نتایج جستجو برای: پیش ماده teos

تعداد نتایج: 127044  

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه مواد و انرژی - پژوهشکده نیمه هادیها 1390

در این پروژه، با استفاده از روش رسوب گذاری مستقیم و رسوب گذاری از کمپلکس، ابتدا سه پیش ماده هیدروکسیدی، کربناتی و اگزالاتی نیکل، تهیه شد. در ادامه با فرایند کلسیناسیون پیش ماده ها، اکسید نیکل نهایی بدست آمد و تاثیر عوامل موثری چون غلظت رسوب دهنده، دمای واکنش، ph محلول، نوع حلال، نحوه افزودن رسوب دهنده، فعال ساز سطحی و دمای کلسیناسیون بر ساختار و بافت ذرات تهیه شده، بررسی شد. نمونه های تولید شده...

2014
Daniel Nurkowski Philipp Buerger Jethro Akroyd Markus Kraft

This work presents a detailed kinetic modelling study of the thermal pyrolysis of tetraethoxysilane (TEOS). A chemical mechanism is proposed based on an analogy between the hydrocarbon branches attached to the central silicon atom and an existing mechanism for the decomposition and combustion of ethanol. Important reaction pathways are identified through element flux and sensitivity analyses. I...

Journal: :Journal of colloid and interface science 2015
Marcell Pálmai Roland Szalay Dorota Bartczak Zoltán Varga Lívia Naszályi Nagy Christian Gollwitzer Michael Krumrey Heidi Goenaga-Infante

A new method was developed for the preparation of highly monodisperse isotopically enriched Si-29 silica nanoparticles ((29)Si-silica NPs) with the purpose of using them as spikes for isotope dilution mass spectrometry (IDMS) quantification of silica NPs with natural isotopic distribution. Si-29 tetraethyl orthosilicate ((29)Si-TEOS), the silica precursor was prepared in two steps starting from...

2010
Malina Raileanu Ligia Todan Maria Crisan Ana Braileanu Adriana Rusu Corina Bradu Adrian Carpov Maria Zaharescu

Pesticides are widely used in agriculture, although they may create hazards both to humans and to the environment. In order to reduce the harmful effects of their administration, there has been made a great effort to find solutions. The porous sol-gel silica materials which are able to entrap different organic molecules represent new studied controlled release carriers. The aim of the present w...

Journal: :Journal of the American Chemical Society 2006
Ruili Liu Yifeng Shi Ying Wan Yan Meng Fuqiang Zhang Dong Gu Zhenxia Chen Bo Tu Dongyuan Zhao

Highly ordered mesoporous polymer-silica and carbon-silica nanocomposites with interpenetrating networks have been successfully synthesized by the evaporation-induced triconstituent co-assembly method, wherein soluble resol polymer is used as an organic precursor, prehydrolyzed TEOS is used as an inorganic precursor, and triblock copolymer F127 is used as a template. It is proposed for the firs...

2007
H. Juárez T. Díaz

A Subatmospheric Pressure Chemical Vapor Deposition (SAPCVD) system was implemented for SiO2 nanometric films deposition on silicon substrates. Tetraethoxysilane (TEOS) and ozone (O3) were used as precursors and they were mixed into the SAPCVD system at 590 Torr. The deposition temperatures ranged from 140 to 265 o C and the deposition time ranged from 1 to 15 min. The measured thicknesses from...

2017
Pey-Shiuan Wu Yi-Ching Lee Yi-Ching Kuo Chih-Chien Lin

Although octyl methoxy cinnamates (OMC) is the most used Ultraviolet B (UVB) filter in sunscreen, it has poor light stability in emulsion system. In this study, OMC/SiO₂ nanoparticles were prepared via sol-gel emulsion method. Tetraethoxy silane (TEOS) was used as the silica source to encapsulate OMC. Modification of experimental parameters such as stirring speed of condensation reaction and em...

2012
Sang-Jin Cho

Organic–inorganic hybrid co-polymer thin films were deposited on silicon(100) substrates under the several ratio of TEOS (tetraethoxysilane) against cyclohexene by plasma enhanced chemical vapour deposition (PECVD) method. Toluene and TEOS were utilized as organic and inorganic precursors each, and hydrogen and argon were also used as a bubbler and carrier gases, respectively. In order to compa...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان - دانشکده علوم پایه 1390

جهت بالا بردن قدرت جذب در کربن فعال، استفاده از یک واسطه مانند لیگند های مختلف بسیار معمول است، در این رو در این طرح سعی شده با استفاده از واسطه آلی اسید اگزالیک میزان جذب فلزات روی جاذب زروژل بهبود یابد. بدین منظور پس از سنتز زروژل teos و بررسی اثر آن بر روی چند فلز سنگین مشخص شد، این واسطه آلی اثرات مثبت خوبی روی افزایش میزان جذب سرب دارد، میزان جذب سرب از mg/g 273 در جاذب teos به بیش از سه ب...

2009
Benito Alcaide Sandra Niembro Alexandr Shafir Adelina Vallribera

Palladium nanoparticles were supported on a fluorous organic-inorganic hybrid material prepared by the sol-gel process without TEOS. Recycling studies on the Heck coupling reaction have shown that the catalyst can be readily recovered and reused.

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