The Experts below are selected from a list of 233925 Experts worldwide ranked by ideXlab platform
Hui Liu - One of the best experts on this subject based on the ideXlab platform.
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fe ii induced Transformation from ferrihydrite to lepidocrocite and goethite
Journal of Solid State Chemistry, 2007Co-Authors: Hui Liu, Meiying Zhu, Yu Wei, Yuhan SunAbstract:Abstract The Transformation of Fe(II)-adsorbed ferrihydrite was studied. Data tracking the formation of products as a function of pH, temperature and time is presented. The results indicate that trace of Fe(II) adsorbed on ferrihydrite can accelerate its Transformation obviously. The products are lepidocrocite and/or goethite and/or hematite, which is different from those without Fe(II). That is, Fe(II) not only accelerates the Transformation of ferrihydrite but also leads to the formation of lepidocrocite by a new path. The behavior of Fe(II) is shown in two aspects—catalytic dissolution–reprecipitation and catalytic solid-State Transformation. The results indicate that a high temperature and a high pH(in the range from 5 to 9) are favorable to solid-State Transformation and the formation of hematite, while a low temperature and a low pH are favorable to dissolution–reprecipitation mechanism and the formation of lepidocrocite. Special attentions were given to the formation mechanism of lepidocrocite and goethite.
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the formation of hematite from ferrihydrite using fe ii as a catalyst
Journal of Molecular Catalysis A-chemical, 2005Co-Authors: Hui Liu, Yu Wei, Yuhan SunAbstract:Abstract The objective of the research is to determine the effects of Fe(II) on the phase Transformation from ferrihydrite to hematite in pH range 5–9 at 100 °C. It is confirmed that Fe(II) is a catalyst in the process of phase Transformation of ferrihydrite. On one hand, Fe(II) can catalyze the formation of hematite by a dissolution/reprecipitation mechanism. On the other hand, Fe(II) can catalyze the formation of hematite by a solid-State Transformation. The species of Fe(II) that take catalytic action on the phase Transformation of ferrihydrite are probably FeOH+ and Fe(OH)2. Both dissolution/reprecipitation and solid-State Transformation can be explained by electron transfer. This phase Transformation from ferrihydrite to hematite, which is called as catalytic phase Transformation, can be employed to synthesize hematite particles rapidly.
Yuhan Sun - One of the best experts on this subject based on the ideXlab platform.
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fe ii induced Transformation from ferrihydrite to lepidocrocite and goethite
Journal of Solid State Chemistry, 2007Co-Authors: Hui Liu, Meiying Zhu, Yu Wei, Yuhan SunAbstract:Abstract The Transformation of Fe(II)-adsorbed ferrihydrite was studied. Data tracking the formation of products as a function of pH, temperature and time is presented. The results indicate that trace of Fe(II) adsorbed on ferrihydrite can accelerate its Transformation obviously. The products are lepidocrocite and/or goethite and/or hematite, which is different from those without Fe(II). That is, Fe(II) not only accelerates the Transformation of ferrihydrite but also leads to the formation of lepidocrocite by a new path. The behavior of Fe(II) is shown in two aspects—catalytic dissolution–reprecipitation and catalytic solid-State Transformation. The results indicate that a high temperature and a high pH(in the range from 5 to 9) are favorable to solid-State Transformation and the formation of hematite, while a low temperature and a low pH are favorable to dissolution–reprecipitation mechanism and the formation of lepidocrocite. Special attentions were given to the formation mechanism of lepidocrocite and goethite.
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the formation of hematite from ferrihydrite using fe ii as a catalyst
Journal of Molecular Catalysis A-chemical, 2005Co-Authors: Hui Liu, Yu Wei, Yuhan SunAbstract:Abstract The objective of the research is to determine the effects of Fe(II) on the phase Transformation from ferrihydrite to hematite in pH range 5–9 at 100 °C. It is confirmed that Fe(II) is a catalyst in the process of phase Transformation of ferrihydrite. On one hand, Fe(II) can catalyze the formation of hematite by a dissolution/reprecipitation mechanism. On the other hand, Fe(II) can catalyze the formation of hematite by a solid-State Transformation. The species of Fe(II) that take catalytic action on the phase Transformation of ferrihydrite are probably FeOH+ and Fe(OH)2. Both dissolution/reprecipitation and solid-State Transformation can be explained by electron transfer. This phase Transformation from ferrihydrite to hematite, which is called as catalytic phase Transformation, can be employed to synthesize hematite particles rapidly.
Ping Li - One of the best experts on this subject based on the ideXlab platform.
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fe ii induced Transformation from ferrihydrite to lepidocrocite and goethite
Journal of Solid State Chemistry, 2007Co-Authors: Ping LiAbstract:The Transformation of Fe(II)-adsorbed ferrihydrite was studied. Data tracking the formation of products as a function of pH, temperature and time is presented. The results indicate that trace of Fe(II) adsorbed on ferrihydrite can accelerate its Transformation obviously. The products are lepidocrocite and/or goethite and/or hematite, which is different from those without Fe(II). That is, Fe(II) not only accelerates the Transformation of ferrihydrite but also leads to the formation of lepidocrocite by a new path. The behavior of Fe(II) is shown in two aspects-catalytic dissolution-reprecipitation and catalytic solid-State Transformation. The results indicate that a high temperature and a high pH(in the range from 5 to 9) are favorable to solid-State Transformation and the formation of hematite, while a low temperature and a low pH are favorable to dissolution-reprecipitation mechanism and the formation of lepidocrocite. Special attentions were given to the formation mechanism of lepidocrocite and goethite. - Graphical abstract: Fe(II)-adsorbed ferrihydrite can rapidly transform into lepidocrocite or/and goethite or/and hematite. Which product dominates depends on the Transformation conditions of ferrihydrite such as temperature, pH, reaction time, etc. In the current system, there exist two Transformation mechanisms. One is dissolution/reprecipitation and the other is solid-State Transformation. The Transformation mechanisms from Fe(II)-adsorbedmore » ferrihydrite to lepidocrocite and goethite were investigated.« less
Shangru Chen - One of the best experts on this subject based on the ideXlab platform.
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estimation of asymptotic stability region and sliding domain of uncertain variable structure systems with bounded controllers
Automatica, 1996Co-Authors: Kuokai Shyu, Shangru ChenAbstract:This work is concerned with the problem of estimating the asymptotic stability region and sliding domain of uncertain variable structure systems with bounded controllers. The properties of the decoupling theorem and strictly positive real function are used to incorporate with the Lyapunov stability to estimate the stability region and the attractive region of the sliding mode. It will be shown that the special State Transformation used in previous work is no longer needed. Obviously, our result is directly related to the original system States.
Kosuke Nagashio - One of the best experts on this subject based on the ideXlab platform.
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molecularly thin anatase field effect transistors fabricated through the solid State Transformation of titania nanosheets
Nanoscale, 2017Co-Authors: S Sekizaki, Minoru Osada, Kosuke NagashioAbstract:We demonstrate the field-effect transistor (FET) operation of a molecularly-thin anatase phase produced through solid State Transformation from Ti0.87O2 nanosheets. A monolayer Ti0.87O2 nanosheet with a thickness of 0.7 nm is a two-dimensional oxide insulator in which Ti vacancies are incorporated, rather than oxygen vacancies. Since the fabrication method, in general, largely affects the film quality, the anatase films derived from the Ti0.87O2 nanosheets show interesting characteristics, such as no photocurrent peak at ∼2 eV, which is related to oxygen vacancies, and a larger band gap of 3.8 eV. The 10 nm thick anatase FETs exhibit superior transport characteristics with a maximum mobility of ∼1.3 cm2 V-1 s-1 and a current on/off ratio of ∼105 at room temperature. The molecularly-thin anatase FET may provide new functionalities, such as field-effect control of catalytic properties.
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molecularly thin anatase field effect transistors fabricated through the solid State Transformation of titania nanosheets
arXiv: Materials Science, 2017Co-Authors: S Sekizaki, Minoru Osada, Kosuke NagashioAbstract:We demonstrate the field-effect transistor (FET) operation of molecularly-thin anatase phase produced through solid State Transformation from Ti0.87O2 nanosheets. Monolayer Ti0.87O2 nanosheet with a thickness of 0.7 nm is two-dimensional oxide insulators in which Ti vacancies are incorporated, rather than oxygen vacancies. Since the fabrication method, in general, largely affects the film quality, the anatase films derived from Ti0.87O2 nanosheet show interesting characteristics, such as no photocurrent peak at ~2 eV, which is related to oxygen vacancies, and a larger band gap of 3.8 eV. The 10-nm thick anatase FETs exhibit superior transport characteristics with a maximum mobility of ~1.3 cm2V-1s-1 and current on/off ratio of ~105 at room temperature. The molecularly-thin anatase FET may provide new functionalities, such as field-effect control of catalytic properties.
