Effects of neutral salt and alkali on ion distributions in the roots,shoots,and leaves of two alfalfa cultivars with differing degrees of salt tolerance

The effects of neutral salt and alkali on the ion distribution were investigated in two alfalfa （Medicago sativa L.） cultivars, including Zhongmu 1, a high salt-tolerant cultivar, and Algonquin, a low salt-tolerant cultivar. The alkali stress expressed more serious growth inhibition than the neutral salt stress at the same Na＋ concentration. Compared with Algonquin, Zhongmu 1 did not exhibit a higher alkali tolerance under the Na2CO3-NaHCO3 treatment with the low Na＋ concentration （50 mmol L-l）. The alkali increased the accumulation of Na＋, Ca2＋, and Mg2＋ in the root and changed the Ca2＋ and Mg2＋ balance in the entire alfalfa plant. The salt and alkali stresses decreased the K＋ and Fe3＋ contents of the roots and leaves, the root Mn2＋ content, and the shoot Zn2＋ content, but they increased the Fe3＋ accumulation of the shoots, the shoot and leaf Cu2＋ contents, and the leaf Zn2＋ content in both alfalfa cultivars. Based on the results obtained under the conditions of this experiment, we found that the salt and alkali stresses reduced the plant growth in both alfalfa cultivars, while the alkali caused a stronger stress than the neutral salt in alfalfa. Thus, we conclude that under hydroponic conditions, the deleterious effects of the alkali on plants are due to the distribution change of some trophic ion balance in the roots, shoots, and leaves of the plants by causing of Na＋, CO3^2-, and/or HCO3- stresses.

Proton pitch angle distributions in the Martian induced magnetosphere: A survey of Tianwen-1 Mars Ion and Neutral Particle Analyzer observations

The pitch angle distributions of ions and electrons can be affected by various processes;thus,they can serve as an important indicator of the physical mechanisms driving the dynamics of space plasmas.From observations from the Mars Ion and Neutral Particle Analyzer onboard the Tianwen-1 orbiter,we calculated the pitch angle distributions of protons in the Martian induced magnetosphere by using information from the magnetohydrodynamically simulated magnetic field,and we statistically analyzed the spatial occurrence pattern of different types of pitch angle distributions.Even though no symmetrical features were seen in the dataset,we found the dominance of the field-aligned distribution type over the energy range from 188 to 6232 eV.Maps of the occurrence rate showed the preferential presence of a trapped-like distribution at the lower altitudes of the surveyed nightside region.Although our results are more or less restricted by the adopted magnetic field,they indicate the complexity of the near-Mars proton pitch angle distributions and infer the possibility of wave–particle interactions in the Martian induced magnetosphere.

Effects of power on ion behaviors in radio-frequency magnetron sputtering of indium tin oxide(ITO)

This study delves into ion behavior at the substrate position within RF magnetron discharges utilizing an indium tin oxide(ITO)target.The positive ion energies exhibit an upward trajectory with increasing RF power,attributed to heightened plasma potential and initial emergent energy.Simultaneously,the positive ion flux escalates owing to amplified sputtering rates and electron density.Conversely,negative ions exhibit broad ion energy distribution functions(IEDFs)characterized by multiple peaks.These patterns are clarified by a combination of radiofrequency oscillation of cathode voltage and plasma potential,alongside ion transport time.This elucidation finds validation in a one-dimensional model encompassing the initial ion energy.At higher RF power,negative ions surpassing 100 e V escalate in both flux and energy,posing a potential risk of sputtering damages to ITO layers.

Unified Hydrodynamics and Pseudorapidity Distributions of Charged Particles Produced in Heavy Ion Collisions at Low Energies at RHIC

In the context of unified hydrodynamics, we discuss the pseudorapidity distributions of the charged particles produced in Au-Au and Cu-Cu collisions at the low RHIC energies of √SNN = 19.6 and 22.4 GeV, respectively. It is found that the unified hydrodynamics alone can give a good description to the experimental measurements. This is different from the collisions at the maximum RHIC energy of √SNN = 200 GeV or at LHC energy of √SNN= 2.76 TeV, in which the leading particles must be taken into account so that we can properly explain the experimental observations.

Ion Density Distribution in an Inductively Coupled Plasma Chamber

The ion density distribution in the reaction chamber was diagnosed by a Langmuir probe. The rules of the ion density distribution were obtained under the pressures of 9 Pa, 13 Pa, 27 Pa and 53 Pa in the reaction chamber, different radio-frequency powers and different positions. The result indicates that the ion density decreases as the pressure increases, and increases as the power decreases. The ion density of axial position z =0 achieves 5.8×1010 on the center of coil under the power of 200 w and pressure of 9 Pa in the reaction chamber.

Simulation Studies of Rib Structure Effect on Discharge Characteristics of Plasma Display Panel

To investigate the effect of the rib structure on the discharge characteristics of the plasma display panel, the potential distribution, particles density distribution and ions incident angle distribution were examined by simulation of a two-dimensional particle-in-cell/Monte Carlo collision, with two kinds of rib structure： the stripe rib structure and the Waffle rib structure. The results showed that the distribution of electric potential at the corner of the discharge cell was almost the same for these two rib structures while in the centre there was a difference between these two rib structures. The striation phenomenon could be observed in both cases. The distribution of density also indicated that the striation phenomenon was accompanied by the firing of discharge, and the Waffle rib structure might reduce the density humps. In the cell with a stripe rib structure, the profiles of the surface charge density along the sustained dielectric layer presented a better fluctuating distribution than that in the cell with a Waffle rib structure. The spatial potential and particle density in the discharge bulk showed that the Waffle ribs could weaken the striation phenomenon, which could be explained by the decrease in the particle numbers in the discharge cell. The simulation results of the ion incident angle showed that most ions impacted the sustained dielectric layer in the normal stripe rib cell with an incident angle in the range of 6° to 19° while with the Waffle rib structure the incident angle of most ions was in the range of 4° to 19°. The Waffle rib structure did not affect the angle distribution of incident ions significantly.

Synthesis and Adsorption Properties of Chelating Resins Containing Sulfoxide and Heterocyclic Functional Groups

Several of new chelating resins containing sulfoxide and heterocyclic functional groups （3-aminopyridine and 2-mercaptobenzothiazole） based on macroporous chloromethylated polystyrene were synthesized and characterized by elemental analysis and infrared spectra. Their adsorption capacities towards Zn^2＋, Cu^2＋, Pb^2＋, Hg^2＋ and Ag^＋ at pH 3.0 and 6.0 were investigated in detail. It was found that the adsorption capacities of the resins containing bis[（3-pyridylaminoethyl）sulfoxide or （2-benzothiazolylthioethyl）sulfoxide for the above ions were higher than that on ones containing single above-mentioned groups.

Reconstruction of Ionization Density Distribution in Hall Thruster Channel from Ion Energy Spectrum of Plasma Jet

Propellant ionization in the Hall thruster discharge channel is a significant process and has strong influence on the thruster＇s efficiency. In this work, the functional relation has been established between the ionization density distribution and the function of the ion energy distribution through the basic equations governing the ion flow in the Hall thruster channel and the method achieved for reconstructing the ionization density distribution inside the channel by ordinary plasma diagnosis of the potential distribution and ion energy spectrum of the plasma jet. The ionization density distributions of single and double charged ions in an ATON-thruster channel have been reconstructed according to the experimental data of the potential distribution along the axis of the channel and the ion energy spectrum of the plasma jet. The agreement between the calculation and experimental results of the percentage of double charged ions proves the validity of our method achieved in this work.

Phase shift effects of radio-frequency bias on ion energy distribution in continuous wave and pulse modulated inductively coupled plasmas

A retarding field energy analyzer（RFEA） is used to measure the time-averaged ion energy distributions（IEDs） on the substrate in both continuous wave（CW） and synchronous pulse modulated radio-frequency（RF） inductively coupled Ar plasmas（ICPs）.The effects of the phase shift θ between the RF bias voltage and the RF source on the IED is investigated under various discharge conditions.It is found that as θ increases from 0 to π,the IED moves towards the low-energy side,and its energy width becomes narrower.In order to figure out the physical mechanism,the voltage waveforms on the substrate are also measured.The results show that as θ increases from 0 to π,the amplitude of the voltage waveform decreases and,meanwhile,the average sheath potential decreases as well.Specifically,the potential drop in the sheath on the substrate exhibits a maximum value at the same phase（i.e.,θ = 0） and a minimum value at the opposite phase（i.e.,θ = π）.Therefore,when ions traverse across the sheath region above the substrate,they obtain less energies at lower sheath potential drop,leading to lower ion energy.Besides,as θ increases from π to 2π,the IEDs and their energy widths change reversely.

The far-field plasma characterization in a 600W Hall thruster plume by laser-induced fluorescence

Non-intrusive characterization of the singly ionized xenon velocity in Hall thruster plume using laser induced fluorescence(LIF)is critical for constructing a complete picture of plume plasma,deeply understanding the ion dynamics in the plume,and providing validation data for numerical simulation.This work presents LIF measurements of singly ionized xenon axial velocity on a grid ranging from 100 to 300 mm in axial direction and from 0 to 50 mm in radial direction for a600 W Hall thruster operating at the nominal condition of discharge voltage 300 V and discharge current 2 A,the influence of discharge voltage is investigated as well.The ion velocity distribution function(IVDF)results in the far-field plume demonstrate a profile of bimodal IVDFs,especially prominent at radial distances greater than channel inner radius of 22 mm at axial position of 100 mm,which is quite different from that of the near-field plume where bimodal IVDFs occur in the central core region for the same power Hall thruster when compared to previous LIF measurements of BHT-600 by Hargus(2010 J.Propulsion Power 26135).Beyond 100 mm,only single-peak IVDFs are measured.The two-dimensional ion velocity vector field indicates the bimodal axial IVDF is merely a geometry effect for the annular discharge channel in the far-field plume.Results about the IVDF,the most probable velocity and the accelerating potential profile along the centerline all indicate that ions are still accelerating at axial distances greater than 100 mm,and the maximum most probable velocity measured at300 mm downstream of the exit plane is about 19 km s-1.In addition,the most probable velocity of ions along radial direction changes a little except the lower velocity ion populations in the bimodal IVDF cases.The ion temperature at axial distances of 10 and 300 mm oscillates along the radial direction,while the ion temperature first increases,and then decreases for the 200 mm case.Finally,the axial position for the ion peak axial velocity on the thruster centerline is shifted upstream for higher discharge voltages,and the velocity curve is becoming steeper with the discharge voltage before reaching the maximum.This observation can be used as a criterion to optimize the thruster performance.

Diagnostics of electron temperature and ions distribution in expanding Al plasmas pumped by a ns-pulsed 1.06μm laser

Resonance lines are extensively used to diagnose electronic temperature Te and ions distribution. However, the analysis of the x-ray spectroscopy emitted from plasmas produced by a ns laser Jsually needs the help of a code or some assumptions. In this paper, a diagnostic idea of using line-pairs emitted from a doubly-excited state is proposed. By using the method presented in this paper, Te and the fractional population ratio of bare nuclei and H-like ions are directly obtained from the emission intensity ratios.

Effects of Salt Stress on Growth and Ion Distribution in Seedlings of Asparagus officinalis L.

An Asparagus officinalis L. cultivar NJ978 was used to study the growing rate, salt ion content and mineral ion uptake and distribution in plants under salt stress. The results showed that salt stress significantly inhibited seedling growth and there was a negative relationship between seedling growth and salt concentration. The seedlings growth showed no significant decrease under low salt stress （NaCl≤50 mmol/L）, while high concentrations of NaCl led to detrimental effects on the growth of A. officinalis L.. With the increase of NaCl concentration, the Na ＋ content increased gradually in A. officinalis L. roots, stems and leaves while the K^＋ and Ca^2＋ contents had slow decreases. Under low salt stress, the seedlings of A. officinalis L. could prevent Na ＋ from transporting to aerial part by withholding Na ＋ in root, which could keep the balance of ions in aerial part, but under high salt stress （NaCl 〉 100 mmol/L）, the aerial part of seedlings accumulated superabundance of Na ＋, which limited the uptake of K^＋ and Ca^2＋ , so seedlings were damaged heavily, which manifested as the gradual decrease of K^＋/Na ＋ and Ca^2＋ /Na ＋ in the roots and aerial part of the seedlings. The selective absorption of K^＋, Ca^2＋ and Na ＋ （AS K,Na and AS Ca,Na ） was significantly increased with increased salinity, while the selective transportation （TS K,Na and TS Ca,Na ） increased at first and then decreased with the increased salinity. Therefore, the strong ability of salt exclusion and the regionalized distribution of ions in roots, stems and leaves could be one of the salt tolerance mechanisms of A. officinalis L.

Evidence of potential change in nonsequential double ionization

Recently,the quantitative rescattering model(QRS)for nonsequential double ionization(NSDI)is modified by taking into account the potential change(PC)due to the presence of electric field at the time of recollision.Using the improved QRS model,we simulate the longitudinal momentum distributions of doubly charged ions He2+by projecting the correlated two-electron momentum distributions for NSDI of He onto the main diagonal.The obtained results are compared directly with the experimental data at different intensities.It is found that when the PC is considered,the width of momentum distributions reduces and the agreement between theory and experiment is improved.

Seasonal variations and size distributions of water-soluble ions in atmospheric aerosols in Beijing, 2012

The characteristics of water-soluble ions in airborne particulate matter in Beijing were investigated using ion chromatography. The results showed that the total concentrations of ions were 83.7 ± 48.9 μg/m3 in spring, 54.0 ± 17.0 μg/m3 in summer, 54.1 ± 42.9 μg/m3 in autumn, and 88.8 ± 47.7 μg/m3 in winter, respectively. Furthermore, out of all the ions, NO3-,SO42-and NH4＋accounted for 81.2% in spring, 78.5% in summer, 74.6% in autumn, and 76.3%in winter. Mg2＋and Ca2＋were mainly associated with coarse particles, with a peak that ranged from 5.8 to 9.0 μm. Na＋, NH4＋and Cl-had a multi-mode distribution with peaks that ranged from 0.43 to 1.1 μm and 4.7 to 9.0 μm. K＋, NO3-, and SO42-were mainly associated with fine particles, with a peak that ranged from 0.65 to 2.1 μm. The concentrations of Na＋, K＋,Mg2＋, Ca2＋, NH4＋, Cl-, NO3-and SO42-were 2.69, 2.32, 1.01, 4.84, 16.9, 11.8, 42.0, and 44.1 μg/m3 in particulate matter（PM） on foggy days, respectively, which were 1.4 to 7.3 times higher than those on clear days. The concentrations of these ions were 2.40, 1.66, 0.92, 4.95, 17.5,7.00, 32.6, and 34.7 μg/m3 in PM on hazy days, respectively, which were 1.2–5.7 times higher than those on clear days.

Effect of Frequency and Power of Bias Applied to Substrate on Plasma Property of Very-High-Frequency Magnetron Sputtering

The effect of the frequency and power of the bias applied to the substrate on plasma properties in 60 MHz（VHF） magnetron sputtering was investigated.The plasma properties include the ion velocity distribution function（IVDF）,electron energy probability function（EEPF）,electron density ne,ion flux Γi,and effective electron temperature Teff.These parameters were measured by a retarding field energy analyzer and a Langmuir probe in the 60 MHz magnetron sputtering,assisted with 13.56 MHz or 27.12 MHz substrate bias.The 13.56 MHz substrate bias led to broadening and multi-peaks IVDFs,Maxwellian EEPFs,as well as high electron density,ion flux,and low electron temperature.The 27.12 MHz substrate bias led to a further increase of electron density and ion flux,but made the IVDFs narrow.Therefore,the frequency of the substrate bias was a possible way to control the plasma properties in VHF magnetron sputtering.

Grinding Characteristics of Multi-component Cement-based Material

The grinding characteristics of two or multi-component material of cli nker with limestone, blast furnace slag and fly ash were studied. Investigation was carried out on the particle size distribution, the Blaine fineness and the s ieve residue of the separate and interground products. The relative contents of clinker and limestone in different size fractions of the interground product wer e examined, and the interaction of two components, which have different grindabi lities, was analyzed. The results show there exists a selective grinding effect during intergrinding, one component can help or hinder the grinding of the other . Making good use of this interaction appropriately not only enhances the grinda bilities of two or multi-component mixtures, which can promote the grinding pro cess of clinker with industrial wastes, but also improves their particle size di stribution and properties.

Effect of cerium ions initial distribution on the crystalline structure and catalytic performance of CeY zeolite

Ce Y samples with different cerium（Ce） ions initial distribution were prepared by diverse preparation processes. The correlative influence of Ce ions distribution on the intracrystalline structure and catalytic mechanism of Y-type zeolite was studied by X-ray diffraction（XRD）, Rietveld refinement, X-ray fluorescence spectrometry（XRF）, energy-dispersive X-ray spectroscopy（EDS）, infrared（IR） spectra, NH3 temperature-programmed desorption（NH3-TPD）, N2 physical adsorption-desorption and micro-activity test（MAT）. The results indicated that Ce ions were concentrated on the surface（supercage） of Ce Y zeolite would reduce the number of acid sites and the ratio of Br？nsted acid and Lewis acid（B/L）. Once Ce ions concentrated in the sodalite cage, it would participate in the coordination with framework oxygen atoms under the condition of steric hindrance. Meanwhile, Ce ions would preferentially promote the B/L value of weak acid by retaining more intracrystalline framework Al atoms in sodalite cage, which was beneficial to the conversion of heavy oil in FCC process. The optimal initial-distribution of Ce ions could not only save the consumption of rare earth resources but also give the best catalytic performance of Ce Y zeolite catalysts, and these advantages and attributes enabled it to have the potential to be applied in industrial applications.

Effect of Salt Stress on Transpiration and Ion Distribution in Seedlings of Four Tree Species

Transpiration rate and ion distribution of pagoda tree, walnut, velvet ash and poplar seedlings treated by NaCl solution of 0, 50, 100, 200 mmol·L-1 were studied. The results showed that there were significant differences in the response to NaCl among the four tree species. Na+ exclusion capacity of pagoda tree was the largest among the four species. The Na+ exclusion capacity of velvet ash was less than that of pagoda tree. Salt excretion capacity of velvet ash was limited. Its salt-tolerance was bigge...

Characteristics of the water-soluble components of aerosol particles in Hefei,China

Size-classified daily aerosol mass concentrations and concentrations of water-soluble inorganic ions were measured in Hefei,China,in four representative months between September 2012 and August 2013.An annual average mass concentration of 169.09μg/m^3 for total suspended particulate（TSP）was measured using an Andersen Mark-II cascade impactor.The seasonal average mass concentration was highest in winter（234.73μg/m^3）and lowest in summer（91.71μg/m^3）.Water-soluble ions accounted for 59.49%,32.90%,48.62%and 37.08%of the aerosol mass concentration in winter,spring,summer,and fall,respectively,which indicated that ionic species were the primary constituents of the atmospheric aerosols.The four most abundant ions were NO3^-,SO4^2-,Ca^2＋ and NH4^＋.With the exception of Ca^2＋,the mass concentrations of water-soluble ions were in an intermediate range compared with the levels for other Chinese cities.Sulfate,nitrate,and ammonium were the dominant fine-particle species,which were bimodally distributed in spring,summer and fall;however,the size distribution became unimodal in winter,with a peak at 1.1–2.1μm.The Ca^2＋ peak occurred at approximately 4.7–5.8μm in all seasons.The cation to anion ratio was close to 1.4,which suggested that the aerosol particles were alkalescent in Hefei.The average NO3^-/SO4^2-mass ratio was 1.10 in Hefei,which indicated that mobile source emissions were predominant.Significant positive correlation coefficients between the concentrations of NH4^＋ and SO4^2-,NH4^＋ and NO3^-,SO4^2-and NO3^-,and Mg^2＋ and Ca^2＋ were also indicated,suggesting that aerosol particles may be present as（NH4）2SO4,NH4HSO4,and NH4NO3.

Raman imaging-assisted customizable assembly of MOFs on cellulose aerogel

Because of a weak interface-bonding force between metal–organic frameworks(MOFs)and substrates and the loss of customization in structural designs owing to the lack of the regulation of ion sites,MOFs tend to escape from the constructed composite template.In this study,the as-prepared 2,2,6,6-tetramethylpiperidyl-1-oxyl(TEMPO)-oxidized algae cellulose nanofibers(TACFs)were used to chelate metal ions at controllable sites and subsequently firmly entangle the assembled MOF crystals.The distribution of ions and synthesized MOFs inside the gel was monitored using Raman imaging technology,which provided an intuitive approach for visually observing the ions and MOF distribution.Using this technology,the synthesized customizable TACFs@ZIF-67 aerogels exhibited a high specific surface area(734.7 m^(2)/g),low density(6.18 mg/cm^(3)),controlled particle distribution,good underwater structural stability,and excellent adsorption of dyes.This study provides a way for solving the dispersion problem of MOFs in nanofibrous aerogels using Raman imaging technology–assisted microcosmic fixed-point design.