Reduction Of Nd Research Articles

Electrodeposition of neodymium from betaine-ethylene glycol deep eutectic solvent using neodymium oxide as a precursor

The electrodeposition of neodymium was investigated in betaine-ethylene glycol (Bet-EG) deep eutectic solvent (DES) containing neodymium oxide (Nd2O3) at different temperatures ranging from 353 K to 373 K. The electrochemical behavior of Nd2O3 dissolved in Bet-EG DES was researched by cyclic voltammetry, potentiodynamic polarization and chronoamperometry methods. Cyclic voltammograms (CVs) manifest that Nd(III) reduction in Bet-EG is an irreversible process with diffusion-controlled, and the reduction overpotential of Nd(III) decreases with the increase of the temperature. The temperature has an impact on the diffusion coefficient of Nd(III) species, obeying the Arrhenius equation. The activation energy is estimated to be 36.78 kJ mol−1. The cathodic polarization analysis shows that the rise of temperature promotes the reduction of Nd(III). The UV–Vis and ESI-MS analyses show that [Nd2(bet)8(H2O)4]6+ complex anions are formed as Nd2O3 is dissolved in Bet-EG DES. Electrodeposited neodymium with various morphologies were characterized and analyzed by EDX, XPS, XRD and SEM. It is found that the electrodeposition temperature has a great effect on the morphology of Nd electrodeposits. Depending on the deposition temperature, metallic Nd with submicron particles or porous structures were obtained.

Impact of Cloud Condensation Nuclei Reduction on Cloud Characteristics and Solar Radiation during COVID-19 Lockdown 2020 in Moscow

We used MODIS observations to retrieve number concentration of cloud droplets (Nd) at cloud lower boundary during spring 2018–2020 for the Moscow region. Looking through the similar synoptic situations of the northern clear air advection, we obtained Nd within the limits of 200–300 cm−3. During the lockdown period, with similar northern advection conditions, the reduction of Nd on 40–50 cm−3 (or 14–16%), with the increase in droplet effective radius by 8 ± 1% and cloud optical thickness reduction by 5 ± 2%, was observed in contrast to the values in typical conditions in 2018–2019. We used these values for setting up corresponding parameters in numerical simulations with the COSMO-Ru model. According to the numerical experiments, we showed that the observed reduction in cloud droplet concentration by 50 cm−3 provides a 5–9 W/m2 (or 9–11%) increase in global irradiance at ground in overcast cloud conditions with LWP = 200–400 g/m2.

Solid-State End-On to Side-On Isomerization of (N═N)2- in {[(R2N)3Nd]2N2}2- (R = SiMe3) Connects In Situ LnIII(NR2)3/K and Isolated [LnII(NR2)3]1- Dinitrogen Reduction.

Examination of the reduction chemistry of Nd(NR2)3 (R = SiMe3) under N2 has provided connections between the in situ Ln(III)-based LnIII(NR2)3/K reductions of N2 that form side-on bound neutral (N=N)2- complexes, [(R2N)2(THF)Ln]2[μ-η2:η2-N2], and the Ln(II)-based [LnII(NR2)3]1- reductions by Sc, Gd, and Tb that form end-on bound (N=N)2- complexes, {[(R2N)3Ln]2[μ-η1:η1-N2]}2-, which are dianions. The reduction of Nd(NR2)3 by KC8 under dinitrogen in Et2O in the presence of 18-crown-6 (18-c-6) forms dark yellow solutions of [K2(18-c-6)3]{[(R2N)3Nd]2N2} at low temperatures that become green as they warm up to -35 °C in a glovebox freezer. Green crystals obtained from the solution turn yellow-brown when cooled below -100 °C, and the yellow-brown compound has an end-on Nd2(μ-η1:η1-N2) structure. The yellow-brown crystals isomerize in the solid state on the diffractometer upon warming, and at -25 °C, the crystals are green and have a side-on Nd2(μ-η2:η2-N2) structure. Collection of X-ray diffraction data at 10 °C intervals from -50 to -90 °C revealed that the isomerization occurs at temperatures below -100 °C. In the presence of tetrahydrofuran (THF), the dianionic {[(R2N)3Nd]2N2}2- system can lose an amide ligand to provide the monoanionic [(R2N)3NdIII(μ-η2:η2-N2)NdIII(NR2)2(THF)]1-, characterized by X-ray crystallography. These data suggest a connection between the in situ Ln(III)/K reductions and Ln(II) reductions that depends on solvent, temperature, the presence of a chelate, and the specific rare-earth metal.

Electroextraction of neodymium from LiCl-KCl melt using binary liquid Ga–Al cathode

The electrochemical behaviour of Nd(III) ion was investigated on inert W, active Ga and Ga–Al cathodes. It is established that the reduction of Nd(III) ion on the inert electrode is a consecutive two-step process while that on the active electrodes is a one-step process. The apparent standard potential of the Nd(III)/Nd redox couple at different temperatures was determined by open-circuit chronopotentiometry and semi-differential method, and the relationship between temperature and apparent standard potential was further discussed. The thermodynamic properties of Nd in Ga and Ga–Al electrodes such as activity coefficient and activity were evaluated via intermittent coulomb titration and temperature dependence test, and the effect of temperature on activity coefficient was verified. Finally, Nd was successfully extracted in form of alloy from molten salt by galvanostatic electrolysis, in which the current efficiency of 91.7% for the electroextraction indicates that the binary liquid Ga–Al electrode has favorable performance.

Electrochemical extraction kinetics of Nd on reactive electrodes

• Pyroprocessing technology is a promising technology for the reprocessing of spent fuel. • It is critical to pursue electrode materials with high An / Ln separation efficiency. • The electrochemical reduction of Nd 3+ on the W electrode is a two-step reduction process. • The kinetic properties of Nd 3+ on W, reactive electrodes were measured. • Cd was evaluated as a favorable electrode material for electrochemical extract ion of Nd. Pyroprocessing technology with molten salt electrolysis as the core is a promising technology for the reprocessing of spent fuel. In this work, the electrochemical reduction mechanism and kinetic properties of Nd 3+ on various electrodes (inert W and reactive Al, Ga, Bi, Cd, Zn, Pb, and Sn electrodes) were systematically investigated and compared in LiCl-KCl eutectic melts using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel techniques. The electrochemical reduction of Nd 3+ was a two-step process on the W electrode including Nd 3+ →Nd 2+ and Nd 2+ →Nd, while it became a one-step process involving three electrons on the reactive electrodes with obvious depolarization effects. Furthermore, the connections between the reduction potentials of Nd 3+ on these reactive cathodes and the formation energies of the electrode-rich alloy phases (Al 11 Nd 3 , Cd 11 Nd, Pb 3 Nd, Zn 17 Nd 2 , Ga 6 Nd, Sn 3 Nd, BiNd 2 ) were established. After evaluating the physicochemical, depolarization and kinetic properties of these reactive electrodes, liquid Cd was considered as the most favorable material for the electrochemical extraction of Nd. In addition, Al, Cd, and Bi are also promising candidates for An / Ln separation.

Electrochemical Study of Nd and Pr Co-Deposition onto Mo and W from Molten Oxyfluorides

Electrodeposition processes of neodymium and praseodymium in molten NdF3 + PrF3 + LiF + 1 wt.%Pr6O11 + 1 wt.%Nd2O3 and NdF3 + PrF3 + LiF + 2 wt.%Pr6O11 + 2 wt.%Nd2O3 electrolytes at 1323 K were investigated. Cyclic voltammetry, square wave voltammetry, and open circuit potentiometry were applied to study the electrochemical reduction of Nd(III) and Pr(III) ions on Mo and W cathodes. It was established that a critical condition for Nd and Pr co-deposition in oxyfluoride electrolytes was a constant praseodymium deposition overpotential of ≈−0.100 V, which was shown to result in co-deposition current densities approaching 6 mAcm−2. Analysis of the results obtained by applied electrochemical techniques showed that praseodymium deposition proceeds as a one-step process involving exchange of three electrons (Pr(III)→Pr(0)) and that neodymium deposition is a two-step process: the first involves one electron exchange (Nd(III)→Nd(II)), and the second involves an exchange of two electrons (Nd(II)→Nd(0)). X-ray diffraction analyses confirmed the formation of metallic Nd and Pr on the working substrate. Keeping the anodic potential to the glassy carbon working anode low results in very low levels of carbon oxides, fluorine and fluorocarbon gas emissions, which should qualify the studied system as an environmentally friendly option for rare earth metal deposition. The newly reported data for Nd and Pr metals co-deposition provide valuable information for the recycling of neodymium-iron-boron magnets.

Physicochemical properties of DMI–LiNO3 solvated ionic liquid and its application in electrodeposition of neodymium at room temperature

The density, conductivity, and viscosity of the 1,3-dimethyl-2-imidazolinone and lithium nitrate (DMI– LiNO3) solvated ionic liquid were measured as a function of temperature. Additionally, the electrochemical mechanism and electrodeposition of neodymium from the DMI–LiNO3 solvated ionic liquid were investigated. Cyclic voltammetry results indicate that the electrochemical reduction of Nd(III) is irreversible and proceeds via one-step with three-electron transfer, which is controlled by diffusion with a diffusion coefficient of 5.08×10−8 cm2/s. Energy- dispersive X-ray spectrometry and X-ray photoelectron spectroscopy data confirm that the electrodeposit obtained after electrodeposition at −4 V (vs Ag) using the DMI–LiNO3–Nd(CF3SO3)3 solvated ionic liquid contains metallic neodymium.

Evaluation of the contribution of new particle formation to cloud droplet in urban atmosphere

Abstract. New particle formation (NPF) is a large source of cloud condensation nuclei (CCN) and cloud droplet in the troposphere. In this study, we quantified the contribution of NPF to cloud droplet number concentration (CDNC, or Nd) at typical updraft velocities (V) in clouds using a field campaign data of aerosol number size distribution and chemical composition observed on May 25–June 18, 2017 in urban Beijing. We show that the NPF drives the variations of CCN and cloud droplet and increases Nd by 30–33 % at V = 0.3–3 m s−1 in urban atmosphere. A markedly reduction in Nd is observed due to water vapor competition with consideration of actual environmental updraft velocity, decreasing by 11.8 ± 5.0 % at V = 3 m s−1 and 19.0 ± 4.5 % at V = 0.3 m s−1 compared to that from a prescribed supersaturation. The effect of water vapor competition becomes smaller at larger V that can provide more sufficient water vapor. Essentially, water vapor competition led to the reduction in Nd by decreasing the environmental maximum supersaturation (Smax) for the activation of aerosol particles. It is shown that Smax was decreased by 14.5–11.7 % for V = 0.3–3 m s−1. Particularly, the largest suppression of cloud droplet formation due to the water vapor competition is presented at extremely high aerosol particle number concentrations. As a result, although a larger increase of CCN-size particles by NPF event is derived on clean NPF day when pre-existing background aerosol particles are very low, there is no large discrepancy in the enhancement of Nd by NPF between the clean and polluted NPF day. We finally show a considerable impact of the primary sources when evaluating the NPF contribution to cloud droplet based on a case study. Our study highlights the importance of fully consideration of both the environmental meteorological conditions and multiple sources (i.e. secondary and primary) to evaluate the NPF effect on clouds and the associated climate effects in polluted regions.

Decreased neurite density within frontostriatal networks is associated with executive dysfunction in temporal lobe epilepsy

ObjectiveExecutive dysfunction is observed in a sizable number of patients with refractory temporal lobe epilepsy (TLE). The frontostriatal network has been proposed to play a significant role in executive functioning, however, because of the complex architecture of these tracts, it is difficult to generate measures of fiber tract microstructure using standard diffusion tensor imaging. To examine the association between frontostriatal network compromise and executive dysfunction in TLE, we applied an advanced, multishell diffusion model, restriction spectrum imaging (RSI), that isolates measures of intraaxonal diffusion and may provide better estimates of fiber tract compromise in TLE. MethodsRestriction spectrum imaging scans were obtained from 32 patients with TLE [16 right TLE (RTLE); 16 left TLE (LTLE)] and 24 healthy controls (HC). An RSI-derived measure of intraaxonal anisotropic diffusion (neurite density; ND) was calculated for the inferior frontostriatal tract (IFS) and superior frontostriatal tract (SFS) and compared between patients with TLE and HC. Spearman correlations were performed to evaluate the relationships between ND of each tract and verbal (i.e., D-KEFS Category Switching Accuracy and Color–Word Interference Inhibition/Switching) and visuomotor (Trail Making Test) set-shifting performances in patients with TLE. ResultsPatients with TLE demonstrated reductions in ND of the left and right IFS, but not SFS, compared with HC. Reduction in ND of left and right IFS was associated with poorer performance on verbal set-shifting in TLE. Increases in extracellular diffusion (isotropic hindered; IH) were not associated with executive dysfunction in the patient group. SignificanceRestriction spectrum imaging-derived ND revealed microstructural changes within the IFS in patients with TLE, which was associated with poorer executive functioning. This suggests that axonal/myelin loss to fiber networks connecting the striatum to the inferior frontal cortex is likely contributing to executive dysfunction in TLE.

Electrochemical Behavior of Neodymium and Formation of Mg–Nd Alloys in Molten Chlorides

The electrochemical behavior of Nd(III) and its coreduction with Mg(II) were investigated on a molybdenum electrode at 1023 K in eutectic NaCl–KCl melts. The results indicate that the reduction of NdCl3 in NaCl–KCl melts is a one-step process with three electrons exchanged, and the reaction is an irreversible diffusion-controlled process at low scan rate with the calculated diffusion coefficient of about 6.8 × 10–5 cm2 s–1. After MgCl2 is introduced to the melts, the reduction of Nd(III) takes place at a more positive potential value due to the formation of Mg–Nd intermetallic compounds through electrochemical co-deposition and chemical reduction of Nd(III) ions by preferentially deposited Mg. The solid intermetallic compounds of Mg3Nd, Mg2Nd, and MgNd observed in open circuit chronopotentiometry curves are transformed to thermodynamically more stable Mg-rich phases of Mg12Nd and Mg41Nd5 when potentiostatic electrolysis at −2.10 V. It has been confirmed by X-ray diffraction and SEM-EDS microscopy that the...

Investigation of electrodeposition behavior for Nd(III) in [P2225][TFSA] ionic liquid by EQCM methods with elevated temperatures

The electrodeposition behavior of Nd(III) in an ionic liquid, triethyl-pentyl-phosphonium bis(trifluoromethyl-sulfonyl) amide ([P2225][TFSA]), was investigated on an electrochemical quartz crystal microbalance (EQCM) at elevated temperatures. Cyclic voltammetry with EQCM measurements of Nd(III) in [P2225][TFSA] at 363, 373 and 378K were performed. A clear cathodic peak with increasing mass and decreasing ηρ (where η is the viscosity and ρ is the density) was observed at −2.79V. Considering the results of our previous investigations, this peak indicated the reduction of Nd(III) to Nd(0) as [Nd(III)(TFSA)5]2−+3e−→Nd(0) + 5[TFSA]−. In addition, the apparent molar mass, Mapp, between −2.49 and −2.94V calculated from the mass change was 140.4gmol−1, which was close to the theoretical value for the electrodeposition reaction of Nd(III)/Nd(0), 144.2gmol−1.Moreover, controlled potential electrolysis with EQCM (CPE/EQCM) measurements at −3.20V was performed for 0.05 and 0.10M Nd(III) in [P2225][TFSA] at 373K. The calculated Mapp values in 0.05 and 0.10M Nd(III) in the initial stage of CPE/EQCM analysis were 147.3 and 148.8gmol−1, respectively, which were close to the theoretical value for reduction of Nd(III) to Nd(0), 144.2gmol−1; thus, electrodeposition of Nd(0) metal was also proved by the CPE/EQCM analysis. Furthermore, energy-dispersive X-ray and X-ray photoelectron spectroscopy analyses of the blackish electrodeposits obtained by the CPE/EQCM measurements were identified as primarily metallic neodymium because the Nd 3d5/2 spectrum was detected within 980.5–981.5eV.

Electrochemical and thermodynamic properties of Nd (III)/Nd (0) couple at liquid Zn electrode in LiCl-KCl melt

The electrode reactions of Nd (III)/Nd couple at liquid Zn and Zn-coated W electrodes in LiCl-KCl melt were investigated in the temperature range of 707–784K. In the both cases, the electrochemical reduction of Nd (III) was observed at a more positive potential than that on an inert W electrode, due to the low activity of Nd in the metal phase. Cyclic voltammetry (CV) recorded at the liquid Zn electrode suggests the existence of a quasi-reversible reaction. The activity coefficient and apparent standard potential have been obtained. On the Zn-coated W electrode, the formation of five obvious non-homogeneous Nd-Zn intermetallic compounds could be observed through CV and open circuit chronopotentiometry (OCP) measurements and the thermodynamics of these intermetallic compounds was also investigated. Electromotive force (emf) measurements for the Nd-Zn intermetallic compounds in two-phase coexisting states were also carried out in the temperature range of 707–784K. Moreover, the standard formation Gibbs energies and the standard equilibrium constant of each Nd-Zn intermetallic compound were also calculated and the thermodynamic stabilities of these compounds at our experimental temperatures were evaluated.

Electrochemical Behavior of Li-B Alloy Anode - Liquid Cadmium Cathode (LCC) System for Electrodeposition of Nd in LiCl-KCl

The performance of Li-B alloy as anode for molten salt electrolysis was firstly investigated. The crystalline phase of the prepared Li-B alloy was identified as Li7B6. The potential profile of Li-B alloy anode was monitored during the electrodeposition of Nd 3+ onto an LCC (liquid cadmium cathode) in molten LiCl-KCl salt at 500 o C. The potential of Li-B alloy was increased from -2.0 V to -1.4 V vs. Ag/AgCl by increasing the applied current from 10 to 50 mA·cm -2 . It was found that not only the anodic dissolution of Li to Li + but also the dissolution of the atomic lithium (Li 0 ) into the LiCl-KCl eutectic salt was observed, fol- lowing the concomitant reduction of Nd 3+ by the Li 0 in Li-B alloy. It was expected that the direct reduction could be restrained by maintaining the anode potential higher that the depo- sition potential of neodymium.

Response of Ni/4H-SiC Schottky barrier diodes to alpha-particle irradiation at different fluences

Irradiation experiments have been carried out on 1.9×1016cm−3 nitrogen-doped 4H-SiC at room temperature using 5.4MeV alpha-particle irradiation over a fluence ranges from 2.6×1010 to 9.2×1011cm−2. Current–voltage (I–V), capacitance–voltage (C–V) and deep level transient spectroscopy (DLTS) measurements have been carried out to study the change in characteristics of the devices and free carrier removal rate due to alpha-particle irradiation, respectively. As radiation fluence increases, the ideality factors increased from 1.20 to 1.85 but the Schottky barrier height (SBHI–V) decreased from 1.47 to 1.34eV. Free carrier concentration, Nd decreased with increasing fluence from 1.7×1016 to 1.1×1016cm−2 at approximately 0.70μm depth. The reduction in Nd shows that defects were induced during the irradiation and have effect on compensating the free carrier. The free carrier removal rate was estimated to be 6480±70cm−1. Alpha-particle irradiation introduced two electron traps (E0.39 and E0.62), with activation energies of 0.39±0.03eV and 0.62±0.08eV, respectively. The E0.39 as attribute related to silicon or carbon vacancy, while the E0.62 has the attribute of Z1/Z2.

Investigation on the electrochemical behavior of neodymium chloride at W, Al and Cd electrodes in molten LiCl-KCl eutectic

Electrochemical behavior of neodymium (III) ion was studied in LiCl-KCl eutectic melt in the temperature range 723-798K on inert tungsten electrode using various transient electrochemical techniques such as cyclic voltammetry, convolution voltammetry, chronopotentiometry and square wave voltammetry. The reduction of Nd(III) ion to Nd metal on tungsten electrode takes place in two steps- Nd(III)/Nd(II) and Nd(II)/Nd(0). The diffusion coefficient of Nd(III) and Nd (II) ions were determined. Reduction of Nd(III) to Nd(II) showed reversible electrode behavior and that for Nd(II) to Nd metal followed the quasi-reversible behavior. Heterogeneous rate constant for the reduction, Nd(II)/Nd(0) was estimated from the convoluted voltammograms. The apparent standard electrode potentials,ENd(III)/Nd(II)*, ENd(II)/Nd(0)* and ENd(III)/Nd(0)* were estimated from the cyclic voltammograms.The electrode behavior of Nd(III) ion on solid aluminium electrode and liquid cadmium electrode was studied by cyclic voltammetry. Under-potential reduction of Nd(III) ion takes place on Al and Cd cathodes in a single step with three electron transfer. The apparent standard electrode potentials, ENd(III)/Nd(Al)* and ENd(III)/Nd(Cd)* were estimated for different temperatures in the range 698-773K. The formation of intermetallics, Al11Nd3 and Cd11Nd were studied from open circuit potential measurement on Al and Cd film electrode respectively. The Gibbs energy of formation for these intermetallics was evaluated. The activity of neodymium in Al/Cd, the excess Gibbs energy and the activity coefficient of neodymium in Al/Cd were estimated from the open circuit potential measurement. SEM-EDX analysis and the XRD pattern of the electro-deposit revealed the formation of Al11Nd3 and Cd11Nd on Al and Cd cathodes respectively.

Muon spin rotation and relaxation inPr1−xNdxOs4Sb12: Magnetic and superconducting ground states

Muon spin rotation and relaxation ($\mu$SR) experiments have been carried out to characterize magnetic and superconducting ground states in the Pr$_{1-x}$Nd$_x$Os$_4$Sb$_{12}$ alloy series. In the ferromagnetic end compound NdOs$_4$Sb$_{12}$ the spontaneous local field at positive-muon ($\mu^+$) sites below the ordering temperature $T_C$ is greater than expected from dipolar coupling to ferromagnetically aligned Nd$^{3+}$ moments, indicating an additional indirect RKKY-like transferred hyperfine mechanism. For 0.45 $\le x \le$ 0.75, $\mu^+$ spin relaxation rates in zero and weak longitudinal applied fields indicate that static fields at $\mu^+$ sites below $T_C$ are reduced and strongly disordered. We argue this is unlikely to be due to reduction of Nd$^{3+}$ moments, and speculate that the Nd$^{3+}$-$\mu^+$ interaction is suppressed and disordered by Pr doping. In an $x$ = 0.25 sample, which is superconducting below $T_c$ = 1.3 K, there is no sign of "spin freezing" (static Nd$^{3+}$ magnetism), ordered or disordered, down to 25 mK. Dynamic $\mu^+$ spin relaxation is strong, indicating significant Nd-moment fluctuations. The $\mu^+$ diamagnetic frequency shift and spin relaxation in the superconducting vortex-lattice phase decrease slowly below $T_c$, suggesting pair breaking and/or possible modification of Fermi-liquid renormalization by Nd spin fluctuations. For 0.25 $\le x \le$ 0.75, the $\mu$SR data provide evidence against phase separation; superconductivity and Nd$^{3+}$ magnetism coexist on the atomic scale.

Electrochemical study of the properties of Nd(III) and Nd(II) ions in molten LiCl-KCl-CsCl eutectic and individual CsCl

The electrochemical behavior of NdCl3 solutions in eutectic LiCl-KCl-CsCl and individual CsCl melts was studied on an inert molybdenum electrode at temperatures in the range 573–943 K. Cyclic and differential pulse voltammetry and potentiometry at zero current and the electromotive forces method were used. The cathode reduction of Nd(III) ions to the metal was found to occur as a sequence of two stages. The formed Nd(II) ions were unstable above 798 K and underwent disproportionation 3Nd(II) ⇔ 2Nd(III) + Nd(m) in the salt melts. The conventional standard redox potential of the Nd(III)/Nd(II) pair in a eutectic LiCl-KCl-CsCl melt was measured over a wide temperature range. The main thermodynamic characteristics of the reaction NdCl2(m) + 1/2Cl2(g) ⇔ NdCl3(m) were determined.

The origin of the coercivity reduction of Nd–Fe–B sintered magnet annealed below an optimal temperature

In order to understand the origin of the coercivity reduction in a sintered Nd–Fe–B magnet that is annealed below an optimal annealing temperature, we performed focused ion beam/scanning electron microscopy tomography of post-sinter annealed magnets. A number of grain boundary cracks were observed between Nd2Fe14B grains and Nd-rich phases in the sample annealed below the optimal temperature. We deduced micromagnetic parameters α and Neff by fitting the temperature dependence of the coercivity. While α was constant regardless of the annealing conditions, Neff increased in the sample annealed below the optimal temperature with the reduced coercivity. This indicates that the reduction of the coercivity is due to the local stray field at the cracks.

Precipitation driving of droplet concentration variability in marine low clouds

The concentration Nd of cloud droplets in marine low clouds is a primary determinant of their ability to reflect sunlight and modulates their ability to precipitate. Previous studies have focused upon aerosol source variability as the key driver of variability in Nd. Here, we use a highly simplified aerosol budget model to examine the impact of precipitation on Nd. This model considers: precipitation (coalescence) scavenging, constrained using new satellite measurements of light precipitation; entrainment of aerosol from above cloud combined with constant aerosol concentration based on recent field observations of aerosol particles in the free troposphere; and sea‐surface aerosol production estimated using a wind speed dependent source function. Despite the highly simplified nature of this model, it skillfully predicts the geographical variability ofNd in regions of extensive marine low clouds. Inclusion of precipitation results in reduction in Nd by factors of 2–3 over the remote oceans. Within 500 km of coastlines the reduction in Nd due to precipitation is weak but in these regions the model is not able to accurately predict Ndbecause of strong pollution sources. In general, neither free‐tropospheric nor surface CCN sources alone are sufficient to maintainNd against precipitation losses. The results demonstrate that even the light precipitation rates typical of marine stratocumulus profoundly impact the radiative properties of marine low clouds.

Reduction of Nd:YAG Capsulotomy Rates After Implantation of a Single-Piece Acrylic Hydrophilic Intraocular Lens with 360° Squared Optic Edge: 24-Month Results

Posterior capsule opacification remains a significant problem following cataract surgery. The aim of the study was to evaluate the incidence of symptomatic posterior capsule opacification requiring Nd:YAG capsulotomy in patients who underwent cataract extraction and implantation of the Rayner C-flex 570C intraocular lens (IOL) (Rayner Intraocular Lens, Ltd., Sussex, UK). A retrospective study of 3,461 eyes that underwent cataract extraction and insertion of the Rayner C-flex IOL from January 2004 to December 2005. The cases that received Nd: YAG capsulotomies were evaluated. Over a 24-month period, 3,461 Rayner C-flex IOLs were implanted. Nd:YAG capsulotomy was performed in 58 of these cases. The rate of Nd:YAG capsulotomy was 0.6% at 12 months and 1.7% at 24 months. The mean time to Nd:YAG capsulotomy was 9.3 months (range: 1.3 to 22.7 months). The follow-up period was 5.3 to 29.0 months. The incidence of symptomatic posterior capsule opacification with the Rayner C-flex IOL is low.