نتایج جستجو برای: hydrothermal process

تعداد نتایج: 1326923  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده ادبیات 1391

nothing affects learners more than assessment, so it is important to involve them in assessment process. involvment of learners in assessment helps them to become autonoumos learners. despite this importance iranian learners specialy javanroodian ones are not activily involved in the process. hence the aim of this thesis is to invesrtigate thier ability in th eassessment process

Journal: :Physical chemistry chemical physics : PCCP 2010
Zhenhe Xu Chunxia Li Dongmei Yang Wenxing Wang Xiaojiao Kang Mengmeng Shang Jun Lin

Nearly monodisperse NaGdF(4) and GdF(3) nanowires/nanorods as well as GdBO(3) microplates/microflowers have been successfully prepared by a designed chemical conversion approach using Gd(OH)(3) nanowires/nanorods as precursors via a facile hydrothermal approach. The Gd(OH)(3) nanowires/nanorods precursors were prepared through a simple hydrothermal process, which then served as sacrificial temp...

2008
J. FIEBIG J. FIETZKE V. LIEBETRAU D. GÜNTHER M. FRISCHE K. ZUMHOLZ T. H. HANSTEEN A. EISENHAUER

The emission of methane and the higher hydrocarbons is observed in both mid-ocean ridge and subduction-related hydrothermal systems. It has been recently reported that methane emanating from an extensional ultramafichydrothermal system originates from the abiogenic reduction of (mantle) CO2 (1). The same process is also known to occur in subaerial subduction-related systems (2). These findings ...

Journal: :Physical chemistry chemical physics : PCCP 2011
Shudong Zhang Bo Shang Jinlong Yang Wensheng Yan Shiqiang Wei Yi Xie

The phase transition process from VO(2) (B) to VO(2) (A) was first observed through a mild hydrothermal approach, using hybrid density functional theory (DFT) calculations and crystallographic VO(2) topology analysis. All theoretical analyses reveal that VO(2) (A) is a thermodynamically stable phase and has a lower formation energy compared with the metastable VO(2) (B). For the first time, X-r...

2002
Keith P. Harrison Robert E. Grimm

[1] Models of hydrothermal groundwater circulation can quantify limits to the role of hydrothermal activity in Martian crustal processes. We present here the results of numerical simulations of convection in a porous medium due to the presence of a hot intruded magma chamber. The parameter space includes magma chamber depth, volume, aspect ratio, and host rock permeability and porosity. A prima...

2015
Liang Chu Zhengfei Qin Jianping Yang Xing’ao Li

Anatase TiO2 nanoparticles with exposed {001} facets were synthesized from Ti powder via a sequential hydrothermal reaction process. At the first-step hydrothermal reaction, H-titanate nanowires were obtained in NaOH solution with Ti powder, and at second-step hydrothermal reaction, anatase TiO2 nanoparticles with exposed {001} facets were formed in NH4F solution. If the second-step hydrotherma...

2008
Kyoungrean Kim Koichi Fujie Toshiharu Fujisawa

Residual solid in excess sludge treated by hydrothermal reaction was investigated as raw material for its recycling. Treated excess sludge and residual solid were also focused on their content change during hydrothermal reaction. Two kinds of excess sludge, obtained from a local food factory and a municipal wastewater treatment process, were tested under various conditions. Following hydrotherm...

2017
Guo-Hua Feng Kuan-Yi Lee

This paper presents a study of lead zirconate titanate (PZT) films hydrothermally grown on a dome-shaped titanium diaphragm. Few articles in the literature address the implementation of hydrothermal PZT films on curved-diaphragm substrates for resonators. In this study, a 50-μm-thick titanium sheet is embossed using balls of designed dimensions to shape a dome-shaped cavity array. Through singl...

2015
M N Georgieva C T S Little A D Ball A G Glover

Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea hydrothermal vent chimneys. Over short periods of time, these tubes can become entirely mineralized within this environment. Documenting the nature of this process in terms of the stages of mineralization, as well as the mineral textures and end products that result, is essentia...

2014
Yu Xia Zhihong Chen Zhengguo Zhang Xiaoming Fang Guozheng Liang

We explore a facile and nontoxic hydrothermal route for synthesis of a Cu2ZnSnS4 nanocrystalline material by using l-cysteine as the sulfur source and ethylenediaminetetraacetic acid (EDTA) as the complexing agent. The effects of the amount of EDTA, the mole ratio of the three metal ions, and the hydrothermal temperature and time on the phase composition of the obtained product have been system...

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