Nitric Oxide Alleviates Oxidative Stress Caused by Lanthanum in Rice Leaves

The effect of NO on lanthanum-induced antioxidant activities in rice was evaluated. The results showed that the uptake and translocation of La from root to shoot were obviously inhibited by 10μmol·L^-1 sodium nitropmsside （SNP）, a donor of NO, in the seedlings grown in Mura B nutrient solution with 100μmol·L^-1 La. Although the content of ascorbate acid （AsA） were scarcely affected by La or NO in our experiment, La decreased significantly the activity of SOD and content of GSH, while promoted H202 content in leaves. Furthermore, NO blocked these La effects. Taken together, the results suggested that NO relieved La toxicity in rice. A possible role for NO effects on antioxidant activity was discussed.

Effects of lanthanum ion-implantation on microstructure of oxide film formed on Co-Cr alloy

Isothermal and cyclic oxidizing behavior of Co-40Cr alloy and its lanthanum ion-implanted samples were studied at 1000 ℃ in the air by thermal-gravimetric analysis （TGA）. Scanning electronic microscopy （SEM） and transmission electronic microscopy （TEM） were used to examine the morphology and structure of oxide film after oxidation. Secondary ion mass spectrum （SIMS） method was used to examine the binding energy change of chromium caused by La-doping and its influence on the formation of Cr2O3 film. laser Raman spectrum was used to examine the stress changes within the oxide film. It was found that lanthanum implantation remarkably reduced isothermal oxidizing rate of Co-40Cr and improved anti-cracking and anti-spalling properties of Cr2O3 oxide film. The reasons for the improvement were mainly that the implanted lanthanum reduced the grain size and internal stress of Cr2O3 oxide and increased high temperature plasticity of the oxide film. Lanthanum mainly existed on the outer surface of Cr2O3 oxide film in the form of fine La2O3 and LaCrO3 spinel particles.

Synthesis and Electrocatalytic Properties of Complex Oxides Containing Lanthanum

A series of perovskite-type complex oxides LaNi1-xRuxO3 were prepared and studied by means of XRD. The effects of some factors on th complex oxides were discussed. Each kind of those perovskite-type complex oxides was used to prepare cathode by composite-electroplating technique. The cathodes were electrochemically charactrized. The results show that these novel cathode exhibit high activities and excellent stabilities during long-term continuous electrolysis with some current interruptions.

Mechanochemical Reaction of Lanthanum Carbonate with Sodium Hydroxide and Preparation of Lanthanum Oxide Nanoparticle

The preparation of nano sized La 2O 3 powder by mechanochemical reaction of lanthanum carbonate with sodium hydroxide and subsequent heat treatment was studied using X ray diffraction, differential thermal and thermo gravimetric analysis and transmission electron microscopy. It was found that the mechanochemical reaction process can be divided into two steps: the first step is the multi phases mechanochemical reaction of lanthanum carbonate with NaOH to form amorphous lanthanum basic carbonate and lanthanum hydroxide, and the second step is the crystallization of basic lanthanum carbonate with the formula of La 2(OH) 2(CO 3) 2·H 2O under a quasi hydrothermal synthesis condition caused by the mechanical ball milling. The synthesized La 2O 3 powder appears clearly separated spherical like monodisperse nano size particles in which particle size ranges from 30 to 50 nm.

Preparation of Lanthanum Nickel Oxide-Coated Ni Sheet Anodes and Their Application to Electrolytic Production of (CF_3)_3N in (CH_3)_4NF·4.0HF Melt

A new process for electrolytic production of a perfluorinated compound, （CF3）3N, using lanthanum nickel oxide-coated Ni sheet anode in the （CH3）4NF· 4.0HF melt at room temperature, was developed. Thin films of the lanthanum nickel oxides were prepared on Ni sheets by sol-gel coating method using polyvinlylpyrrolidone（PVP）. The main components of the thin films were La2O3, LaNiO3, and La2NiO4 at 500, 750 and 1000℃, respectively. The anode performance in the （CH3）4NF·4.0HF melt depends greatly on the main component of the thin film, and the LaNiO3-coated Ni sheet anode gives the best anode performance. The potential of LaNiO3-coated Ni sheet anode remains constant at 5.9 V during electrolysis at 20 mA·cm^-2 in the （CH3）4NF·4.0HF melt for 100 h. This is because LaNiO3 and NiF3 and/or Ni2F5, the latter of which was formed during electrolysis, in the film give a high electronic conductivity to the surface film during electrolysis. The maximum mole fraction of （CF3）3N （21.4%） was obtained at 20 mA·cm^-2 in （CH3）4NF·4.0HF melt using the LaNiO3-coated Ni sheet.

Influence of MgO contents on silica supported nano-size gold catalyst for carbon monoxide total oxidation

A series of nano-size gold catalysts were prepared by deposition-precipitation method using silica material promoted with different amounts of MgO as the carrier. The influences of MgO addition on the structure and property of the nano-size gold catalysts were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, O2 temperature-programmed desorption （O2-TPD）, and inductively coupled with plasma atomic emission spectroscopy （ICP-AES） techniques. The total oxidation of CO was chosen as the probe reaction. The results suggest that for the gold catalysts supported on the silica material after MgO modification, the size of the gold particles is pronouncedly reduced, the oxygen mobility is enhanced, and the catalytic activity for low-temperature CO oxidation is greatly improved. The gold catalyst modified by 6 wt% MgO （Mg/SiO2 weight ratio） shows higher CO oxidation activity, over which the temperature of CO total oxidation is lower about 150 K than that over the silica directly supported gold catalyst.

Lanthanum Chloride Inhibiting Expression of Inducible Nitric Oxide Synthase in RAW264.7 Macrophages Induced by Lipopolysaccharide

Nitric oxide（NO）and its reaction products were key players in the pathophysiology of sepsis and shock.The present study was designed to explore the effects of lanthanum chloride（LaCl3）on inducible nitric oxide synthase（iNOS）expression,at both gene and protein levels,in RAW264.7 macrophages induced by Lipopolysaccharide（LPS）.Reverse transcription polymerase chain reaction（RT-PCR）,immunofluorescence,and western blot were employed to measure iNOS gene expression,localization,and protein expression respectively.NO production in culture supernatants was detected by the nitrate reductase method.The results showed that LaCl3 significantly attenuated the iNOS gene and protein expression,as well as NO production in RAW264.7cells induced by LPS.

Plasma-Sprayed Coating of an Apatite-Type Lanthanum Silicate Electrolyte for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs)

Apatite-type lanthanum silicate was successfully synthesized via a solid state re- action protocol at 1400~C in a vacuum for 4 hours. The powder was synthesized faster and at a lower reaction temperature than by conventional solid state reaction methods. The resulting powder was used in the fabrication of a coating deposited by atmospheric plasma spray （APS） technology. The microstructure of the coating was analyzed by X-ray diffraction and scanning electron microscopy. Heat treatment was found to fully crystallize the coating, increasing its den-sity. The ionic conductivity of the apatite coating was 0.39 （0.054） mS/cm at 850 （700） ℃, and its activation energy was 0.67 eV.

Spectral properties of Ce^(3+) doped yttrium lanthanum oxide transparent ceramics

Ce3＋-doped yttrium lanthanum oxide （Y0.9La0.1）2O3 transparent ceramics is fabricated with nanopowders and sintered in H2 atmosphere. The spectral properties of Ce：（Y0.9La0.1）2O3 transparent ceramics are investigated. There appear two characteristic absorption peaks of Ce3＋ ions at 230~nm and 400~nm, separately. It is found that Ce3＋ ions can efficiently produce emission at 384~nm from （Y0.9La0.1）2O3 transparent ceramic host, while the emission is completely quenched in Re2O3 （Re=Y, Lu, La） host materials.

Direct Determination of Trace Silicon in Lanthanum Oxide by Using a Selective Volatility and Slurry Sampling-FETV-ICP-AES

A new method for determination of trace silicon in high purity lanthanum oxide by using electrothermal vaporization (ETV) ICP AES with polytetrafluoroethylene(PTFE) slurry as a fluorinating reagent has been proposed. Under the optimized experimental conditions, the fluorination reactions of analyte(Si) and matrix(La) with PTFE in the graphite furnace took place at high temperature, and the fractional volatilily between Si and La was observed. Based on this principle the matrix interference could be eliminated. The detection limit of Si was 4.0 μg·L -1 , and the RSD was 3.4%( C =0.2 mg·L -1 , n =10). The procedure proposed has been applied successfully to determine trace Si in La 2O 3 without any chemical pre treatment.

Determination of Non-Rare Earth Impurities in High Purity Lanthanum Oxide by Inductively Coupled Plasma Atomic Emission Spectrometry after HPLC Separation Using P507 Resin

A new method for the determination of trace non-rare earth elements (NREEs) impurities in high-purity lanthanum oxide by HPLC combined with ICP-AES is proposed. The chromatographic retention behaviors of matrix (La) and NREEs were studied using 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate (P507) chelating resin as the stationary phase and dilute nitric acid as the mobile phase. It is found that the use of pH 1.7 nitric acid enables effective elution of NREEs from HPLC column, but the lanthanum remains on the column. The experimental results show that a favorable separation between matrix lanthanum and NREEs can be obtained within 15 min. The method proposed is applied to the determination of 8 NREEs impurities in high-purity La2O3. The recoveries of 8 NREEs are in the range of 90 % similar to 110 %.

Structural and Optical Properties of Zinc Borotellurite Glass Co-Doped with Lanthanum and Silver Oxide

A series of zinc borotellurite glass co-doped with lanthanum and silver oxide with the chemical formula of [{[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}0.96(La2O3)0.04]1-x(Ag2O)x where the molar frac-tion of silver oxide, x = 0.02, 0.04, 0.06, 0.08 and 0.10 had been successfully prepared via the conventional melt-quenching technique. The structural properties of the glasses were unveiled through X-ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) spectroscopy while optical properties of the glasses were investigated with Ultra Violet Visible (UV-Vis) spectropho-toscopy. The short range periodic atomic arrangement in the glass matrix that implies the amorphous nature of the glass was confirmed with the presence of a broad hump in the XRD pattern. On the other hand, the three absorption bands observable in the FTIR spectra had proven the existence of BO4, BO3 as well as TeO4 units in the glass network. The absorbance values retrieved from UV-Vis spectroscopy were utilized to calculate the indirect energy band gap and Urbach energy values of the fabricated glass. By employing the equations proposed by Mott and Davis, the obtained indirect energy band gap have val-ues ranging from 2.16 to 4.16 eV.The decreasing trend in indirect energy band gap and increasing Urbach energy values were related to the increasing num-ber of nonbridging oxygen (NBO) in the glass that is created from the breaking of Te-O-Te or B-O-B bonds after lanthanum as well as silver oxide are incor-porated into the zinc borotellurite glass network.

Improving the performance of solid oxide electrolysis cell with gold nanoparticles-modified LSM-YSZ anode

Gold, as the common current collector in solid oxide electrolysis cell(SOEC), is traditionally considered to be inert for oxygen evolution reaction at the anode of SOEC. Herein, gold nanoparticles were loaded onto conventional strontium doped lanthanum manganite-yttria stabilized zirconia(LSM-YSZ) anode, which evidently improved the performance of oxygen evolution reaction at 800 °C. The current densities at 1.2 V and 1.4 V increased by 60.0% and 46.9%, respectively, after loading gold nanoparticles onto the LSM-YSZ anode. Physicochemical characterizations and electrochemical measurements suggested that the improved SOEC performance was attributed to the accelerated electron transfer of elementary process in anodic polarization reaction and the newly generated triple phase boundaries in gold nanoparticles-loaded LSMYSZ anode.

Growing kinetics and structural characterization of oxide film formed on La-doped Co-40Cr alloy

The isothermal and cyclic oxidizing kinetics of Co-40Cr alloy and its lanthanum ion-implanted samples were studied at 1000 ℃ in air by thermal-gravity analysis （TGA）. Scanning electronic microscopy （SEM） and transmission electronic microscopy （TEM）） were used to examine the oxidized film＇s morphology and the structure after oxidation. Secondary ion mass spectrum （SIMS） method was used to examine the binding energy change of chromium caused by La-doping and its influence on formation of Cr2O3 film. Laser Raman spectrum was used to examine the tress changes within oxidized films. It was found that lanthanum implantation remarkably reduced the isothermal oxidizing rate of Co-40Cr and improved the anti-cracking and anti-spalling properties of Cr2O3 film. The reasons were that the implanted lanthanum reduced the grain size and internal stress of Cr2O3 oxide, increased the high temperature plasticity of oxidized film. Lanthanum mainly existed in the outer surface of Cr2O3 film in the forms of fine La2O3 and LaCrO3 spinel panicles.

Effect of Lanthanum on Methanol Fuel Exhaust Deep Oxidation over Palladium Catalyst

The performance of deep oxidation of methanol on supported Pd catalyst was exami ned by a chromatograph-micro-reactor. The results show that the add ition of La into γ-Al 2O 3 support can affect greatly the performance of t he Pd catalyst. In the absence of CO, La can decrease the content of oxygen-c ontaining intermediate, although La can not lower the light-off temperature of methanol oxidation. In the presence of CO, La can lower the light-off tem perature, decrease the amount of CO adsorption, and weaken evidently 'CO inhibi tion' to the oxidation of methanol. By XPS technique, it is shown that La modi fies the electronic structure of Pd, which attributes to the modifications of th e catalytic performance.

Effect of nano-size nickel particles on wear resistance and high temperature oxidation resistance of ultrafine ceramic coating

In order to improve the wear resistance and high temperature oxidation resistance of titanium and titanium alloy, the high temperature ultra fine ceramic coating containing nano-size nickel particles was prepared by flow coat method on the surface of industrially pure titanium TB1-0. The effects of nano-size nickel particles on the wear resistance and high temperature oxidation resistance of coating substrate system were investigated through oxidation kinetics experiment and wear resistance test. The morphologies of the specimens were examined by means of optical microscopy, scanning electron microscopy and X-ray diffraction. The results show that the high temperature ultra fine ceramic coating has notable protection effect on industrially pure titanium TB1-0 from oxidation. The oxidation and wear resistance properties of the coating can be effectively improved by adding nano-size nickel particles. The oxidative mass gain of the specimen decreases from 11.33 mg·cm-2 to 5.25 mg·cm-2 and the friction coefficient decreases from 1.1 to 0.6 by adding nano-size nickel particles, and the coating containing 10% （mass fraction） nano-size nickel shows the optimum properties.

Carbon dioxide reforming of methane on monolithic Ni/Al_2O_3-based catalysts

Nickel-alumina catalysts supported on cordierite monoliths of honeycomb structure surpass essentially the conventional granulated ones with respect to the output in carbon dioxide reforming of methane. Adjusting the surface acid-base properties of catalysts by introduction of alkali metal （Na, K） oxides inhibits the carbonization and as a result, improves the operational stability of these catalysts. An effect of promotion of nickel-alumina based composite doped by lanthanum oxide is found. This effect, caused by an additional route for the CO2 activation on Ni-La2O3/Al2O3/cordierite catalyst, is displayed in increase of methane conversion under conditions of an oxidant excess.

Hydrogen production via autothermal reforming of ethanol over noble metal catalysts supported on oxides

Hydrogen was produced over noble metal（Ir, Ru, Rh, Pd） catalysts supported on various oxides, including γ-Al2O3, CeO2, ZrO2 and La2O3, via the autothermal reforming reaction of ethanol （ATRE） and oxidative reforming reaction of ethanol （OSRE）. The conversion of ethanol and selectivites for hydrogen and byproducts such as methane, ethylene and acetaldehyde were studied. It was found that lanthana alone possessed considerable activity for the ATRE reaction, which could be used as a functional support for ATRE catalysts. It was demonstrated that Ir/La2O3 prevented the formation of methane, and Rh/La2O3 encumbered the production of ethylene and acetaldehyde. ATRE reaction was carried out over La2O3-supported catalysts （Ir/La2O3） with good stability on stream, high conversion, and excellent hydrogen selectivity approaching thermodynamic limit under autothermal condition. Typically, 3.4H2 molecules can be extracted from a pair of ethanol and water molecules over Ir（5wt%）/La2O3. The results presented in this paper indicate that Ir/La2O3 can be used as a promising catalyst for hydrogen production via ATRE reaction from renewable ethanol.

Electrochemical performance and stability of Sr-doped LaMnO_(3)-infiltrated yttria stabilized zirconia oxygen electrode for reversible solid oxide fuel cells

Porous Sr-doped lanthanum manganite–yttria stabilized zirconia(LSM–YSZ)oxygen electrode is prepared by an infiltration process for a reversible solid oxide fuel cell(RSOFC).X-ray diffraction and SEM analysis display that perovskite phase LSM submicro particles are evenly distributed in the porous YSZ matrix.Polarization curves and electrochemical impedance spectra are conducted for the RSOFC at 800 and 850C under both SOFC and SOEC modes.At 850℃,the single cell has the maximum power density of~726 mW/cm^(2)under SOFC mode,and electrolysis voltage of 1.35 V at 1 A/cm^(2)under SOEC mode.Fuel cell/water electrolysis cycle shows the cell has good performance stability during 6 cycles,which exhibits the LSM–YSZ oxygen electrode has high electrochemical performance and good stability.The results suggest that netw ork-like LSM–YSZ electrode made by infiltration process could be a promising oxygen electrode for high temperature RSOFCs.