نتایج جستجو برای: transition metal oxide

تعداد نتایج: 593225  

Polyaniline/polystyrene (PAni/PS) composites were prepared in aqueous solution by polymerization of styrene and aniline in two-stages. Firstly styrene polymerize by using Ammonium persulfate (APS) as an oxidant in the presence of various surfactants such as poly(vinyl pyrrolidone) (PVP), hydroxypropylcellulose (HPC), poly(vinyl alcohol) (PVA) and surfactive dopant sodium dodecylbenzenesulfonate...

2012
Takashi Mizokawa

Some transition metal oxides have frustrated electronic states under multiphase competition due to strongly correlated d electrons with spin, charge, and orbital degrees of freedom and exhibit drastic responses to external stimuli such as optical excitation. Here, we present photoemission studies on Pr0.55(Ca1 - ySry)0.45MnO3 (y = 0.25), SrTiO3, and Ti1 - xCoxO2 (x = 0.05, 0.10) under laser ill...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2011
somayeh mahmoodi mohammad reza ehsani marzieh hamidzadeh

the oxidative coupling of methane (ocm) over m-na-mn/sio2 catalysts (m=w, cr, nb and v) was investigated using a continuous-flow quartz reactor at 775°c, 1 atm and 100 cm3min-1 gas flow rates, and correlated with the observed structure and redox properties.the interaction effects of the metal-metal and metal-support on the methane conversion and c2+ yield were investigated using x-ray diffracti...

2015
Hai-Tian Zhang Lei Zhang Debangshu Mukherjee Yuan-Xia Zheng Ryan C. Haislmaier Nasim Alem Roman Engel-Herbert

Transition metal oxides offer functional properties beyond conventional semiconductors. Bridging the gap between the fundamental research frontier in oxide electronics and their realization in commercial devices demands a wafer-scale growth approach for high-quality transition metal oxide thin films. Such a method requires excellent control over the transition metal valence state to avoid perfo...

Journal: :Physical review letters 2001
J Burgy M Mayr V Martin-Mayor A Moreo E Dagotto

The influence of quenched disorder on the competition between ordered states separated by a first-order transition is investigated. A phase diagram with features resembling quantum-critical behavior is observed, even using classical models. The low-temperature paramagnetic regime consists of coexisting ordered clusters, with randomly oriented order parameters. Extended to manganites, this state...

2015
Woobin Lee Seungbeom Choi Kyung Tae Kim Jingu Kang Sung Kyu Park Yong-Hoon Kim

We report a derivative spectroscopic method for determining insulator-to-semiconductor transition during sol-gel metal-oxide semiconductor formation. When an as-spun sol-gel precursor film is photochemically activated and changes to semiconducting state, the light absorption characteristics of the metal-oxide film is considerable changed particularly in the ultraviolet region. As a result, a pe...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه پلیمر و پتروشیمی ایران - پژوهشکده علوم و تکنولوژی پلیمر 1391

پلیمریزاسیون اتیلن مدت های مدیدی است که از روش های مختلف انجام شده است این روش ها از پلیمریزاسیون رادیکالی در دما وفشار بالا آغاز شد و به مرور زمان حجم تولیدآن با استفاده از سیستم های کاتالیستی به شدت افزایش یافت. پلیمریزاسیون های کاتالیستی نسبت به روش های سابق پلیمریزاسیون مزایای بسیار زیادی دربرداشت که از جمله می توان به پایین آمدن دما وفشار واکنش تا حد بسیار قابل توجه اشاره کرد. اما یکی از ا...

In this paper, we have focused on the preparation and characterization of copper oxide nanoparticles by solid state thermal decomposition of copper(I) iodide in the presence of thiosemicarbazone ligands without the need for a catalyst, employing toxic solvent, template or surfactant and complicated equipment, which makes it efficient, one-step, simple and environment-friendly. CuO nanoparticles...

Journal: :Nature chemistry 2011
Jin Suntivich Hubert A Gasteiger Naoaki Yabuuchi Haruyuki Nakanishi John B Goodenough Yang Shao-Horn

The prohibitive cost and scarcity of the noble-metal catalysts needed for catalysing the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries limit the commercialization of these clean-energy technologies. Identifying a catalyst design principle that links material properties to the catalytic activity can accelerate the search for highly active and abundant transition-metal-oxi...

Journal: :Science 2005
Elbio Dagotto

A wide variety of experimental results and theoretical investigations in recent years have convincingly demonstrated that several transition metal oxides and other materials have dominant states that are not spatially homogeneous. This occurs in cases in which several physical interactions-spin, charge, lattice, and/or orbital-are simultaneously active. This phenomenon causes interesting effect...

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