هدف: هدف پژوهش حاضر، تبیین طراحی مدل مطلوب برای گزینش دانشجو در دانشگاه فرهنگیان ایران است.مواد و روش‌ها: رویکرد حاکم بر کیفی بوده با استفاده از روش نظریه داده بنیاد انجام شده است. شرکت‌کنندگان عبارت بودند صاحب‌نظران تعلیم تربیت، اساتید، دست‌اندرکاران پذیرش (مدیران کارشناسان) فرهنگیان، دانشجویانی که طول شش سال قبل فارغ‌التحصیل شدند اکنون مدارس شاغل هستند نمونه‏گیری هدفمند 27 نفر آنان انتخاب آن‌...

هدف از این پژوهش اعتبار سنجی پرسشنامه جدید ۴ عاملی سیستم خود انگیزشی زبان دوم بعنوان یکی عوامل تاثیرگذار بر یادگیری انگلیسی بوده است. در تحقیق طرح پیمایشی به شیوه ی الگوی معادلات ساختاری نوع تحلیل تأییدی استفاده شده تعداد ۵۹۹ نفر (۳۰۸ دانشجوی خانم و ۲۹۱ آقا) سطح پیش متوسطه رده سنی ۲۵-۱۸سال که دانشگاه آزاد اسلامی – واحد تهران شرق رشته های مختلف تحصیلی مشغول تحصیل می باشند، شرکت کردند. آنجائیکه ا...

Ta8(μ3-O)2(μ-O)8(μ-OEt)6(OEt)14 (1) was obtained by the controlled hydrolysis of tantalum ethoxide Ta(OEt)5 in the presence of ammonia. Compound 1 is considered as the intermediate building block in the sol-gel polymerization of Ta(OEt)5. Further hydrolysis of compound 1 yielded nanoparticles of Ta2O5, which were characterized by various techniques such as TGA-DTA-DSC, UV-vis DRS, XRD, SEM, TEM...

Sol-gel method was applied to synthesize ultrafine nano α-alumina particles using aqueous solutions of aluminum isopropoxide and 0.5 M aluminum nitrate hydrate. Sodium dodecylbenzen suffocate and Sodium bis-2ethylhexyl sulfosuccinate were also used as surfactant stabilizing agents. The prepared solution was stirred for 48 hours at 60°C, then, the resultant gelled mass was dried at 90°C, and fin...

The waste shell was utilized as a bioresource of calcium oxide (CaO) in catalyzing a transesterification to produce biodiesel (methyl ester). The economic and environmen-friendly catalysts were prepared by a calcination method at 700-1,000°C for 4 h. The heterogeneous catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and the B...

Two new metal-organic framework (MOF) structures, IRMOF-3b and -3c, were prepared by ring-opening reaction of 1,3-propanesultone and 2-methylaziridine with an amine functionalized MOF, IRMOF-3. The new structures are permanently functionalized with covalently linked sulfonate and alkyamine units, respectively. The underlying framework structure is retained after reaction as confirmed by powder ...

Titania-supported palladium, gold and bimetallic nanoparticles (second-generation nanoparticles) demonstrate promising photocatalytic properties. However, due to unusual reactivity, second-generation nanoparticles can be hazardous for living organisms. Considering the ever-growing number of new types of nanoparticles that can potentially contaminate the environment, a determination of their tox...

A novel photocatalyst based on TiO2-PANI composite supported on small pieces of cork has been reported. It was prepared by simple impregnation method of the polyaniline (PANI)-modified TiO2 on cork. The TiO2-PANI/Cork catalyst shows the unique feature of floating on the water surface. The as-synthesized catalyst was characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM), t...

During the past 20 years, multiwall carbon nanotubes (MWCNTs) have become an important industrial material. Hundreds of tons are produced each year. This review is a survey of the scientific literature, motivated by industrial requirements and guidelines for environment, health and safety compliance. Sampling, size, area, density, color, crystallinity, as well as purity compared to properties o...

Anatase phase TiO2 nanostructures (Nanoparticles and nanorods) were prepared by two different methods. The prepared samples were characterized with Powder X-ray diffraction (PXRD), Field emission scanning electron microscopy (FESEM), High resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET) method and Barrett-Joyner-Halenda (BJH) analysis. The PXRD pattern shows tha...