نتایج جستجو برای: free xerogel

تعداد نتایج: 514214  

Journal: :Catalysis Today 2023

Platinum group metal-free catalysts have been intensively investigated in the last decades as an alternative to platinum with aim of lowering cost polymer electrolyte fuel cells. In particular, iron-nitrogen-carbon (Fe-N-C) has proved be most active towards oxygen reduction reaction. For practical application, a hierarchical pore structure is required, micropores favouring creation sites and la...

2012
BEATA GROBELNA ANNA SYNAK PIOTR BOJARSKI

The new material consisting of Gd1.6Dy0.4(WO4)3 incorporated into silica xerogel was prepared via the coprecipitation method. The luminescence properties of the studied material were analyzed by means of emission and excitation spectra, including the result of luminescence lifetimes of Dy(III) ion. The enhanced yellow emission due to the excitation energy transfer from group to Dy(III) ion upon...

2012
Juliana P. S. Sousa Manuel F. R. Pereira José L. Figueiredo

Carbon xerogels were prepared by the polycondensation of resorcinol and formaldehyde using three different solution pH values and the gels were carbonized at three different temperatures. Results show that it is possible to tailor the pore texture of carbon xerogels by adjusting the pH of the initial solution and the carbonization temperature. Materials with different textural properties were o...

Journal: :Journal of Physical Chemistry & Biophysics 2014

2009
Tammy P. Chou Guozhong Cao

Xerogels consisting of SiO2 and TiO2 were explored for controlled release of brilliant blue FCF (BBF). Both SiO2 and SiO2–TiO2 xerogels were prepared by way of sol–gel processing, and the BBF release behavior was compared. SiO2–TiO2 xerogels with varying TiO2 content were also studied and the BBF release behavior was determined for each SiO2–TiO2 xerogel. It was found that the release of BBF fr...

2008
Mohamad Hajj-Hassan Timothy Gonzalez Ebrahim Ghafar-Zadeh Hagop Djeghelian Vamsy Chodavarapu Mark Andrews Daniel Therriault

We describe an automated robotic technique called direct-dispense to fabricate a polymeric platform that supports optical sensor arrays. Direct-dispense, which is a type of the emerging direct-write microfabrication techniques, uses fugitive organic inks in combination with cross-linkable polymers to create microfluidic channels and other microstructures. Specifically, we describe an applicatio...

Journal: :Journal of controlled release : official journal of the Controlled Release Society 2005
Zhijian Wu Hyeonwoo Joo Tai Gyu Lee Kangtaek Lee

We investigate the controlled release of lidocaine hydrochloride from the doped silica-based xerogels. In the xerogel preparation, tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), and propyltriethoxysilane (PTES) are used as precursors, and a nonionic surfactant Igepal CO 720 is used as a dopant. The experimental results suggest that the release of lidocaine hydrochloride can be easily c...

پایان نامه :دانشگاه آزاد اسلامی واحد علوم پزشکی تهران - دانشکده پزشکی 1390

مقدمه : استعمال سیگار و مواد مخدر از جمله معضلات رایج بهداشتی محسوب می شوند. نه تنها استعمال سیگار، بلکه مواجه با دود آنها نیز عواقب زیادی را برای انسان ایجاد می نماید. در معرض دود سیگار بودن نیز خطر ابتلا به سرطان و بیماری های قلبی و عروقی را افزایش می دهد. یکی از عوامل مطرح شده در مورد مصرف سیگار اختلال در روند التیام زخم می باشد. بر همین اساس بر آن شدیم که به بررسی اثر مصرف سیگار بر روی باز ...

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