Efficient in-situ end-functionalization of polydienes by isothiocyanate via neodymium mediated coordinative chain transfer polymerization system

End-functionalization of polydiene rubbers can not only improve its compatibility with inorganic fillers,but also enhance the overall mechanical properties.Nevertheless,for traditional neodymium(Nd)diene polymerization systems,it is highly challenging to achieve such end-functionalizations,because most of polydienyl chains are capped withη3-allyl-Nd moiety during the end of polymerization,which shows very poor reactivity with nucleophile compounds.We launched a new diene polymerization strategy calling coordinative chain transfer polymerization(CCTP)[1].In such a system,all the polydienyl chains are capped withη1-allyl-Al moieties,which reveal greater reactivity with cyclic esters and epoxide compounds,providing an effective manner to prepare polydiene-polyester amphiphilic block copolymers.Inspired by such findings,we now show herein how such types of chain-ends react with isot-hiocyanate to demonstrate an efficient in-situ manner to access end-functionalized polydienes by using CCTP.

Artificial Neural Network and Fuzzy Logic Based Techniques for Numerical Modeling and Prediction of Aluminum-5%Magnesium Alloy Doped with REM Neodymium

In this study, the mechanical properties of aluminum-5%magnesium doped with rare earth metal neodymium were evaluated. Fuzzy logic (FL) and artificial neural network (ANN) were used to model the mechanical properties of aluminum-5%magnesium (0-0.9 wt%) neodymium. The single input (SI) to the fuzzy logic and artificial neural network models was the percentage weight of neodymium, while the multiple outputs (MO) were average grain size, ultimate tensile strength, yield strength elongation and hardness. The fuzzy logic-based model showed more accurate prediction than the artificial neutral network-based model in terms of the correlation coefficient values (R).

Effects of neodymium addition on microstructure and mechanical properties of near-eutectic Al-12Si alloys

The microstructure and mechanical properties of near-eutectic Al-12 Si alloys modified with 0-0.4% Nd（mass fraction） were investigated. The results indicate that a submicro- or nano-sized Al2 Nd phase is observed in the modified alloy with 0.3% Nd. The morphology of the α（Al） phase is significantly refined in the Nd-modified alloys. The primary Si morphology simultaneously changes into a fine, particle-like morphology, and the morphology of eutectic Si becomes fine-fibrous instead of coarse-acicular. Relatively few growth twins are observed on the surface of the Si plate in the Al-12Si-0.3Nd alloy at the optimal modification level. The mechanical property test results confirm that the mechanical properties of the as-cast Al-12 Si alloys are enhanced after the Nd addition, with optimal ultimate tensile strength（UTS） of 252 MPa and elongation（EL） of 13% at an Nd content of 0.3%. The improved mechanical properties are attributed to the refined morphology of Si phase and the formation of the Al2 Nd phase.

Preparation and photocatalytic activity of neodymium doping titania loaded to silicon dioxide

Neodymium doping titania was loaded to silicon dioxide to prepare Nd/TiO2-SiO2 by sol-gel method and Nd/TiO2-SiO2 was characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform-infrared spectroscopy （FT-IR） and diffuse reflectance spectra （DRS）. Photocatalytic activities of Nd/TiO2-SiO2 with different neodymium contents were evaluated by degradation of methyl orange. The light absorption of Nd/TiO2-SiO2 increased with increasing doping neodymium in a visible light range of 388-619 nm, and Nd doping was in favor of decreasing the recombination of photo-generated electrons with holes. Nd and SiO2 improved the photocatalytic activity of TiO2. The optimal molar fraction of Nd to Ti was 0.1%, and the optimum calcination temperature was 600 ℃. The highest degradation rate of methyl orange was 82.9% after irradiation for 1 h.

Study on Electrochemical Formation of Neodymium-Iron Alloy

The cyclic voltammetry was used to investigate the electrode processes of Nd(III) reduced on iron electrode and Nd(III),Fe(II) reduced on molybdenum electrode in molten chlorides. The Nd-Fe and Nd-rich RE-Fe alloys contained rare earth up to 90wt% were prepared by consumable cathode and electrolytic codeposition. The mechanism of electrochemical formation of Nd-Fe alloy had been discussed.

Ion imprinted polymer particles of neodymium:synthesis,characterization and selective recognition

Neodymium ion imprinted polymer（Nd^3＋-IIP） particles for selective solid-phase extraction of Nd^3＋ were prepared and determined with inductively coupled plasma atomic emission spectrometry（ICP-AES）.The unleached Nd^3＋-IIP particles were prepared by the copoly-merization of Nd^3＋-5,7-dichloroquinoline-8-ol-4-vinylpyridine ternary complex with styrene and divinyl benzene, then Nd^3＋ was leached to obtain Nd^3＋-IIP particles.The adsorption capacity of the Nd3＋-IIP was 35.18 mg/g.The largest selectivity coefficient for Nd3＋ in the presence of competitive ions such as La^3＋, Ce^3＋, Pr^3＋ and Sm^3＋ was over 110.The proposed method was validated by analyzing two certified reference materials（GBW07301a sediment and GBW07401 soil） and the determined values were in a good agreement with standard values.The method was convenient, selective, sensitive and applicable to the determination of trace Nd^3＋ in environmental samples with complicated matrix.

Low-pressure pulse flushing choledochoscopy combined with neodymium laser lithotripsy for the treatment of intrahepatic bile duct stones

Cholelithiasis is a common and frequently occurring disease in East Asia.Intrahepatic bile duct stone is a benign disease,but the recurrence rate is high.The incidence of postoperative residual stones after traditional manual stone removal can be30%–96%^([1]).The emergence of endoscopes is therefore a milestone in the treatment of hepatolithiasis.Among the various approaches,choledochoscopy combined with laser lithotripsy has become the main procedure for intrahepatic bile duct stone removal^([2]).Lithotripsy alone has the disadvantages of low stoneremoving efficiency and blurred choledochoscope vision while performing the procedure.Currently,our team has achieved satisfactory results in the removal of intrahepatic bile duct stones with low-pressure pulse flushing and neodymium laser lithotripsy.

Effect of Neodymium on Physiological Activities in Oilseed Rape during Calcium Starvation

It was reported that rare earth elements promote plant growth and other physiological activities. Since the ion radius of Nd3+ is very close to that of Ca2+, the interaction between Nd and Ca might be one of the important mechanisms to be understand. Seedlings treated with 3 Umol·T, -1 Nd(NO3)3 in Ca2+ -deficient solution, and the effect of Nd on their membrane damage in oilseed rape(Brassica napus L.) was studied. It shows that the symptom of Ca-starvation is relieved and the peroxidation process in rape is inhibited. It indicates that adding Nd can lower relative permeability of the root and MDA content in leaves and increase CAT, POD, and SOD activities in rape. Likewise, the Nd addition to Hoagland solution shags similar result. The interpretation is that the effect is a consequence of substitution of Nd function for some Ca function through interacting with cellular membrane.

Separation and estimation of nanofiltration membrane transport parameters for cerium and neodymium

Lanthanides are widely used in various commercial applications, which results in public exposure to them, and it is a matter of concern. Many methods were used to remove lanthanides from wastewaters generated from their commercial use. In the present work, nanofiltration membrane process was used to remove the cerium and neodymium from their respective feed solutions. The feed and permeates were analyzed for solute concentration by inductively coupled plasma-atomic emission spectroscopy. Irreversible thermodynamics Spiegler-Kedem model, in combination with the film theory, was used to estimate the membrane transport parameters, viz., reflection coefficient of membrane and solute permeability, and mass transfer coefficient to study their dependence on feed solute concentration.

Study on F-F Transitions of Powdered Neodymium Compounds by Photoacoustic Spectroscopy

Photoacoustic (PA) spectra of powdered neodymium oxide (Nd 2O 3 (A type)), neodymium hydrated chloride (NdCl 3·6H 2O) and neodymium fluoride (NdF 3) were reported. PA band shifts as compared to their positions in aqueous Nd 3+ are used to calculate the nephelauxetic parameters of the compounds. The variation of these parameters and correlation with the nature of metal ligand bonding were discussed. A novel method is introduced to determine the relative values of oscillator strengths and Judd Ofelt parameters of powdered samples using PA spectroscopy. It is found that a linear correlation exists between relative values of τ 2 and oscillator strengths of hypersensitive transitions of the title compounds. It is hopetul that the new method of PA technique may serve for the Judd Ofelt quantitative analysis of powdered rare earth compounds.

A HIGHLY ACTIVE NEODYMIUM CHLORIDE ISOPROPANOL COMPLEX/MODIFIED METHYLALUMINOXANE CATALYST FOR PREPARING POLYISOPRENE WITH HIGH CIS-1,4 STEREOSPECIFICITY AND NARROW MOLECULAR WEIGHT DISTRIBUTION

Neodymium chloride isopropanol complex （NdCl3.3＇prOH） activated by modified methylaluminoxane （MMAO） was examined in isoprene polymerization in hexane, with regards to Nd compounds, aluminum （Al） compounds, [Al]/[Nd] ratio, polymerization temperature and time. NdCl3＇3iprOH exhibited high activity producing polymers feasting high cis-l,4 stereospecificity （〉 96%）, very high molecular weight （Mn 〉 1.0 × 10^6） and fairly narrow molecular weight distribution （MWD, Mw/Mn 〈 2.0） simultaneously. In comparison, neodymium isopropoxide also showed high activity providing polymers with narrow MWD （Mw/Mn = 2.07）, but somewhat low cis-1,4 content （ca. 92%）, while neodymium chloride had no activity under present polymerization conditions. The Al compounds affected the polymer yield in the order of Al（i-Bu）3 〉 MMAO 〉 Al（i-Bu）2H. MMAO as cocatalyst afforded polyisoprene with high Mn over 1.0 × 10^6, whereas as stronger chain transfer agent than MMAO, AI（i-Bu）3 and AI（i-Bu）EH yielded polymers with low Mn （1.0 × 10^5-8.0 × 10^5）. NdCl3·3＇PrOH/MMAO catalyst showed a fairly good catalytic activity even at relatively low [Al]/[Nd] ratio of 30, and the produced polymer remained high cis-1,4 content of 95.8% along with high Mn over 1.0× 10^6 even at elevated temperatures up to 70℃. The polymerization rate is of the first order with respect to the concentration of isoprene. The mechanism of active species formation was discussed preliminarily.

Polymerization of isoprene catalyzed by neodymium heterocyclic Schiff base complex

Neodymium-based heterocyclic Schiff base complex was prepared and applied for the coordination polymerization of isoprene. This complex polymerized isoprene to afford products featuring high cis-1,4 stereospecificity （ca. 95%） and high molecular weight （ca, 10^5） in the presence of the triisobutyl aluminium （AliBu3） as cocatalyst, The microstructure of obtained polyisoprene was investigated by FTIR, 1^H NMR. Two different kinds of active centers in the catalyst system were examined by GPC method.

Changes in endogenous hormone levels and redox status during enhanced adventitious rooting by rare earth element neodymium of Dendrobium densiflorum shoot cuttings

The effects of neodymium nitrate （Nd^3＋） on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3＋ （5 μmol/L） to culture medium significantly increased rooting frequency. Histological investigation showed that Nd^3＋ did not change the process of root initiation. Nd^3＋ did not influence total endogenous cytokinin levels, but significantly increased the level of endogenous indole-3-acetic acid （IAA） in the base of shoot cuttings. Compared to the control, the ratio of IAA/cytokinins was very high in the Nd^3＋ treatment. These results suggested that the enhanced rooting frequency may be related to the increase in endogenous IAA level in Nd^3＋ treatment. Analysis of enzyme activities showed that the enhanced accumulation of the endogenous IAA by Nd^3＋ should not be attributed to inhibition of IAA decomposition by IAA oxidase or promotion of cytokinin decomposition by cytokinin oxidase. Besides, Nd^3＋ increased the ratio of reduced glutathione （GSH） and oxidized glutathione （GSSG） in the process of adventitious rooting while the ratio of ascorbate （ASC） to dehydroascorbate （DHA） was not affected.

Effects of Carbonate on Exchangeability and Bioavailability of Exogenous Neodymium in Soil

The effects of carbonate on the exchangeability and the bioavailability of exogenous neodymium in soil were studied by Nd-147 isotopic tracer method. Exchangeable Nd was extracted by I mol(.)L(-1) NaAc (pH8.2) in the experiment. The results indicate that whether carbonate exists in soil or not, beyond 99% of exogenous Nd is adsorbed by soil. Low-concentration carbonate (0.8 similar to 1.6 g(.)kg(-1)) can reduce exchangeable Nd concentration in soil, while high-concentration carbonate (4.0 g(.)kg(-1)) impacts little on the exchangeable Nd concentration. In addition, carbonate of 0.8 similar to 1.6 g(.)kg(-1) in soil can inhibit wheat seedlings to absorb Nd. However, when the carbonate concentration rises to 4.0 g(.)kg(-1) the inhibition will become indistinct.

Distribution and Accumulation of Neodymium and Its Effect on Secretion of Progesterone in Mice

Distribution and accumulation of Nd, and its effect on secretion of progesterone in mice were studied using radioisotope tracer ((()^(147)Nd)) technique. Following single intraperitoneal administration of neodymium traced with (()^(147)Nd) at a dose of 200 mg·kg^(-1), uneven distribution of the radioactive Nd occurred in various tissues and organs. Much amount of (()^(147)Nd) accumulates in the bone, and the residue increases with the lapse of time. Some amount of radioactivity was also detected in eyes, blood and brain, but the accumulation decreased with the time due to excretion and re-distribution in mice. In comparison with controls, concentration of progesterone is found to be significantly lower in the serum of administered mice, indicating a significantly inhibitory effect of Nd on secretion of progesterone.

Physicochemical properties of DMI-LiNO_(3) 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(DMILiNO_(3))solvated ionic liquid were measured as a function of temperature.Additionally,the electrochemical mechanism and electrodeposition of neodymium from the DMI-LiNO_(3) 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) cm^(2)/s.Energydispersive X-ray spectrometry and X-ray photoelectron spectroscopy data confirm that the electrodeposit obtained after electrodeposition at-4 V(vs Ag)using the DMI-LiNO_(3)-Nd(CF_(3)SO_(3))_(3) solvated ionic liquid contains metallic neodymium.

Neodymium-doped Yttrium Aluminum Garnet Transparent Laser Ceramics Prepared by Co-precipitation Method

Transparent polycrystaUine neodymiumdoped yttrium aluminum garnet ceramics （Nd：YAG） with better chemical stability, excellent optical and high temperature mechanical property is becoming a new laser host material. The Nd：YAG precursor powders with loosely dispersed, slightly agglomerated and YAG cubic crystal phase were synthesized at 1100 ℃ by the co-precipitation method combined with the reverse strike,

Effects of Neodymium on Growth, Pectinase Activity and Mycelium Permeability of Fusarium oxysporum

The diameter of the colony of Fusarium oxysporum in solid medium, and the mycelium growth, pectinase activity, and mycelium permeability of Fusarium oxysporum in liquid medium under varying concentrations of Nd^3＋ （0, 2, 4, 10, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 300, and 400 mg·L^-1） were measured. The results indicated that the growth of Fusarium oxysporum was stimulated in solid medium when the concentration of Nd^3＋ ranges from 2 to 180 mg·L^-1, whereas it was inhibited when Nd^3 ＋ concentration was greater than 200 mg· L^-1. The colonies were fewer and smaller when Nd^3 ＋ was used in the solid medium. The growth of Fusarium oxysporum was inhibited in liquid medium when Nd^3＋ was used. The inhibition rate showed by the dry weight of mycelium ranged from 4.83% to 52.18% and inereased with Nd^3 ＋ concentration. The pectinase activity decreased compared with that of controls. When the concentration of Nd^3 ＋ was 10 and 400 mg· L^- 1, the pectinase activity decreased by 95 % at both concentrations. Mycelium cell membrane permeability increased when Nd^3 ＋ concentrations ranged from 10 to 400 mg· L^-1 but decreased when Nd^3＋ concentration was 2 mg· L^-1.

Thermochemistry on Coordination Behavior of Neodymium Chloride Hydrate with Diethylammonium Diethyldithiocarbamate

The complex of neodymium chloride lower hydrate with diethylammonium diethyldithiocarbamate (D-DDC) was synthesized conveniently in absolute alcohol and dry N_2 atmosphere. The title complex was identified as Et_2NH_2[Nd(S_2CNEt_2)_4] by chemical and elemental analyses and the bonding characteristics of which was characterized by IR. The enthalpies of solution of neodymium chloride hydrate and D-DDC in absolute alcohol at 298.15 K and the enthalpies change of liquid-phase reaction of formation for Et_2NH_2[Nd (S_2CNEt_2)_4] at different temperatures were determined by microcalorimetry. On the basis of experimental and calculated results, three thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), the rate constant and three kinetic parameters (the apparent activation energy, the pre-exponential constant and the reaction order) of liquid-phase reaction of formation were obtained. The enthalpy change of the solid-phase title reaction at 298.15 K was calculated by a thermochemical cycle.

Investigation on tribological behaviors of neodymium dialkyldithiophosphate

Neodymium dialkylthiophosphate （NdDDP） with alkyls of isopropyl and isooctyl were synthesized by exchanged reaction respectively. The structures of the two NdDDPs were determined using IR and XRD. Properties of anti-wear and friction-reducing of the two additives were investigated with four ball experiment and the commercial anti-wear additive ZDDP was selected as control. The elemental analysis of the wear scars after 10 s friction at low stress were investigated by EDXA （Energy Dispersion Analysis of X-ray）. Primary results showed that the NdDDPs possess better lubrication ability than ZDDP. This might mainly be contributed to the formation of a boundary film containing Nd2O3, FeS and sulphate, phosphate, organo-sulfide, etc., and a neodymium-rich diffused layer which changes the crystal structure of the surface of friction materials.