نتایج جستجو برای: al si

تعداد نتایج: 504581  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1390

در این پایان نامه با هدف دستیابی به کاتالیستی که بتواند پایداری خود را در شرایط سخت عملیاتی فرایند شکست کاتالیستی-حرارتی به منظور تولید اولفین های سبک حفظ کند، زئولیت hzsm-5 به دلیل ساختار و خصوصیات منحصر به فرد آن با نسبتهای مختلفsi/al انتخاب شد. به جهت بهبود خوصیات اسیدی و قلیایی کاتالیست و عملکرد بهتر در واکنش های شکست، عنصر سریوم برای اصلاح کاتالیست انتخاب شد. همچنین به جهت حفظ ساختار کاتال...

2008
Luyan Sun Bruce E. Kane LUYAN SUN Christopher J. Lobb

Title of dissertation: CHARACTERIZATION OF METAL-OXIDE-SEMICONDUCTOR STRUCTURES AT LOW TEMPERATURES USING SELF-ALIGNED AND VERTICALLY COUPLED ALUMINUM AND SILICON SINGLE-ELECTRON TRANSISTORS Luyan Sun, Doctor of Philosophy, 2008 Dissertation directed by: Dr. Bruce E. Kane Department of Physics I incorporate an Al-AlOx-Al single-electron transistor (SET) as the gate of a narrow (∼ 100 nm) metal-...

Journal: Evidence Based Care 2012

Background: The Trauma is one of the most important health problems and a leading cause of death in 4th decade of life. Mortality due to accidents has a critical situation in Iran and mortality rate is increasing10-15% annually. Aim: To assess the relationship of shock index with trauma patient’s mortality after first 24 hours of admission at Khatam-al-Anbia Hospital in Iranshahr. Method A cros...

2017
Y. E. Kalay L. Scott Chumbley Iver E. Anderson Ralph E. Napolitano

The rapid solidification microstructure of gas-atomized Al-Si powders of 15, 18, 25, and 50 wt pct Si were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In order of increasing particle size, the powders exhibited microcellular Al, cellular/dendritic Al, eutectic Al, and primary Si growth morphologies. Interface velocity and undercooling were estim...

2014
Zimin Li Zhaoliang Song Jean-Thomas Cornelis

The continental bio-cycling of silicon (Si) plays a key role in global Si cycle and as such partly controls global carbon (C) budget through nutrition of marine and terrestrial biota, accumulation of phytolith-occluded organic carbon (PhytOC) and weathering of silicate minerals. Despite the key role of elemental composition of phytoliths on their solubility in soils, the impact of plant cultiva...

2011
Aniruddha Biswas Donald J. Siegel David N. Seidman

Atom-probe tomography, transmission electron microscopy, X-ray diffraction and first-principles calculations are employed to study: (i) compositional evolution of GPII zones and h0 precipitates; and (ii) solute segregation at a-Al/h0 interfaces in Al–1.7 at.% Cu (Al–4 wt.% Cu) alloys. GPII zones are observed after aging at 438 K for 8 h, whereas higher aging temperatures, 463 K for 8 h and 533 ...

In this study, pure powders such as molybdenum, silicon, aluminum and titanium carbide were utilized to produce MoSi2 compound, MoSi2 /20 Vol % TiC composite, MoSi2-x Al alloyed compound and MoSi2-x Al/20 Vol % TiC alloyed composite. The initial powders were mixed in specified ratios, and then, were activated by mechanical milling. Milled powders were compacted, synthesized and sintered in the...

درودیان, مسعود, طیبی فرد, سید علی , یزدانی راد, رحیم, احمدی, کامران,

X-ray powder diffraction data for Mo2.85Al1.91Si4.81 are presented here. The new Mo2.85Al1.91Si4.81 compound was successfully prepared, using the self-propagating high-temperature synthesis (SHS) technique. The starting atomic mixture of reactant powders was Mo + 2(1 - x)Si + 2xAl with 0.2 ≤ x ≤ 0.5. The final powder compound obtained by the SHS technique was determined to be in x = 0.2; Mo(Si,...

2011
MUHAMMAD ZARIF BRIAN MCKAY PETER SCHUMACHER

Al-5 wt pct Si master-alloys with controlled Sr and/or P addition/s were produced using super purity Al 99.99 wt pct and Si 99.999 wt pct materials in an arc melter. The master-alloy was melt-spun resulting in the production of thin ribbons. The Al matrix of the ribbons contained entrained Al-Si eutectic droplets that were subsequently investigated. Differential scanning calorimetry, thermodyna...

2008
E. J. Martínez

DTA analysis was used to investigate the solidification reactions of alloy A319 with either 12 or 136 ppm of Sr added. Strontium does not affect primary solidification of (Al) dendrites but modifies the kinetics of the (Al)–Si eutectic. The effects of Sr level and of cooling rate on the characteristic temperatures for the (Al)–Si and other eutectic reactions are described.

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