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محمد رضوانی

عضو هیات علمی دانشگاه تبریز

[ 1 ] - بررسی شیشه سرامیک های شفاف Li2O-Al2O3-SiO2 در حضور آلاینده ی Nd2O3

شیشه‌سرامیک‌های شفاف سیستم LAS را اصطلاحا شیشه‌سرامیک‌های اپتیکی دقیق می‌نامند که در کاربردهایی نظیر فوتونیک، لیزرهای حالت جامد، تقویت کننده‌های نوری و غیره استفاده می‌شوند. هدف از این پژوهش، بهینه‌سازی شرایط تبلور این نوع شیشه‌سرامیک‌ها در حضور آلاینده‌ی Nd2O3 می‌باشد. بدین‌منظور، آنالیز حرارتی افتراقی(DTA) برای بررسی رفتار حرارتی‌ و تعیین دماهای تبلور، آنالیز پراش اشعه‌ی ‌X برای بررسی بلورهای...

[ 10 ] - Immobilization of Glucose oxidase on Meso-porous Glass-ceramic with the Skeleton of CaTi4(PO¬4)6

Microporous glass ceramic with skeleton of CaTi4(PO¬4)6 with average pore size of 12.7 nm has been synthesized and used as a carrier of glucose oxidase. The glass ceramic was prepared by controlled heat treatment of glass samples, which causes the phase separation in their structure and creates CaTi4(PO¬4)6 and β-Ca3(PO4)2 phases. The β-Ca3(PO4)2 phase was dissolved by soaking the glass ceramic...

[ 11 ] - MECHANICAL AND CHEMICAL PROPERTIES OF SiO2-Al2O3-CaO-MgO (R2O) GLASS CERAMICS IN THE PRESENCE OF VARIOUS NUCLEATING AGENTS

Abstract: The application of inexpensive materials such as copper, zinc, lead, iron and steel slag in manufacturing of glass and glass-ceramic products in construction industry, lining materials as anti-corrosion and anti-abrasion coatings in metals and etc, has led to considerable progress in glass technology in recent years. The composition of slag glass-ceramics is mainly located in the ...

[ 12 ] - بررسی اثر ترکیب، چگونگی سرمایش و نوع محفظه ذوب در شیشه سرامیک سیستم 2-TiO5O2CaO-P

در این پژوهش با توجه به کاربرد شیشه فسفاتی سیستم 2-TiO 5O 2CaO-P در شیشه سرامیک‌های فسفاتی، ترکیبات گوناگونی در سامانه یاد شده تهیه شد. اثرات بوته‌ی ذوب، زمان ذوب و چگونگی سرمایش بر روی ترکیب بهینه بررسی شد. برای این منظور از آنالیزهای XRDو FT-IR<...

[ 13 ] - بررسی و ساخت شیشه سرامیکهای سرباره ای با استحکام مکانیکی و سختی بالا با استفاده از جوانه زاهای مختلف

� ��� در سالهای اخیر استفاده از مواد ضایعاتی از جمله سرباره هلی مس، روی، سرب، آهن و فولاد برای ساخت محصولات شیشه ای و شیشه سرامیک در صنایع ساختمانی، مواد آستری به عنوان پوششهای ضد خوردگی و ضدسایش در فلزات و ... منجر به پیشرفتهای قابل توجهی در تکنولوژی شیشه شده است. ترکیب شیشه سرامیکهای سرباره ای عمدتاً در سیستم SiO2-Al2O3-CaO-MgO �قرار گرفته که یکی از مشکلات اصلی استفاده از این مواد در ساخت محصو...

[ 14 ] - بررسی اثر ترکیب جوانه‌زاها بر رفتار تبلور شیشه سرامیک سیستم (LAS) Li2O-Al2O3-SiO2

در تحقیق حاضر ترکیبات مختلف شیشه سرامیک سیستم لیتیم آلومینو سیلیکاتLi2O-Al2O3-SiO2 (LAS) به?منظور ساخت شیشه سرامیک با ضریب انبساط حرارتی پائین مورد بررسی قرار گرفت. رفتار جوانه?زنی و تبلور شیشه پایه بهینه شده با انتخاب عوامل جوانه?زای TiO2، ZrO2، P2O5، Y2O3 و CeO2 به?صورت منفرد، دوتائی، سه تائی و چهارتائی با استفاده از آنالیز حرارتی DTA مورد مطالعه قرار گرفت. در مورد نمونه?های بهینه شده دماهای ...

[ 15 ] - Microstructure, mechanical and thermal properties of chalcogenide glasses and glass-ceramics based on Se-As-Ge system nucleated by Sn

In particular, chalcogenide glasses and glass-ceramics are new materials that exhibit good transparency in infrared region (0.8-12µm). We can overcome the main weakness of these glasses by improving the hardness through controlling crystallization. In this paper, we report results of a study on chalcogenide glasses in the ternary system of As-Se-Ge with nominal composition of Snx (Se...

[ 16 ] - An investigation on the effect of acetone and DMF as solvent on synthesis of P2O5-CaO-Na2O-TiO2 glass powder by sol-gel method

The sol-gel synthesis method allows greater control over glass morphology at a relatively low processing temperature (200 °C) in comparison with melt-derived glasses. In present study, phosphate-based glasses with the general formula of (P2O5)55-(CaO)25-(Na2O)10-(TiO2)10 was synthesized via a novel and facil...

[ 17 ] - Determination of the Nucleation and Crystallization Parameters for Making Nanoporous Titanium Phosphate Glass-ceramics

Nanoporous glass-ceramics were prepared with composition 45CaO-25TiO2-35P2O5 (mol%). Two molar percent of Na2O was added as a flux to the composition. With the aforementioned composition, glass melted and crystallized into glass-ceramics containing β-Ca3(PO4)2 and CaTi4(PO4)6 as the main phases. The differential thermal analysis (DTA) was conducted to determine the suitable temperatures f...

[ 18 ] - Fabrication and Structural Characterization of Se-Ge Chalcogenide Glasses by Means of Melt Quenching Technique

The structural and optical characterization of Se-Ge alloys during melt quenching technique was the goal of this study. In this regards, five different samples of Se100-xGex (x= 10, 20, 30, 40, 50) were prepared by conventional melt quenching in quartz ampoule. The produced samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calori...

[ 19 ] - Optical characterization of BK7 borosilicate glasses containing different amounts of CeO2

Borosilicate BK7 glasses doped with different amounts of CeO2 (0.5,1,1.5%) were prepared by the convenient melting process in this work. DTA analysis proved that 0.5-1% CeO2 has a network modifier role and then up to 1.5% it shows network former role.For structural studies, FT-IR and Raman spectroscopy were carried out. Fermi energy level, direct/ indirect optical band gap and Urbach energy wer...

[ 20 ] - Investigation of crystallization and sinterability properties of BaO-Al2O3-SiO2 glass-ceramics containing K2O and B2O3

BaO -SiO2-Al2O3 glass ceramics containing K2O and B2O3 were prepared using conventional melting of powered batches, quenching in water and crystallization of sintered glass. XRD patterns introducehexacelsian and celsian as two major crystallized phases in sintered glass-ceramics. Presence of K2O enhances crystallization of hexacelsianin comparison withB2O3.Observations showed sintering temperat...

[ 21 ] - Luminescence Properties of Oxyfluoride Glass and Glass Ceramic Doped with Y3 + Ions

 Oxyfluoride glass ceramics containing CaF2nano-crystals doped with Y3+ ions were prepared by one-step crystallization of SiO2- Al2O3- CaO- CaF2 glasses at different temperatures. X- ray diffraction (XRD) results have revealed that CaF2 was the only precipitated crystalline phase in glass ceramic samples. According to the XRD results, a glass ceramic was selected as the best sample in order to ...

[ 22 ] - The Crystallization Effect on the Optical Properties of Oxyfluoride Glass-Ceramics Containing CaF2 Nanocrystals Doped with Y3+ Ions

In the present study, the oxyfluoride glasses of SiO2-Al2O3-CaF2 system containing different amounts of Y3+ ions were prepared through the convenient melting method. The crystallization temperatures and size of the CaF2 nanocrystals were obtained from DTA curves and XRD patterns, respectively. As a consequence, the optimum amount...

[ 23 ] - Fabrication and Investigation of Se-Ge Glass-Ceramics in the Presence of Ga and Sn Additives

The Chalcogenide glasses were fabricated by melting and quenching techniques in the Se-Ge system at the presence of 1mol% Ga and 3, 5, and 7mol% Sn. Differential Scanning Calorimetry (DSC) analysis was conducted to extract the heat treatment of the samples. Fourier Transform Infrared (FTIR) spectroscopy analysis was also performed in a range of 2-16µm. The Glass samples were heat-treated at 450...

[ 24 ] - Comparison of Semiconducting Behavior and Optical Properties of Oxyfluoride Glasses of SiO2-Al2O3-BaF2 and SiO2-Al2O3-CaF2 Systems

Amorphous semiconductors are materials with a brilliant prospect for a wide range of optical applications like solar cells, optical sensors, optical devices, and memories. The purpose of the present research was to study the semiconducting optical properties of SiO2-Al2O3-CaF2 and SiO2-Al2O3-BaF2 oxyfluoride...

[ 25 ] - An Investigation into the Effects of Composition and BaF2 Content on the Structure and Crystallization Behavior of SiO2-Al2O3-K2O-BaF2 Oxyfluoride Glasses

Nowadays, oxyfluoride glasses have received much attention from photonic researchers as they benefit from the advantages of both oxide and fluoride glasses (low phonon energy in parallel with high mechanical and chemical durability). The purppose of this paper was to study the different glass compositions in SiO2-Al2O3-K2O-BaF2 system and i...

[ 26 ] - Addition of Alumina to Nanoporous Calcium Titanium Phosphate Glass-Ceramics and its Effects on Crystallization Behavior

Microporous Calcium Titanium Phosphate glass-ceramics have many uses in high-tech industries. For example, they have applications in catalysts industry. In this study, different molar percentages of alumina were added to a glass with P2O5 30, CaO 45, TiO2 25 (mol%) composition. The samples were melted at 1350°C and crystallization heat treatment was performed on...