نتایج جستجو برای: si وsiga
تعداد نتایج: 74952 فیلتر نتایج به سال:
in this research, using pyrolysis of phenolic resin in the presence of silicon particles, the sic ceramic composite is formed. the samples were prepared by introducing 30, 35, 40, 45 and 50 wt% of si particles to the phenolic resin. the samples were cured at 180°c then carbonized at 1100°c. the final carbonized c/si composites are hot-pressed at 1500°c in inert atmosphere, which is more than th...
مقدمه: سونوگرافی کمی استخوان (qus)، روشی کم هزینه، ارزان و غیرتهاجمی برای سنجش تراکم استخوان است. هدف این مطالعه تعیین حدود طبیعی پارامترهای qus در یک جمعیت ایرانی است. مواد و روش ها: استخوان پاشنه پا در 259 فرد سالم 76-20 ساله (شرکت کنندگان مطالعه imos که به روش تصادفی از سطح شهر تهران انتخاب شده بودند) به روش qus با استفاده از دستگاه achilles+ در بخش bmd مرکز تحقیقات غدد علوم پزشکی تهران بررس...
شاخص si عبارت است از مقدار شیب منحنی رطوبتی در نقطه عطف وقتی که منحنی رطوبتی براساس مقدار رطوبت جرمی خاک در برابر لگاریتم طبیعی مکش خاک (در مبنای e)، رسم می¬شود و به عنوان شاخص کیفیت فیزیکی خاک (si) در نظر گرفته ¬می¬شود. از آنجایی¬که اندازه¬گیری شاخص si بسیار وقت¬گیر و پر¬هزینه است استفاده از توابع انتقالی بسیاری برای تخمین آن پیشنهاد شده ¬است. به این منظور از 58 نمونه خاک که به صورت سطحی (cm 1...
Polymorphous Si is a nanostructured form of hydrogenated amorphous Si that contains a small fraction of Si nanocrystals or clusters. Its thermally induced transformations such as relaxation, dehydrogenation, and crystallization have been studied by calorimetry and evolved gas analysis as a complementary technique. The observed behavior has been compared to that of conventional hydrogenated amor...
Model and Methods Energy Hamiltonian.To extend a structure-based model to systems with multiple basins, we modified the contact map and the dihedral angles. Note that all the residue indexes are rearranged from 1 to 366 in the model. To include the side chain dynamics on the conformational change of enzyme, we developed a coarse-grained model in which each amino acid is represented by one or tw...
Soils of the tropics and sub-tropics are typically acid and depleted of soluble sources of silicon (Si) due to weathering and leaching associated with high rainfall and temperatures. Together with intensive cropping, this leads to marginal or deficient plant Si levels in Si-accumulating crops such as rice and sugarcane. Although such deficiencies can be corrected with exogenous application of S...
The efficacy of high-load, short-duration isometric contractions, delivered as one vs. two sessions per day, on blunting inactivity-induced adaptations in the medial gastrocnemius (MG) were compared. Adult rats were assigned to a control (Con) or spinal cord-isolated (SI) group where one limb was stimulated (SI-Stim) while the other served as a SI control (SI-C). One bout of stimulation (BION m...
We have explored the radiation response of the HfO2/Si system with a combination of capacitance versus voltage and electron spin resonance measurements on capacitor and bare oxide structures subjected to Co gamma irradiation and vacuum ultraviolet irradiation. Our studies have utilized both (100)Si and (111)Si substrate structures. Capacitors have been irradiated under both positive and negativ...
Silicon (Si) is taken up from the soil as monosilicic acid by plant roots, transported to leaves and deposited as phytoliths, amorphous silica (SiO2) bodies, which are a key component of anti-herbivore defense in grasses. Silicon transporters have been identified in many plant species, but the mechanisms underpinning Si transport remain poorly understood. Specifically, the extent to which Si up...
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