurities. The comparison of undoped and Rare-Earth doped crystals reveal that the IGIs are introduced during co-doping of Eu{sup 3+} or Er{sup 3+} with concentration at much lower levels of order 100 ppb. The strong coupling regime between an ensemble of IGI spins and WGM photons have been demonstrated at 18.4 GHz and near zero field. This approach together with useful optical properties of these ions opens avenues for “spins-in-solids” Quantum Electrodynamics.

Ion release from magnesium materials in physiological solutions under different oxygen tensions.

Science.gov (United States)

Feyerabend, Frank; Drücker, Heiko; Laipple, Daniel; Vogt, Carla; Stekker, Michael; Hort, Norbert; Willumeit, Regine

2012-01-01

Although magnesium as degradable biomaterial already showed clinical proof of concepts, the design of new alloys requires predictive in vitro methods, which are still lacking. Incubation under cell culture conditions to obtain "physiological" corrosion may be a solution. The aim of this study was to analyse the influence of different solutions, addition of proteins and of oxygen availability on the corrosion of different magnesium materials (pure Mg, WE43, and E11) with different surface finishing. Oxygen content in solution, pH, osmolality and ion release were determined. Corrosion led to a reduction of oxygen in solution. The influence of oxygen on pH was enhanced by proteins, while osmolality was not influenced. Magnesium ion release was solution-dependent and enhanced in the initial phase by proteins with delayed release of alloying elements. The main corrosion product formed was magnesium carbonate. Therefore, cell culture conditions are proposed as first step toward physiological corrosion.

The strongly coupled quark-gluon plasma created at RHIC

International Nuclear Information System (INIS)

Heinz, Ulrich

2009-01-01

The relativistic heavy-ion collider (RHIC) was built to re-create and study in the laboratory the extremely hot and dense matter that filled our entire universe during its first few microseconds. Its operation since June 2000 has been extremely successful, and the four large RHIC experiments have produced an impressive body of data which indeed provide compelling evidence for the formation of thermally equilibrated matter at unprecedented temperatures and energy densities-a 'quark-gluon plasma (QGP)'. A surprise has been the discovery that this plasma behaves like an almost perfect fluid, with extremely low viscosity. Theorists had expected a weakly interacting gas of quarks and gluons, but instead we seem to have created a strongly coupled plasma liquid. The experimental evidence strongly relies on a feature called 'elliptic flow' in off-central collisions, with additional support from other observations. This paper explains how we probe the strongly coupled QGP, describes the ideas and measurements which led to the conclusion that the QGP is an almost perfect liquid, and shows how they tie relativistic heavy-ion physics into other burgeoning fields of modern physics, such as strongly coupled Coulomb plasmas, ultracold systems of trapped atoms and superstring theory

Radiation blistering of Nb implanted sequentially with helium ions of different energies (3-500 keV)

International Nuclear Information System (INIS)

Guseva, M.I.; Gusev, V.; Krasulin, U.L.; Martinenko, U.V.; Das, S.K.; Kaminsky, M.S.

1976-01-01

Cold rolled, polycrystalline niobium samples were irradiated at room temperature with 4 He + ions sequentially at 14 different energies over an energy range from 3 keV--500 keV in steps of 50 keV. The dose for each energy was chosen to give an approximately uniform concentration of helium between the implant depths corresponding to 3 keV and 500 keV. In one set of experiments the irradiations were started at the Kurchatov Institute with 3 keV 4 He + ions and extended up to 80 keV in several steps. Subsequently, the same target area was irradiated with 4 He + ions at Argonne National Laboratory (ANL) starting at 100 keV and increased to 500 keV in steps of 50 keV. Another set of irradiations were started at ANL with 500 keV 4 He + ions and continued with decreasing ion energies to 100 keV. Subsequently, the same area was irradiated at the Kurchatov Institute starting at 80 keV and continued with decreasing ion energies to 3 keV. Both sets of irradiations were completed for two different total doses, 0.5 C cm -2 and 1.0 C cm -2

Radial and tangential friction in heavy ion strongly damped collisions

International Nuclear Information System (INIS)

Jain, A.K.; Sarma, N.

1979-01-01

Deeply inelastic heavy ion collisions have been successfully described in terms of a nucleon exchange mechanism between two nucleon clouds. This model has also predicted the large angular momentum that is induced in the colliding nuclei. However computations were simplified in the earlier work by assuming that the friction was perturbation on the elastic scattering trajectory. Results of a more rigorous calculation are reported and the effect of modification of the trajectory on the energy transfer, the angular momentum induced and on the ratio of the radial to the tangential friction coefficients is reported. (auth.)

Influence of different ions doping on the antibacterial properties of MgO nanopowders

Energy Technology Data Exchange (ETDEWEB)

Rao, Yuanyuan; Wang, Wei, E-mail: weiwang@hust.edu.cn; Tan, Fatang; Cai, Yuncheng; Lu, Junwen; Qiao, Xueliang

2013-11-01

Compared with other inorganic antibacterial agents, magnesium oxide (MgO) nanopowders exhibit a unique antibacterial mechanism and various advantages in applications, having attracted extensive attention. In this study, MgO nanopowders doped with different ions (Li{sup +}, Zn{sup 2+} and Ti{sup 4+}) were synthesized by a sol–gel method, respectively. The structures and morphologies of the as-obtained precursors and nanopowders were characterized and confirmed by X-ray diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. The influence of three metal ions doping on the antibacterial properties of MgO nanopowders was also investigated by their bactericidal activity against Escherichia coli (E. coli, ATCC 25922) using the broth microdilution method and the agar method. The results show that Li-doped MgO exhibits better antibacterial activity, Zn-doped and Ti-doped MgO display poorer antibacterial activity than pure MgO. It can be concluded that the influence of different ions doping on the antibacterial properties of MgO mainly lies on oxygen vacancies and basicity of nanopowders.

Highly Resolved Measurements of a Developing Strong Collisional Plasma Shock

Science.gov (United States)

Rinderknecht, Hans G.; Park, H.-S.; Ross, J. S.; Amendt, P. A.; Higginson, D. P.; Wilks, S. C.; Haberberger, D.; Katz, J.; Froula, D. H.; Hoffman, N. M.; Kagan, G.; Keenan, B. D.; Vold, E. L.

2018-03-01

The structure of a strong collisional shock front forming in a plasma is directly probed for the first time in laser-driven gas-jet experiments. Thomson scattering of a 526.5 nm probe beam was used to diagnose temperature and ion velocity distribution in a strong shock (M ˜11 ) propagating through a low-density (ρ ˜0.01 mg /cc ) plasma composed of hydrogen. A forward-streaming population of ions traveling in excess of the shock velocity was observed to heat and slow down on an unmoving, unshocked population of cold protons, until ultimately the populations merge and begin to thermalize. Instabilities are observed during the merging, indicating a uniquely plasma-phase process in shock front formation.

Light ion production for a future radiobiological facility at CERN: preliminary studies.

Science.gov (United States)

Stafford-Haworth, Joshua; Bellodi, Giulia; Küchler, Detlef; Lombardi, Alessandra; Röhrich, Jörg; Scrivens, Richard

2014-02-01

Recent medical applications of ions such as carbon and helium have proved extremely effective for the treatment of human patients. However, before now a comprehensive study of the effects of different light ions on organic targets has not been completed. There is a strong desire for a dedicated facility which can produce ions in the range of protons to neon in order to perform this study. This paper will present the proposal and preliminary investigations into the production of light ions, and the development of a radiobiological research facility at CERN. The aims of this project will be presented along with the modifications required to the existing linear accelerator (Linac3), and the foreseen facility, including the requirements for an ion source in terms of some of the specification parameters and the flexibility of operation for different ion types. Preliminary results from beam transport simulations will be presented, in addition to some planned tests required to produce some of the required light ions (lithium, boron) to be conducted in collaboration with the Helmholtz-Zentrum für Materialien und Energie, Berlin.

Simulation study of two-ion hybrid resonance heating

International Nuclear Information System (INIS)

Riyopoulos, S.; Tajima, T.

1986-02-01

A one-dimensional low-noise, low-frequency electromagnetic particle simulation code that is appropriate for investigation of ion cyclotron resonance heating (ICRH) is developed. Retaining the hyperbolicity of the electromagnetic waves and exploiting nearly one-dimensional characteristics (perpendicular to the external magnetic field) of the ICRH, we use the guiding center electron approximation for the transverse electronic current calculation. We observe mode conversion of the incoming magnetosonic wave into the electrostatic ion-ion hybrid mode accompanied by strong ion-heating. The dependence of this heating on the different plasma parameters is examined through a series of simulations, focusing mainly on wave incidence from the high field side. Because K/sub parallel/ = 0 in our runs, the conventional Landau damping cannot explain the ion heating. Non-linear mechanisms for energy transfer are discussed. Our numerical results demonstrate the importance of the non-linear wave particle interaction for energy transfer are discussed. Our numerical results demonstrate the importance of the non-linear wave particle interaction for energy absorption during radio frequency heating in the ion cyclotron regime. 32 refs., 17 figs

Measurement of the density profile of pure and seeded molecular beams by femtosecond ion imaging

Energy Technology Data Exchange (ETDEWEB)

Meng, Congsen [LaserLaB Amsterdam, VU University Amsterdam, de Boelelaan 1083, 1081 HV Amsterdam (Netherlands); Department of Physics, National University of Defense Technology, Changsha 410073 (China); Janssen, Maurice H. M. [LaserLaB Amsterdam, VU University Amsterdam, de Boelelaan 1083, 1081 HV Amsterdam (Netherlands)

2015-02-15

Here, we report on femtosecond ion imaging experiments to measure the density profile of a pulsed supersonic molecular beam. Ion images are measured for both a molecular beam and bulk gas under identical experimental conditions via femtosecond multiphoton ionization of Xe atoms. We report the density profile of the molecular beam, and the measured absolute density is compared with theoretical calculations of the centre line beam density. Subsequently, we discuss reasons accounting for the differences between measurements and calculations and propose that strong skimmer interference is the most probable cause for the differences. Furthermore, we report on experiments measuring the centre line density of seeded supersonic beams. The femtosecond ion images show that seeding the heavy Xe atom at low relative seed fractions (1%-10%) in a light carrier gas like Ne results in strong relative enhancements of up to two orders of magnitude.

Time-resolved and integrated angular distributions of plume ions from silver at low and medium laser fluence

DEFF Research Database (Denmark)

Christensen, Bo Toftmann; Schou, Jørgen

2013-01-01

Laser impact on metals in the UV regime results in a significant number of ablated plume ions even at moderate fluence (0.7–2.4 J/cm2). The ablated particles are largely neutrals at the lowest fluence, but the fraction of ions increases strongly with fluence. The ion flow in different directions...... from a silver target irradiated by a laser beam at a wavelength of 355 nm in vacuum was measured with a hemispherical array of Langmuir probes. The time-of-flight spectra in all directions, as well as the total angular yield were determined. The angular distribution peaks strongly in forward direction...

Industrial ion sources broadbeam gridless ion source technology

CERN Document Server

Zhurin, Viacheslav V

2012-01-01

Due to the large number of uses of ion sources in academia and industry, those who utilize these sources need up to date and coherent information to keep themselves abreast of developments and options, and to chose ideal solutions for quality and cost-effectiveness. This book, written by an author with a strong industrial background and excellent standing, is the comprehensive guide users and developers of ion sources have been waiting for. Providing a thorough refresher on the physics involved, this resource systematically covers the source types, components, and the operational parameters.

Fluorescence profiles and cooling dynamics of laser-cooled Mg+ ions in a linear rf ion trap

International Nuclear Information System (INIS)

Zhao Xianzhen; Ryjkov, Vladimir L.; Schuessler, Hans A.

2006-01-01

Fluorescence line profiles and their implications on the cooling dynamics of the Mg + ions stored in a linear rf trap are studied. The line profile is dictated by the temperature of the ion cloud at different laser detunings. The upper bound of the lowest temperature was estimated for different values of the rf trapping potential amplitude and the buffer gas pressure. A general trend of this ultimate temperature to increase with the rf trapping voltage and buffer gas pressure is expected, with an abrupt change at some critical value corresponding to the transition to and from a strongly correlated liquid or crystal state. While on the one hand this expectation was confirmed when the buffer gas pressure was varied; on the other hand the influence of the amplitude of the trapping voltage on the ultimate temperature shows an interesting new feature of first dipping down before the sharp increase occurs

Canonical Transform Method for Treating Strongly Anisotropy Magnets

DEFF Research Database (Denmark)

Cooke, J. F.; Lindgård, Per-Anker

1977-01-01

An infinite-order perturbation approach to the theory of magnetism in magnets with strong single-ion anisotropy is given. This approach is based on a canonical transformation of the system into one with a diagonal crystal field, an effective two-ion anisotropy, and reduced ground-state corrections....... A matrix-element matching procedure is used to obtain an explicit expression for the spin-wave energy to second order. The consequences of this theory are illustrated by an application to a simple example with planar anisotropy and an external magnetic field. A detailed comparison between the results...

Progress in the production of intense ion beams and the formation of proton layers

International Nuclear Information System (INIS)

Kapetanakos, C.A.; Golden, J.; Marsh, S.J.; Mahaffey, R.A.

1977-01-01

The results on ion sources and the application of ion beams to the formation of proton layers and rings are presented. Ion beams have been produced on three different generators. Some results from the experiments performed on the Gamble 2 generator are presented. The Gamble 2 generator with coaxial anode-cathode configuration, hollow beam cross-section produces power levels of 0.6-1.2 MV with peak ion current of 200 kA. The number of protons in the beam 4x10 16 . Peak ion currents is excess 200 kA, energy 1 MeV, ion current density 1 kA/cm 2 . Magnetic field configuration to provide formation of strong proton layers is shown

Standard test methods for the strong-base resins used in the recovery of uranium

International Nuclear Information System (INIS)

Ford, M.A.; Lombaard, L.R.

1986-01-01

There are no detailed specifications for the strong-base ion-exchange resins used in continuous ion-exchange plants, and it was considered that a very useful purpose would be served by the publication of a series of standard laboratory tests on which such specifications could be based. This report describes test methods that are relevant to the ion-exchange recovery of uranium. They include tests of the physical properties of strong-base resins (relative density, particle-size distribution, and moisture content) and of their chemical properties (theoretical capacity, equilibrium capacity, kinetics of loading and elution). Included are several supporting procedures that are used in conjunction with these methods

Evaluation of different methods for measuring the impedance of Lithium-ion batteries during ageing

DEFF Research Database (Denmark)

Stroe, Daniel Loan; Swierczynski, Maciej Jozef; Stroe, Ana-Irina

2015-01-01

The impedance represents one of the most important performance parameters of the Lithium-ion batteries since it used for power capability calculations, battery pack and system design, cooling system design and also for state-of-health estimation. In the literature, different approaches...... are presented for measuring the impedance of Lithium-ion batteries and electrochemical impedance spectroscopy and dc current pulses are the most used ones; each of these approaches has its own advantages and drawbacks. The goal of this paper is to investigate which of the most encountered impedance measurement...... approaches is the most suitable for measuring the impedance of Lithium-ion batteries during ageing....

Theoretical analysis of the multiple resonances for many-level spin systems. The four-level spin system of s electron ions subjected to strong microwave fields

International Nuclear Information System (INIS)

Popescu, F.F.; Marica, F.

1994-01-01

The analytic steady state solutions of master equation for the density matrix of a multilevel spin system in dilute paramagnetic crystals at high temperature, subjected to strong microwave fields, are discussed. These solutions enable to obtain the populations of the levels, and the microwave powers absorbed or emitted by the crystal, in the presence of one, two or more microwave fields. A detailed theoretical study of the maser effects for s electron ions with nuclear spin one-half is carried out. In the case of three frequency correlated strong fields, when 'the spectroscopic' bridge conditions are fulfilled, sensitive detections, or high efficient generations of microwaves of frequency higher than those of the pumping fields are predicted. (author) 16 figs., 16 refs

Investigation on gallium ions impacting monolayer graphene

Energy Technology Data Exchange (ETDEWEB)

Wu, Xin; Zhao, Haiyan, E-mail: hyzhao@tsinghua.edu.cn; Yan, Dong; Pei, Jiayun [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, P. R. Chinaand Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

2015-06-15

In this paper, the physical phenomena of gallium (Ga{sup +}) ion impacting monolayer graphene in the nanosculpting process are investigated experimentally, and the mechanisms are explained by using Monte Carlo (MC) and molecular dynamics (MD) simulations. Firstly, the MC method is employed to clarify the phenomena happened to the monolayer graphene target under Ga{sup +} ion irradiation. It is found that substrate has strong influence on the damage mode of graphene. The mean sputtering yield of graphene under 30 keV Ga{sup +} ion irradiation is 1.77 and the least ion dose to completely remove carbon atoms in graphene is 21.6 ion/nm{sup 2}. Afterwards, the focused ion beam over 21.6 ion/nm{sup 2} is used for the irradiation on a monolayer graphene supported by SiO2 experimentally, resulting in the nanostructures, i.e., nanodot and nanowire array on the graphene. The performances of the nanostructures are characterized by atomic force microscopy and Raman spectrum. A plasma plume shielding model is put forward to explain the nanosculpting results of graphene under different irradiation parameters. In addition, two damage mechanisms are found existing in the fabrication process of the nanostructures by using empirical MD simulations. The results can help us open the possibilities for better control of nanocarbon devices.

From heavy ions to exotic atoms

OpenAIRE

Indelicato, Paul; Trassinelli, Martino

2005-01-01

We review a number of experiments and theoretical calculations on heavy ions and exotic atoms, which aim at providing informations on fundamental interactions. Among those are propositions of experiments for parity violation measurements in heavy ions and high-precision mesurements of He-like transition energies in highly charged ions. We also describe recent experiments on pionic atoms, that make use of highly-charged ion transitions to obtain accurate measurements of strong interaction shif...

Ion distributions in RC at different energy levels retrieved from TWINS ENA images by voxel CT tech

Science.gov (United States)

Ma, S. Y.; McComas, David; Xu, Liang; Goldstein, Jerry; Yan, Wei-Nan

2012-07-01

Distributions of energetic ions in the RC regions in different energy levels are retrieved by using 3-D voxel CT inversion method from ENA measurements onboard TWINS constellation during the main phase of a moderate geomagnetic storm. It is assumed that the ion flux distribution in the RC is anisotropic in regard to pitch angle which complies with the adiabatic invariance of the magnetic moment as ion moving in the dipole magnetic mirror field. A semi-empirical model of the RC ion distribution in the magnetic equator is quoted to form the ion flux distribution shape at off-equatorial latitudes by mapping. For the concerned time interval, the two satellites of the TWINS flying in double Molnia orbits were located in nearly the same meridian plane at vantage points widely separated in magnetic local time, and both more than 5 RE geocentric distance from the Earth. The ENA data used in this study are differential fluxes averaged over 12 sweeps (corresponding to an interval of 16 min.) at different energy levels ranging from about 1 to 100 keV. The retrieved ion distributions show that in total the main part of the RC is located in the region with L value larger than 4, tending to increase at larger L. It reveals that there are two distinct dominant energy bands at which the ion fluxes are significantly larger magnitude than at other energy levels, one is at lower level around 2 keV and the other at higher level of 30-100 keV. Furthermore, it is very interesting that the peak fluxes of the RC ions at the two energy bands occurred in different magnetic local time, low energy ions appear preferentially in after midnight, while the higher energy ions mainly distributed around midnight and pre-midnight. This new profile is worthy of further study and needs to be demonstrated by more cases.

Mesocosm Community Response Sensitivities to Specific Conductivity Comprised of Different Major Ions

Science.gov (United States)

Traditional toxicity test assays have been used to evaluate the relative sensitivity to different major ion mixtures as a proxy for understanding what the response of aquatic species growing in their natural environment would be during exposure to specific conductivity stress ema...

The covalent effect on the energy levels of d3 ions in tetragonal compounds

International Nuclear Information System (INIS)

Li, Dong-Yang; Du, Mao-Lu

2015-01-01

For d 3 ions in covalent compounds with tetragonal symmetry, this paper presents a complete energy matrix, in which the different covalence of t 2 and e orbitals is considered not only in the electrostatic repulsions part of energy matrix elements but also in the crystal-field potential part of energy matrix elements. With taking and no taking the crystal field parameter B 00 0 into account, the effect of covalence on the energy levels of d 3 ions system were investigated, respectively. The investigation shows that it is very necessary for considering the different covalence of t 2 and e orbitals in both electrostatic repulsions part and crystal-field potential part when the optical properties of d 3 ions in strong covalent compounds with tetragonal symmetry is investigated. On the other hand, the crystal field parameter B 00 0 has a significant effect on the energy levels, and should be considered in investigations of d 3 ions in strong covalent compounds with tetragonal symmetry. Application to calculating the energy levels for Co 2+ in CdGa 2 Se 4 , the calculated results are in agreement with the experiment data

Quantitative interpretation of heavy ion effects: Comparison of different systems and endpoints

Science.gov (United States)

Kiefer, J.

For a quantitative interpretation of biological heavy ion action the following parameters have to be taken into account: variations of energy depositions in microscopical sites, the dependence of primary lesion formation on local energy density and changes in repairability. They can be studied in objects of different size and with different sensitivities. Results on survival and mutation induction in yeast and in mammalian cells will be compared with theoretical predictions. It is shown that shouldered survival curves of diploid yeast can be adequately described if the final slope is adjusted according to the varying production of primary lesions. This is not the case for mammalian cells where the experiments show a rapid loss of the shoulder with LET, contrary to theoretical expectations. This behaviour is interpreted to mean that the repairability of heavy ion lesions is different in the two systems. Mutation induction is theoretically expected to decrease with higher LET. This is found in yeast but not in mammalian cells where it actually increases. These results suggest a higher rate of misrepair in mammalian cells.

Cavity QED experiments with ion Coulomb crystals

DEFF Research Database (Denmark)

Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan

2009-01-01

Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained.......Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained....

Atomic physics of strongly correlated systems

International Nuclear Information System (INIS)

Lin, C.D.

1986-01-01

This abstract summarizes the progress made in the last year and the future plans of our research in the study of strongly correlated atomic systems. In atomic structure and atomic spectroscopy we are investigating the classification and supermultiplet structure of doubly excited states. We are also beginning the systematic study of triply excited states. In ion-atom collisions, we are exploring an AO-MO matching method for treating multi-electron collision systems to extract detailed information such as subshell cross sections, alignment and orientation parameters, etc. We are also beginning ab initio calculations on the angular distributions for electron transfer processes in low-energy (about 10-100eV/amu) ion-atom collisions in a full quantum mechanical treatment of the motion of heavy particles

Study on the growth of aligned carbon nanotubes controlled by ion bombardment

International Nuclear Information System (INIS)

Wang Biben; Zhang Bing; Zheng Kun; Hao Wei; Wang Wanlu; Liao Kejun

2004-01-01

Aligned carbon nanotubes were prepared by plasma-enhanced hot filament chemical vapor deposition using CH 4 , H 2 and NH 3 as reaction gases. It was investigated how different negative bias affects the growth of aligned carbon nanotubes. The results indicate that the average diameter of the aligned carbon nanotubes is reduced and the average length of the aligned carbon nanotubes is increased with increasing negative bias. Because of the occurrence of glow discharge, a cathode sheath forms near the substrate surface, and a number of ions are produced in it, and a very strong electrical field builds up near the substrate surface. Under the effect of the field, the strong bombardment of ions on the substrate surface will influence the growth of aligned carbon nanotubes. Combined with related theories, authors have analyzed and discussed the ion bombardment effects on the growth of the aligned carbon nanotudes

Turbulent transport of energetic ions

International Nuclear Information System (INIS)

Dannert, Tilman; Hauff, Thilo; Jenko, Frank; Guenter, Sibylle

2006-01-01

Approaching ITER operation, the issue of anomalous transport of fast particles becomes more and more important. This is partly because the ITER heating and current drive system relies heavily on neutral beam injection. Moreover burning plasmas are heated by fast fusion α particles.Fusion α particles are characterised by a fixed energy and an isotropic velocity distribution. Therefore they have gyroradii one magnitude larger than the thermal ions. The dependency of the particle diffusion of α test particles on the Kubo number K = VExBτc/λc (VExB mean E x B velocity, τc, λc correlation time and length of the turbulent potential) is presented. For different turbulent regimes, different dependency of the diffusion on the gyroradius is found. For large Kubo numbers, the transport is found to remain constant for gyroradii up to the correlation length of the potential, whereas it is drastically reduced in the small Kubo number regime.In the second part, a model for beam ions injected along the equilibrium magnetic field is described. The beam ions are treated gyrokinetically in a self-consistent way with the equilibrium distribution function taken as a shifted Maxwellian. The implications of such a model for the Vlasov equation, the field equations, and the calculation of moments and fluxes are discussed. Linear and nonlinear results, obtained with the gyrokinetic flux tube code GENE show the existence of a new instability driven by fast beam ions. The instability has a maximum growth rate at perpendicular wave numbers of kyρs ∼ 0.15 and depends mainly on the beam velocity and the density gradient of the beam ions. This instability leads to a replacement of bulk ion particle transport by fast ion particle transport, connected to a strongly enhanced heat flux. In the presence of this instability, the turbulent particle and heat transport is dominated by fast ions

Evaluation of the stability of uranyl peroxo-carbonato complex ions in carbonate media at different temperatures

International Nuclear Information System (INIS)

Kim, Kwang-Wook; Lee, Keun-Young; Chung, Dong-Yong; Lee, Eil-Hee; Moon, Jei-Kwon; Shin, Dong-Woo

2012-01-01

Highlights: ► The stability of peroxide in uranyl peroxo carbonato complex solutions with different temperatures was characterized. ► The decomposition rate of uranyl peroxo carbonato complex ion to uranyl tris-carbonato complex ion was observed to increase with temperature ► The decomposition kinetics of uranyl peroxo carbonato complex ions was evaluated by absorption and Raman spectroscopies. ► A precipitate of uranyl peroxo carbonato complex solution was evaluated with XRD. - Abstract: This work studied the stability of peroxide in uranyl peroxo carbonato complex ions in a carbonate solution with hydrogen peroxide using absorption and Raman spectroscopies, and evaluated the temperature dependence of the decomposition characteristics of uranyl peroxo carbonato complex ions in the solution. The uranyl peroxo carbonato complex ions self-decomposed more rapidly into uranyl tris-carbonato complex ions in higher temperature carbonate solutions. The concentration of peroxide in the solution without free hydrogen peroxide represents the concentration of uranyl peroxo carbonato complex ions in a mixture of uranyl peroxo carbonato complex and uranyl tris-carbonato complex ions. The self-decomposition of the uranyl peroxo carbonato complex ions was a first order reaction, and its activation energy was evaluated to be 7.144 × 10 3 J mol −1 . The precipitation of sodium uranium oxide hydroxide occurred when the amount of uranyl tris-carbonato complex ions generated from the decomposition of the uranyl peroxo carbonato complex ions exceeded the solubility of uranyl tris-carbonato ions in the solution at the solution temperature.

Different routes, same pathways: Molecular mechanisms under silver ion and nanoparticle exposures in the soil sentinel Eisenia fetida

International Nuclear Information System (INIS)

Novo, Marta; Lahive, Elma; Díez-Ortiz, María; Matzke, Marianne; Morgan, Andrew J.; Spurgeon, David J.; Svendsen, Claus; Kille, Peter

2015-01-01

Use of nanotechnology products is increasing; with silver (Ag) nanoparticles particularly widely used. A key uncertainty surrounding the risk assessment of AgNPs is whether their effects are driven through the same mechanism of action that underlies the toxic effects of Ag ions. We present the first full transcriptome study of the effects of Ag ions and NPs in an ecotoxicological model soil invertebrate, the earthworm Eisenia fetida. Gene expression analyses indicated similar mechanisms for both silver forms with toxicity being exerted through pathways related to ribosome function, sugar and protein metabolism, molecular stress, disruption of energy production and histones. The main difference seen between Ag ions and NPs was associated with potential toxicokinetic effects related to cellular internalisation and communication, with pathways related to endocytosis and cilia being significantly enriched. These results point to a common final toxicodynamic response, but initial internalisation driven by different exposure routes and toxicokinetic mechanisms. - Highlights: • Molecular effects underlying Ag ions and NPs exposure were studied in Eisenia fetida. • Full transcriptomic study of a genetically characterised lineage. • NPs and ions presented a similar toxicodynamic response. • Internalisation of the two Ag forms by different toxicokinetic mechanisms. - Transcriptomic analyses after exposure of earthworms to silver NPs or ions showed a final common toxicodynamic response, but internalisation by different toxicokinetic mechanisms

Selective permeability of uranyl peroxide nanocages to different alkali ions: influences from surface pores and hydration shells

International Nuclear Information System (INIS)

Gao, Yunyi; Haso, Fadi; Zhou, Jing; Hu, Lang; Liu, Tianbo; Szymanowski, Jennifer E.S.; Burns, Peter C.

2015-01-01

The precise guidance to different ions across the biological channels is essential for many biological processes. An artificial nanopore system will facilitate the study of the ion-transport mechanism through nanosized channels and offer new views for designing nanodevices. Herein we reveal that a 2.5 nm-sized, fullerene-shaped molecular cluster Li_4_8_+_mK_1_2(OH)_m[UO_2(O_2)(OH)]_6_0_-(H_2O)_n (m∼20 and n∼310) (U_6_0) shows selective permeability to different alkali ions. The subnanometer pores on the water-ligand-rich surface of U_6_0 are able to block Rb"+ and Cs"+ ions from passing through, while allowing Na"+ and K"+ ions, which possess larger hydrated sizes, to enter the interior space of U_6_0. An interestingly high entropy gain during the binding process between U_6_0 and alkali ions suggests that the hydration shells of Na"+/K"+ and U_6_0 are damaged during the interaction. The ion selectivity of U_6_0 is greatly influenced by both the morphologies of the surface nanopores and the dynamics of the hydration shells. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

TBI server: a web server for predicting ion effects in RNA folding.

Science.gov (United States)

Zhu, Yuhong; He, Zhaojian; Chen, Shi-Jie

2015-01-01

Metal ions play a critical role in the stabilization of RNA structures. Therefore, accurate prediction of the ion effects in RNA folding can have a far-reaching impact on our understanding of RNA structure and function. Multivalent ions, especially Mg²⁺, are essential for RNA tertiary structure formation. These ions can possibly become strongly correlated in the close vicinity of RNA surface. Most of the currently available software packages, which have widespread success in predicting ion effects in biomolecular systems, however, do not explicitly account for the ion correlation effect. Therefore, it is important to develop a software package/web server for the prediction of ion electrostatics in RNA folding by including ion correlation effects. The TBI web server http://rna.physics.missouri.edu/tbi_index.html provides predictions for the total electrostatic free energy, the different free energy components, and the mean number and the most probable distributions of the bound ions. A novel feature of the TBI server is its ability to account for ion correlation and ion distribution fluctuation effects. By accounting for the ion correlation and fluctuation effects, the TBI server is a unique online tool for computing ion-mediated electrostatic properties for given RNA structures. The results can provide important data for in-depth analysis for ion effects in RNA folding including the ion-dependence of folding stability, ion uptake in the folding process, and the interplay between the different energetic components.

TBI server: a web server for predicting ion effects in RNA folding.

Directory of Open Access Journals (Sweden)

Yuhong Zhu

Full Text Available Metal ions play a critical role in the stabilization of RNA structures. Therefore, accurate prediction of the ion effects in RNA folding can have a far-reaching impact on our understanding of RNA structure and function. Multivalent ions, especially Mg²⁺, are essential for RNA tertiary structure formation. These ions can possibly become strongly correlated in the close vicinity of RNA surface. Most of the currently available software packages, which have widespread success in predicting ion effects in biomolecular systems, however, do not explicitly account for the ion correlation effect. Therefore, it is important to develop a software package/web server for the prediction of ion electrostatics in RNA folding by including ion correlation effects.The TBI web server http://rna.physics.missouri.edu/tbi_index.html provides predictions for the total electrostatic free energy, the different free energy components, and the mean number and the most probable distributions of the bound ions. A novel feature of the TBI server is its ability to account for ion correlation and ion distribution fluctuation effects.By accounting for the ion correlation and fluctuation effects, the TBI server is a unique online tool for computing ion-mediated electrostatic properties for given RNA structures. The results can provide important data for in-depth analysis for ion effects in RNA folding including the ion-dependence of folding stability, ion uptake in the folding process, and the interplay between the different energetic components.

Ion source techniques for high-speed processing of material surface by ion beams

International Nuclear Information System (INIS)

Ishikawa, Junzo

1990-01-01

The present paper discusses some key or candidate techniques for future ion source development and such ion sources developed by the author. Several types of microwave ion sources for producing low charge state ions have been developed in Japan. When a microwave plasma cathode developed by the author is adapted to a Kaufman type ion source, the electron emission currents are found to be 2.5 A for argon gas and 0.5-0.9 A for oxygen gas. An alternative ionization method for metal atoms is strongly required for high-speed processing of material surface by metal-ion beams. Detailed discussion is made of collisional ionization of vaporized atoms, and negative-ion production (secondary negative-ion emission by sputtering). An impregnated electrode type liquid-metal ion source developed by the author, which has a porous tip structure, is described. The negative-ion production efficiency is quite high. The report also presents a neutral and ionized alkaline-metal bombardment type heavy negative-ion source, which consists of a cesium plasma ion source, suppressor, target electrode, negative-ion extraction electrode, and einzel lens. (N.K.)

Theory of Spin Waves in Strongly Anisotropic Magnets

DEFF Research Database (Denmark)

Lindgård, Per-Anker; Cooke, J. F.

1976-01-01

A new infinite-order perturbation approach to the theory of spin waves in strongly anisotropic magnets is introduced. The system is transformed into one with effective two-ion anisotropy and considerably reduced ground-state corrections. A general expression for the spin-wave energy, valid to any...

Equilibration and hydrodynamics at strong and weak coupling

NARCIS (Netherlands)

Schee, Wilke van der

2017-01-01

We give an updated overview of both weak and strong coupling methods to describe the approach to a plasma described by viscous hydrodynamics, a process now called hydrodynamisation. At weak coupling the very first moments after a heavy ion collision is described by the colour-glass condensate

Hardening by ion implantation of VT1-0 alloy having different grain size

Energy Technology Data Exchange (ETDEWEB)

Nikonenko, Alisa, E-mail: aliska-nik@mail.ru; Kurzina, Irina, E-mail: kurzina99@mail.ru [National Research Tomsk State University, 36, Lenin Str., 634050, Tomsk (Russian Federation); Popova, Natalya, E-mail: natalya-popova-44@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk Russia (Russian Federation); Nikonenko, Elena, E-mail: vilatomsk@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Str., 634050, Tomsk (Russian Federation); Kalashnikov, Mark, E-mail: kmp1980@mail.ru [Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk Russia (Russian Federation)

2016-01-15

The paper presents a transmission electron microscopy (TEM) study of the structural and phase state of commercially pure titanium implanted by aluminum ions. TEM study has been carried out for two types of grains, namely coarse (0.4 µm) and small (0.5 µm). This paper presents details of the yield stress calculations and the analysis of strength components for the both grain types in two areas of the modified layer: at a distance of 0-150 nm (surface area I) and ∼300 nm (central area II) from the irradiated surface. It is shown that the ion implantation results in a considerable hardening of the entire thickness of the implanted layer in the both grain types. The grain size has, however, a different effect on the yield stress in areas I and II. Thus, near the ion-alloyed layer, the yield stress decreases with the increase of the grain size, whilst area II demonstrates its increase. Moreover, the contribution to the general hardening of the alloy made by certain hardening mechanisms differs from contributions made by each of these mechanisms in each certain case.

Effect of Ion Beam Irradiation on Silicon Carbide with Different Microstructures

International Nuclear Information System (INIS)

Park, Kyeong Hwan; Park, Ji Yeon; Kim, Weon Ju; Jung, Choong Hwan; Ryu, Woo Seog

2006-01-01

SiC and SiC/SiC composites are one of promising candidates for structural materials of the next generation energy systems such as the gas-cooled reactors and fusion reactors. This anticipation yields many material issues, and radiation effects of silicon carbide are recognized as an important research subject. Silicon carbide has diverse crystal structures (called polytypes), such as α-SiC (hexagonal structure), β-SiC (cubic structure) and amorphous SiC. Among these polytypes, β-SiC has been studied as matrix material in SiC/SiC composites. Near-stoichiometric β-SiC with high crystallinity and purity is considered as suitable material in the next generation energy system and matrix material in SiC/SiC composites because of its excellent radiation resistance. Highly pure and crystalline β-SiC and SiC/SiC composites could be obtained by the chemical vapor deposition (CVD) and Infiltration (CVI) process using a gas mixture of methyltrichlorosilane (CH 3 SiCl 3 , MTS) and purified H 2 . SiC produced by the CVD method has different grain size and microstructural morphology depended on the process conditions such as temperature, pressure and the input gas ratio. In this work, irradiation effects of silicon carbide were investigated using ion beam irradiation with emphasis on the influence of grain size and grain boundary. MeV ion irradiation at low temperature makes amorphous phase in silicon carbide. The microstructures and mechanical property changes of silicon carbide with different structures were analyzed after ion beam irradiation

A Substantial Plume of Escaping Planetary Ions in the MSE Northern Hemisphere Observed by MAVEN

Science.gov (United States)

Dong, Y.; Fang, X.; Brain, D. A.; McFadden, J. P.; Halekas, J. S.; Connerney, J. E. P.; Curry, S.; Harada, Y.; Luhmann, J. G.; Jakosky, B. M.

2015-12-01

The Mars-solar wind interaction accelerates and transports planetary ions away from Mars through a number of processes, including pick-up by the electromagnetic fields. The Mars Atmospheric and Volatile EvolutioN (MAVEN) spacecraft has frequently detected strong escaping planetary ion fluxes in both tailward and upstream solar wind motional electric field directions since the beginning of its science phase in November 2014. Our statistical study using three-month MAVEN data from November 2014 through February 2015 illustrates a substantial plume-like escaping planetary ion population organized by the upstream electric field with strong fluxes widely distributed in the northern hemisphere of the Mars-Sun-Electric-field (MSE) coordinate system, which is generally consistent with model predictions. The plume constitutes an important planetary ion escape channel from the Martian atmosphere in addition to the tailward escape. The >25eV O+ escape rate through the plume is estimated to be ~35% of the tailward escape and ~25% of the total escape. We will compare the dynamics of the plume and tailward escaping ions based on their velocity-space distributions with respect to the electromagnetic fields. We will also discuss the variations of the plume characteristics between different ion species (O+, O2+, and CO2+) and from the effect of different solar wind and interplanetary magnetic field (IMF) conditions.

The ion polytropic coefficient in a collisionless sheath containing hot ions

Energy Technology Data Exchange (ETDEWEB)

Lin, Binbin; Xiang, Nong, E-mail: xiangn@ipp.ac.cn; Ou, Jing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China)

2016-08-15

The fluid approach has been widely used to study plasma sheath dynamics. For a sheath containing hot ions whose temperature is greater than the electron's, how to truncate the fluid hierarchy chain equations while retaining to the fullest extent of the kinetic effects is always a difficult problem. In this paper, a one-dimensional, collisionless sheath containing hot ions is studied via particle-in-cell simulations. By analyzing the ion energy equation and taking the kinetic effects into account, we have shown that the ion polytropic coefficient in the vicinity of the sheath edge is approximately constant so that the state equation with the modified polytropic coefficient can be used to close the hierarchy chain of the ion fluid equations. The value of the polytropic coefficient strongly depends on the hot ion temperature and its concentration in the plasma. The semi-analytical model is given to interpret the simulation results. As an application, the kinetic effects on the ion saturation current density in the probe theory are discussed.

Use of water as displacing agent in ion exchange chromatographic separation of isotope of boron using weak base ion exchange resin

International Nuclear Information System (INIS)

Sharma, B.K.; Mohanakrishnan, G.; Anand Babu, C.; Krishna Prabhu, R.

2008-01-01

Experiments were undertaken to study the feasibility of using weakly basic anion exchange resin for enrichment of isotopes of boron by ion exchange chromatography and water as eluent. The results of experiments carried out to determine total chloride capacity (TCC), strong base capacity (SBC) of the resin at different concentrations of boric acid and enrichment profiles are reported in this paper. (author)

Carbon ions of different linear energy transfer (LET values induce apoptosis & G2 cell cycle arrest in radio-resistant melanoma cells

Directory of Open Access Journals (Sweden)

Žakula Jelena

2016-01-01

Full Text Available Background & objectives: The main goal when treating malignancies with radiation is to deprive tumour cells of their reproductive potential. One approach is to induce tumour cell apoptosis. This study was conducted to evaluate the ability of carbon ions ( [12] C to induce apoptosis and cell cycle arrest in human HTB140 melanoma cells. Methods: In this in vitro study, human melanoma HTB140 cells were irradiated with the 62 MeV/n carbon ( [12] C ion beam, having two different linear energy transfer (LET values: 197 and 382 keV/μm. The dose range was 2 to 16 Gy. Cell viability was estimated by the sulforhodamine B assay seven days after irradiation. The cell cycle and apoptosis were evaluated 48 h after irradiation using flow cytometry. At the same time point, protein and gene expression of apoptotic regulators were estimated using the Western blot and q-PCR methods, respectively. Results: Cell viability experiments indicated strong anti-tumour effects of [12] C ions. The analysis of cell cycle showed that [12] C ions blocked HTB140 cells in G2 phase and induced the dose dependent increase of apoptosis. The maximum value of 21.8 per cent was attained after irradiation with LET of 197 keV/μm at the dose level of 16 Gy. Pro-apoptotic effects of [12] C ions were confirmed by changes of key apoptotic molecules: the p53, Bax, Bcl-2, poly ADP ribose polymerase (PARP as well as nuclear factor kappa B (NFκB. At the level of protein expression, the results indicated significant increases of p53, NFκB and Bax/Bcl-2 ratio and PARP cleavage. The Bax/Bcl-2 mRNA ratio was also increased, while no change was detected in the level of NFκB mRNA. Interpretation & conclusions: The present results indicated that anti-tumour effects of [12] C ions in human melanoma HTB140 cells were accomplished through induction of the mitochondrial apoptotic pathway as well as G2 arrest.

Evidence for an ultrafast breakdown of the BeO band structure due to swift argon and xenon ions.

Science.gov (United States)

Schiwietz, G; Czerski, K; Roth, M; Grande, P L; Koteski, V; Staufenbiel, F

2010-10-29

Auger-electron spectra associated with Be atoms in the pure metal lattice and in the stoichiometric oxide have been investigated for different incident charged particles. For fast incident electrons, for Ar7+ and Ar15+ ions as well as Xe15+ and Xe31+ ions at velocities of 6% to 10% the speed of light, there are strong differences in the corresponding spectral distributions of Be-K Auger lines. These differences are related to changes in the local electronic band structure of BeO on a femtosecond time scale after the passage of highly charged heavy ions.

Mechanical and tribological properties of AISI 304 stainless steel nitrided by glow discharge compared to ion implantation and plasma immersion ion implantation

International Nuclear Information System (INIS)

Foerster, C.E.; Serbena, F.C.; Silva, S.L.R. da; Lepienski, C.M.; Siqueira, C.J. de M.; Ueda, M.

2007-01-01

Results about mechanical and tribological behavior of AISI 304 stainless steel nitrided by three different ion beam processes - glow discharge (GD), ion implantation (II) and plasma immersion ion implantation (PI3) are reported. Expanded austenite γ N and nitrides phases (Fe 2+x N, γ'-Fe 4 N and Cr-N) were identified as a function of nitriding conditions. Hardness (H) and elastic modulus (E) profiles were obtained by instrumented penetration. The hardness reached values as high as 21 GPa by PI3. Tribological behavior was studied by reciprocating sliding tests with a WC (Co) ball at room temperature (RT) in dry condition. Different wear regimes were identified in the friction coefficient profiles. The profile form and the running-in distance are strongly dependent on the nitriding process. Adhesive and abrasive wear components can be inferred from these friction profiles. Hardness and tribological performance, after the nitriding processes, are discussed in terms of surface microstructure

A heavy ion pre-injector for the ICT-ion implanter

International Nuclear Information System (INIS)

Bhattacharya, P.K.; Gaonkar, S.; Wagh, A.G.; Hattangadi, V.A.; Sarma, N.

1976-01-01

A cheap and versatile hollow cathode electron bombardment ion source system including its ion extraction-cum-focussing assembly for obtaining intense heavy ion beams of solids and gases is described. The extractor region is designed to include more than 15deg total beam angle of extracted beam for producing focused ion current densities upto 60mA/cm 2 to serve as a pre-injector for the ICT(insulated core transformer) type ion implanter. The extraction-cum-focussing lens is a low aberration strong Einzel lens system of all araldite and metal construction with optical elements of proper quality and location to suit low voltage injection and subsequent ion analysis. The injection can be selected anywhere between 2 to 10 keV for singly charged ions with typical extraction currents of 500/μ, using a ring anode and a source aperture of 20 mil. Einzel lens focussing assembly allows continuous adjustment of the beam convergence to about 5deg and the beam size to approximately 5mm in diameter with about 10 KV central electrode potential. Test results of source characteristics for both the accelerating and decelerating model of beam formation have been made. (author)

An investigation of the mass spectra of secondary ions ejected from the single crystal surface of semiconductors

International Nuclear Information System (INIS)

Koval', A.G.; Mel'nikov, V.N.; Enukov, Yu.V.

1976-01-01

The mass spectra of secondary positive and negative ions, ejected by an Ar + ion beam from the (100) face of an epitaxial film of the semiconductor Alsub(x)Gasub(1-x)As were investigated. There are many various secondary ions in the mass spectrum under investigation. They may be divided into four groups according to their origins. Mass spectra of secondary positive and negative secondary ions differ much, either in their composition or the intensities of homogeneous ions. The I(T) dependences (I=the current of corresponding secondary ions, T=target temperature) were obtained for secondary and negative ions taken from groups differing by their origin. The I(T) dependences were obtained at several oxygen pressures in a chamber. For the ions with 'superficial' origin a strong dependence of their current on target temperature is observed. Oxygen pressure increase leads to substantial change of the I(T)curves. (Auth.)

Evaluation of the stability of uranyl peroxo-carbonato complex ions in carbonate media at different temperatures

Energy Technology Data Exchange (ETDEWEB)

Kim, Kwang-Wook, E-mail: nkwkim@kaeri.re.kr [Korea Atomic Energy Research Institute, 1045 Daedeok daero, Yuseong, Daejeon 305-353 (Korea, Republic of); Lee, Keun-Young; Chung, Dong-Yong; Lee, Eil-Hee; Moon, Jei-Kwon [Korea Atomic Energy Research Institute, 1045 Daedeok daero, Yuseong, Daejeon 305-353 (Korea, Republic of); Shin, Dong-Woo [Gyeongsang National University, 900 Gajwa, Jinju 660-701 (Korea, Republic of)

2012-09-30

Highlights: Black-Right-Pointing-Pointer The stability of peroxide in uranyl peroxo carbonato complex solutions with different temperatures was characterized. Black-Right-Pointing-Pointer The decomposition rate of uranyl peroxo carbonato complex ion to uranyl tris-carbonato complex ion was observed to increase with temperature Black-Right-Pointing-Pointer The decomposition kinetics of uranyl peroxo carbonato complex ions was evaluated by absorption and Raman spectroscopies. Black-Right-Pointing-Pointer A precipitate of uranyl peroxo carbonato complex solution was evaluated with XRD. - Abstract: This work studied the stability of peroxide in uranyl peroxo carbonato complex ions in a carbonate solution with hydrogen peroxide using absorption and Raman spectroscopies, and evaluated the temperature dependence of the decomposition characteristics of uranyl peroxo carbonato complex ions in the solution. The uranyl peroxo carbonato complex ions self-decomposed more rapidly into uranyl tris-carbonato complex ions in higher temperature carbonate solutions. The concentration of peroxide in the solution without free hydrogen peroxide represents the concentration of uranyl peroxo carbonato complex ions in a mixture of uranyl peroxo carbonato complex and uranyl tris-carbonato complex ions. The self-decomposition of the uranyl peroxo carbonato complex ions was a first order reaction, and its activation energy was evaluated to be 7.144 Multiplication-Sign 10{sup 3} J mol{sup -1}. The precipitation of sodium uranium oxide hydroxide occurred when the amount of uranyl tris-carbonato complex ions generated from the decomposition of the uranyl peroxo carbonato complex ions exceeded the solubility of uranyl tris-carbonato ions in the solution at the solution temperature.

Convoy electron production by heavy ions in solids

International Nuclear Information System (INIS)

Sellin, I.A.

1984-01-01

The term convoy electron refers to those electrons ejected in fast ion-atom and ion-solid collisions closely matched in vector velocity to that of the incident heavy particles responsible for their ejection. Similarities and differences among electrons ejected into such states through binary electron capture to continuum and electron loss to continuum processes in single ion-atom encounters are compared and contrasted to more complex ejection processes occurring in solid targets. Puzzles posed by the apparent strong projectile Z dependence but weak emergent ion charge dependence of the yield in the case of solid targets are reviewed. Very recent progress in resolving these puzzles has been made by recent observations that the apparent mean free path for electron scattering out of the forward direction within the target is observed to be an order of magnitude greater than that for free electrons of equal velocity provided the projectile charge is high. 13 references, 2 figures, 1 table

Effect of Coulomb collision on the negative ion extraction mechanism in negative ion sources.

Science.gov (United States)

Goto, I; Miyamoto, K; Nishioka, S; Mattei, S; Lettry, J; Abe, S; Hatayama, A

2016-02-01

To improve the H(-) ion beam optics, it is necessary to understand the energy relaxation process of surface produced H(-) ions in the extraction region of Cs seeded H(-) ion sources. Coulomb collisions of charged particles have been introduced to the 2D3V-PIC (two dimension in real space and three dimension in velocity space particle-in-cell) model for the H(-) extraction by using the binary collision model. Due to Coulomb collision, the lower energy part of the ion energy distribution function of H(-) ions has been greatly increased. The mean kinetic energy of the surface produced H(-) ions has been reduced to 0.65 eV from 1.5 eV. It has been suggested that the beam optics of the extracted H(-) ion beam is strongly affected by the energy relaxation process due to Coulomb collision.

Different types of pre-lithiated hard carbon as negative electrode material for lithium-ion capacitors

International Nuclear Information System (INIS)

Zhang, Jin; Liu, Xifeng; Wang, Jing; Shi, Jingli; Shi, Zhiqiang

2016-01-01

Highlights: • Two types of HC materials with different properties as negative electrode. • Lithium ion intercalation plateau of HC affects electrochemical performance of LIC. • The electrochemical performance of LIC is operated at different potential ranges. • The selection of HC and appropriate potential range of LIC have been proposed. - ABSTRACT: Lithium-ion capacitors (LICs) are assembled with activated carbon (AC) cathode and pre-lithiated hard carbon (HC) anode. Two kinds of HC materials with different physical and electrochemical behaviors have been investigated as the negative electrodes for LIC. Compared with spherical HC, the irregular HC shows a distinct lithium ion intercalation plateau in the charge–discharge process. The existence of lithium ion intercalation plateau for irregular HC greatly affects the electrochemical behavior of HC negative electrode and AC positive electrode. The effect of working potential range on the electrochemical performance of LIC-SH and LIC-IH is investigated by the galvanostatic charging–discharging, electrochemical impedance tests and cycle performance testing. The charge–discharge potential range of the irregular HC negative electrode is lower than the spherical HC electrode due to the existence of lithium ion intercalation plateau, which is conducive to the sufficient utilization of the AC positive electrode. The working potential range of LIC should be controlled to realize the optimization of electrochemical performance of LIC. LIC-IH at the working potential range of 2.0-4.0 V exhibits the optimal electrochemical performance, high energy density up to 85.7 Wh kg −1 and power density as high as 7.6 kW kg −1 (based on active material mass of two electrodes), excellent capacity retention about 96.0% after 5000 cycles.

Fully kinetic simulation of ion acoustic and dust-ion acoustic waves

International Nuclear Information System (INIS)

Hosseini Jenab, S. M.; Kourakis, I.; Abbasi, H.

2011-01-01

A series of numerical simulations is presented, based on a recurrence-free Vlasov kinetic model using kinetic phase point trajectories. All plasma components are modeled kinetically via a Vlasov evolution equation, then coupled through Poisson's equation. The dynamics of ion acoustic waves in an electron-ion and in a dusty (electron-ion-dust) plasma configuration are investigated, focusing on wave decay due to Landau damping and, in particular, on the parametric dependence of the damping rate on the dust concentration and on the electron-to-ion temperature ratio. In the absence of dust, the occurrence of damping was observed, as expected, and its dependence to the relative magnitude of the electron vs ion temperature(s) was investigated. When present, the dust component influences the charge balance, enabling dust-ion acoustic waves to survive Landau damping even in the extreme regime where T e ≅ T i . The Landau damping rate is shown to be minimized for a strong dust concentration or/and for a high value of the electron-to-ion temperature ratio. Our results confirm earlier theoretical considerations and contribute to the interpretation of experimental observations of dust-ion acoustic wave characteristics.

A three-scale model for ionic solute transport in swelling clays incorporating ion-ion correlation effects

Science.gov (United States)

Le, Tien Dung; Moyne, Christian; Murad, Marcio A.

2015-01-01

A new three-scale model is proposed to describe the movement of ionic species of different valences in swelling clays characterized by three separate length scales (nano, micro, and macro) and two levels of porosity (nano- and micropores). At the finest (nano) scale the medium is treated as charged clay particles saturated by aqueous electrolyte solution containing monovalent and divalent ions forming the electrical double layer. A new constitutive law is constructed for the disjoining pressure based on the numerical resolution of non-local problem at the nanoscale which, in contrast to the Poisson-Boltzmann theory for point charge ions, is capable of capturing the short-range interactions between the ions due to their finite size. At the intermediate scale (microscale), the two-phase homogenized particle/electrolyte solution system is represented by swollen clay clusters (or aggregates) with the nanoscale disjoining pressure incorporated in a modified form of Terzaghi's effective principle. At the macroscale, the electro-chemical-mechanical couplings within clay clusters is homogenized with the ion transport in the bulk fluid lying in the micro pores. The resultant macroscopic picture is governed by a three-scale model wherein ion transport takes place in the bulk solution strongly coupled with the mechanics of the clay clusters which play the role of sources/sinks of mass to the bulk fluid associated with ion adsorption/desorption in the electrical double layer at the nanoscale. Within the context of the quasi-steady version of the multiscale model, wherein the electrolyte solution in the nanopores is assumed at instantaneous thermodynamic equilibrium with the bulk fluid in the micropores, we build-up numerically the ion-adsorption isotherms along with the constitutive law of the retardation coefficients of monovalent and divalent ions. In addition, the constitutive law for the macroscopic swelling pressure is reconstructed numerically showing patterns of

Surface depression of glass and surface swelling of ceramics induced by ion implantation

International Nuclear Information System (INIS)

Ikeyama, Masami; Saitoh, Kazuo; Nakao, Setsuo; Niwa, Hiroaki; Tanemura, Seita; Miyagawa, Yoshiko; Miyagawa, Souji

1994-01-01

By the measurement of the change of the surface shapes of the glass and ceramics in which ion implantation was performed, it was clarified that glass surface was depressed, and ceramic surface swelled. These depression and swelling changed according to the kinds of ions, energy and the amount to be implanted and the temperature of samples. It became clear that the depression of glass surface was nearly proportional to the range of flight of the implanted ions, and the swelling of ceramic surface showed different state in the silicon nitride with strong covalent bond and the alumina and sapphire with strong ionic bond. For the improvement of the mechanical characteristics of solid materials such as hardness, strength, toughness, wear resistance, oxidation resistance and so on, attention has been paid to the surface reforming by high energy ion implantation at MeV level. The change of shapes of base materials due to ion implantation is not always negligible. The experiment was carried out on sintered silicon nitride and alumina, polished sapphire single crystals and quartz glass. The experimental method and the results are reported. (K.I.)

Ion Elevators and Escalators in Multilevel Structures for Lossless Ion Manipulations

Energy Technology Data Exchange (ETDEWEB)

Ibrahim, Yehia M.; Hamid, Ahmed M.; Cox, Jonathan T.; Garimella, Venkata BS; Smith, Richard D.

2017-01-19

We describe two approaches based upon ion ‘elevator’ and ‘escalator’ components that allow moving ions to different levels in structures for lossless ion manipulations (SLIM). Guided by ion motion simulations we designed elevator and escalator components providing essentially lossless transmission in multi-level designs based upon ion current measurements. The ion elevator design allowed ions to efficiently bridge a 4 mm gap between levels. The component was integrated in a SLIM and coupled to a QTOF mass spectrometer using an ion funnel interface to evaluate the m/z range transmitted as compared to transmission within a level (e.g. in a linear section). Mass spectra for singly-charged ions of m/z 600-2700 produced similar mass spectra for both elevator and straight (linear motion) components. In the ion escalator design, traveling waves (TW) were utilized to transport ions efficiently between two SLIM levels. Ion current measurements and ion mobility (IM) spectrometry analysis illustrated that ions can be transported between TW-SLIM levels with no significant loss of either ions or IM resolution. These developments provide a path for the development of multilevel designs providing e.g. much longer IM path lengths, more compact designs, and the implementation of much more complex SLIM devices in which e.g. different levels may operate at different temperatures or with different gases.

Ion Elevators and Escalators in Multilevel Structures for Lossless Ion Manipulations.

Science.gov (United States)

Ibrahim, Yehia M; Hamid, Ahmed M; Cox, Jonathan T; Garimella, Sandilya V B; Smith, Richard D

2017-02-07

We describe two approaches based upon ion "elevator" and "escalator" components that allow moving ions to different levels in structures for lossless ion manipulations (SLIM). Guided by ion motion simulations, we designed elevator and escalator components based upon ion current measurements providing essentially lossless transmission in multilevel designs. The ion elevator design allowed ions to efficiently bridge a 4 mm gap between levels. The component was integrated in a SLIM and coupled to a QTOF mass spectrometer using an ion funnel interface to evaluate the m/z range transmitted as compared to transmission within a level (e.g., in a linear section). The analysis of singly charged ions of m/z 600-2700 produced similar mass spectra for both elevator and straight (linear motion) components. In the ion escalator design, traveling waves (TW) were utilized to transport ions efficiently between two SLIM levels. Ion current measurements and ion mobility (IM) spectrometry analysis illustrated that ions can be transported between TW-SLIM levels with no significant loss of either ions or IM resolution. These developments provide a path for the development of multilevel designs providing, e.g., much longer IM path lengths, more compact designs, and the implementation of much more complex SLIM devices in which, e.g., different levels may operate at different temperatures or with different gases.

Strongly interacting matter in magnetic fields

CERN Document Server

Landsteiner, Karl; Schmitt, Andreas; Yee, Ho-Ung

2013-01-01

The physics of strongly interacting matter in an external magnetic field is presently emerging as a topic of great cross-disciplinary interest for particle, nuclear, astro- and condensed matter physicists. It is known that strong magnetic fields are created in heavy ion collisions, an insight that has made it possible to study a variety of surprising and intriguing phenomena that emerge from the interplay of quantum anomalies, the topology of non-Abelian gauge fields, and the magnetic field. In particular, the non-trivial topological configurations of the gluon field induce a non-dissipative electric current in the presence of a magnetic field. These phenomena have led to an extended formulation of relativistic hydrodynamics, called chiral magnetohydrodynamics. Hitherto unexpected applications in condensed matter physics include graphene and topological insulators. Other fields of application include astrophysics, where strong magnetic fields exist in magnetars and pulsars. Last but not least, an important ne...

Ion acceleration at the earth's bow shock: A review of observations in the upstream region

International Nuclear Information System (INIS)

Gosling, J.T.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.

1979-01-01

Positive ions are accelerated at or near the earth's bow shock and propagate into the upstream region. Two distinctly different population of these ions, distinguished by their greatly different spectral and angular widths, can be identified there. The type of ion population observed in the upstream region is strongly correlated with the presence or absence of long-period compresive waves in the solar wind. Very few ions are accelerated in the vicinity of the shock to energies much above about 100 keV. It is not yet clear whether the most energetic ions (i.e. those near 100 keV) are accelerated at the shock or in the broad disturbed region upstream from the shock. In either case stochastic acceleration by turbulent electrostatic fields seems to be the most viable candidate for the acceleration of the most energetic particles

Ion acceleration at the earth's bow shock: a review of observations in the upstream region

International Nuclear Information System (INIS)

Gosling, J.T.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.

1979-01-01

Positive ions are accelerated at or near the earth's bow shock and propagate into the upstream region. Two distinctly different populations of these ions, distinguished by their greatly different spectral and angular widths, can be identified there. The type of ion population observed in the upstream region is strongly correlated with the presence or absence of long-period compressive waves in the solar wind. Very few ions are accelerated in the vicinity of the shock to energies much above about 100 keV. It is not yet clear whether the most energetic ions (i.e., those near 100 keV) are accelerated at the shock or in broad disturbed region upstream from the shock. In either case stochastic acceleration by turbulent electrostatic fields seems to be the most viable candidate for the acceleration of the most energetic particles

He{sup 3+}{sub 2} and HeH{sup 2+} molecular ions in a strong magnetic field: The Lagrange-mesh approach

Energy Technology Data Exchange (ETDEWEB)

Olivares Pilón, Horacio, E-mail: holivare@ulb.ac.be [Physique Quantique, CP 165/82, Université Libre de Bruxelles, B 1050 Brussels (Belgium)

2012-04-09

Accurate calculations for the ground state of the molecular ions He{sup 3+}{sub 2} and HeH{sup 2+} placed in a strong magnetic field B≳10{sup 2} a.u. (≈2.35×10{sup 11} G) using the Lagrange-mesh method are presented. The Born–Oppenheimer approximation of zero order (infinitely massive centers) and the parallel configuration (molecular axis parallel to the magnetic field) are considered. Total energies are found with 9–10 s.d. The obtained results show that the molecular ions He{sup 3+}{sub 2} and HeH{sup 2+} exist at B>100 a.u. and B>1000 a.u., respectively, as predicted in Turbiner and López Vieyra (2007) while a saddle point in the potential curve appears for the first time at B∼80 a.u. and B∼740 a.u., respectively. -- Highlights: ► Application of the Lagrange-mesh method to two exotic molecular systems. ► He{sup 3+}{sub 2} and HeH{sup 2+} exist at B>100 a.u. and B>1000 a.u., respectively. ► Accurate results for the total energy. ► A saddle point in the potential appears at B∼80 a.u. and B∼740 a.u., respectively.

Correlated electron-ion collisions in a strong laser field; Korrelierte Elektron-Ion-Stoesse in starken Laserfeldern

Energy Technology Data Exchange (ETDEWEB)

Ristow, T.

2007-12-17

Electron-ion-collisions in plasmas in the presence of an ultra-short intensive laser pulse can cause high energy transfers to the electrons. During the collision the oscillation energy of the electron in the laser field is changed into drift energy. In this regime, multi-photon processes, known from the ionization of neutral atoms (Above-Threshold Ionization), and successive, so called correlated collisions, are important. The subject of the thesis is a study of binary Coulomb collisions in strong laser fields. The collisions are treated both in the context of classical Newtonian mechanics and in the quantum-mechanical framework by the Schroedinger equation. In the classical case a simplified instantaneous collision model and a complete dynamical treatment are discussed. Collisions can be treated instantaneously, if the ratio of the impact parameter to the quiver amplitude is small. The energy distributions calculated in this approximation show an elastic peak and a broad plateau due to rescattered electrons. At incident velocities smaller than the quiver velocity, correlated collisions are observed in the electron trajectories of the dynamical model. This effect leads to characteristic momentum distributions of the electrons, that are explicitly calculated and compared with the results of the instantaneous model. In addition, the time-dependence of the collisions is discussed in the framework of a singular perturbation theory. The complete description of the Coulomb scattering requires a quantum-mechanical description. A time-dependent method of wave-packet scattering is used and the corresponding time-dependent three-dimensional Schroedinger equation is solved by an implicit ADImethod on a spatial grid. The momentum and the energy distributions of the scattered electrons are calculated by the Fourier transformation of the wavefunction. A comparison of the scattering from a repulsive and an attractive potential is used to distinguish between simple collisions and

Subauroral Ion-neutral Coupling During the March 2015 Superstorm

Science.gov (United States)

Zhang, S.; Erickson, P. J.; Foster, J. C.; Holt, J. M.; Coster, A. J.; Makela, J. J.; Noto, J.; Meriwether, J. W.; Otsuka, Y.; Nicolls, M. J.; McCready, M. A.

2015-12-01

The arrival of solar Coronal Mass Ejection materials overlapping a high-speed solar wind stream originated from a nearby coronal hole caused huge magnetic disturbances during March 17-18, 2015. We have coordinated an international campaign to monitor their geospace effects using ground-based facilities, including incoherent scatter radars and Fabry-Perot Interferometers in the America sectors and other instruments in East Asia sectors, forming an observational network along approximately the 60W/120E meridional circle. The presentation will provide highlights of these observations, with a focus on the ion-neutral coupling processes at subauroral and mid-latitudes. One of the most stiking findings is the northward neutral wind surge, observed in multiple sites, accompanying strong westward winds developed at earlier times. We ascribe this unexpected wind disturbances to Subauroal Polarization Stream (SAPS) asscoated strong plasma flows driving ion-neutral coupling. SAPS and strong ion flow were observed by Millstone Hill ISR and DMSP in situ measurements. We will also report the Millstone Hill ISR observations of a significant enhancement in the storm-time molecular ion composition in the F1-region height. This enhancement appears to be caused by strong vertical ion drift due to penetration electric fields.

The thermal evolution of targets under plasma focus pulsed ion implantation

International Nuclear Information System (INIS)

Sanchez, G.; Feugeas, J.

1997-01-01

Pulsed ion beam implantation with plasma focus has proved to be an effective method of metal surface treatment for tribological purposes. Nevertheless, the pulsed nature and the continuous energy spectrum of the ion beams differ from those of the standard ion implantation processes. In this paper a model of the thermal evolution of the surface layers of stainless steel, titanium and copper, during and after nitrogen and argon ion beam incidence, is presented using the finite-difference method. In the calculations, the geometry and physical characteristics of the ion beams, the single-ion-solid interaction process and the thermal properties of the materials were used. The results showed a strong thermal effect consisting in the generation of transitory heating slopes and heating speeds as high as ∼3600 K μm -1 and ∼40 K ns -1 respectively, with maximum temperatures that can reach even the material evaporation point at the surface layers. The cooling down process, through the thermal conduction mechanism at the target bulk, turns out to be fast enough to produce the complete thermal relaxation of the target in only a few microseconds after the end of the ion beam incidence. The results presented are contrasted with experiments performed in similar conditions to those used in the numerical model. (Author)

Observation of water separated ion-pairs between cations and phospholipid headgroups.

Science.gov (United States)

van der Post, Sietse T; Hunger, Johannes; Bonn, Mischa; Bakker, Huib J

2014-04-24

In this work, we present evidence for ion pair formation of cations with a high surface charge density (Na(+) and Ca(2+)) and phosphate groups of phospholipids. We used femto-second infrared pump-probe and dielectric spectroscopy to probe the dynamics of water molecules in solutions of phosphorylethanolamine and different types of cations. We find that sodium and calcium cooperatively retard the dynamics of water in solutions of phosphorylethanolamine, implying the formation of solvent separated ion pairs. This ion-specific interaction is absent for potassium, cesium and ammonium. We compare our results to dielectric spectroscopy experiments, which probes the rotation of all dipolar molecules and ions in solution. The rotation of the dipolar phosphorylethanolamine ion shows that long-lived ion-pairs are only formed with calcium and not with ammonium, cesium, potassium, and sodium. This finding implies that the association between calcium and the phosphate is strong with lifetimes exceeding 200 ps, while the interaction with sodium is relatively short-lived (∼20-100 ps).

MMS Observations of Protons and Heavy Ions Acceleration at Plasma Jet Fronts

Science.gov (United States)

Catapano, F.; Retino, A.; Zimbardo, G.; Cozzani, G.; Breuillard, H.; Le Contel, O.; Alexandrova, A.; Mirioni, L.; Cohen, I. J.; Turner, D. L.; Perri, S.; Greco, A.; Mauk, B.; Torbert, R. B.; Russell, C. T.; Khotyaintsev, Y. V.; Lindqvist, P. A.; Ergun, R.; Giles, B. L.; Fuselier, S. A.; Moore, T. E.; Burch, J.

2017-12-01

Plasma jet fronts in the Earth's magnetotail are kinetic-scale boundaries separating hot fast plasma jets, generally attributed to reconnection outflows, from colder ambient plasma. Jet fronts are typically associated with a sharp increase of the vertical component of the magnetic field Bz, an increase of the plasma temperature and a drop of plasma density. Spacecraft observations and numerical simulations indicate that jet fronts are sites of major ion acceleration. The exact acceleration mechanisms as well as the dependence of such mechanisms on ion composition are not fully understood, yet. Recent high-resolution measurements of ion distribution functions in the magnetotail allow for the first time to study the acceleration mechanisms in detail. Here, we show several examples of jet fronts and discuss ion acceleration therein. We show fronts that propagate in the mid-tail magnetotail both as isolated laminar boundaries and as multiple boundaries embedded in strong magnetic fluctuations and turbulence. We also show fronts in the near-Earth jet braking region, where they interact with the dipolar magnetic field and are significantly decelerated/diverted. Finally, we study the acceleration of different ion species (H+, He++, O+) at different types of fronts and we discuss possible different acceleration mechanisms and how they depend on the ion species.

Use of Elements of the Stewart Model (Strong Ion Approach) - SID3, SID4, Atot/A-, SIDe and SIG for the Diagnostics of Respiratory Acidosis in Brachycephalic Dogs.

Science.gov (United States)

Sławuta, P; Sapikowski, G; Sobieraj, B

2016-09-01

Buffer systems of blood and tissues, which have the ability to bind with and give up hydrogen ions, participate in maintaining the acid-base balance (ABB) of the organism. According to the classic model, the system of carbonic acid and bicarbonates, where the first component serves the role of an acid and the second a base, determines plasma pH. The so-called Stewart model, which assumes that ions in blood serum can be separated into completely dissociated - nonbuffer and not dissociated - buffer ions which may give up or accept H+ions, also describes the ABB of the organism. The goal of the study was to find out whether, during respiratory acidosis, the values of SID3, SID4, Atot/A-, SIDe and SIG change. The study was carried out on 60 adult dogs of the boxer breed (32 males and 28 females) in which, on the basis of an arterial blood test, respiratory acidosis was found. A strong overgrowth of the soft palate tissue requiring a surgical correction was the cause of the ABB disorder. Prior to surgery and on the 14th day after the surgery, venous and arterial blood was drawn from each dog. ABB parameters were determined in the arterial blood sample: the blood pH, pCO2 and HCO3-. In the venous blood, concentration of Na+, K+, Cl-, lactate-, albumins, and Pinorganic was determined. On the basis of the obtained data, the values of SID3, SID4, SIDe, A- and SIG, before and after the surgery, were calculated. In spite of the fact that the average concentration of ions, albumins, Pinorganic and lactate in the blood serum of dogs before and after the surgical procedure was similar and within the physiological norms, the values of SID3, SIDe and SIG, calculated on the basis of the former, displayed statistically significant differences. On the basis of the results obtained, it can be stated that the values of SID3, SIDe and SIG change during respiratory acidosis and may be helpful in the diagnostics of ABB disorders in brachycephalic dogs.

Hole dynamics and spin currents after ionization in strong circularly polarized laser fields

International Nuclear Information System (INIS)

Barth, Ingo; Smirnova, Olga

2014-01-01

We apply the time-dependent analytical R-matrix theory to develop a movie of hole motion in a Kr atom upon ionization by strong circularly polarized field. We find rich hole dynamics, ranging from rotation to swinging motion. The motion of the hole depends on the final energy and the spin of the photoelectron and can be controlled by the laser frequency and intensity. Crucially, hole rotation is a purely non-adiabatic effect, completely missing in the framework of quasistatic (adiabatic) tunneling theories. We explore the possibility to use hole rotation as a clock for measuring ionization time. Analyzing the relationship between the relative phases in different ionization channels we show that in the case of short-range electron-core interaction the hole is always initially aligned along the instantaneous direction of the laser field, signifying zero delays in ionization. Finally, we show that strong-field ionization in circular fields creates spin currents (i.e. different flow of spin-up and spin-down density in space) in the ions. This phenomenon is intimately related to the production of spin-polarized electrons in strong laser fields Barth and Smirnova (2013 Phys. Rev. A 88 013401). We demonstrate that rich spin dynamics of electrons and holes produced during strong field ionization can occur in typical experimental conditions and does not require relativistic intensities or strong magnetic fields. (paper)

Ion beam modification of surfaces for biomedical applications

International Nuclear Information System (INIS)

Sommerfeld, Jana

2014-01-01

Human life expectancy increased significantly within the last century. Hence, medical care must ever be improved. Optimizing artificial replacements such as hip joints or stents etc. is of special interest. For this purpose, new materials are constantly developed or known ones modified. This work focused on the possibility to change the chemistry and topography of biomedically relevant materials such as diamond-like carbon (DLC) and titanium dioxide (TiO 2 ) by means of ion beam irradiation. Mass-separated ion beam deposition was used in order to synthesize DLC layers with a high sp 3 content (> 70%), a sufficiently smooth surface (RMS<1 nm) and a manageable film thickness (50 nm). The chemistry of the DLC layers was changed by ion beam doping with different ion species (Ag,Ti) and concentrations. Additionally, the surface topography of silicon and titanium dioxide was altered by ion beam irradiation under non-perpendicular angle of incidence. The created periodic wave structures (so-called ripples) were characterized and their dependency on the ion energy was investigated. Moreover, ripples on silicon were covered with a thin DLC layer in order to create DLC ripples. The biocompatibility of all samples was investigated by adsorption experiments. For this purpose, human plasma fibrinogen (HPF) was used due to its ambiphilic character, which allows the protein to assume different conformations on materials with different hydrophilicities. Moreover, HPF is a crucial factor in the blood coagulation process. This work comes to the conclusion that the interaction of both, the surface chemistry and topography, has a strong influence on the adsorption behavior of HPF and thus the biocompatibility of a material. Both factors can be specifically tuned by means of ion beam irradiation.

Modified multipole structure for electron cyclotron resonance ion sources

International Nuclear Information System (INIS)

Suominen, P.

2006-01-01

Highly-charged heavy-ion beams are usually produced with Electron Cyclotron Resonance Ion Sources (ECRIS) where the microwave heated plasma is confined in a strong magnetic field. The magnetic field is divided into an axial part (produced by solenoid magnets) and to a radial part (produced by multipole magnet). Experiments have shown that the radial magnetic field component plays a crucial role in the production of highly-charged ions. However, in several modern ECRIS the radial magnetic field strength is below the optimum value, mainly due to the limits in permanent magnet technology. Unfortunately, methods to increase the radial magnetic field strength while still using permanent magnets are often limited. In this thesis work new techniques to improve the radial magnetic field have been studied by simulations and experiments. Due to the computer simulations performed a remarkable radial magnetic field improvement was reached with a relatively simple and cost-effective idea called the Modified MultiPole Structure (MMPS). The MMPS differs strongly from former studies as here the magnetic field is increased only locally without affecting the plasma size. It was not known how this would affect the properties of the plasma and production of highly-charged heavy ions. Consequently, the idea had to be studied experimentally and a new MMPS plasma chamber prototype was designed and constructed for the JYFL 6.4 GHz ECRIS. The new construction is versatile and made it possible to perform several new types of measurements. These showed that the MMPS works well and is especially applicable to increase very high charge-state ion production. Typically the ion current increases by a factor of 2 - 3 in the case of highly charged ions such as Ar 16+ . (orig.)

Modified multipole structure for electron cyclotron resonance ion sources

Energy Technology Data Exchange (ETDEWEB)

Suominen, P.

2006-07-01

Highly-charged heavy-ion beams are usually produced with Electron Cyclotron Resonance Ion Sources (ECRIS) where the microwave heated plasma is confined in a strong magnetic field. The magnetic field is divided into an axial part (produced by solenoid magnets) and to a radial part (produced by multipole magnet). Experiments have shown that the radial magnetic field component plays a crucial role in the production of highly-charged ions. However, in several modern ECRIS the radial magnetic field strength is below the optimum value, mainly due to the limits in permanent magnet technology. Unfortunately, methods to increase the radial magnetic field strength while still using permanent magnets are often limited. In this thesis work new techniques to improve the radial magnetic field have been studied by simulations and experiments. Due to the computer simulations performed a remarkable radial magnetic field improvement was reached with a relatively simple and cost-effective idea called the Modified MultiPole Structure (MMPS). The MMPS differs strongly from former studies as here the magnetic field is increased only locally without affecting the plasma size. It was not known how this would affect the properties of the plasma and production of highly-charged heavy ions. Consequently, the idea had to be studied experimentally and a new MMPS plasma chamber prototype was designed and constructed for the JYFL 6.4 GHz ECRIS. The new construction is versatile and made it possible to perform several new types of measurements. These showed that the MMPS works well and is especially applicable to increase very high charge-state ion production. Typically the ion current increases by a factor of 2 - 3 in the case of highly charged ions such as Ar16+. (orig.)

Quark-gluon plasma in strong magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Kalaydzhyan, Tigran

2013-04-15

One of the fundamental problems in subatomic physics is the determination of properties of matter at extreme temperatures, densities and electromagnetic fields. The modern ultrarelativistic heavy-ion experiments are able to study such states (the quark-gluon plasma) and indicate that the physics at extreme conditions differs drastically from what is known from the conventional observations. Also the theoretical methods developed mostly within the perturbative framework face various conceptual problems and need to be replaced by a nonperturbative approach. In this thesis we study the physics of the strongly-coupled quark-gluon plasma in external magnetic fields as well as general electromagnetic and topological properties of the QCD and QCD-like systems. We develop and apply various nonperturbative techniques, based on e.g. gauge-gravity correspondence, lattice QCD simulations, relativistic hydrodynamics and condensed-matter-inspired models.

Quark-gluon plasma in strong magnetic fields

International Nuclear Information System (INIS)

Kalaydzhyan, Tigran

2013-04-01

One of the fundamental problems in subatomic physics is the determination of properties of matter at extreme temperatures, densities and electromagnetic fields. The modern ultrarelativistic heavy-ion experiments are able to study such states (the quark-gluon plasma) and indicate that the physics at extreme conditions differs drastically from what is known from the conventional observations. Also the theoretical methods developed mostly within the perturbative framework face various conceptual problems and need to be replaced by a nonperturbative approach. In this thesis we study the physics of the strongly-coupled quark-gluon plasma in external magnetic fields as well as general electromagnetic and topological properties of the QCD and QCD-like systems. We develop and apply various nonperturbative techniques, based on e.g. gauge-gravity correspondence, lattice QCD simulations, relativistic hydrodynamics and condensed-matter-inspired models.

The creation of strongly coupled plasmas using an intense heavy ion beam: low-entropy compression of hydrogen and the problem of hydrogen metallization

Energy Technology Data Exchange (ETDEWEB)

Tahir, N A [Institut fuer Theoretische Physik, Universitaet Frankfurt, Postfach 11 19 32, 60054 Frankfurt (Germany); Piriz, A R [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Shutov, A [Institute for Problems in Chemical Physics Research, Chernogolovka, Russia (Russian Federation); Varentsov, D [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgarten Str. 9, 64289 Darmstadt (Germany); Udrea, S [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgarten Str. 9, 64289 Darmstadt (Germany); Hoffmann, D H H [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgarten Str. 9, 64289 Darmstadt (Germany); Juranek, H [Fachbereich Physik, Universitaet Rostock, 18051 Rostock (Germany); Redmer, R [Fachbereich Physik, Universitaet Rostock, 18051 Rostock (Germany); Portugues, R F [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Lomonosov, I [Institute for Problems in Chemical Physics Research, Chernogolovka, Russia (Russian Federation); Fortov, V E [Institute for Problems in Chemical Physics Research, Chernogolovka, Russia (Russian Federation)

2003-06-06

Intense heavy ion beams deposit energy very efficiently over extended volumes of solid density targets, thereby creating large samples of strongly coupled plasmas. Intense beams of energetic heavy ions are therefore an ideal tool to research this interesting field. It is also possible to design experiments using special beam-target geometries to achieve low-entropy compression of samples of matter. This type of experiments is of particular interest for studying the problem of hydrogen metallization. In this paper we present a design study of such a proposed experiment that will be carried out at the future heavy ion synchrotron facility SIS100, at the Gesellschaft fuer Schwerionenforschung, Darmstadt. This study has been done using a two-dimensional hydrodynamic computer code. The target consists of a solid hydrogen cylinder that is enclosed in a thick shell of lead whose one face is irradiated with an ion beam which has an annular (ring shaped) focal spot. The beam intensity and other parameters are considered to be the same as expected at the future SIS100 facility. The simulations show that due to multiple shock reflection between the cylinder axis and the lead-hydrogen boundary, one can achieve up to 20 times solid density in hydrogen while keeping the temperature as low as a few thousand K. The corresponding pressure is of the order of 10 Mbar. These values of the physical parameters lie within the range of theoretically predicted values for hydrogen metallization. We have also carried out a parameter study of this problem by varying the target and beam parameters over a wide range. It has been found that the results are very insensitive to such changes in the input parameters.

The creation of strongly coupled plasmas using an intense heavy ion beam: low-entropy compression of hydrogen and the problem of hydrogen metallization

International Nuclear Information System (INIS)

Tahir, N A; Piriz, A R; Shutov, A; Varentsov, D; Udrea, S; Hoffmann, D H H; Juranek, H; Redmer, R; Portugues, R F; Lomonosov, I; Fortov, V E

2003-01-01

Intense heavy ion beams deposit energy very efficiently over extended volumes of solid density targets, thereby creating large samples of strongly coupled plasmas. Intense beams of energetic heavy ions are therefore an ideal tool to research this interesting field. It is also possible to design experiments using special beam-target geometries to achieve low-entropy compression of samples of matter. This type of experiments is of particular interest for studying the problem of hydrogen metallization. In this paper we present a design study of such a proposed experiment that will be carried out at the future heavy ion synchrotron facility SIS100, at the Gesellschaft fuer Schwerionenforschung, Darmstadt. This study has been done using a two-dimensional hydrodynamic computer code. The target consists of a solid hydrogen cylinder that is enclosed in a thick shell of lead whose one face is irradiated with an ion beam which has an annular (ring shaped) focal spot. The beam intensity and other parameters are considered to be the same as expected at the future SIS100 facility. The simulations show that due to multiple shock reflection between the cylinder axis and the lead-hydrogen boundary, one can achieve up to 20 times solid density in hydrogen while keeping the temperature as low as a few thousand K. The corresponding pressure is of the order of 10 Mbar. These values of the physical parameters lie within the range of theoretically predicted values for hydrogen metallization. We have also carried out a parameter study of this problem by varying the target and beam parameters over a wide range. It has been found that the results are very insensitive to such changes in the input parameters

Review of stopping power and Coulomb explosion for molecular ion in plasmas

Directory of Open Access Journals (Sweden)

Guiqiu Wang

2018-03-01

Full Text Available We summarize our theoretical studies for stopping power of energetic heavy ion, diatomic molecular ions and small clusters penetrating through plasmas. As a relevant research field for the heavy ion inertial confinement fusion (HICF, we lay the emphasis on the dynamic polarization and correlation effects of the constituent ion within the molecular ion and cluster for stopping power in order to disclose the role of the vicinage effect on the Coulomb explosion and energy deposition of molecules and clusters in plasma. On the other hand, as a promising scheme for ICF, both a strong laser field and an intense ion beam are used to irradiate a plasma target. So the influence of a strong laser field on stopping power is significant. We discussed a large range of laser and plasma parameters on the coulomb explosion and stopping power for correlated-ion cluster and C60 cluster. Furthermore, in order to indicate the effects of different cluster types and sizes on the stopping power, a comparison is made for hydrogen and carbon clusters. In addition, the deflection of molecular axis for diatomic molecules during the Coulomb explosion is also given for the cases both in the presence of a laser field and laser free. Finally, a future experimental scheme is put forward to measure molecular ion stopping power in plasmas in Xi'an Jiaotong University of China. Keywords: Molecules, Stopping power, Coulomb explosion, Vicinage effect, Laser, PACS Codes: 34.50.Bw, 52.40.Mj, 61.85.+p, 34.50.Dy

Anomalous surface behavior of hydrated guanidinium ions due to ion pairing

Science.gov (United States)

Ekholm, Victor; Vazdar, Mario; Mason, Philip E.; Bialik, Erik; Walz, Marie-Madeleine; Öhrwall, Gunnar; Werner, Josephina; Rubensson, Jan-Erik; Jungwirth, Pavel; Björneholm, Olle

2018-04-01

Surface affinity of aqueous guanidinium chloride (GdmCl) is compared to that of aqueous tetrapropylammonium chloride (TPACl) upon addition of sodium chloride (NaCl) or disodium sulfate (Na2SO4). The experimental results have been acquired using the surface sensitive technique X-ray photoelectron spectroscopy on a liquid jet. Molecular dynamics simulations have been used to produce radial distribution functions and surface density plots. The surface affinities of both TPA+ and Gdm+ increase upon adding NaCl to the solution. With the addition of Na2SO4, the surface affinity of TPA+ increases, while that of Gdm+ decreases. From the results of MD simulations it is seen that Gdm+ and SO4 2 - ions form pairs. This finding can be used to explain the decreased surface affinity of Gdm+ when co-dissolved with SO4 2 - ions. Since SO4 2 - ions avoid the surface due to the double charge and strong water interaction, the Gdm+-SO4 2 - ion pair resides deeper in the solutions' bulk than the Gdm+ ions. Since TPA+ does not form ion pairs with SO4 2 -, the TPA+ ions are instead enriched at the surface.

Energy exchange in strongly coupled plasmas with electron drift

International Nuclear Information System (INIS)

Akbari-Moghanjoughi, M.; Ghorbanalilu, M.

2015-01-01

In this paper, the generalized viscoelastic collisional quantum hydrodynamic model is employed in order to investigate the linear dielectric response of a quantum plasma in the presence of strong electron-beam plasma interactions. The generalized Chandrasekhar's relativistic degeneracy pressure together with the electron-exchange and Coulomb interaction effects are taken into account in order to extend current research to a wide range of plasma number density relevant to big planetary cores and astrophysical compact objects. The previously calculated shear viscosity and the electron-ion collision frequencies are used for strongly coupled ion fluid. The effect of the electron-beam velocity on complex linear dielectric function is found to be profound. This effect is clearly interpreted in terms of the wave-particle interactions and their energy-exchange according to the sign of the imaginary dielectric function, which is closely related to the wave attenuation coefficient in plasmas. Such kinetic effect is also shown to be in close connection with the stopping power of a charged-particle beam in a quantum plasma. The effect of many independent plasma parameters, such as the ion charge-state, electron beam-velocity, and relativistic degeneracy, is shown to be significant on the growing/damping of plasma instability or energy loss/gain of the electron-beam

Pulsed, Inductively Generated, Streaming Plasma Ion Source for Heavy Ion Fusion Linacs

International Nuclear Information System (INIS)

Steven C. Glidden; Howard D Sanders; John B. Greenly; Daniel L. Dongwoo

2006-01-01

This report describes a compact, high current density, pulsed ion source, based on electrodeless, inductively driven gas breakdown, developed to meet the requirements on normalized emittance, current density, uniformity and pulse duration for an ion injector in a heavy-ion fusion driver. The plasma source produces >10 (micro)s pulse of Argon plasma with ion current densities >100 mA/cm2 at 30 cm from the source and with strongly axially directed ion energy of about 80 eV, and sub-eV transverse temperature. The source has good reproducibility and spatial uniformity. Control of the current density during the pulse has been demonstrated with a novel modulator coil method which allows attenuation of the ion current density without significantly affecting the beam quality. This project was carried out in two phases. Phase 1 used source configurations adapted from light ion sources to demonstrate the feasibility of the concept. In Phase 2 the performance of the source was enhanced and quantified in greater detail, a modulator for controlling the pulse shape was developed, and experiments were conducted with the ions accelerated to >40 kV

Magnetospheric Multiscale (MMS) Observations of Energetic Ion Response to Magnetotail Dipolarization Events

Science.gov (United States)

Cohen, I. J.; Mauk, B.; Anderson, B. J.; Sitnov, M. I.; Motoba, T.; Ohtani, S.; Gkioulidou, M.; Fuselier, S. A.; Giles, B. L.; Strangeway, R. J.; Torbert, R. B.; Burch, J. L.

2017-12-01

Observations from the Energetic Ion Spectrometer (EIS) instruments aboard MMS have shown angular (pitch, elevation, azimuthal) asymmetries of energetic (>10s of keV) ions corresponding to dipolarization events in the near-Earth and distant magnetotail. In particular, EIS distinguishes the species composition of these ions (protons, helium, oxygen) and reveals apparent species-based differences in their response. This study presents analysis of the dynamic injection and mass-dependent response of energetic ions that likely result from the kinetic response of the ions to the time-varying electric and magnetic fields associated with injection process. Analysis is focused on discriminating between truly kinetic responses to the dynamics and the features that arise from large gyro-radii particles in the vicinity of strong spatial gradients. The study will focus on EIS measurements and include supplementary data from the FIELDS, FPI, and HPCA instruments.

Functional implications of species differences in the size and morphology of the isthmo optic nucleus (ION in birds.

Directory of Open Access Journals (Sweden)

Cristián Gutiérrez-Ibáñez

Full Text Available In birds, there is a retinofugal projection from the brain to the retina originating from the isthmo optic nucleus (ION in the midbrain. Despite a large number of anatomical, physiological and histochemical studies, the function of this retinofugal system remains unclear. Several functions have been proposed including: gaze stabilization, pecking behavior, dark adaptation, shifting attention, and detection of aerial predators. This nucleus varies in size and organization among some species, but the relative size and morphology of the ION has not been systematically studied. Here, we present a comparison of the relative size and morphology of the ION in 81 species of birds, representing 17 different orders. Our results show that several orders of birds, besides those previously reported, have a large, well-organized ION, including: hummingbirds, woodpeckers, coots and allies, and kingfishers. At the other end of the spectrum, parrots, herons, waterfowl, owls and diurnal raptors have relatively small ION volumes. ION also appears to be absent or unrecognizable is several taxa, including one of the basal avian groups, the tinamous, which suggests that the ION may have evolved only in the more modern group of birds, Neognathae. Finally, we demonstrate that evolutionary changes in the relative size and the cytoarchitectonic organization of ION have occurred largely independent of phylogeny. The large relative size of the ION in orders with very different lifestyles and feeding behaviors suggest there is no clear association with pecking behavior or predator detection. Instead, our results suggest that the ION is more complex and enlarged in birds that have eyes that are emmetropic in some parts of the visual field and myopic in others. We therefore posit that the ION is involved in switching attention between two parts of the retina i.e. from an emmetropic to a myopic part of the retina.

Strong solutions for an incompressible Navier-Stokes/Allen-Cahn system with different densities

Science.gov (United States)

Li, Yinghua; Huang, Mingxia

2018-06-01

In this paper, we investigate a coupled Navier-Stokes/Allen-Cahn system describing a diffuse interface model for two-phase flow of viscous incompressible fluids with different densities in a bounded domain Ω \\subset R^N(N=2,3). We prove the existence and uniqueness of local strong solutions to the initial boundary value problem when the initial density function ρ _0 has a positive lower bound.

Complete single ionization momentum spectra for strong perturbation collisions

International Nuclear Information System (INIS)

Olson, R.E.; Wood, C.J.

1997-09-01

The combination of recoil ion and ionized electron momentum spectroscopy provides an unparalleled method to investigate the details of ion-atom collision dynamics in kinematically complete experiments. To predict singleionization scattering behavior at the level now realized by experiment, the classical trajectory three-body Monte Carlo method has been used to obtain complete momenta information for the ionized electron, recoil ion, and projectile in the collision plane defined by the incident projectile and outgoing recoil ion. Strongly coupled systems were considered where the charge state of the projectile divided by the speed of the collision q/v is greater than unity. Illustrated are 3.6 MeV/u Se 28+ and 9.5 MeV/u Ni 26+ collisions on He where experimental data are available. The theoretical results are in good agreement with these data and calculations have been performed for 165 keV/u and 506 keV/u C 6+ +He to compare results for the same q/v perturbation strengths. (orig.)

Effect of Coulomb collision on the negative ion extraction mechanism in negative ion sources

Energy Technology Data Exchange (ETDEWEB)

Goto, I., E-mail: goto@ppl.appi.keio.ac.jp; Nishioka, S.; Abe, S.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Mattei, S.; Lettry, J. [CERN, 1211 Geneva 23 (Switzerland)

2016-02-15

To improve the H{sup −} ion beam optics, it is necessary to understand the energy relaxation process of surface produced H{sup −} ions in the extraction region of Cs seeded H{sup −} ion sources. Coulomb collisions of charged particles have been introduced to the 2D3V-PIC (two dimension in real space and three dimension in velocity space particle-in-cell) model for the H{sup −} extraction by using the binary collision model. Due to Coulomb collision, the lower energy part of the ion energy distribution function of H{sup −} ions has been greatly increased. The mean kinetic energy of the surface produced H{sup −} ions has been reduced to 0.65 eV from 1.5 eV. It has been suggested that the beam optics of the extracted H{sup −} ion beam is strongly affected by the energy relaxation process due to Coulomb collision.

Ion Acceleration by Double Layers with Multi-Component Ion Species

Science.gov (United States)

Good, Timothy; Aguirre, Evan; Scime, Earl; West Virginia University Team

2017-10-01

Current-free double layers (CFDL) models have been proposed to explain observations of magnetic field-aligned ion acceleration in plasmas expanding into divergent magnetic field regions. More recently, experimental studies of the Bohm sheath criterion in multiple ion species plasma reveal an equilibration of Bohm speeds at the sheath-presheath boundary for a grounded plate in a multipole-confined filament discharge. We aim to test this ion velocity effect for CFDL acceleration. We report high resolution ion velocity distribution function (IVDF) measurements using laser induced fluorescence downstream of a CFDL in a helicon plasma. Combinations of argon-helium, argon-krypton, and argon-xenon gases are ionized and measurements of argon or xenon IVDFs are investigated to determine whether ion acceleration is enhanced (or diminished) by the presence of lighter (or heavier) ions in the mix. We find that the predominant effect is a reduction of ion acceleration consistent with increased drag arising from increased gas pressure under all conditions, including constant total gas pressure, equal plasma densities of different ions, and very different plasma densities of different ions. These results suggest that the physics responsible for acceleration of multiple ion species in simple sheaths is not responsible for the ion acceleration observed in these expanding plasmas. Department of Physics, Gettysburg College.

Ion acoustic waves in the solar wind

International Nuclear Information System (INIS)

Gurnett, D.A.; Frank, L.A.

1978-01-01

Plasma wave measurements on the Helios I and 2 spacecraft have revealed the occurrence of electric field turbulence in the solar wind at frequencies between the electron and ion plasma frequencies. Wavelength measurements with the Imp 6 spacecraft now provide strong evidence that these waves are short-wavelength ion acoustic waves which are Doppler-shifted upward in frequency by the motion of the solar wind. Comparison of the Helios results with measurements from the earth-orbiting Imp 6 and 8 spacecraft shows that the ion acoustic turbulence detected in interplanetary space has characteristics essentially identical to those of bursts of electrostatic turbulence generated by protons streaming into the solar wind from the earth's bow shock. In a few cases, enhanced ion acoustic wave intensities have been observed in direct association with abrupt increases in the anisotropy of the solar wind electron distribution. This relationship strongly suggests that the ion acoustic waves detected by Helios far from the earth are produced by an electron heat flux instability, as was suggested by Forslund. Possible related mechanisms which could explain the generation of ion acoustic waves by protons streaming into the solar wind from the earth's bow shock are also considered

Complexation of trivalent actinide ions (Am3+, Cm3+) with humic acid: a comparison of different experimental methods

International Nuclear Information System (INIS)

Kim, J.I.; Rhee, D.S.; Wimmer, H.; Buckau, G.; Klenze, R.

1993-01-01

The complexation of trivalent metal ions with humic acid has been studied at pH 4 and 5 in 0.1 M NaClO 4 by three different experimental methods, i.e. UV spectroscopy, time resolved laser fluorescence spectroscopy (TRLFS) and ultrafiltration. The direct speciation of the metal ion and its humate complex in the reaction process has been made by UV spectroscopy for Am(III) in the micromolar concentration range and by TRLFS for Cm(III) in the nanomolar concentration range. The ultrafiltration is used with the lowest pore size of filter (ca. 1 nm) to separate the uncomplexed metal ion from its complexed species. The concentrations of both metal ion and humic acid are varied in such a manner that the effective functional groups of the humic acid becomes loaded with metal ions from 1% to nearly 100%. The loading capacity of the humic acid for the trivalent metal ion, determined separately at each pH, is introduced into the evaluation of complexation constants. The variation of the metal ion concentration from 6 x 10 -8 mol/l to 4 x 10 -5 mol/l does not show any effect on the complexation reaction. The three different methods give rise to constants being comparable with one another. The average value of the constants thus determined is log β = 6.24±0.28 for the trivalent actinide ions. (orig.)

The use of elements of the Stewart model (Strong Ion Approach) for the diagnostics of respiratory acidosis on the basis of the calculation of a value of a modified anion gap (AGm) in brachycephalic dogs.

Science.gov (United States)

Sławuta, P; Glińska-Suchocka, K; Cekiera, A

2015-01-01

Apart from the HH equation, the acid-base balance of an organism is also described by the Stewart model, which assumes that the proper insight into the ABB of the organism is given by an analysis of: pCO2, the difference of concentrations of strong cations and anions in the blood serum - SID, and the total concentration of nonvolatile weak acids - Acid total. The notion of an anion gap (AG), or the apparent lack of ions, is closely related to the acid-base balance described according to the HH equation. Its value mainly consists of negatively charged proteins, phosphates, and sulphates in blood. In the human medicine, a modified anion gap is used, which, including the concentration of the protein buffer of blood, is, in fact, the combination of the apparent lack of ions derived from the classic model and the Stewart model. In brachycephalic dogs, respiratory acidosis often occurs, which is caused by an overgrowth of the soft palate, making it impossible for a free air flow and causing an increase in pCO2--carbonic acid anhydride The aim of the present paper was an attempt to answer the question whether, in the case of systemic respiratory acidosis, changes in the concentration of buffering ions can also be seen. The study was carried out on 60 adult dogs of boxer breed in which, on the basis of the results of endoscopic examination, a strong overgrowth of the soft palate requiring a surgical correction was found. For each dog, the value of the anion gap before and after the palate correction procedure was calculated according to the following equation: AG = ([Na+ mmol/l] + [K+ mmol/l])--([Cl- mmol/l]+ [HCO3- mmol/l]) as well as the value of the modified AG--according to the following equation: AGm = calculated AG + 2.5 x (albumins(r)--albumins(d)). The values of AG calculated for the dogs before and after the procedure fell within the limits of the reference values and did not differ significantly whereas the values of AGm calculated for the dogs before and after

Modeling Temperature Development of Li-Ion Battery Packs in Hybrid Refuse Truck Operating at Different Ambient Conditions

DEFF Research Database (Denmark)

Coman, Paul Tiberiu; Veje, Christian

2014-01-01

This paper presents a dynamic model for simulating the heat dissipation and the impact of Phase Change Materials (PCMs) on the peak temperature in Lithium-ion batteries during discharging operation of a hybrid truck under different ambient temperatures.......This paper presents a dynamic model for simulating the heat dissipation and the impact of Phase Change Materials (PCMs) on the peak temperature in Lithium-ion batteries during discharging operation of a hybrid truck under different ambient temperatures....

Local particle flux reversal under strongly sheared flow

International Nuclear Information System (INIS)

Terry, P.W.; Newman, D.E.; Ware, A.S.

2003-01-01

The advection of electron density by turbulent ExB flow with linearly varying mean yields a particle flux that can reverse sign at certain locations along the direction of magnetic shear. The effect, calculated for strong flow shear, resides in the density-potential cross phase. It is produced by the interplay between the inhomogeneities of magnetic shear and flow shear, but subject to a variety of conditions and constraints. The regions of reversed flux tend to wash out if the turbulence consists of closely spaced modes of different helicities, but survive if modes of a single helicity are relatively isolated. The reversed flux becomes negligible if the electron density response is governed by electron scales while the eigenmode is governed by ion scales. The relationship of these results to experimentally observe flux reversals is discussed

State-of-charge inconsistency estimation of lithium-ion battery pack using mean-difference model and extended Kalman filter

Science.gov (United States)

Zheng, Yuejiu; Gao, Wenkai; Ouyang, Minggao; Lu, Languang; Zhou, Long; Han, Xuebing

2018-04-01

State-of-charge (SOC) inconsistency impacts the power, durability and safety of the battery pack. Therefore, it is necessary to measure the SOC inconsistency of the battery pack with good accuracy. We explore a novel method for modeling and estimating the SOC inconsistency of lithium-ion (Li-ion) battery pack with low computation effort. In this method, a second-order RC model is selected as the cell mean model (CMM) to represent the overall performance of the battery pack. A hypothetical Rint model is employed as the cell difference model (CDM) to evaluate the SOC difference. The parameters of mean-difference model (MDM) are identified with particle swarm optimization (PSO). Subsequently, the mean SOC and the cell SOC differences are estimated by using extended Kalman filter (EKF). Finally, we conduct an experiment on a small Li-ion battery pack with twelve cells connected in series. The results show that the evaluated SOC difference is capable of tracking the changing of actual value after a quick convergence.

Ion heating in minority ICRH experiments on JET

International Nuclear Information System (INIS)

Start, D.F.H.; Bhatnagar, V.; Bures, M.

1991-06-01

Bulk ion heating by high power H-minority ICRH has been demonstrated in JET during both pellet enhanced performance H-mode experiments (PEP + H - mode) and in density limit studies. In the PEP + H - mode plasmas the electron and ion temperatures both reached 10 keV at an electron density of 7 x 10 19 /m 3 . According to Fokker-Planck calculations the power from the minority was transfered almost equally to the electrons and majority ions as a result of both the high electron density, n e , and the high minority density, n h , (n h /n e ≅ 0.15). For the first time with ICRH on JET a central ion temperature greater than the central electron temperature was achieved. In the density limit experiments which involved strong gas puffing into limiter discharges, there was strong evidence of a transfer from electron heating to ion heating as the electron density was ramped up to 8 x 10 19 /m 3 . (Author)

Chloride (Cl−) ion-mediated shape control of palladium nanoparticles

International Nuclear Information System (INIS)

Nalajala, Naresh; Chakraborty, Arup; Bera, Bapi; Neergat, Manoj

2016-01-01

The shape control of Pd nanoparticles is investigated using chloride (Cl − ) ions as capping agents in an aqueous medium in the temperature range of 60–100 °C. With weakly adsorbing and strongly etching Cl − ions, oxygen plays a crucial role in shape control. The experimental factors considered are the concentration of the capping agents, reaction time and reaction atmosphere. Thus, Pd nanoparticles of various shapes with high selectivity can be synthesized. Moreover, the removal of Cl − ions from the nanoparticle surface is easier than that of Br − ions (moderately adsorbing and etching) and I − ions (strongly adsorbing and weakly etching). The cleaned Cl − ion-mediated shape-controlled Pd nanoparticles are electrochemically characterized and the order of the half-wave potential of the oxygen reduction reaction in oxygen-saturated 0.1 M HClO 4 solution is of the same order as that observed with single-crystal Pd surfaces. (paper)

Contribution to the study of molecular multi-ionisation and multifragmentation in strong laser field

International Nuclear Information System (INIS)

Hering, P.

1999-12-01

Molecular multi-ionization in strong laser field is studied using different experimental and theoretical techniques. In the 10 13 -10 16 W/cm 2 laser intensity range, the strong non-linear laser-molecule coupling allows the absorption of energies necessary to the ejection of valence electrons. The double ionization is characterized by the production of doubly charged molecular ions and by charge separation channels such as A + + B + . For molecular charge states greater than two, the multi-ionization dynamics study is based on the observables due to the multifragmentation, which are the fragments charge states and initial momenta. For strong intensities in the 1015-1016 w/cm 2 range, the multicharged atomic ions production efficiency depends on the initial electronic density localization of the molecule. For intensities less than 5 x 10 14 w/cm 2 , double ionization leads to the simultaneous emission of two electrons from the molecule. The two-missing electrons fragmentation channels appear at internuclear equilibrium distance following the Franck-Condon principle. For more than two-missing electrons channels, the internuclear distance of excitation is more difficult to determine. However the reported different experiments show that the multifragmentation dynamics is independent of the electronic emission dynamics. The theoretical approach is based on the Thomas-Fermi equations and allows a non-perturbative description of the laser-molecule coupling. The calculated fragmentation kinetic energies are smaller than the coulombic repulsion energies calculated at the internuclear equilibrium distance because of an electronic screening effect. This model reproduce the experimental fragmentation 'energy releases obtained experimentally for molecules such as N 2 , CO 2 or N 2 O. (author)

Separation of different ion structures in atmospheric pressure photoionization-ion mobility spectrometry-mass spectrometry (APPI-IMS-MS).

Science.gov (United States)

Laakia, Jaakko; Adamov, Alexey; Jussila, Matti; Pedersen, Christian S; Sysoev, Alexey A; Kotiaho, Tapio

2010-09-01

This study demonstrates how positive ion atmospheric pressure photoionization-ion mobility spectrometry-mass spectrometry (APPI-IMS-MS) can be used to produce different ionic forms of an analyte and how these can be separated. When hexane:toluene (9:1) is used as a solvent, 2,6-di-tert-butylpyridine (2,6-DtBPyr) and 2,6-di-tert-4-methylpyridine (2,6-DtB-4-MPyr) efficiently produce radical cations [M](+*) and protonated [M + H](+) molecules, whereas, when the sample solvent is hexane, protonated molecules are mainly formed. Interestingly, radical cations drift slower in the drift tube than the protonated molecules. It was observed that an oxygen adduct ion, [M + O(2)](+*), which was clearly seen in the mass spectra for hexane:toluene (9:1) solutions, shares the same mobility with radical cations, [M](+*). Therefore, the observed mobility order is most likely explained by oxygen adduct formation, i.e., the radical cation forming a heavier adduct. For pyridine and 2-tert-butylpyridine, only protonated molecules could be efficiently formed in the conditions used. For 1- and 2-naphthol it was observed that in hexane the protonated molecule typically had a higher intensity than the radical cation, whereas in hexane:toluene (9:1) the radical cation [M](+*) typically had a higher intensity than the protonated molecule [M + H](+). Interestingly, the latter drifts slower than the radical cation [M](+*), which is the opposite of the drift pattern seen for 2,6-DtBPyr and 2,6-DtB-4-MPyr. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

Highlights from STAR heavy ion program arXiv

CERN Document Server

Okorokov, V.A.

Recent experimental results obtained in STAR experiment at the Relativistic heavy-ion collider (RHIC) with ion beams will be discussed. Investigations of different nuclear collisions in some recent years focus on two main tasks, namely, detail study of quark-gluon matter properties and exploration of the quantum chromodynamics (QCD) phase diagram. Results at top RHIC energy show clearly the collective behavior of heavy quarks in nucleus-nucleus interactions. Jet and heavy hadron measurements lead to new constraints for energy loss models for various flavors. Heavy-ion collisions are unique tool for the study of topological properties of theory as well as the magneto-hydrodynamics of strongly interacting matter. Experimental results obtained for discrete QCD symmetries at finite temperatures confirm indirectly the topologically non-trivial structure of QCD vacuum. Finite global vorticity observed in non-central Au+Au collisions can be considered as important signature for presence of various chiral effects in ...

Strong correlation and ferromagnetism in (Ga,Mn)As and (Ga,Mn)N

International Nuclear Information System (INIS)

Filippetti, A.; Spaldin, N.A.; Sanvito, S.

2005-01-01

The band energies of the ferromagnetic diluted magnetic semiconductors (Ga,Mn)As and (Ga,Mn)N are calculated using a self-interaction-free approach which describes covalent and strongly correlated electrons without adjustable parameters. Both materials are half-metallic, although the contribution of Mn-derived d states to the bands around the Fermi energy is very different in the two cases. In (Ga,Mn)As the bands are strongly p-d hybridized, with a dominance of As p states. In contrast in (Ga,Mn)N the Fermi energy lies within three flat bands of mainly d character that are occupied by two electrons. Thus the Mn ion in (Ga,Mn)N behaves as a deep trap acceptor, with the hole at 1.39 eV above the GaN valence band top, and is in excellent agreement with the experimental data

Measurement of diffusion coefficient of thallium ion in H2O and D2O systems at different concentrations

International Nuclear Information System (INIS)

Das, A.; Changdar, S.N.

1992-01-01

Sliding cell method, developed in our laboratory, has been used to measure the inter diffusion coefficient of thallium ion in thallous sulphate solution over a wide concentration range using both water and heavy water as solvent at 35degC. The results have been analysed from the point of view of both ion-ion and ion-solvent interactions. The comparison of the diffusivities of the same ion in D 2 O and H 2 O electrolyte solutions at the same temperature indicate that the addition of salt affects the two solvent differently. (author). 8 refs., 1 fig., 1 tab

Self-consistent Study of Fast Particle Redistribution by Alfven Eigenmodes During Ion Cyclotron Resonance Heating

International Nuclear Information System (INIS)

Bergkvist, T.; Hellsten, T.; Johnson, T.

2006-01-01

Alfven eigenmodes (AEs) excited by fusion born α particles can degrade the heating efficiency of a burning plasma and throw out αs. To experimentally study the effects of excitation of AEs and the redistribution of the fast ions, ion cyclotron resonance heating (ICRH) is often used. The distribution function of thermonuclear αs in a reactor is expected to be isotropic and constantly renewed through DT reactions. The distribution function of cyclotron heated ions is strongly anisotropic, and the ICRH do not only renew the distribution function but also provide a strong decorrelation mechanism between the fast ions and the AE. Because of the sensitivity of the AE dynamics on the details of the distribution function, the location of the resonance surfaces in phase space and the extent of the overlapping resonant regions for different AEs, a self-consistent treatment of the AE excitation and the ICRH is necessary. Interactions of fast ions with AEs during ICRH has been implemented in the SELFO code. Simulations are in good agreement with the experimentally observer pitch-fork splitting and rapid damping of the AE as ICRH is turned off. The redistribution of fast ions have been studied in the presence of several driven AEs. (author)

Si-nanoparticle synthesis using ion implantation and MeV ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Chulapakorn, T.; Wolff, M.; Primetzhofer, D.; Possnert, G. [Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 751 20 Uppsala (Sweden); Sychugov, I.; Suvanam, S.S.; Linnros, J. [Royal Institute of Technology, School of Information and Communication Technology, P.O. Box Electrum 229, 164 40 Kista (Sweden); Hallen, A. [Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 751 20 Uppsala (Sweden); Royal Institute of Technology, School of Information and Communication Technology, P.O. Box Electrum 229, 164 40 Kista (Sweden)

2015-12-15

A dielectric matrix with embedded Si-nanoparticles may show strong luminescence depending on nanoparticles size, surface properties, Si-excess concentration and matrix type. Ion implantation of Si ions with energies of a few tens to hundreds of keV in a SiO{sub 2} matrix followed by thermal annealing was identified as a powerful method to form such nanoparticles. The aim of the present work is to optimize the synthesis of Si-nanoparticles produced by ion implantation in SiO{sub 2} by employing MeV ion irradiation as an additional annealing process. The luminescence properties are measured by spectrally resolved photoluminescence including PL lifetime measurement, while X-ray reflectometry, atomic force microscopy and ion beam analysis are used to characterize the nanoparticle formation process. The results show that the samples implanted at 20%-Si excess atomic concentration display the highest luminescence and that irradiation of 36 MeV {sup 127}I ions affects the luminosity in terms of wavelength and intensity. It is also demonstrated that the nanoparticle luminescence lifetime decreases as a function of irradiation fluence. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Proceedings of the 'INS workshop on ECR ion sources for multiply-charged heavy ions'

International Nuclear Information System (INIS)

1995-02-01

This workshop was held on December 1 and 2, 1994 at the Institute for Nuclear Study, University of Tokyo. The performance of ion sources is crucial for all researches and applications that use ion beam. The performance of ECR ion sources is strongly dependent on heuristic knowledge and innovation. From these viewpoints, it is useful to exchange information on the status of the existing sources, the performance of the new sources, and the design of the future sources between the source builders and the users. There were unexpected more than 70 participants and 20 contributions. The lectures were given on the present status of NIRS-ECR, SF-ECR, INS ISOL-ECR, RCNP ECR and EBIS ion sources, the production of multiply charged metallic ions with Hyper ECR or by plasma cathode method, the processing of ceramic rods and the ion production with OCTOPUS, the modeling of multi-charged ion production, the design of an advanced minimum B for ECR multi-charged ion source, the design, construction and operation of 18 GHz HiECR ion source, the construction and test operation of JAERI 18 GHz ion source, the design of an ECR ion source for the HIMAC, a 14.5 GHz ECR ion source at RIKEN, TMU 14 GHz ECR ion source, ''NANOGAN'' ECR ion source and its irradiation system, the optimization of the ECR ion source for optically pumped polarized ion source and so on. (K.I.)

Proceedings of the `INS workshop on ECR ion sources for multiply-charged heavy ions`

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-02-01

This workshop was held on December 1 and 2, 1994 at the Institute for Nuclear Study, University of Tokyo. The performance of ion sources is crucial for all researches and applications that use ion beam. The performance of ECR ion sources is strongly dependent on heuristic knowledge and innovation. From these viewpoints, it is useful to exchange information on the status of the existing sources, the performance of the new sources, and the design of the future sources between the source builders and the users. There were unexpected more than 70 participants and 20 contributions. The lectures were given on the present status of NIRS-ECR, SF-ECR, INS ISOL-ECR, RCNP ECR and EBIS ion sources, the production of multiply charged metallic ions with Hyper ECR or by plasma cathode method, the processing of ceramic rods and the ion production with OCTOPUS, the modeling of multi-charged ion production, the design of an advanced minimum B for ECR multi-charged ion source, the design, construction and operation of 18 GHz HiECR ion source, the construction and test operation of JAERI 18 GHz ion source, the design of an ECR ion source for the HIMAC, a 14.5 GHz ECR ion source at RIKEN, TMU 14 GHz ECR ion source, ``NANOGAN`` ECR ion source and its irradiation system, the optimization of the ECR ion source for optically pumped polarized ion source and so on. (K.I.).

Electron cooling of highly charged ions in penning traps; Elektronenkuehlung hochgeladener Ionen in Penningfallen

Energy Technology Data Exchange (ETDEWEB)

Moellers, B.

2007-02-08

For many high precision experiments with highly charged ions in ion traps it is necessary to work with low energy ions. One possibility to slow ions down to a very low energy in a trap is electron cooling, a method, which is already successfully used in storage rings to produce ion beams with high phase space density. Fast ions and a cold electron plasma are inserted into a Penning trap. The ions lose their energy due to Coulomb interaction with the electrons while they cross the plasma, the electrons are heated. The cooling time is the time, which is needed to cool an ion from a given initial energy to a low final energy. To calculate cooling times it is necessary to solve coupled differential equations for the ion energy and electron temperature. In a Penning trap the strong external magnetic field constitutes a theoretical challenge, as it influences the energy loss of the ions in an electron plasma, which can no longer be calculated analytically. In former estimates of cooling times this influence is neglected. But simulations show a dramatic decrease of the energy loss in the presence of a strong magnetic field, so it is necessary to investigate the effect of the magnetic field on the cooling times. This work presents a model to calculate cooling times, which includes both the magnetic field and the trap geometry. In a first step a simplified model without the external trap potential is developed. The energy loss of the ions in the magnetized electron plasma is calculated by an analytic approximation, which requires a numerical solution of integrals. With this model the dependence of the cooling time on different parameters like electron and ion density, magnetic field and the angle between ion velocity and magnetic field is studied for fully ionized uranium. In addition the influence of the electron heating is discussed. Another important topic in this context is the recombination between ions and electrons. The simplified model for cooling times allows to

Quasi-monoenergetic ion beam acceleration by laser-driven shock and solitary waves in near-critical plasmas

International Nuclear Information System (INIS)

Zhang, W. L.; Qiao, B.; Huang, T. W.; Shen, X. F.; You, W. Y.; Yan, X. Q.; Wu, S. Z.; Zhou, C. T.; He, X. T.

2016-01-01

Ion acceleration in near-critical plasmas driven by intense laser pulses is investigated theoretically and numerically. A theoretical model has been given for clarification of the ion acceleration dynamics in relation to different laser and target parameters. Two distinct regimes have been identified, where ions are accelerated by, respectively, the laser-induced shock wave in the weakly driven regime (comparatively low laser intensity) and the nonlinear solitary wave in the strongly driven regime (comparatively high laser intensity). Two-dimensional particle-in-cell simulations show that quasi-monoenergetic proton beams with a peak energy of 94.6 MeV and an energy spread 15.8% are obtained by intense laser pulses at intensity I_0 = 3 × 10"2"0" W/cm"2 and pulse duration τ = 0.5 ps in the strongly driven regime, which is more advantageous than that got in the weakly driven regime. In addition, 233 MeV proton beams with narrow spread can be produced by extending τ to 1.0 ps in the strongly driven regime.

Quasi-monoenergetic ion beam acceleration by laser-driven shock and solitary waves in near-critical plasmas

Energy Technology Data Exchange (ETDEWEB)

Zhang, W. L.; Qiao, B., E-mail: bqiao@pku.edu.cn; Huang, T. W.; Shen, X. F.; You, W. Y. [Center for Applied Physics and Technology, HEDPS, and State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006 (China); Yan, X. Q. [Center for Applied Physics and Technology, HEDPS, and State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Wu, S. Z. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Zhou, C. T.; He, X. T. [Center for Applied Physics and Technology, HEDPS, and State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)

2016-07-15

Ion acceleration in near-critical plasmas driven by intense laser pulses is investigated theoretically and numerically. A theoretical model has been given for clarification of the ion acceleration dynamics in relation to different laser and target parameters. Two distinct regimes have been identified, where ions are accelerated by, respectively, the laser-induced shock wave in the weakly driven regime (comparatively low laser intensity) and the nonlinear solitary wave in the strongly driven regime (comparatively high laser intensity). Two-dimensional particle-in-cell simulations show that quasi-monoenergetic proton beams with a peak energy of 94.6 MeV and an energy spread 15.8% are obtained by intense laser pulses at intensity I{sub 0} = 3 × 10{sup 20 }W/cm{sup 2} and pulse duration τ = 0.5 ps in the strongly driven regime, which is more advantageous than that got in the weakly driven regime. In addition, 233 MeV proton beams with narrow spread can be produced by extending τ to 1.0 ps in the strongly driven regime.

Damage induced in semiconductors by swift heavy ion irradiation

International Nuclear Information System (INIS)

Levalois, M.; Marie, P.

1999-01-01

The behaviour of semiconductors under swift heavy ion irradiation is different from that of metals or insulators: no spectacular effect induced by the inelastic energy loss has been reported in these materials. We present here a review of irradiation effects in the usual semiconductors (silicon, germanium and gallium arsenide). The damage is investigated by means of electrical measurements. The usual mechanisms of point defect creation can account for the experimental results. Besides, some results obtained on the wide gap semiconductor silicon carbide are reported. Concerning the irradiation effects induced by heavy ions in particle detectors, based on silicon substrate, we show that the deterioration of the detector performances can be explained from the knowledge of the substrate properties which are strongly perturbed after high doses of irradiation. Finally, some future ways of investigation are proposed. The silicon substrate is a good example to compare the irradiation effects with different particles such as electrons, neutrons and heavy ions. It is then necessary to use parameters which account for the local energy deposition, in order to describe the damage in the material

Measurements of ion velocity separation and ionization in multi-species plasma shocks

Science.gov (United States)

Rinderknecht, Hans G.; Park, H.-S.; Ross, J. S.; Amendt, P. A.; Wilks, S. C.; Katz, J.; Hoffman, N. M.; Kagan, G.; Vold, E. L.; Keenan, B. D.; Simakov, A. N.; Chacón, L.

2018-05-01

The ion velocity structure of a strong collisional shock front in a plasma with multiple ion species is directly probed in laser-driven shock-tube experiments. Thomson scattering of a 263.25 nm probe beam is used to diagnose ion composition, temperature, and flow velocity in strong shocks ( M ˜6 ) propagating through low-density ( ρ˜0.1 mg/cc) plasmas composed of mixtures of hydrogen (98%) and neon (2%). Within the preheat region of the shock front, two velocity populations of ions are observed, a characteristic feature of strong plasma shocks. The ionization state of the Ne is observed to change within the shock front, demonstrating an ionization-timescale effect on the shock front structure. The forward-streaming proton feature is shown to be unexpectedly cool compared to predictions from ion Fokker-Planck simulations; the neon ionization gradient is evaluated as a possible cause.

Are nanoscale ion aggregates present in aqueous solutions of guanidinium salts?

Science.gov (United States)

Hunger, Johannes; Niedermayer, Stefan; Buchner, Richard; Hefter, Glenn

2010-11-04

A detailed investigation using broadband dielectric relaxation spectroscopy (DRS) has been made of the aqueous solutions of guanidinium chloride and carbonate, GdmCl(aq) and Gdm₂CO₃(aq), at 25 °C. The spectra indicate that Gdm(+) ions, C(NH₂)₃(+), do not bind strongly to water nor are they hydrophobically hydrated; rather they appear to have a most unusual ability to dissolve in water without altering its dynamics. Although DRS is particularly sensitive to the presence of ion pairs, only weak ion pairing was detected in Gdm₂CO₃(aq) solutions and none at all in GdmCl(aq). Surprisingly, no evidence was found for the existence of the higher order homo- and heteroionic nanoscale aggregates that have been identified in recent years by Mason and co-workers using molecular dynamics simulations and neutron diffraction. Possible reasons for this discrepancy are discussed. The present DR spectra and other solution properties of GdmCl(aq) and Gdm₂CO₃(aq), such as apparent molar volumes and electrical conductivities, are shown to have strong similarities to those of the corresponding Na+ salts. However, such solutions also differ remarkably from their Na(+) analogues (and all other simple electrolytes in aqueous solution) in that their average water relaxation times correlate strongly with their bulk viscosities. The biological implications of the present results are briefly discussed.

Calculation Of Extraction Optics For Ion System With Plazma Emitter

CERN Document Server

Frolov, B A

2004-01-01

The 2-D code for simulating of ion optics system of positive ion extraction from a plasma source is described. Example calculation of 100 kV optics for the extraction ion IHEP gun is presented. The trajectories of particles and emittance plots are resulted. The aberrations influ-ence strongly on ion optics for considered geometry.

Determination of Na+ and K+ ions in the high-level liquid waste by ion chromatography (IC)

International Nuclear Information System (INIS)

Chen Lianzhong; Ma Guilan

1992-01-01

The determination of Na + and k + ions in the high-level liquid waste is investigated using ion chromatography. In order to protect the low capacity ion exchange resin in single column IC and remove the transition metal as well as other heavy metal ions that are contained in liquid waste, the pretreatment column with EDTA chelating resin is used. Those impurity metal ions are strongly absorbed by EDTA chelating resin and 100% of Na + and K + ions in the solution are eluted. The ability of the decontamination of EDTA chelating resin is satisfactory. The sample of the high-level liquid waste is diluted appropriately, then an aliquot of the sample is passed through the pretreatment column with EDTA chelating resin, the eluate is analysed by single column ion chromatography. The precision of this method is better than 5% for the determination of Na + and K + ions (at μg· ml -1 level)

Aqueous photochemical reactions of chloride, bromide, and iodide ions in a diode-array spectrophotometer. Autoinhibition in the photolysis of iodide ions.

Science.gov (United States)

Kalmár, József; Dóka, Éva; Lente, Gábor; Fábián, István

2014-03-28

The aqueous photoreactions of three halide ions (chloride, bromide and iodide) were studied using a diode array spectrophotometer to drive and detect the process at the same time. The concentration and pH dependences of the halogen formation rates were studied in detail. The experimental data were interpreted by improving earlier models where the cage complex of a halogen atom and an electron has a central role. The triiodide ion was shown to exert a strong inhibiting effect on the reaction sequence leading to its own formation. An assumed chemical reaction between the triiodide ion and the cage complex interpreted the strong autoinhibition effect. It is shown that there is a real danger of unwanted interference from the photoreactions of halide ions when halide salts are used as supporting electrolytes in spectrophotometric experiments using a relatively high intensity UV light source.

Fragment ion and electron emission from C sub 6 sub 0 by fast heavy ion impact

CERN Document Server

Mizuno, T; Itoh, A; Tsuchida, H; Nakai, Y

2003-01-01

Correlation between electron emission and fragmentation of C sub 6 sub 0 was studied using 847keV Si sup + ions. Mass distribution of fragment ions, number distribution of secondary electrons, and final charge distribution of outgoing projectiles were successfully measured by means of a triple coincidence time-of-flight method. Strong correlation was observed for electron emission and fragmentation.

A Langmuir probe system for high power RF-driven negative ion sources on high potential

International Nuclear Information System (INIS)

McNeely, P; Christ-Koch, S; Fantz, U; Dudin, S V

2009-01-01

A fully automated Langmuir probe system capable of operating simultaneously with beam extraction has been developed and commissioned for the negative hydrogen ion source testbeds at IPP Garching. It allows the measurement of temporal and spatial distributions of the plasma parameters within a single plasma pulse ( 10 18 m -3 ) and hot (T e > 10 eV) plasma with bi-Maxwellian electron energy distribution at low pressures. The plasma found near the plasma grid is very different being of low density (≤10 17 m -3 ) and very cold (T e < 2 eV). This plasma is also strongly influenced by the presence of caesium, the potential of the plasma grid, and if an ion beam is extracted from the source. Caesium strongly reduces the plasma potential of the source and enhances the negative ion density near the plasma grid. Extracting an ion beam is observed to reduce the electron density and increase the potential near the plasma grid. Applying a potential greater than the plasma potential to the plasma grid is found to significantly decrease the electron density near the plasma grid.

Ion Selectivity Mechanism in a Bacterial Pentameric Ligand-Gated Ion Channel

International Nuclear Information System (INIS)

Wang, Hailong; Cheng, Xiaolin

2011-01-01

The proton-gated ion channel from Gloeobacter violaceus (GLIC) is a prokaryotic homolog of the eukaryotic nicotinic acetylcholine receptor (nAChR) that responds to the binding of neurotransmitter acetylcholine and mediates fast signal transmission. Recent emergence of a high resolution crystal structure of GLIC captured in a potentially open state allowed detailed, atomic-level insight into ion conduction and selectivity mechanisms in these channels. Herein, we have examined the barriers to ion conduction and origins of ion selectivity in the GLIC channel by the construction of potential of mean force (PMF) profiles for sodium and chloride ions inside the transmembrane region. Our calculations reveal that the GLIC channel is open for a sodium ion to transport, but presents a ∼10 kcal/mol free energy barrier for a chloride ion, which arises primarily from the unfavorable interactions with a ring of negatively charged glutamate residues (E-2) at the intracellular end and a ring of hydrophobic residues (I9) in the middle of the transmembrane domain. Our collective findings further suggest that the charge selection mechanism can, to a large extent, be attributed to the narrow intracellular end and a ring of glutamate residues in this position their strong negative electrostatics and ability to bind cations. By contrast, E19 at the extracellular entrance only plays a minor role in ion selectivity of GLIC. In addition to electrostatics, both ion hydration and protein dynamics are found to be crucial for ion conduction as well, which explains why a chloride ion experiences a much greater barrier than a sodium ion in the hydrophobic region of the pore.

Femtoscopic analysis of baryon correlations in ultra-relativistic heavy-ion collisions registered by ALICE

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00361630

Heavy-ion collisions at ultra-relativistic energies give a unique possibility to create and to analyse the Quark-Gluon Plasma predicted by the theory of Quantum Chromodynamics. The research on the properties of such state of matter is crucial for understanding the features of the strongly interacting system. Experimental results reveal the collective behaviour of matter created in the heavy-ion collisions at ultra-relativistic energies. The existence of this effect can be verified by the measurement of the transverse mass dependence of the source size extracted using different particle species. Such characteristics can be determined using the analysis technique called femtoscopy. This method is based on the correlations of particles with small relative momenta which originate from the effects of Quantum Statistics as well as the strong and Coulomb Final State Interactions. A recent analysis of the particle production at the highest available collision energies of heavy-ion collisions reveals the puzzling res...

Influence of ion size and charge on osmosis.

Science.gov (United States)

Cannon, James; Kim, Daejoong; Maruyama, Shigeo; Shiomi, Junichiro

2012-04-12

Osmosis is fundamental to many processes, such as in the function of biological cells and in industrial desalination to obtain clean drinking water. The choice of solute in industrial applications of osmosis is highly important in maximizing efficiency and minimizing costs. The macroscale process of osmosis originates from the nanoscale properties of the solvent, and therefore an understanding of the mechanisms of how these properties determine osmotic strength can be highly useful. For this reason, we have undertaken molecular dynamics simulations to systematically study the influence of ion size and charge on the strength of osmosis of water through carbon nanotube membranes. Our results show that strong osmosis occurs under optimum conditions of ion placement near the region of high water density near the membrane wall and of maintenance of a strong water hydration shell around the ions. The results in turn allow greater insight into the origin of the strong osmotic strength of real ions such as NaCl. Finally, in terms of practical simulation, we highlight the importance of avoiding size effects that can occur if the simulation cell is too small.

Automated system for efficient microwave power coupling in an S-band ECR ion source driven under different operating conditions

Energy Technology Data Exchange (ETDEWEB)

Muguira, L., E-mail: lmuguira@essbilbao.org [ESS-Bilbao, Edificio Rectorado, Vivero de Empresas, 48940 Leioa (Bizkaia) (Spain); Portilla, J. [University of Basque Country (UPV/EHU), Department of Electricity and Electronics, Science and Technology Faculty, 48940 Leioa (Bizkaia) (Spain); Gonzalez, P.J.; Garmendia, N.; Feuchtwanger, J. [ESS-Bilbao, Edificio Rectorado, Vivero de Empresas, 48940 Leioa (Bizkaia) (Spain); Etxebarria, V. [University of Basque Country (UPV/EHU), Department of Electricity and Electronics, Science and Technology Faculty, 48940 Leioa (Bizkaia) (Spain); Eguiraun, M.; Arredondo, I.; Miracoli, R.; Belver, D. [ESS-Bilbao, Edificio Rectorado, Vivero de Empresas, 48940 Leioa (Bizkaia) (Spain)

2014-03-21

This article presents an automated system for optimizing the microwave power coupling to the plasma generated in a proton/deuteron Electron Cyclotron Resonance (ECR) source, based on a specific model of a rectangular waveguide triple-stub tuner and the integrated measurement and control electronics, helping to get stable plasma states. The control and improvement of the RF power absorption into the plasma is a complex process, essential for the ion source development and optimization under different operating conditions. A model and a matching algorithm for the triple-stub tuner have been developed and, besides, different methods to accurately measure the power transfer in a waveguide RF system have been studied and deployed in the ESS-Bilbao ion source system. The different parts have been integrated through a controller, which allows to run an automatic plasma matching system in closed loop. The behavior of the system implemented for low and high power regimes has been tested under different conditions: with several load impedances, with plasma inside the chamber, in continuous wave and pulsed wave operation modes, demonstrating power absorption typically over 90% in all the ion source configurations. The developed system allows to achieve significant improvement in the ECR ion source power absorption efficiency, both in continuous and pulsed mode. The automatic tuning unit enhances the system operation finding an optimum solution much faster than manually, also behaving as an adaptive system able to respond in few pulses to ion source configuration changes to maintain the power coupling as high as possible. - Highlights: • An automated system optimizing plasma and microwave power interaction is presented. • A model and a matching algorithm for the triple-stub tuner have been developed. • Different methods to measure the power transfer have been studied and deployed. • The system works for low or high power regimes under different ion source conditions. �

Automated system for efficient microwave power coupling in an S-band ECR ion source driven under different operating conditions

International Nuclear Information System (INIS)

Muguira, L.; Portilla, J.; Gonzalez, P.J.; Garmendia, N.; Feuchtwanger, J.; Etxebarria, V.; Eguiraun, M.; Arredondo, I.; Miracoli, R.; Belver, D.

2014-01-01

This article presents an automated system for optimizing the microwave power coupling to the plasma generated in a proton/deuteron Electron Cyclotron Resonance (ECR) source, based on a specific model of a rectangular waveguide triple-stub tuner and the integrated measurement and control electronics, helping to get stable plasma states. The control and improvement of the RF power absorption into the plasma is a complex process, essential for the ion source development and optimization under different operating conditions. A model and a matching algorithm for the triple-stub tuner have been developed and, besides, different methods to accurately measure the power transfer in a waveguide RF system have been studied and deployed in the ESS-Bilbao ion source system. The different parts have been integrated through a controller, which allows to run an automatic plasma matching system in closed loop. The behavior of the system implemented for low and high power regimes has been tested under different conditions: with several load impedances, with plasma inside the chamber, in continuous wave and pulsed wave operation modes, demonstrating power absorption typically over 90% in all the ion source configurations. The developed system allows to achieve significant improvement in the ECR ion source power absorption efficiency, both in continuous and pulsed mode. The automatic tuning unit enhances the system operation finding an optimum solution much faster than manually, also behaving as an adaptive system able to respond in few pulses to ion source configuration changes to maintain the power coupling as high as possible. - Highlights: • An automated system optimizing plasma and microwave power interaction is presented. • A model and a matching algorithm for the triple-stub tuner have been developed. • Different methods to measure the power transfer have been studied and deployed. • The system works for low or high power regimes under different ion source conditions. �

Angular dependence of EEDF in ion-beam plasma

International Nuclear Information System (INIS)

Dudin, S.V.

1995-01-01

In a previous paper the results of measurements of electron energy distribution function (EEDF) in ion-beam plasma created by low energy broad ion beam had been presented regardless of the angular dependence of the electron distribution. The present work is specifically aimed towards elucidating the spatial structure of the EEDF in the ion-beam plasma. To solve this problem combination of the techniques of cylindrical probe, large plate probe (5 x 5 mm) and two-grid enegoanalyzer was used. Directional operation of the probes makes possible measurement of angular dependence of electron distribution function which is anisotropic in high energy region. To optimize the construction of the probe-analyzer, experiments with grids were performed, which had different size, mesh, and transparency, under different potentials, and with different distances between grids. Numerical simulation of the analyzer was performed too. It is derived that optimal design for measurements in isotropic plasma is the most plate, thin two-grid probe with maximum angular covering. Investigation of angular dependence of EEDF has shown that the distribution of trapped electrons is completely isotropic, whereas in the energy range of var-epsilon > e var-phi pl (var-phi pl - plasma potential) a strong anisotropy of the EEDF is observed

Nanodiamonds act as Trojan horse for intracellular delivery of metal ions to trigger cytotoxicity.

Science.gov (United States)

Zhu, Ying; Zhang, Yu; Shi, Guosheng; Yang, Jinrong; Zhang, Jichao; Li, Wenxin; Li, Aiguo; Tai, Renzhong; Fang, Haiping; Fan, Chunhai; Huang, Qing

2015-02-05

Nanomaterials hold great promise for applications in the delivery of various molecules with poor cell penetration, yet its potential for delivery of metal ions is rarely considered. Particularly, there is limited insight about the cytotoxicity triggered by nanoparticle-ion interactions. Oxidative stress is one of the major toxicological mechanisms for nanomaterials, and we propose that it may also contribute to nanoparticle-ion complexes induced cytotoxicity. To explore the potential of nanodiamonds (NDs) as vehicles for metal ion delivery, we used a broad range of experimental techniques that aimed at getting a comprehensive assessment of cell responses after exposure of NDs, metal ions, or ND-ion mixture: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Trypan blue exclusion text, optical microscope observation, synchrotron-based scanning transmission X-ray microscopy (STXM) and micro X-ray fluorescence (μXRF) microscopy, inductively coupled plasma-mass spectrometry (ICP-MS), reactive oxygen species (ROS) assay and transmission electron microscopy (TEM) observation. In addition, theoretical calculation and molecular dynamics (MD) computation were used to illustrate the adsorption properties of different metal ion on NDs as well as release profile of ion from ND-ion complexes at different pH values. The adsorption capacity of NDs for different metal ions was different, and the adsorption for Cu2+ was the most strong among divalent metal ions. These different ND-ion complexes then had different cytotoxicity by influencing the subsequent cellular responses. Detailed investigation of ND-Cu2+ interaction showed that the amount of released Cu2+ from ND-Cu2+ complexes at acidic lysosomal conditions was much higher than that at neutral conditions, leading to the elevation of intracellular ROS level, which triggered cytotoxicity. By theoretical approaches, we demonstrated that the functional carbon surface and cluster structures of NDs made them

Communication: Strong laser alignment of solvent-solute aggregates in the gas-phase

Science.gov (United States)

Trippel, Sebastian; Wiese, Joss; Mullins, Terry; Küpper, Jochen

2018-03-01

Strong quasi-adiabatic laser alignment of the indole-water-dimer clusters, an amino-acid chromophore bound to a single water molecule through a hydrogen bond, was experimentally realized. The alignment was visualized through ion and electron imaging following strong-field ionization. Molecular-frame photoelectron angular distributions showed a clear suppression of the electron yield in the plane of the ionizing laser's polarization, which was analyzed as strong alignment of the molecular cluster with ⟨cos2 θ2D⟩ ≥ 0.9.

Effects of low central fuelling on density and ion temperature profiles in reversed shear plasmas on JT-60U

Energy Technology Data Exchange (ETDEWEB)

Takenaga, H; Ide, S; Sakamoto, Y; Fujita, T [Japan Atomic Energy Agency, Naka Ibaraki 311-0193 (Japan)], E-mail: takenaga.hidenobu@jaea.go.jp

2008-07-15

Effects of low central fuelling on density and ion temperature profiles have been investigated using negative ion based neutral beam injection and electron cyclotron heating (ECH) in reversed shear plasmas on JT-60U. Strong internal transport barrier (ITB) was maintained in density and ion temperature profiles, when central fuelling was decreased by switching positive ion based neutral beam injection to ECH after the strong ITB formation. Similar density and ion temperature ITBs were formed for the low and high central fuelling cases during the plasma current ramp-up phase. Strong correlation between the density gradient and the ion temperature gradient was observed, indicating that particle transport and ion thermal transport are strongly coupled or the density gradient assists the ion temperature ITB formation through suppression of drift wave instabilities such as ion temperature gradient mode. These results support that the density and ion temperature ITBs can be formed under reactor relevant conditions.

Effects of low central fuelling on density and ion temperature profiles in reversed shear plasmas on JT-60U

Science.gov (United States)

Takenaga, H.; Ide, S.; Sakamoto, Y.; Fujita, T.; JT-60 Team

2008-07-01

Effects of low central fuelling on density and ion temperature profiles have been investigated using negative ion based neutral beam injection and electron cyclotron heating (ECH) in reversed shear plasmas on JT-60U. Strong internal transport barrier (ITB) was maintained in density and ion temperature profiles, when central fuelling was decreased by switching positive ion based neutral beam injection to ECH after the strong ITB formation. Similar density and ion temperature ITBs were formed for the low and high central fuelling cases during the plasma current ramp-up phase. Strong correlation between the density gradient and the ion temperature gradient was observed, indicating that particle transport and ion thermal transport are strongly coupled or the density gradient assists the ion temperature ITB formation through suppression of drift wave instabilities such as ion temperature gradient mode. These results support that the density and ion temperature ITBs can be formed under reactor relevant conditions.

Electrochemical properties of ion implanted silicon

International Nuclear Information System (INIS)

Pham minh Tan.

1979-11-01

The electrochemical behaviour of ion implanted silicon in contact with hydrofluoric acid solution was investigated. It was shown that the implanted layer on silicon changes profoundly its electrochemical properties (photopotential, interface impedance, rest potential, corrosion, current-potential behaviour, anodic dissolution of silicon, redox reaction). These changes depend strongly on the implantation parameters such as ion dose, ion energy, thermal treatment and ion mass and are weakly dependent on the chemical nature of the implantation ion. The experimental results were evaluated and interpreted in terms of the semiconductor electrochemical concepts taking into account the interaction of energetic ions with the solid surface. The observed effects are thus attributed to the implantation induced damage of silicon lattice and can be used for profiling of the implanted layer and the electrochemical treatment of the silicon surface. (author)

Studies of electron cyclotron resonance ion source plasma physics

International Nuclear Information System (INIS)

Tarvainen, O.

2005-01-01

This thesis consists of an introduction to the plasma physics of electron cyclotron resonance ion sources (ECRIS) and a review of the results obtained by the author and co-workers including discussion of related work by others. The thesis begins with a theoretical discussion dealing with plasma physics relevant for the production of highly charged ions in ECR ion source plasmas. This is followed by an overview of different techniques, such as gas mixing and double frequency heating, that can be used to improve the performance of this type of ion source. The experimental part of the work consists of studies related to ECRIS plasma physics. The effect of the gas mixing technique on the production efficiency of different ion beams was studied with both gaseous and solid materials. It was observed that gas mixing improves the confinement of the heavier element while the confinement of the lighter element is reduced. When the effect of gas mixing on MIVOC-plasmas was studied with several mixing gases it was observed that applying this technique can reduce the inevitable carbon contamination by a significant factor. In order to understand the different plasma processes taking place in ECRIS plasmas, a series of plasma potential and emittance measurements was carried out. An instrument, which can be used to measure the plasma potential in a single measurement without disturbing the plasma, was developed for this work. Studying the plasma potential of ECR ion sources is important not only because it helps to understand different plasma processes, but also because the information can be used as an input parameter for beam transport simulations and ion source extraction design. The experiments performed have revealed clear dependencies of the plasma potential on certain source parameters such as the amount of carbon contamination accumulated on the walls of the plasma chamber during a MIVOC-run. It was also observed that gas mixing affects not only the production efficiency

Ion-Ion Plasmas Produced by Electron Beams

Science.gov (United States)

Fernsler, R. F.; Leonhardt, D.; Walton, S. G.; Meger, R. A.

2001-10-01

The ability of plasmas to etch deep, small-scale features in materials is limited by localized charging of the features. The features charge because of the difference in electron and ion anisotropy, and thus one solution now being explored is to use ion-ion plasmas in place of electron-ion plasmas. Ion-ion plasmas are effectively electron-free and consist mainly of positive and negative ions. Since the two ion species behave similarly, localized charging is largely eliminated. However, the only way to produce ion-ion plasmas at low gas pressure is to convert electrons into negative ions through two-body attachment to neutrals. While the electron attachment rate is large at low electron temperatures (Te < 1 eV) in many of the halogen gases used for processing, these temperatures occur in most reactors only during the afterglow when the heating fields are turned off and the plasma is decaying. By contrast, Te is low nearly all the time in plasmas produced by electron beams, and therefore electron beams can potentially produce ion-ion plasmas continuously. The theory of ion-ion plasmas formed by pulsed electron beams is examined in this talk and compared with experimental results presented elsewhere [1]. Some general limitations of ion-ion plasmas, including relatively low flux levels, are discussed as well. [1] See the presentation by D. Leonhardt et al. at this conference.

Design and simulation of ion optics for ion sources for production of singly charged ions

Science.gov (United States)

Zelenak, A.; Bogomolov, S. L.

2004-05-01

During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments.

Design and simulation of ion optics for ion sources for production of singly charged ions

International Nuclear Information System (INIS)

Zelenak, A.; Bogomolov, S.L.

2004-01-01

During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments

The role of the ion-molecule and molecule-molecule interactions in the formation of the two-ion average force interaction potential

CERN Document Server

Ajrian, E A; Sidorenko, S N

2002-01-01

The effect of the ion-molecule and intermolecular interactions on the formation of inter-ion average force potentials is investigated within the framework of a classical ion-dipole model of electrolyte solutions. These potentials are shown to possess the Coulomb asymptotics at large distances while in the region of mean distances they reveal creation and disintegration of solvent-shared ion pairs. The calculation results provide a qualitatively authentic physical picture which is experimentally observed in strong electrolytes solutions. In particular, an increased interaction between an ion and a molecule enhances formation of ion pairs in which the ions are separated by one solvent molecule

Bright branes for strongly coupled plasmas

International Nuclear Information System (INIS)

Mateos, David; Patino, Leonardo

2007-01-01

We use holographic techniques to study photon production in a class of finite temperature, strongly coupled, large-N c SU(N c ) quark-gluon plasmas with N f c quark flavours. Our results are valid to leading order in the electromagnetic coupling constant but non-perturbatively in the SU(N c ) interactions. The spectral function of electromagnetic currents and other related observables exhibit an interesting structure as a function of the photon frequency and the quark mass. We discuss possible implications for heavy ion collision experiments

Seasonal variation of Martian pick-up ions: Evidence of breathing exosphere

Science.gov (United States)

Yamauchi, M.; Hara, T.; Lundin, R.; Dubinin, E.; Fedorov, A.; Sauvaud, J.-A.; Frahm, R. A.; Ramstad, R.; Futaana, Y.; Holmstrom, M.; Barabash, S.

2015-12-01

The Mars Express (MEX) Ion Mass Analyser (IMA) found that the detection rate of the ring-like distribution of protons in the solar wind outside of the bow shock to be quite different between Mars orbital summer (around perihelion) and orbital winter (around aphelion) for four Martian years, while the north-south asymmetry is much smaller than the perihelion-aphelion difference. Further analyses using eight years of MEX/IMA solar wind data between 2005 and 2012 has revealed that the detection frequency of the pick-up ions originating from newly ionized exospheric hydrogen with certain flux strongly correlates with the Sun-Mars distance, which changes approximately every two years. Variation due to the solar cycle phase is not distinguishable partly because this effect is masked by the seasonal variation under the MEX capability of plasma measurements. This finding indicates that the variation in solar UV has a major effect on the formation of the pick-up ions, but this is not the only controlling factor.

Prognostics of Lithium-Ion Batteries Based on Wavelet Denoising and DE-RVM

Science.gov (United States)

Zhang, Chaolong; He, Yigang; Yuan, Lifeng; Xiang, Sheng; Wang, Jinping

2015-01-01

Lithium-ion batteries are widely used in many electronic systems. Therefore, it is significantly important to estimate the lithium-ion battery's remaining useful life (RUL), yet very difficult. One important reason is that the measured battery capacity data are often subject to the different levels of noise pollution. In this paper, a novel battery capacity prognostics approach is presented to estimate the RUL of lithium-ion batteries. Wavelet denoising is performed with different thresholds in order to weaken the strong noise and remove the weak noise. Relevance vector machine (RVM) improved by differential evolution (DE) algorithm is utilized to estimate the battery RUL based on the denoised data. An experiment including battery 5 capacity prognostics case and battery 18 capacity prognostics case is conducted and validated that the proposed approach can predict the trend of battery capacity trajectory closely and estimate the battery RUL accurately. PMID:26413090

Preferential solvation, ion pairing, and dynamics of concentrated aqueous solutions of divalent metal nitrate salts

Science.gov (United States)

Yadav, Sushma; Chandra, Amalendu

2017-12-01

We have investigated the characteristics of preferential solvation of ions, structure of solvation shells, ion pairing, and dynamics of aqueous solutions of divalent alkaline-earth metal nitrate salts at varying concentration by means of molecular dynamics simulations. Hydration shell structures and the extent of preferential solvation of the metal and nitrate ions in the solutions are investigated through calculations of radial distribution functions, tetrahedral ordering, and also spatial distribution functions. The Mg2+ ions are found to form solvent separated ion-pairs while the Ca2+ and Sr2+ ions form contact ion pairs with the nitrate ions. These findings are further corroborated by excess coordination numbers calculated through Kirkwood-Buff G factors for different ion-ion and ion-water pairs. The ion-pairing propensity is found to be in the order of Mg(NO3) 2 lead to the presence of substantial dynamical heterogeneity in these solutions of strongly interacting ions. The current study helps us to understand the molecular details of hydration structure, ion pairing, and dynamics of water in the solvation shells and also of ion diffusion in aqueous solutions of divalent metal nitrate salts.

Gaseous odd- and even-electron ions

International Nuclear Information System (INIS)

Wagner, W.; Heimbach, H.; Levsen, K.

1980-01-01

The principal collision-induced fragmentations of simple protonated ketones, aldehydes, ethers, amines, sulphides, alcohols, acids, nitriles and halides are discussed. These protonated molecules decompose mainly by loss of alkane, alkene and RX (R = alkyl, H; X = OH, SH, NH 2 , Br, I). Substantial radical losses are only observed for small protonated molecules. Deuterium-labelling demonstrates that the X-H bond is particularly strong. The fragmentation of (MH) + ions is compared with that of the corresponding (M) + sup(.) ions is compared with that of the corresponding (M) + sup(.) ions. The spectra of the (M) + sup(.) ions are dominated by direct bond cleavages, in particular α-cleavages, as a result of both the stability of the ionic fragment and the loose transition state. In (MH) + ions direct bond cleavages lead to energetically less favourable products. Thus rearrangement reactions play a more important role in the decomposition of these ions. (MH) + ions are more stable relative to fragmentation than (M) + sup(.) ions. (orig.)

Non-Uniformity of Ion Implantation in Direct-Current Plasma Immersion Ion Implantation

International Nuclear Information System (INIS)

Cheng-Sen, Liu; Yu-Jia, Fan; Nan, Zhang; Li, Guan; Yuan, Yao; De-Zhen, Wang

2010-01-01

A particle-in-cell simulation is developed to study dc plasma immersion ion implantation. Particular attention is paid to the influence of the voltage applied to the target on the ion path, and the ion flux distribution on the target surface. It is found that the potential near the aperture within the plasma region is not the plasma potential, and is impacted by the voltage applied to the implanted target. A curved equipotential contour expands into the plasma region through the aperture and the extent of the expansion depends on the voltage. Ions accelerated by the electric field in the sheath form a beam shape and a flux distribution on the target surface, which are strongly dependent on the applied voltage. The results of the simulations demonstrate the formation mechanism of the grid-shadow effect, which is in agreement with the result observed experimentally. (physics of gases, plasmas, and electric discharges)

Dynamics of dissociation versus ionization in strong laser fields

International Nuclear Information System (INIS)

DiMauro, L.F.; Yang, B.

1993-01-01

In this paper, experimental results are presented which clearly demonstrate the effectiveness that an external field has in altering the dissociation dynamics. The experiment examines the strong-field dissociation dynamics of molecular hydrogen ions and its deuterated isotopes. These studies involve multiphoton excitation in the intensity regime of 10 11-14 W/cm 2 with the fundamental and second harmonic of a ND:YAG or ND:YLF laser system. Measurements include energy resolved electron and mass spectroscopy which provide useful probes in elucidating the interaction dynamics predicted by existing models. The example this in this paper, examines the strong-field dissociation of H 2 + , HD + , and D 2 + at green (0.5 μm) and (1μm) frequencies. The diatomic ions are formed via multiphonon ionization of the neutral precursor which is physically separable from the dissociation process. This study provides the first observation of the dynamics associated with the above threshold dissociation (ATD) process and analogies will be made with the more familiar above threshold ionization (ATI) phenomenon

Bimodal distribution of damage morphology generated by ion implantation

International Nuclear Information System (INIS)

Mok, K.R.C.; Jaraiz, M.; Martin-Bragado, I.; Rubio, J.E.; Castrillo, P.; Pinacho, R.; Srinivasan, M.P.; Benistant, F.

2005-01-01

A nucleation and evolution model of damage based on amorphous pockets (APs) has recently been developed and implemented in an atomistic kinetic Monte Carlo simulator. In the model, APs are disordered structures (I n V m ), which are agglomerates of interstitials (I) and vacancies (V). This model has been used to study the composition and size distribution of APs during different ion implantations. Depending strongly on the dose rate, ion mass and implant temperature, the APs can evolve to a defect population where the agglomerates have a similar number of I and V (n ∼ m), or to a defect population with pure I (m ∼ 0) and pure V (n ∼ 0) clusters, or a mixture of APs and clusters. This behaviour corresponds to a bimodal (APs/clusters) distribution of damage. As the AP have different thermal stability compared to the I and V clusters, the same damage concentration obtained through different implant conditions has a different damage morphology and, consequently, exhibit a different resistance to subsequent thermal treatments

Bayesian Integrated Data Analysis of Fast-Ion Measurements by Velocity-Space Tomography

DEFF Research Database (Denmark)

Salewski, M.; Nocente, M.; Jacobsen, A.S.

2018-01-01

Bayesian integrated data analysis combines measurements from different diagnostics to jointly measure plasma parameters of interest such as temperatures, densities, and drift velocities. Integrated data analysis of fast-ion measurements has long been hampered by the complexity of the strongly non...... framework. The implementation for different types of diagnostics as well as the uncertainties are discussed, and we highlight the importance of integrated data analysis of all available detectors....

Fragment ion distribution in charge-changing collisions of 2-MeV Si ions with C60

Science.gov (United States)

Itoh, A.; Tsuchida, H.; Miyabe, K.; Majima, T.; Nakai, Y.

2001-09-01

We have measured positive fragment ions produced in collisions of 2 MeV Siq+ (q=0, 1, 2, 4) projectiles with a C60 molecular target. The measurement was performed with a time-of-flight coincidence method between fragment ions and charge-selected outgoing projectiles. For all the charge-changing collisions investigated here, the mass distribution of small fragment ions C+n (n=1-12) can be approximated fairly well by a power-law form of n-λ as a function of the cluster size n. The power λ derived from each mass distribution is found to change strongly according to different charge-changing collisions. As a remarkable experimental finding, the values of λ(loss) in electron loss collisions are almost the same for the same final charge states k irrespective of the initial charge q, exhibiting a nearly perfect linear relationship with k. We also performed calculations of the projectile ionization on the basis of the semiclassical approximation and obtained inelastic energy deposition for individual collision processes. The estimated energy deposition is found to have a simple correlation with the experimentally determined values of λ(loss).

Range of plasma ions in cold cluster gases near the critical point

Energy Technology Data Exchange (ETDEWEB)

Zhang, G. [Cyclotron Institute, Texas A& M University, 77843 College Station, TX (United States); Quevedo, H.J. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States); Bonasera, A., E-mail: abonasera@comp.tamu.edu [Cyclotron Institute, Texas A& M University, 77843 College Station, TX (United States); Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Donovan, M.; Dyer, G.; Gaul, E. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States); Guardo, G.L. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Gulino, M. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Libera Universita' Kore, 94100 Enna (Italy); La Cognata, M.; Lattuada, D. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Palmerini, S. [Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Istituto Nazionale di Fisica Nucleare, Section of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Pizzone, R.G.; Romano, S. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Smith, H. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States); Trippella, O. [Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Istituto Nazionale di Fisica Nucleare, Section of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Anzalone, A.; Spitaleri, C. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Ditmire, T. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States)

2017-05-18

We measure the range of plasma ions in cold cluster gases by using the Petawatt laser at the University of Texas-Austin. The produced plasma propagated in all directions some hitting the cold cluster gas not illuminated by the laser. From the ratio of the measured ion distributions at different angles we can estimate the range of the ions in the cold cluster gas. It is much smaller than estimated using popular models, which take only into account the slowing down of charged particles in uniform matter. We discuss the ion range in systems prepared near a liquid–gas phase transition. - Highlights: • We present experimental results obtained at the UT Petawatt laser facility, Austin, TX. • The ion range is strongly modified for cluster gases as compared to its value in a homogeneous system. • Large fluctuations are found if the cluster gas is prepared near the liquid–gas phase transition region.

Range of plasma ions in cold cluster gases near the critical point

International Nuclear Information System (INIS)

Zhang, G.; Quevedo, H.J.; Bonasera, A.; Donovan, M.; Dyer, G.; Gaul, E.; Guardo, G.L.; Gulino, M.; La Cognata, M.; Lattuada, D.; Palmerini, S.; Pizzone, R.G.; Romano, S.; Smith, H.; Trippella, O.; Anzalone, A.; Spitaleri, C.; Ditmire, T.

2017-01-01

We measure the range of plasma ions in cold cluster gases by using the Petawatt laser at the University of Texas-Austin. The produced plasma propagated in all directions some hitting the cold cluster gas not illuminated by the laser. From the ratio of the measured ion distributions at different angles we can estimate the range of the ions in the cold cluster gas. It is much smaller than estimated using popular models, which take only into account the slowing down of charged particles in uniform matter. We discuss the ion range in systems prepared near a liquid–gas phase transition. - Highlights: • We present experimental results obtained at the UT Petawatt laser facility, Austin, TX. • The ion range is strongly modified for cluster gases as compared to its value in a homogeneous system. • Large fluctuations are found if the cluster gas is prepared near the liquid–gas phase transition region.

Ion cyclotron emission by spontaneous emission

Energy Technology Data Exchange (ETDEWEB)

Da Costa, O [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Gresillon, D [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises

1994-07-01

The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs.

Ion cyclotron emission by spontaneous emission

International Nuclear Information System (INIS)

Da Costa, O.; Gresillon, D.

1994-01-01

The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs

Studies on regularities of metal ion sorption from seawater by clinoptilolytes of different origin

International Nuclear Information System (INIS)

Khamizov, R.Kh.; Butenko, T.Yu.; Bronov, L.V.; Skovyra, V.V.; Novikova, V.A.; AN SSSR, Vladivostok

1988-01-01

The regularities of metal ion sorption from sea water by different clinoptilolyte (CP) samples are studied with the purpose of choosing the most prospective sorbents to extract strontium and rubidium. It is shown that the internal diffusion is the sorption rate determining stage. The dependence of effective coefficients of internal diffusion on the exchange level is determined. The distribution coefficients and those of single metal ion separation are determined, the series of sorption selectivity are determined. All CP studied can be used for initial Rb concentration from sea water, and to extract strontium it is advisable to use zeolites of Dzegvi and Tedzami deposits

Use of Novel Highly Selective Ion Exchange Media for Minimizing the Waste Arising from Different NPP and Other Liquids

International Nuclear Information System (INIS)

Tusa, Esko; Harjula, Risto; Lehto, Jukka

2003-01-01

Highly selective inorganic ion exchangers give new possibilities to implement and operate new innovative treatment systems for radioactive liquids. Because of high selectivity these ion exchangers can be used even in liquids of high salt concentrations. Only selected target nuclides will be separated and inactive salts are left in the liquid, which can be released or recategorized. Thus, it is possible to reduce the volume of radioactive waste dramatically. On the other hand, only a small volume of highly selective material is required in applications, which makes it possible to design totally new types of compact treatment systems. The major benefit of selective ion exchange media comes from the very large volume reduction of radioactive waste in final disposal. It is also possible to save in investment costs, because small ion exchanger volumes can be used and handled in a very small facility. This paper describes different applications of these highly selective ion exchangers, both commercial fullscale applications and laboratory tests, to give the idea of their efficiency for different liquids

Interaction of a neutral composite particle with a strong Coulomb field

International Nuclear Information System (INIS)

Wong, Cheuk-Yin.

1988-01-01

The author discusses the interaction of the quasi-composite (e/sup /plus//e/sup /minus//) system with an external electromagnetic field. This problem addresses the question of the origin of strong positron lines in quasi-elastic heavy-ion reactions. 3 refs

Setup of an ion-beam facility for the nanostructuration of 2D materials with highly charged ions

International Nuclear Information System (INIS)

Hopster, Johannes

2014-01-01

This work deals with the interaction of highly charged ions with surfaces. When an ion approaches a surface, its potential energy is deposited into the surface via a cascade of electronic processes. A strong electronic excitation of the surface results, which is localized in a nanometer sized region. As a consequence of further mechanisms, this excitation may lead to nanostructures being of topographic, structural or chemical modifications of the material. During this work, a setup of a complete ion beamline was constructed. The beamline offers production, focussing and charge separation of ion beams as well as irradiations of surfaces with highly charged ions. Additionally, new methods for beam profile and particle density analysis via Raman microscopy on graphene are presented. Experimental results of highly charged ions impinging on 2D materials provide the second part of this work. Ion induced nanostructures on lamellar materials, i.e. MoS 2 as well as single layers of graphene, could be identified and analyzed. Each of them were triggered by the potential energy of the ions. Processes of the ion surface interaction could be deduced qualitatively from the data. Local regions of enhanced friction on graphene could be detected by Friction Force Microscopy after irradiations. Thresholds for defect creation were established regarding the potential energy, which depend strongly on the kinetic energy of the ions. In terms of the over the barrier model, this dependency could be related to the time of flight the ion spends above the surface. Defects on irradiated graphene as well as on free standing graphene were analyzed via Raman microscopy. Possible dependencies of the defect diameters and nature on the layer number as well as on the presence of a substrate were proved. It was shown, that graphene becomes locally hydrogenated by the impact of highly charged ions. Such a chemical modification leads to an enhanced friction as well as to an appearance of defect modes

Epidermal Expression and Regulation of Interleukin-33 during Homeostasis and Inflammation: Strong Species Differences.

Science.gov (United States)

Sundnes, Olav; Pietka, Wojciech; Loos, Tamara; Sponheim, Jon; Rankin, Andrew L; Pflanz, Stefan; Bertelsen, Vibeke; Sitek, Jan C; Hol, Johanna; Haraldsen, Guttorm; Khnykin, Denis

2015-07-01

IL-33 is a novel IL-1 family member with a putative role in inflammatory skin disorders and a complex biology. Therefore, recent conflicting data regarding its function in experimental models justify a close assessment of its tissue expression and regulation. Indeed, we report here that there are strong species differences in the expression and regulation of epidermal IL-33. In murine epidermis, IL-33 behaved similar to an alarmin, being constitutively expressed in keratinocyte nuclei and rapidly lost during acute inflammation. By contrast, human and porcine IL-33 were weakly expressed or absent in keratinocytes of noninflamed skin but induced during acute inflammation. To this end, we observed that expression of IL-33 in human keratinocytes but not murine keratinocytes was strongly induced by IFN-γ, and this upregulation completely depended on the presence of EGFR ligands. Accordingly, IFN-γ increased the expression of IL-33 in the basal layers of the epidermis in human ex vivo skin cultures only, despite good evidence of IFN-γ activity in cultures from both species. Together these findings demonstrate that a full understanding of IL-33 function in clinical settings must take species-specific differences into account.

Preparation of cold Mg+ion clouds for sympathetic cooling of highly charged ions at SPECTRAP

International Nuclear Information System (INIS)

Cazan, Radu Mircea

2012-02-01

The bound electrons in hydrogen-like or lithium-like heavy ions experience extremely strong electric and magnetic fields in the surrounding of the nucleus. Laser spectroscopy of the ground-state hyperfine splitting in the lead region provides a sensitive tool to test strong-field quantum electro dynamics (QED), especially in the magnetic sector. Previous measurements on hydrogen-like systems performed in an electron-beam ion trap (EBIT) or at the experimental storage ring (ESR) were experimentally limited in accuracy due to statistics, the large Doppler broadening and the ion energy. The full potential of the QED test can only be exploited if measurements for hydrogen- and lithium-like ions are performed with accuracy improved by 2-3 orders of magnitude. Therefore, the new Penning trap setup SPECTRAP - dedicated for laser spectroscopy on trapped and cooled highly charged ions - is currently commissioned at GSI Darmstadt. Heavy highly charged ions will be delivered to this trap by the HITRAP facility in the future. SPECTRAP is a cylindrical Penning trap with axial access for external ion injection and radial optical access mounted inside a cold-bore superconducting Helmholtz-type split-coil magnet. To reach the targeted accuracy in laser spectroscopy, an efficient and fast cooling process for the highly charged ions must be employed. This can be realized by sympathetic cooling with a cloud of laser-cooled light ions. Within this thesis work, a laser system and an ion source for the production of such a 24 Mg + ion cloud was developed and commissioned at SPECTRAP. An all-solid-state laser system for the generation of 279.6 nm light was designed and built. It consists of a fiber laser at 1118.5 nm followed by frequency quadrupling using two successive second-harmonic generation stages with actively stabilized ring resonators and nonlinear crystals. The laser system can deliver more than 15 mW of UV laser power under optimal conditions and requires little maintenance

The Breeding of a Pigment Mutant Strain of Steroid Hydroxylation Aspergillus Flavus by Low Energy Ion Implantation

International Nuclear Information System (INIS)

Ye Hui; Ma Jingming; Feng Chun; Cheng Ying; Zhu Suwen; Cheng Beijiu

2009-01-01

In the process of the fermentation of steroid C 11 α-hydroxylgenation strain Aspergillus flavus AF-ANo208, a red pigment is derived, which will affect the isolation and purification of the target product. Low energy ion beam implantation is a new tool for breeding excellent mutant strains. In this study, the ion beam implantation experiments were performed by infusing two different ions: argon ion (Ar + ) and nitrogen ion (N + ). The results showed that the optimal ion implantation was N + with an optimum dose of 2.08 x 10 15 ions/cm 2 , with which the mutant strain AF-ANm16 that produced no red pigment was obtained. The strain had high genetic stability and kept the strong capacity of C11α-hydroxylgenation, which could be utilized in industrial fermentation. The differences between the original strain and the mutant strain at a molecular level were analyzed by randomly amplified polymorphic DNA (RAPD). The results indicated that the frequency of variation was 7.00%, which would establish the basis of application investigation into the breeding of pigment mutant strains by low energy ion implantation. (ion beam bioengineering)

Strong ion exchange in centrifugal partition extraction (SIX-CPE): effect of partition cell design and dimensions on purification process efficiency.

Science.gov (United States)

Hamzaoui, Mahmoud; Hubert, Jane; Reynaud, Romain; Marchal, Luc; Foucault, Alain; Renault, Jean-Hugues

2012-07-20

The aim of this article was to evaluate the influence of the column design of a hydrostatic support-free liquid-liquid chromatography device on the process efficiency when the strong ion-exchange (SIX) development mode is used. The purification of p-hydroxybenzylglucosinolate (sinalbin) from a crude aqueous extract of white mustard seeds (Sinapis alba L.) was achieved on two types of devices: a centrifugal partition chromatograph (CPC) and a centrifugal partition extractor (CPE). They differ in the number, volume and geometry of their partition cells. The SIX-CPE process was evaluated in terms of productivity and sinalbin purification capability as compared to previously optimized SIX-CPC protocols that were carried out on columns of 200 mL and 5700 mL inner volume, respectively. The objective was to determine whether the decrease in partition cell number, the increase in their volume and the use of a "twin cell" design would induce a significant increase in productivity by applying higher mobile phase flow rate while maintaining a constant separation quality. 4.6g of sinalbin (92% recovery) were isolated from 25 g of a crude white mustard seed extract, in only 32 min and with a purity of 94.7%, thus corresponding to a productivity of 28 g per hour and per liter of column volume (g/h/LV(c)). Therefore, the SIX-CPE process demonstrates promising industrial technology transfer perspectives for the large-scale isolation of ionized natural products. Copyright © 2012 Elsevier B.V. All rights reserved.

Heavy-ion radiography and heavy-ion computed tomography

International Nuclear Information System (INIS)

Fabrikant, J.I.; Holley, W.R.; McFarland, E.W.; Tobias, C.a.

1982-02-01

Heavy-ion projection and CT radiography is being developed into a safe, low-dose, noninvasive radiological procedure that can quantitate and image small density differences in human tissues. The applications to heavy-ion mammography and heavy-ion CT imaging of the brain in clinical patients suggest their potential value in cancer diagnosis

Strong and Electromagnetic Interactions at SPS Energies

CERN Document Server

Ribicki, Andrzej

2009-01-01

Particle production in peripheral Pb+Pb collisions has been measured at a beam energy of 158 GeV per nucleon, corresponding to psNN 17.3 GeV. The measurements provide full double differential coverage in a wide range of longitudinal and transverse momenta, including the central (“mid-rapidity”) area and extending far into the projectile fragmentation region. The resulting analysis shows the heavy ion reaction as a mixture of different processes. In particular, surprising phenomena, like the presence of large and strongly varying structures in the shape of the double differential cross section d2s /dxFd pT , are induced by the final state electromagnetic interaction between produced particles and the charged spectator system. This effect is largest at low transverse momenta, where it results in a deep valley in the xF -dependence of the produced p+/p− ratio. The basic characteristics of the electromagnetic phenomenon described above agree with the results of a theoretical analysis, performed by means of ...

Two-photon processes in highly charged ions

International Nuclear Information System (INIS)

Jahrsetz, Thorsten

2015-01-01

Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

Two-photon processes in highly charged ions

Energy Technology Data Exchange (ETDEWEB)

Jahrsetz, Thorsten

2015-03-05

Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

Effects of the spaces available for cations in strongly acidic cation-exchange resins on the exchange equilibria by quaternary ammonium ions and on the hydration states of metal ions.

Science.gov (United States)

Watanabe, Yuuya; Ohnaka, Kenji; Fujita, Saki; Kishi, Midori; Yuchi, Akio

2011-10-01

The spaces (voids) available for cations in the five exchange resins with varying exchange capacities and cross-linking degrees were estimated, on the basis of the additivity of molar volumes of the constituents. Tetraalkylammonium ions (NR(4)(+); R: Me, Et, Pr) may completely exchange potassium ion on the resin having a larger void radius. In contrast, the ratio of saturated adsorption capacity to exchange capacity of the resin having a smaller void radius decreased with an increase in size of NR(4)(+) ions, due to the interionic contacts. Alkali metal ions could be exchanged quantitatively. While the hydration numbers of K(+), Rb(+), and Cs(+) were independent of the void radius, those of Li(+) and Na(+), especially Na(+), decreased with a decrease in void radius. Interionic contacts between the hydrated ions enhance the dehydration. Multivalent metal ions have the hydration numbers, comparable to or rather greater than those in water. A greater void volume available due to exchange stoichiometry released the interionic contacts and occasionally promoted the involvement of water molecules other than directly bound molecules. The close proximity between ions in the conventional ion-exchange resins having higher exchange capacities may induce varying interactions.

Double atom ionization by multicharged ions and strong electromagnetic field: correlation effects in a continuous spectrum

International Nuclear Information System (INIS)

Presnyakov, L.P.; Uskov, D.B.

1997-01-01

The nonstationary theory of double ionization of two-electron atoms in collisions with multicharged ions or under the impact of intensive electromagnetic field is developed. The approach, making it possible to study both problems by uniform method, is formulated. The two-electron wave function of continuous spectrum, accounting for interaction of electrons with atomic nucleus, external ionizer and between themselves is obtained. The calculation results on the helium atoms double ionization by multicharged ions is a good quantitative agreement with available experimental data

Is the Number of Different MRI Findings More Strongly Associated with Low Back Pain Than Single MRI Findings?

DEFF Research Database (Denmark)

Hancock, Mark J; Kjaer, Per; Kent, Peter

2017-01-01

STUDY DESIGN: A cross-sectional and longitudinal analysis using 2 different data sets OBJECTIVE.: To investigate if the number of different MRI findings present is more strongly associated with low back pain (LBP) than single MRI findings. SUMMARY OF BACKGROUND DATA: Most previous studies have....... The outcome for the cross-sectional study was presence of LBP during the last year. The outcome for the longitudinal study was days to recurrence of activity limiting LBP. In both data sets we created an aggregate score of the number of different MRI findings present in each individual and assessed...... investigated the associations between single MRI findings and back pain rather than investigating combinations of MRI findings. If different individuals have different pathoanatomic sources contributing to their pain, then combinations of MRI findings may be more strongly associated with LBP. METHODS...

Cation-Size-Dependent Conformational Locking of Glutamic Acid by Alkali Ions: Infrared Photodissociation Spectroscopy of Cryogenic Ions.

Science.gov (United States)

Klyne, Johanna; Bouchet, Aude; Ishiuchi, Shun-Ichi; Fujii, Masaaki; Dopfer, Otto

2018-03-01

Consolidated knowledge of conformation and stability of amino acids and their clusters is required to understand their biochemical recognition. Often, alkali ions interact with amino acids and proteins. Herein, infrared photodissociation (IRPD) spectra of cryogenic metalated glutamic acid ions (GluM + , M = Li-Cs) are systematically analyzed in the isomer-specific fingerprint and XH stretch ranges (1100-1900, 2600-3600 cm -1 ) to provide a direct measure for cation-size-dependent conformational locking. GluM + ions are generated by electrospray ionization and cooled down to 15 K in a cryogenic quadrupole ion trap. The assignment of the IRPD spectra is supported by density functional theory calculations at the dispersion-corrected B3LYP-D3/aug-cc-pVTZ level. In the global minimum of GluM + , the flexibility of Glu is strongly reduced by the formation of rigid ionic CO···M + ···OC metal bridges, corresponding to charge solvation. The M + binding energy decreases monotonically with increasing cation size from D 0 = 314 to 119 kJ/mol for Li-Cs. Whereas for Li and Na only the global minimum of GluM + is observed, for K-Cs at least three isomers exist at cryogenic temperature. The IRPD spectra of cold GluM + ions are compared to IR multiple-photon dissociation spectra measured at room temperature. Furthermore, we elucidate the differences of the impact of protonation and metalation on the structure and conformational locking of Glu.

A Cadmium Ion-selective Membrane Electrode Based on Strong Acidic Organic-inorganic Composite Cation-exchanger: Polyaniline Ce(IV Molybdate

Directory of Open Access Journals (Sweden)

Syed Ashfaq NABI

2008-05-01

Full Text Available A cadmium ion-selective composite cation-exchanger polyaniline Ce(IV molybdate was used as electroactive component for the construction of a ion-selective membrane electrode. The membrane electrode showed a Nerstian response for Cd(II ions over a wide concentration range 5 × 10-6 – 1 × 10-1 with a sub-Nerstian slope of 27 mV per decade change in concentration of cadmium ions. The limit of detection was also ascertained to be 5 × 10-6 M. It has a fast response time 15 s and can be very well utilized for more than three months with out any appreciable divergence in potentials. The optimum pH for the smooth functioning of this electrode was found to be in the Ph range of 2.5 – 7.5. The electrode also showed better selectivity for Cd(II ions over many other interfering ions. The practical utility of membrane electrode was demonstrated by using as indicator electrode for the potentiometric titration of Cd(II with EDTA and determination of cadmium content in drain water.

Measurement of ion beam angular distribution at different helium gas pressures in a plasma focus device by large-area polycarbonate detectors

Energy Technology Data Exchange (ETDEWEB)

Sohrabi, M.; Habibi, M., E-mail: mortezahabibi@gmail.com; Ramezani, V. [Amirkabir University of Technology, Energy Engineering and Physics Department (Iran, Islamic Republic of)

2017-02-15

The paper presents an experimental study and analysis of full helium ion density angular distributions in a 4-kJ plasma focus device (PFD) at pressures of 10, 15, 25, and 30 mbar using large-area polycarbonate track detectors (PCTDs) (15-cm etchable diameter) processed by 50-Hz-HV electrochemical etching (ECE). Helium ion track distributions at different pressures, in particular, at the main axis of the PFD are presented. Maximum ion track density of ~4.4 × 10{sup 4} tracks/cm{sup 2} was obtained in the PCTD placed 6 cm from the anode. The ion distributions for all pressures applied are ring-shaped, which is possibly due to the hollow cylindrical copper anode used. The large-area PCTD processed by ECE proves, at the present state-of-theart, a superior method for direct observation and analysis of ion distributions at a glance with minimum efforts and time. Some observations of the ion density distributions at different pressures are reported and discussed.

Real-time detection of metal ions using conjugated polymer composite papers.

Science.gov (United States)

Lee, Ji Eun; Shim, Hyeon Woo; Kwon, Oh Seok; Huh, Yang-Il; Yoon, Hyeonseok

2014-09-21

Cellulose, a natural polymeric material, has widespread technical applications because of its inherent structural rigidity and high surface area. As a conjugated polymer, polypyrrole shows practical potential for a diverse and promising range of future technologies. Here, we demonstrate a strategy for the real-time detection and removal of metal ions with polypyrrole/cellulose (PPCL) composite papers in solution. Simply, the conjugated polymer papers had different chemical/physical properties by applying different potentials to them, which resulted in differentiable response patterns and adsorption efficiencies for individual metal ions. First, large-area PPCL papers with a diameter of 5 cm were readily obtained via vapor deposition polymerization. The papers exhibited both mechanical flexibility and robustness, in which polypyrrole retained its redox property perfectly. The ability of the PPCL papers to recognize metal ions was examined in static and flow cells, in which real-time current change was monitored at five different applied potentials (+1, +0.5, 0, -0.5, and -1 V vs. Ag/AgCl). Distinguishable signals in the PPCL paper responses were observed for individual metal ions through principal component analysis. Particularly, the PPCL papers yielded unique signatures for three metal ions, Hg(ii), Ag(i), and Cr(iii), even in a real sample, groundwater. The sorption of metal ions by PPCL papers was examined in the flow system. The PPCL papers had a greatly superior adsorption efficiency for Hg(ii) compared to that of the other metal ions. With the strong demand for the development of inexpensive, flexible, light-weight, and environmentally friendly devices, the fascinating characteristics of these PPCL papers are likely to provide good opportunities for low-cost paper-based flexible or wearable devices.

Energy conversion through mass loading of escaping ionospheric ions for different Kp values

Science.gov (United States)

Yamauchi, Masatoshi; Slapak, Rikard

2018-01-01

By conserving momentum during the mixing of fast solar wind flow and slow planetary ion flow in an inelastic way, mass loading converts kinetic energy to other forms - e.g. first to electrical energy through charge separation and then to thermal energy (randomness) through gyromotion of the newly born cold ions for the comet and Mars cases. Here, we consider the Earth's exterior cusp and plasma mantle, where the ionospheric origin escaping ions with finite temperatures are loaded into the decelerated solar wind flow. Due to direct connectivity to the ionosphere through the geomagnetic field, a large part of this electrical energy is consumed to maintain field-aligned currents (FACs) toward the ionosphere, in a similar manner as the solar wind-driven ionospheric convection in the open geomagnetic field region. We show that the energy extraction rate by the mass loading of escaping ions (ΔK) is sufficient to explain the cusp FACs, and that ΔK depends only on the solar wind velocity accessing the mass-loading region (usw) and the total mass flux of the escaping ions into this region (mloadFload), as ΔK ˜ -mloadFloadu2sw/4. The expected distribution of the separated charges by this process also predicts the observed flowing directions of the cusp FACs for different interplanetary magnetic field (IMF) orientations if we include the deflection of the solar wind flow directions in the exterior cusp. Using empirical relations of u0 ∝ Kp + 1.2 and Fload ∝ exp(0.45Kp) for Kp = 1-7, where u0 is the solar wind velocity upstream of the bow shock, ΔK becomes a simple function of Kp as log10(ΔK) = 0.2 ṡ Kp + 2 ṡ log10(Kp + 1.2) + constant. The major contribution of this nearly linear increase is the Fload term, i.e. positive feedback between the increase of ion escaping rate Fload through the increased energy consumption in the ionosphere for high Kp, and subsequent extraction of more kinetic energy ΔK from the solar wind to the current system by the increased

Investigation of the microstructures of ion beams emitted from PF-1000 at different angles to the Z-axis

Energy Technology Data Exchange (ETDEWEB)

Skladnik-Sadowska, E.; Czaus, K.; Malinowski, K.; Kwiatkowski, R.; Zebrowski, J. [The Andrzej Soltan Institute for Nuclear Studies, IPJ, 05-400 Otwock-Swierk (Poland); Sadowski, M.J. [The Andrzej Soltan Institute for Nuclear Studies, IPJ, 0R-400 Otwock-Swierk (Poland)] [Institute of Plasma Physics and Laser Microfusion, IPPLM, 01-497 Warsaw (Poland); Paduch, M.; Scholz, M. [Institute of Plasma Physics and Laser Microfusion, IPPLM, 01-497 Warsaw (Poland); Kubes, P. [Czech Technical University, CVUT, 166-27 Prague (Czech Republic); Garkusha, I.E. [Institute of Plasma Physics, NSC KIPT, 61-108 Kharkov (Ukraine); Talebitaher, A. [Plasma Radiation Sources Laboratory, NIE NTU, 637616 Singapore (Singapore)

2011-07-01

The paper describes diagnostics of fast ion beams emitted from the large PF-1000 facility operated at 21-27 kV, 290-480 kJ. The use was made of pinhole cameras equipped with PM-355 nuclear track detectors and placed at different angles to the discharge axis. The ion measurements performed at 0 degree angle, as well as those at 60 degrees angle showed a complex spatial structure of the fast ion beams. The ion measurements, which were for the first time performed in the upstream direction (at 180 degrees angle), have proved that some fast deuteron beams are emitted also in the upstream direction. This document is composed of a paper and a poster. (authors)

Understanding the anisotropic ion distributions within magnetotail dipolarizing flux bundles

Science.gov (United States)

Zhou, X.; Runov, A.; Angelopoulos, V.; Birn, J.

2017-12-01

Dipolarizing flux bundles (DFBs), earthward-propagating structures with enhanced northward magnetic field (Bz) component, are usually believed to carry a different plasma population from that in the ambient magnetotail plasma sheet. The ion distribution functions within the DFB, however, are recently found to be largely controlled by the ion adiabaticity parameter κ in the ambient plasma sheet outside the DFBs. According to these observations, the ambient κ values of 2-3 usually correspond to a strong perpendicular anisotropy of suprathermal ions within the DFBs, whereas for lower κ values the ions inside the DFBs become more isotropic. Here we utilize a simple, test-particle model to explore the nature of the anisotropy and its dependence on the ambient κ values. We find that the ion anisotropy originates from successive ion reflections and reentries to the DFBs, during which the ions can be consecutively accelerated in the perpendicular direction by the DFB-carried electric field. This acceleration process may be interrupted, however, when the magnetic field lines are highly curved in the ambient plasma sheet. In this case, the ion trajectories are most stochastic outside the DFB region, which makes the reflected ions less likely to return to the DFBs for another cycle of acceleration; as a consequence, the perpendicular ion anisotropy does not appear. Given that the DFB ions are a free energy source for instabilities when they are injected towards Earth, our simple model (that reproduces most observational features on the anisotropic DFB ion distributions) may shed new lights on the coupling process between the magnetotail and the inner magneosphere.

Wave Propagation in an Ion Beam-Plasma System

DEFF Research Database (Denmark)

Jensen, T. D.; Michelsen, Poul; Juul Rasmussen, Jens

1979-01-01

The spatial evolution of a velocity- or density-modulated ion beam is calculated for stable and unstable ion beam plasma systems, using the linearized Vlasov-Poisson equations. The propagation properties are found to be strongly dependent on the form of modulation. In the case of velocity...

Ion beam neutralization using three-dimensional electron confinement by surface modification of magnetic poles

Energy Technology Data Exchange (ETDEWEB)

Nicolaescu, Dan, E-mail: Dan.Nicolaescu@kt2.ecs.kyoto-u.ac.jp [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Sakai, Shigeki [Nissin Ion Equipment Co., Ltd., 575 Kuze Tonoshiro-cho, Minami-ku, Kyoto 601-8205 (Japan); Gotoh, Yasuhito [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Ishikawa, Junzo [Department of Electronics and Information Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan)

2011-07-21

Advanced implantation systems used for semiconductor processing require transportation of quasi-parallel ion beams, which have low energy ({sup 11}B{sup +}, {sup 31}P{sup +},{sup 75}As{sup +}, E{sub ion}=200-1000 eV). Divergence of the ion beam due to space charge effects can be compensated through injection of electrons into different regions of the ion beam. The present study shows that electron confinement takes place in regions of strong magnetic field such as collimator magnet provided with surface mirror magnetic fields and that divergence of the ion beam passing through such regions is largely reduced. Modeling results have been obtained using Opera3D/Tosca/Scala. Electrons may be provided by collision between ions and residual gas molecules or may be injected by field emitter arrays. The size of surface magnets is chosen such as not to disturb ion beam collimation, making the approach compatible with ion beam systems. Surface magnets may form thin magnetic layers with thickness h=0.5 mm or less. Conditions for spacing of surface magnet arrays for optimal electron confinement are outlined.

Investigating the Fundamentals of Molecular Depth Profiling Using Strong-field Photoionization of Sputtered Neutrals

Science.gov (United States)

Willingham, D.; Brenes, D. A.; Winograd, N.; Wucher, A.

2010-01-01

Molecular depth profiles of model organic thin films were performed using a 40 keV C60+ cluster ion source in concert with TOF-SIMS. Strong-field photoionization of intact neutral molecules sputtered by 40 keV C60+ primary ions was used to analyze changes in the chemical environment of the guanine thin films as a function of ion fluence. Direct comparison of the secondary ion and neutral components of the molecular depth profiles yields valuable information about chemical damage accumulation as well as changes in the molecular ionization probability. An analytical protocol based on the erosion dynamics model is developed and evaluated using guanine and trehalose molecular secondary ion signals with and without comparable laser photoionization data. PMID:26269660

Chemical degradation and morphological instabilities during focused ion beam prototyping of polymers.

Science.gov (United States)

Orthacker, A; Schmied, R; Chernev, B; Fröch, J E; Winkler, R; Hobisch, J; Trimmel, G; Plank, H

2014-01-28

Focused ion beam processing of low melting materials, such as polymers or biological samples, often leads to chemical and morphological instabilities which prevent the straight-forward application of this versatile direct-write structuring method. In this study the behaviour of different polymer classes under ion beam exposure is investigated using different patterning parameters and strategies with the aim of (i) correlating local temperatures with the polymers' chemistry and its morphological consequences; and (ii) finding a way of processing sensitive polymers with lowest chemical degradation while maintaining structuring times. It is found that during processing of polymers three temperature regimes can be observed: (1) at low temperatures all polymers investigated show stable chemical and morphological behaviour; (2) very high temperatures lead to strong chemical degradation which entails unpredictable morphologies; and (3) in the intermediate temperature regime the behaviour is found to be strongly material dependent. A detailed look reveals that polymers which rather cross-link in the proximity of the beam show stable morphologies in this intermediate regime, while polymers that rather undergo chain scission show tendencies to develop a creeping phase, where material follows the ion beam movement leading to instable and unpredictable morphologies. Finally a simple, alternative patterning strategy is suggested, which allows stable processing conditions with lowest chemical damage even for challenging polymers undergoing chain scission.

Xe ion beam induced rippled structures on differently oriented single-crystalline Si surfaces

Energy Technology Data Exchange (ETDEWEB)

Hanisch, Antje; Grenzer, Joerg; Facsko, Stefan [Forschungszentrum Dresden-Rossendorf, Institut fuer Ionenstrahlphysik und Materialforschung, PO Box 510119, 01314 Dresden (Germany); Biermanns, Andreas; Pietsch, Ullrich, E-mail: A.Hanisch@fzd.d [Universitaet Siegen, Festkoerperphysik, 57068 Siegen (Germany)

2010-03-24

We report on Xe{sup +} induced ripple formation at medium energy on single-crystalline silicon surfaces of different orientations using substrates with an intentional miscut from the [0 0 1] direction and a [1 1 1] oriented wafer. The ion beam incidence angle with respect to the surface normal was kept fixed at 65{sup 0} and the ion beam projection was parallel or perpendicular to the [1 1 0] direction. By a combination of atomic force microscopy, x-ray diffraction and high-resolution transmission electron microscopy we found that the features of the surface and subsurface rippled structures such as ripple wavelength and amplitude and the degree of order do not depend on the surface orientation as assumed in recent models of pattern formation for semiconductor surfaces. (fast track communication)

Divalent Ion Parameterization Strongly Affects Conformation and Interactions of an Anionic Biomimetic Polymer

Energy Technology Data Exchange (ETDEWEB)

Daily, Michael D.; Baer, Marcel D.; Mundy, Christopher J.

2016-03-10

The description of peptides and the use of molecular dynamics simulations to refine structures and investigate the dynamics on an atomistic scale are well developed. Through a consensus in this community over multiple decades, parameters were developed for molecular interactions that only require the sequence of amino-acids and an initial guess for the three-dimensional structure. The recent discovery of peptoids will require a retooling of the currently available interaction potentials in order to have the same level of confidence in the predicted structures and pathways as there is presently in the peptide counterparts. Here we present modeling of peptoids using a combination of ab initio molecular dynamics (AIMD) and atomistic resolution classical forcefield (FF) to span the relevant time and length scales. To properly account for the dominant forces that stabilize ordered structures of peptoids, namely steric-, electrostatic, and hydrophobic interactions mediated through sidechain-sidechain interactions in the FF model, those have to be first mapped out using high fidelity atomistic representations. A key feature here is not only to use gas phase quantum chemistry tools, but also account for solvation effects in the condensed phase through AIMD. One major challenge is to elucidate ion binding to charged or polar regions of the peptoid and its concomitant role in the creation of local order. Here, similar to proteins, a specific ion effect is observed suggesting that both the net charge and the precise chemical nature of the ion will need to be described. MDD was supported by MS3 (Materials Synthesis and Simulation Across Scales) Initiative at Pacific Northwest National Laboratory. Research was funded by the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MDB acknowledges support from US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Material & Engineering. CJM acknowledges

Studies of endothelial monolayer formation on irradiated poly-L-lactide acid with ions of different stopping power and velocity

International Nuclear Information System (INIS)

Arbeitman, Claudia R.; Grosso, Mariela F. del; Ibañez, Irene L.; Behar, Moni; Grasselli, Mariano; Bermúdez, Gerardo García

2015-01-01

In this work we study cell viability, proliferation and morphology of bovine aortic endothelial cells (BAEC) cultured on poly-L-lactide acid (PLLA) modified by heavy ion irradiation. In a previous study comparing ions beams with the same stopping power we observed an increase in cell density and a better cell morphology at higher ion velocities. In the present work we continued this study using heavy ions beam with different stopping power and ion velocities. To this end thin films of 50 μm thickness were irradiated with 2 MeV/u and 0.10 MeV/u ion beams provided the Tandar (Buenos Aires, Argentina) and Tandetron (Porto Alegre, Brazil) accelerators, respectively. The results suggest that a more dense and elongated cell shapes, similar to the BAEC cells on the internal surface of bovine aorta, was obtained for stopping power of 18.2–22.1 MeV cm 2 mg −1 and ion velocity of 2 MeV/u. On the other hand, for low ion velocity 0.10 MeV/u the cells present a more globular shapes.

The ions displacement through glasses

International Nuclear Information System (INIS)

Sevegnani, F.X.

1980-01-01

A method to introduce sodium, potassium, lithium, calcium, iron and other ions in vacuum or gas light bulb by mean of a strong stationay electric field. The experiments showed that the mass deposited inside the bulbs obey Faraday's law of electrolysis, although the process of mass transfer is not that of a conventional electrolysis. A method which allows to show that hydrogen ions do not penetrate the glass structure is also described. Using radioactive tracers, it is shown that heavy ions, such PO 4 --- do not penetrate the glass structure. The vitreous state and the glass properties were studied for interpreting experimental results. (Author) [pt

Design study of primary ion provider for relativistic heavy ion collider electron beam ion source.

Science.gov (United States)

Kondo, K; Kanesue, T; Tamura, J; Okamura, M

2010-02-01

Brookhaven National Laboratory has developed the new preinjector system, electron beam ion source (EBIS) for relativistic heavy ion collider (RHIC) and National Aeronautics and Space Administration Space Radiation Laboratory. Design of primary ion provider is an essential problem since it is required to supply beams with different ion species to multiple users simultaneously. The laser ion source with a defocused laser can provide a low charge state and low emittance ion beam, and is a candidate for the primary ion source for RHIC-EBIS. We show a suitable design with appropriate drift length and solenoid, which helps to keep sufficient total charge number with longer pulse length. The whole design of primary ion source, as well as optics arrangement, solid targets configuration and heating about target, is presented.

MMS Observations of Ion-Scale Magnetic Island in the Magnetosheath Turbulent Plasma

Science.gov (United States)

Huang, S. Y.; Sahraoui, F.; Retino, A.; Contel, O. Le; Yuan, Z. G.; Chasapis, A.; Aunai, N.; Breuillard, H.; Deng, X. H.; Zhou, M.;

Shape manipulation of ion irradiated Ag nanoparticles embedded in lithium niobate

International Nuclear Information System (INIS)

Wolf, Steffen; Rensberg, Jura; Johannes, Andreas; Ronning, Carsten; Thomae, Rainer; Smit, Frederick; Neveling, Retief; Bharuth-Ram, Krish; Moodley, Mathew; Bierschenk, Thomas; Rodriguez, Matias; Afra, Boshra; Ridgway, Mark; Hasan, Shakeeb Bin; Rockstuhl, Carsten

2016-01-01

Spherical silver nanoparticles were prepared by means of ion beam synthesis in lithium niobate. The embedded nanoparticles were then irradiated with energetic "8"4Kr and "1"9"7Au ions, resulting in different electronic energy losses between 8.1 and 27.5 keV nm"−"1 in the top layer of the samples. Due to the high electronic energy losses of the irradiating ions, molten ion tracks are formed inside the lithium niobate in which the elongated Ag nanoparticles are formed. This process is strongly dependent on the initial particle size and leads to a broad aspect ratio distribution. Extinction spectra of the samples feature the extinction maximum with shoulders on either side. While the maximum is caused by numerous remaining spherical nanoparticles, the shoulders can be attributed to elongated particles. The latter could be verified by COMSOL simulations. The extinction spectra are thus a superposition of the spectra of all individual particles. (paper)

Fluorescent carbon quantum dot hydrogels for direct determination of silver ions.

Science.gov (United States)

Cayuela, A; Soriano, M L; Kennedy, S R; Steed, J W; Valcárcel, M

2016-05-01

The paper reports for the first time the direct determination of silver ion (Ag(+)) using luminescent Carbon Quantum Dot hydrogels (CQDGs). Carbon Quantum Dots (CQDs) with different superficial moieties (passivate-CQDs with carboxylic groups, thiol-CQDs and amine-CQDs) were used to prepare hybrid gels using a low molecular weight hydrogelator (LMWG). The use of the gels results in considerable fluorescence enhancement and also markedly influences selectivity. The most selective CQDG system for Ag(+) ion detection proved to be those containing carboxylic groups onto their surface. The selectivity towards Ag(+) ions is possibly due to its flexible coordination sphere compared with other metal ions. This fluorescent sensing platform is based on the strong Ag-O interaction which can quench the photoluminescence of passivate-CQDs (p-CQDs) through charge transfer. The limit of detection (LOD) and quantification (LOQ) of the proposed method were 0.55 and 1.83µgmL(-1), respectively, being applied in river water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Time-resolved angular distributions of plume ions from silver at low and medium laser fluence

DEFF Research Database (Denmark)

Christensen, Bo Toftmann; Schou, Jørgen

Even at moderate fluence (0.6 -2.4 J/cm2) laser impact on metals in the UV regime results in a significant number of ions emitted from the surface. The ablated particles are largely neutrals at the lowest fluence, but the fraction of ions increases strongly with fluence. We have irradiated silver...... in a vacuum chamber (~ 10-7 mbar) with a Nd:YAG laser at a wavelength of 355 nm and made detailed measurements of the time-resolved angular distribution. The ion flow in different directions has been measured with a hemispherical array of Langmuir probes, by which the time-of-flight spectra, as well...

Evaluation of cell behavior on modified polypropylene with swift heavy ion irradiation

International Nuclear Information System (INIS)

Arbeitman, Claudia R.; Ibañez, Irene L.; García Bermúdez, Gerardo; Durán, Hebe; Grosso, Mariela F. del; Salguero, Noelia; Mazzei, Rubén

2012-01-01

Ion beam irradiation is a well known means to change the physico-chemical properties of polymers, and induced bio and citocompatibility in controlled conditions and in selected areas of surface. However, the enhancement of cell adhesion on a modified substrate does not mean that the surface is adequate for functional cells. The purpose of the present work is to study proliferation, changes in cytoskeleton and cell morphology on substrates as a function of irradiation parameters. We irradiated polypropylene with sulfur (S) ion-beam at energies of 110 MeV with fluences between 1 × 10 6 and 2 × 10 10 ions cm −2 . NIH 3T3 cells were cultured on each sample. Cell morphology was observed using phase contrast microscopy and cytoskeleton proteins with fluorescence microscopy. The analysis show different cellular responses as a functions of irradiation parameter, strongly suggests that different underlying substratum can result in distinct types of cytoskeleton reorganization.

Evaluation of cell behavior on modified polypropylene with swift heavy ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Arbeitman, Claudia R., E-mail: arbeitman@tandar.cnea.gov.ar [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA, Av. Gral. Paz 1499, 1650 San Martin, Bs. As. (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ, CABA (Argentina); Ibanez, Irene L. [CONICET, Av. Rivadavia 1917, C1033AAJ, CABA (Argentina); Garcia Bermudez, Gerardo [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA, Av. Gral. Paz 1499, 1650 San Martin, Bs. As. (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ, CABA (Argentina); Duran, Hebe [CONICET, Av. Rivadavia 1917, C1033AAJ, CABA (Argentina); Gerencia de Desarrollo Tecnologico y Proyectos Especiales, TANDAR-CNEA (Argentina); Grosso, Mariela F. del [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA, Av. Gral. Paz 1499, 1650 San Martin, Bs. As. (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ, CABA (Argentina); Salguero, Noelia [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA, Av. Gral. Paz 1499, 1650 San Martin, Bs. As. (Argentina); Mazzei, Ruben [U.A. Tecnologicas y Agropecuarias, CNEA (Argentina)

2012-02-15

Ion beam irradiation is a well known means to change the physico-chemical properties of polymers, and induced bio and citocompatibility in controlled conditions and in selected areas of surface. However, the enhancement of cell adhesion on a modified substrate does not mean that the surface is adequate for functional cells. The purpose of the present work is to study proliferation, changes in cytoskeleton and cell morphology on substrates as a function of irradiation parameters. We irradiated polypropylene with sulfur (S) ion-beam at energies of 110 MeV with fluences between 1 Multiplication-Sign 10{sup 6} and 2 Multiplication-Sign 10{sup 10} ions cm{sup -2}. NIH 3T3 cells were cultured on each sample. Cell morphology was observed using phase contrast microscopy and cytoskeleton proteins with fluorescence microscopy. The analysis show different cellular responses as a functions of irradiation parameter, strongly suggests that different underlying substratum can result in distinct types of cytoskeleton reorganization.

Importance of Ion Packing on the Dynamics of Ionic Liquids during Micropore Charging.

Science.gov (United States)

He, Yadong; Qiao, Rui; Vatamanu, Jenel; Borodin, Oleg; Bedrov, Dmitry; Huang, Jingsong; Sumpter, Bobby G

2016-01-07

Molecular simulations of the diffusion of EMIM(+) and TFSI(-) ions in slit-shaped micropores under conditions similar to those during charging show that in pores that accommodate only a single layer of ions, ions diffuse increasingly faster as the pore becomes charged (with diffusion coefficients even reaching ∼5 × 10(-9) m(2)/s), unless the pore becomes very highly charged. In pores wide enough to fit more than one layer of ions, ion diffusion is slower than in the bulk and changes modestly as the pore becomes charged. Analysis of these results revealed that the fast (or slow) diffusion of ions inside a micropore during charging is correlated most strongly with the dense (or loose) ion packing inside the pore. The molecular details of the ions and the precise width of the pores modify these trends weakly, except when the pore is so narrow that the ion conformation relaxation is strongly constrained by the pore walls.

Ion Concentration- and Voltage-Dependent Push and Pull Mechanisms of Potassium Channel Ion Conduction.

Directory of Open Access Journals (Sweden)

Kota Kasahara

Full Text Available The mechanism of ion conduction by potassium channels is one of the central issues in physiology. In particular, it is still unclear how the ion concentration and the membrane voltage drive ion conduction. We have investigated the dynamics of the ion conduction processes in the Kv1.2 pore domain, by molecular dynamics (MD simulations with several different voltages and ion concentrations. By focusing on the detailed ion movements through the pore including selectivity filter (SF and cavity, we found two major conduction mechanisms, called the III-IV-III and III-II-III mechanisms, and the balance between the ion concentration and the voltage determines the mechanism preference. In the III-IV-III mechanism, the outermost ion in the pore is pushed out by a new ion coming from the intracellular fluid, and four-ion states were transiently observed. In the III-II-III mechanism, the outermost ion is pulled out first, without pushing by incoming ions. Increases in the ion concentration and voltage accelerated ion conductions, but their mechanisms were different. The increase in the ion concentrations facilitated the III-IV-III conductions, while the higher voltages increased the III-II-III conductions, indicating that the pore domain of potassium channels permeates ions by using two different driving forces: a push by intracellular ions and a pull by voltage.

Strong charge state dependence of H+ and H2+ sputtering induced by slow highly charged ions

International Nuclear Information System (INIS)

Kakutani, N.; Azuma, T.; Yamazaki, Y.; Komaki, K.; Kuroki, K.

1995-01-01

Secondary ion emission has been studied for very slow ( similar 0.01ν B ) highly charged Ar and N ions bombarding C 60 containing hydrogen as an impurity. It is found that the fragmentations of C 60 are very rare even for Ar 16+ bombardments. On the other hand, the sputtering of H + and H 2 + has been observed to increase drastically as a function of incident charge q like q γ (e.g., γ similar 4.6 for H + sputtering by 500 eV Ar q+ ). (orig.)

Direct Observation of Strong Ion Coupling in Laser-Driven Shock-Compressed Targets

International Nuclear Information System (INIS)

Ravasio, A.; Benuzzi-Mounaix, A.; Loupias, B.; Ozaki, N.; Rabec le Gloahec, M.; Koenig, M.; Gregori, G.; Daligault, J.; Delserieys, A.; Riley, D.; Faenov, A. Ya.; Pikuz, T. A.

2007-01-01

In this Letter we report on a near collective x-ray scattering experiment on shock-compressed targets. A highly coupled Al plasma was generated and probed by spectrally resolving an x-ray source forward scattered by the sample. A significant reduction in the intensity of the elastic scatter was observed, which we attribute to the formation of an incipient long-range order. This speculation is confirmed by x-ray scattering calculations accounting for both electron degeneracy and strong coupling effects. Measurements from rear side visible diagnostics are consistent with the plasma parameters inferred from x-ray scattering data. These results give the experimental evidence of the strongly coupled ionic dynamics in dense plasmas

Importance of diffuse metal ion binding to RNA.

Science.gov (United States)

Tan, Zhi-Jie; Chen, Shi-Jie

2011-01-01

RNAs are highly charged polyanionic molecules. RNA structure and function are strongly correlated with the ionic condition of the solution. The primary focus of this article is on the role of diffusive ions in RNA folding. Due to the long-range nature of electrostatic interactions, the diffuse ions can contribute significantly to RNA structural stability and folding kinetics. We present an overview of the experimental findings as well as the theoretical developments on the diffuse ion effects in RNA folding. This review places heavy emphasis on the effect of magnesium ions. Magnesium ions play a highly efficient role in stabilizing RNA tertiary structures and promoting tertiary structural folding. The highly efficient role goes beyond the mean-field effect such as the ionic strength. In addition to the effects of specific ion binding and ion dehydration, ion-ion correlation for the diffuse ions can contribute to the efficient role of the multivalent ions such as the magnesium ions in RNA folding.

Fast-ion transport studies using FIDA spectroscopy at the ASDEX Upgrade tokamak

International Nuclear Information System (INIS)

Geiger, Benedikt

2013-01-01

A good confinement of fast-ions, i.e. ions with energies above the thermal energy, is essential for the success of fusion devices as it determines, amongst others, the plasma performance and the heating and current drive efficiencies. In case of a turbulent or magneto-hydrodynamic (MHD) active background plasma, various mechanisms have to be considered in order to estimate the spatial distribution of the fast-ions: the slowing down and radial diffusion by Coulomb collisions on electrons and ions, the effect of potential fluctuations and the effect of perturbations of the magnetic field structure. These can lead to a broadening of the fast-ion distribution function which is not yet completely understood. At the fusion experiment ASDEX Upgrade, the fast-ions are generated by heating sources such as neutral beam injection (NBI). Their transport properties can be studied by a fast-ion D-alpha (FIDA) spectroscopy diagnostic which has been built in the framework of this thesis. Through charge exchange reactions with neutrals, fast-ions can receive a bound electron and emit Balmer alpha line radiation. This so-called FIDA radiation can be measured with large Doppler shifts and is localized along the NBI path where a high density of neutrals is present. The FIDA diagnostic uses radially distributed lines of sight that intersect, in the horizontal and in the vertical plane, the path of a 2.5 MW NBI heating source. Thereby different parts of the fast-ion phase space above 25 keV can be analyzed. To interpret the FIDA radiation quantitatively, a forward modelling code has been implemented, tested and further developed. The code calculates, based on theoretical fast-ion distribution functions, synthetic FIDA spectra that can be compared to the measurement. In MHD-quiescent plasmas, the possible effect of turbulence on the fast-ion transport has been investigated with the FIDA diagnostic. The measurements obtained under different experimental conditions, such as during on- and

Ion track membranes providing heat pipe surfaces with capillary structures

International Nuclear Information System (INIS)

Akapiev, G.N.; Dmitriev, S.N.; Erler, B.; Shirkova, V.V.; Schulz, A.; Pietsch, H.

2003-01-01

The microgalvanic method for metal filling of etched ion tracks in organic foils is of particular interest for the fabrication of microsized structures. Microstructures like copper whiskers with a high aspect ratio produced in ion track membranes are suitable for the generation of high-performance heat transfer surfaces. A surface with good heat transfer characteristics is defined as a surface on which a small temperature difference causes a large heat transfer from the surface material to the liquid. It is well-known that a porous surface layer transfers to an evaporating liquid a given quantity of heat at a smaller temperature difference than does a usual smooth surface. Copper whiskers with high aspect ratio and a density 10 5 per cm 2 form such a porous structure, which produces strong capillary forces and therefore a maximum of heat transfer coefficients

Preparation of cold Mg{sup +}ion clouds for sympathetic cooling of highly charged ions at SPECTRAP

Energy Technology Data Exchange (ETDEWEB)

Cazan, Radu Mircea

2012-02-15

The bound electrons in hydrogen-like or lithium-like heavy ions experience extremely strong electric and magnetic fields in the surrounding of the nucleus. Laser spectroscopy of the ground-state hyperfine splitting in the lead region provides a sensitive tool to test strong-field quantum electro dynamics (QED), especially in the magnetic sector. Previous measurements on hydrogen-like systems performed in an electron-beam ion trap (EBIT) or at the experimental storage ring (ESR) were experimentally limited in accuracy due to statistics, the large Doppler broadening and the ion energy. The full potential of the QED test can only be exploited if measurements for hydrogen- and lithium-like ions are performed with accuracy improved by 2-3 orders of magnitude. Therefore, the new Penning trap setup SPECTRAP - dedicated for laser spectroscopy on trapped and cooled highly charged ions - is currently commissioned at GSI Darmstadt. Heavy highly charged ions will be delivered to this trap by the HITRAP facility in the future. SPECTRAP is a cylindrical Penning trap with axial access for external ion injection and radial optical access mounted inside a cold-bore superconducting Helmholtz-type split-coil magnet. To reach the targeted accuracy in laser spectroscopy, an efficient and fast cooling process for the highly charged ions must be employed. This can be realized by sympathetic cooling with a cloud of laser-cooled light ions. Within this thesis work, a laser system and an ion source for the production of such a {sup 24}Mg{sup +} ion cloud was developed and commissioned at SPECTRAP. An all-solid-state laser system for the generation of 279.6 nm light was designed and built. It consists of a fiber laser at 1118.5 nm followed by frequency quadrupling using two successive second-harmonic generation stages with actively stabilized ring resonators and nonlinear crystals. The laser system can deliver more than 15 mW of UV laser power under optimal conditions and requires little

Ionomers for Ion-Conducting Energy Materials

Science.gov (United States)

Colby, Ralph

For ionic actuators and battery separators, it is vital to utilize single-ion conducting ionomers that avoid the detrimental polarization of other ions. Single-ion conducting ionomers are synthesized based on DFT calculations, with low glass transition temperatures (facile dynamics) to prepare ion-conducting membranes for battery separators that conduct Li+ or Na+. Characterization by X-ray scattering, dielectric spectroscopy, FTIR, NMR and linear viscoelasticity collectively develop a coherent picture of ionic aggregation and both counterion and polymer dynamics. 7Li NMR diffusion measurements find that diffusion is faster than expected by conductivity using the Nernst-Einstein equation, which means that the majority of Li diffusion occurs by ion pairs moving with the polymer segmental motion. Segmental motion only contributes to ionic conduction in the rare event that one of these ion pairs has an extra Li (a positive triple ion). This leads us to a new metric for ion-conducting soft materials, the product of the cation number density p0 and their diffusion coefficient D; p0D is the diffusive flux of lithium ions. This new metric has a maximum at intermediate ion content that corresponds to the overlap of ion pair polarizability volumes. At higher ion contents, the ion pairs interact strongly and form larger aggregation states that retard segmental motion of both mobile ion pairs and triple ions.

Equilibrium and stability in strongly inhomogeneous plasmas

International Nuclear Information System (INIS)

Mynick, H.E.

1978-10-01

The equilibrium of strongly inhomogeneous, collisionless, slab plasmas, is studied using a generalized version of a formalism previously developed, which permits the generation of self-consistent equilibria, for plasmas with arbitrary magnetic shear, and variation of magnetic field strength. A systematic procedure is developed for deriving the form of the guiding-center Hamiltonian K, for finite eta, in an axisymmetric geometry. In the process of obtaining K, an expression for the first adiabatic invariant (the gyroaction) is obtained, which generalizes the usual expression 1/2 mv/sub perpendicular/ 2 /Ω/sub c/ (Ω/sub c/ = eB/mc), to finite eta and magnetic shear. A formalism is developed for the study of the stability of strongly-inhomogeneous, magnetized slab plasmas; it is then applied to the ion-drift-cyclotron instability

Ion cyclotron emission due to collective instability of fusion products and beam ions in TFTR and JET