Oxides (Total 18562 Papers Found)

Oxides (18562 Papers Found)
Industrial development and agricultural intensification are projected to increase in the humid tropics over the next few decades, increasing the emissions, transport and deposition of nitrogen-containing compounds. Most studies of the consequences of enhanced nitrogen deposition have been performed in temperate ecosystems in which biological processes are limited by nitrogen supply; they indicate that added nitrogen is retained up to decades before losses as nitrogen oxides or as nitrate (NO3− ...
The presence of snow greatly perturbs the composition of near-surface polar air, and the higher concentrations of hydroxyl radicals (OH) observed result in a greater oxidative capacity of the lower atmosphere. Emissions of nitrogen oxides, nitrous acid, light aldehydes, acetone, and molecular halogens have also been detected. Photolysis of nitrate ions contained in the snow appears to play an important role in creating these perturbations. OH formed in the snowpack can oxidize organic matter and ...
Gold (Au) is an interesting catalytic material because of its ability to catalyze reactions, such as partial oxidations, with high selectivities at low temperatures; but limitations arise from the low O2 dissociation probability on Au. This problem can be overcome by using Au nanoparticles supported on suitable oxides which, however, are prone to sintering. Nanoporous Au, prepared by the dealloying of AuAg alloys, is a new catalyst with a stable structure that is active without any support. It c ...
CRYSTAL growth in gels is becoming increasingly recognized as a promising technique for the preparation of single crystals of substances which are slightly soluble in water and which cannot be conveniently grown from the melt or from the vapour1. The growth of single crystals of many metal oxides is of considerable interest, particularly for basic studies of their electronic properties and other pertinent characteristics. Single crystal growth in gels at near ambient temperatures offers a possib ...
In this work, we report our recent progress on monolithic integration of magneto-optical oxide thin films and nonreciprocal photonic devices on silicon. We demonstrate strong Faraday rotation of - 6000 deg/cm at 1550 nm wavelength in silicon integrated Ce<sub>1.5</sub>Y<sub>1.5</sub>Fe<sub>5</sub>O<sub>12</sub> films, which exceeds the Faraday rotation of epitaxial CeiY<sub>2</sub>Fe<sub>5</sub>Oi<sub>2</sub> thi ...
The influence of metal elements in three Pd alloys on the bonding to porcelain was examined. The high-temperature oxidation behavior of metal elements in alloys, structure and morphology of oxidation zones on the alloy surface and the appearance of bonding between alloy and fused porcelain at the interface were studied by ESCA and EPMA. From ESCA analysis, metal oxides such as PdO, SnO2, In2O3, CuO or Cu2O, Sb2O3 or Sb2O5 were formed on the surface of the alloy after degassing (preheating) and h ...
Manganese (Mn) oxides are among the strongest mineral oxidants in the environment and impose significant influence on mobility and bioavailability of redox-active substances, such as arsenic, chromium, and pharmaceutical products, through oxidation processes. Oxidizing potentials of Mn oxides are determined by Mn valence states (2+, 3+, 4+). In this study, the effects of beam damage during electron energy-loss spectroscopy (EELS) in the transmission electron microscope have been investigated to ...
This investigation examined the instantaneous adsorption of NO(x) by moisture-saturated zeolites at ambient temperature. Among the zeolites studied, Faujasite exhibited the highest adsorption capacity owing to its relatively large pore size. Besides, the influence of cation was demonstrated by comparing the adsorption of zeolites with different cation densities (NaX vs. NaY, mesoporous silica MCM-48-like vs. Faujasite) and treatments (ion exchange of NaY with Cu(2+)). For the adsorption of NO, t ...
Polycyclic aromatic hydrocarbons (PAH) concentrations were measured in particles collected in oil tankers during refitting operations in which oxyacetylene flames were used. High levels of benzopyrene (8.3 +/- 7.2 mg/1000 m3) and nitrogen oxides (from 2 to 20 ppm) were detected. The fraction of collected smoke, soluble in cycloesane, was injected into the peritoneum of Balb/C mice. The frequency of sister chromatid exchange (SCE) induced in bone marrow cells was evaluated. A significant and dose ...
The aim of this study was to evaluate whether yerba maté alcoholic extracts at very low concentrations (0.01 and 0.1%), prevent/retard lipid peroxidation in beef hamburgers without impairing sensory acceptability. For this TBARs and hexanal levels, fatty acid profile and cholesterol oxides were evaluated as oxidation parameters in beef hamburgers during 90 days’ storage. The addition of 0.01% yerba maté ethanolic extracts proved inefficient in restraining the lipid peroxidation while the add ...
A catalyst/solvent-free, one-pot and operationally simple method for the synthesis of quinoline-substituted α-hydroxy carboxylic derivatives by the hydroxyheteroarylation of olefins with quinoline N-oxides is reported. The reaction features a high atom-economy, mild and reagent/solvent-free conditions, broad substrate scope and good selectivity with high yields. A preliminary mechanistic study to shed light into the reaction pathway was also carried out. ...
Conductive oxides RuOx as alternative electrode on high-k HfO2 gate dielectric have been fabricated by ultrahigh-vacuum sputtering and subsequently oxidized using oxygen plasma. The energy-band alignment for the RuOx /HfO2/Si system and the oxidation-state dependence of barrier height for RuOx contacting to HfO2 dielectrics has been analyzed by x-ray photoemission spectroscopy. The valenceand conduction-band offsets of HfO2/Si are determined to be 3.05±0.1 and 1.48±0.1 eV, respectively. The ba ...
Glassy carbon electrode (GCE) was modified with metal oxides (MO = Fe3O4, ZnO) nanoparticles doped phthalocyanine (Pc) and functionalized MWCNTs, and the electrocatalytic properties were studied. Successful synthesis of the metal oxide nanoparticles and the MO/Pc/MWCNT composite were confirmed using FTIR, Raman and SEM techniques. The electrodes were characterized using cyclic voltammetry (CV) technique. The electrocatalytic behaviour of the electrode towards epinephrine (EP) and norepinephr ...
A method has been developed for the production of (13)N-labeled ammonia in usable quantities with negligible contamination. A system was developed and a process for the production of nitrogen-13 ammonium ions from a target material in the form of a dilute solution of ethanol in natural water, i.e. the bombardment of oxygen-16 with protons within the target material. The system includes a device for producing a proton beam which travels along a pre selected path and strikes the target material in ...
The objective of the present work was to investigate the possibility of improving the hydrogen-storage capacity of mesoporous MCM-41 containing nickel (Ni) oxides (Ni/MCM-41). The MCM-41 and Ni/MCM-41 were prepared using a hydrothermal process as a function of Ni content (2, 5, and 10 wt.% in the MCM-41). The surface functional groups of the Ni/MCM-41 were identified by Fourier transform infrared spectroscopy (FTIR). The structure and morphology of the Ni/MCM-41 were characterized by X-ray diffr ...
In everyday life, the word “magnetism” most often refers to solid materials, metals, alloys, oxides. As for molecules, they are considered to be isolated, non-magnetic objects. Nevertheless, to be or not to be (magnetic) is not the appropriate question: everything is magnetic; the true problem lies in determining how. The purpose of this lecture is to illustrate the magnetism of molecules through some experiments. ...
Tebuquine is a 4-aminoquinoline that shows significantly more potency as an antimalarial than amodiaquine and chloroquine both in vitro and in vivo. To explore the conformation in the rate-limiting step and to elucidate pharmacophoric properties of tebuquine-related analogues, molecular shape analysis (MSA) along with molecular field analysis (MFA) methods were applied on a series of 5-[(7-chloro-4-quinolinyl)amino]-3-[(alkylamino)methyl][1,1'-biphenyl]-2-ol analogues and their Nomega-oxides pos ...
The self-assembly of 4-hydroxypyridine-2,6-dicarboxylic acid (H(3)CAM) and pyridine-2,6-dicarboxylic acid (H2PDA) with Zn(II) salts under hydrothermal conditions gave two novel coordination polymers {[Zn(HCAM)].H2O}n (1) and {[Zn(PDA)(H2O)(1.5)]}n (1a). 1 and 1a comprise of a 2D (4,4) net and a 1D zigzag chain, respectively, in which a new coordination mode of PDA is found. The reactions of H(3)CAM and H2PDA with Nd2O3 in the M/L ratio 2:3 gave {[Nd2(HCAM)3(H2O)4].2H2O}n (2) and {[Nd(2)(PDA)3(H2 ...
The mechanism of Fe<sup>3+</sup>catalyzed oxidation of S(IV) is the combination of catalyzed oxidation and radical reaction, the O<sub>2</sub><sup>-</sup> produced from the oxygen in solution plays a very important role for the oxidation of S(IV),which determines the mode and process of the reaction. In the absence of catalyst, the oxidation of S(IV) is relatively slow in the liquid, the reaction rate depends on the concentration of dissolved oxygen. When pH i ...
This work investigates properties of gate oxides grown on nitrogen-implanted substrates. It was demonstrated that the location of nitrogen peak in the gate oxide, once fixed at the beginning of the oxidation step, does not change with continued oxidation. Using this property, nitrogen peak was engineered near the gate oxide interface with substrate and was shown to suppress boron penetration more effectively without any significant degradation of the channel mobility in comparison to the case wh ...
The recent development of strain sensor devices which can actively monitor human body motion has attracted tremendous attention, for application in various wearable electronics and human-machine interfaces. In this study, as materials for strain sensor devices, we exploit the low-cost, carbon-based, 3-dimensional (3D) printable composite dough. The dough is prepared via a chemical method based on the formation of electrostatic assemblies between 1-dimensional, amine-functionalized, multi-walled ...
Eight novel silicate, phosphate and borate glass compositions (coded as NCLx, where x = 1 to 8), containing different oxides (i.e. MgO, MnO2, Al2O3, CaF2, Fe2O3, ZnO, CuO, Cr2O3) were designed and evaluated alongside apatite-wollastonite (used as comparison material), as potential biomaterials for bone tissue repair and regeneration. Glass frits of all the formulations were processed to have particle sizes under 53 μm, with their morphology and dimensions subsequently investigated by scannin ...
Technetium is a long-lived product of nuclear fission that readily forms the soluble pertechnetate anion [TcO(4)](-). Green rusts (layered hydrous oxides containing both Fe(II) and Fe(III) and with interlayer sulfate or carbonate anions) concentrate >99.8% of 99Tc, present as [TcO(4)](-), from aqueous solution, even in the presence of high concentrations of NaNO(3), a common constituent of radioactive waste streams. The mechanism of removal from solution is apparently reduction and formation ...
The prevalence of asthma and allergic disorders was assessed in 9-11 year-old children in Leipzig and Halle in East Germany, as well as in Munich, West Germany. Both East German cities are heavily polluted due to private burning of coal and industrial emissions, while Munich has low smoke emissions but heavy road traffic. All fourth grade pupils in Munich were compared with those in Leipzig and Halle. Non-specific airway disease (bronchitis), cough, and autumn/winter nasal symptoms were most pre ...
We demonstrate that the glass-transition temperature (T(g)) of a polymer sphere template is a crucial factor in the production of three-dimensionally ordered macroporous (3DOM) materials. Metal nitrate dissolved in ethylene glycol-methanol was infiltrated into the void of a face-centered, close-packed colloidal crystal of poly(methyl methacrylate) (PMMA)-based spheres. The metal nitrate reacts with EG to form a metal oxalate (or metal glycoxylate) solid (nitrate oxidation) in the void of the tem ...
La1-xSrxCoO3-δ belongs to the group of perovskite oxides of the ABO3 structure, with a trivalent rare earth in the A position (La) and a trivalent metal ion in the B position (Co). Doping with divalent Srions at the trivalent La-positions creates oxygen vacancies which give the oxide catalytic properties to H2O2. However, the conventional techniques which are used to prepare this oxide such as chemical methods, are not suitable for making a thin film. In this paper, a thin layer of La1-xSrxCoO3 ...
Transparent conductive oxides (TCOs) play a crucial role in solar cells by efficiently transmitting sunlight and extracting photo-generated charge. Here, we show how nanophotonics concepts can be used to transform TCO films into effective photon management layers for solar cells. This is accomplished by patterning the TCO layer present on virtually every thin-film solar cell into an array of subwavelength beams that support optical (Mie) resonances. These resonances can be exploited to concentra ...
Carbon-supported precious metal catalysts are widely used in heterogeneous catalysis and electrocatalysis, and enhancement of catalyst dispersion and stability by controlling the interfacial structure is highly desired. Here we report a new method to deposit metal oxides and metal nanoparticles on graphene and form stable metal-metal oxide-graphene triple junctions for electrocatalysis applications. We first synthesize indium tin oxide (ITO) nanocrystals directly on functionalized graphene sheet ...
UNLABELLED Regulatory agencies have shifted their emphasis from measuring emissions during certification cycles to measuring emissions during actual use. Emission measurements in this research were made from two different large ships at sea to compare the Simplified Measurement Method (SMM) compliant with the International Maritime Organization (IMO) NOx Technical Code to the Portable Emission Measurement Systems (PEMS) compliant with the US. Environmental Protection Agency (EPA) 40 Code of Fede ...
Harmful effects of potentially toxic elements (PTE's) in soils relate to their geochemically reactive fraction. To assess the degree of the reactivity, specific extractions or models are needed. Here we applied a 0.43 M HNO(3) chemical extraction to assess reactive pools of a broad range of PTE's in 136 contaminated and non-contaminated soils. Furthermore we derived Freundlich-type models based on commonly available soil properties (pH, organic carbon and clay) as well as extended models that us ...
Catechols bind strongly to several metal oxides and can thus be used as a binding group for generating self-assembled monolayers. Furthermore, their derivatives can be used to produce well-defined, centimeter-scale surface-chemical gradients on technologically relevant surfaces, such as titanium dioxide (TiO(2)). A simple dip-and-rinse gradient-preparation technique was utilized to produce surface-hydrophobicity gradients from perfluoro-alkyl catechols and nitrodopamine (ND). Chemical compositio ...
A simple and highly sensitive method is proposed for determination of trace amount of cerium. New method involves bleaching of greenish colour dye-malachite green, by the action of iodine, which is released by reaction between potassium iodide and cerium (IV) in acidic medium. Beer’s law is obeyed over concentration range of 0.6 to 4.6 μg cerium (IV) in final volume of 25 ml (0.024-0.184 ppm). Molar absorptivity and Sandell’s sensitivity were found to be 1.36 x 10 l mol cm and 0.002 μg cm, ...
Ground level ozone is one of the major air pollutants that the EPA is trying to control. Not only is it a major cause of smog, but it is a health threat especially for persons with lung, bronchial and other breathing problems. The EPA reports that more people in the USA are exposed to unacceptable levels of ozone than all the other criteria pollutants combined. Ozone is also harmful to growing plants resulting in agricultural losses. This low-level ozone is not a natural air constituent. It is g ...
The effect of enhancement reagents on the efficiency of electrokinetic remediation of Cu contaminated red soil is evaluated. The enhancement agents were a mix of organic acids, including lactic acid+NaOH, HAc-NaAc and HAc-NaAc+EDTA. The soil was prepared to an initial Cu concentration of 438 mgkg(-1) by incubating the soil with CuSO4 solution in a flooded condition for 1 month. Sequential extraction showed that Cu was partitioned in the soil as follows: 195 mgkg(-1) as water soluble and exchange ...
Zinc contamination in near- and sub-surface environments is a serious threat to many ecosystems and to public health. Sufficient understanding of Zn speciation and transport mechanisms is therefore critical to evaluating its risk to the environment and to developing remediation strategies. The geochemical and mineralogical characteristics of contaminated soils in the vicinity of a Zn ore transportation route were thoroughly investigated using a variety of analytical techniques (sequential extrac ...
  • Jian Liu, Feng Zhang, Bao Zhu, Chao-yi Xia,
  • Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases
  • 2011
OBJECTIVE To establish a method for rapid detecting nitric oxide (NO) and nitrogen dioxide(NO2) in the workplace air with infrared spectrometer. METHODS The method of infrared spectrometer was developed to detect nitrogen oxide in laboratory, then applied to detect the concentration of nitrogen oxide in workplace air. The present method was compared with National Standard Methods. RESULTS NO and NO2 in air were detected simultaneously with the infrared spectrometer, not interfering each othe ...
We studied the inorganic particulate contained in the lung parenchyma of 10 subjects (5 males and 5 females) resident in an urban area and not occupationally exposed to dusts. A total of 17 mineral types were identified, along with 16 metal elements in the form of oxides and sulfides. Approximately 70% of the minerals were made up of phyllosilicates, in particular clay, mica, and talc; three metal elements, Fe, Al, and Ti, accounted for more than 75% of the recovered oxide particles. The mean co ...
  • ,
  • 2000
A new approach for the detection of real-time properties of flames will be used in this project to develop improved diagnostics and controls for natural gas fired furnaces. The flame image sensing involves the use of both video cameras and optical spectroscopic observations along with advanced image analysis and pattern recognition techniques. These techniques will be used to identify flame features that can be correlated with the air/fuel ratio, level of nitrogen oxide emissions, and flame temp ...
The flame temperature of three kinds of solid propellants was measured by passive remote sensing FTIR with the resolution of 1 cm(-1). These three kinds of solid propellants are adulterate nano-scale metal oxide particles, adulterate normal metal oxide particles, and propellant without any adulterations. The main components of the solid propellant are nitrocellulose and nitroglycerin. The metallic oxides, including 6 nm CuO, 56 nm Fe2O3, 16 nm NiO, and correspondingly the normal particles, were ...
Chemical remediation has attracted increasing attention for heavy metal contaminated soils because of its relatively low cost and high efficiency. In this study laboratory incubation and column leaching experiments were conducted to understand the mechanisms of copper (Cu) immobilization by calcium water treatment residue (Ca-WTR) and to estimate the optimal rate for remediating Cu-contaminated soils. The results showed that Ca-WTR amendment significantly raised soil pH and decreased water solub ...