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Article
Preparation and Characterization of Silicon Dioxide Nanostructures by DC Reactive Closed-Field Unbalanced Magnetron Sputtering

Authors: Mohammed A. Hameed --- Zahraa M. Jabbar
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2016 Volume: 12 Issue: 4 Pages: 13-18
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

In this work, silicon dioxide nanostructures were prepared by a reactive closed-field unbalanced magnetron dc plasma sputtering technique. The target of p-type silicon was sputtered in presence of argon-oxygen gas mixture used for plasma generation and oxidation of silicon sputtered atoms. The x-ray diffraction patterns showed that only distinct peak corresponding to the crystal plane of (101) was observed with reasonable intensity. This is typical behavior of nanostructures. The scanning electron microscopy of the prepared samples showed that certain gas mixtures can produce the smallest particles with high probability for large grains to grow. Uniform distributed particles could be obtained using different mixtures. The energy-dispersive x-ray spectroscopy showed that only silicon and oxygen have appeared in the final sample with different weight percentages depending on the mixing ratio of the argon and oxygen gases. The SiO2 prepared in this work are very good candidates to be employed in random gain media as scattering particles.


Article
Conjunctional Freezing-Assisted Ultrasonic Extraction of Silicon Dioxide Nanopowders from Thin Films Prepared by Physical Vapor Deposition Technique

Author: Oday A. Hammadi
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2019 Volume: 15 Issue: 4 Pages: 23-28
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

In this work, the effects of different extraction parameters on the particle size of the nanopowders extracted from silicon dioxide thin film samples were studied. These nanopowders were obtained by the conjunctional freezing-assisted ultrasonic extraction method. Results showed that extraction parameters such as freezing temperature, ultrasonic frequency and application time are very effective in determining the nanoparticle size, which is very important for many applications and uses of highly-pure nanomaterials and nanostructures.


Article
Evaluation the Effect of Addition of Plasma Treated Polypropylene Fiber and Silanized Silicon Dioxide Nanoparticles Composite on Some Properties of Heat-Polymerized Polymethylmethacrylate

Authors: Ahmed G. Ahmed احمد غيث احمد --- Intisar J. Ismail انتصار جميل اسماعيل
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2016 Volume: 28 Issue: 4 Pages: 1-8
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Polymethylmethacrylate (PMMA) is the most commonly used material in denture construction. This material is far from ideal in fulfilling the mechanical requirements, like low impact and transverse strength and poor thermal conductivity are present in this material.The purpose of this study was to study the effect of addition a composite which include 1%wt silanized silicone dioxide nano fillers (SiO2) and 1wt% oxygen plasma treated polypropylene fiber (PP) on some properties of heat cured acrylic resin denture base material (PMMA).Materials and methods: One hundred (100) prepared specimens were divided into five groups according to the tests, each group consisted of 20 specimens and these were subdivided into two groups (unreinforced heat cured acrylic resin as control group)and reinforced acrylic resin with ( 1%wt Nano SiO2 and 1% wt oxygen plasma treated polypropylene fibers) group. The transverse strength¸ impact strength, indentation hardness (shoreD), surface roughness and water sorption and solubility were investigated. The results were statistically analyzed using descriptive and t-test.Results: The results of this study show that a highly significant increase in impact strength (10.4939 Kj/m2),surface hardness (89.9375) surface roughness (0.9498) and water sorption (0.0171mg/cm2) was observed with the addition of 1%wt silanized (SiO2) nanoparticles and 1%wt oxygen plasma treated polypropylene fibers to (PMMA) , also significant decrease in transverse strength (103.4753 N/mm2), nonsignificant decrease occurred in water solubility which was (0.0005mg/cm2).Conclusion: The incorporation of 1%wt silanized SiO2 nanoparticles and 1%wt oxygen plasma treated polypropylene fiber to heat cure PMMA form a composite improves the impact strength, surface hardness and surface roughness of acrylic resin, at the same time this addition increase the water sorption and decrease water solubility; while significant decrease in transverse strength


Article
Silicon Dioxide Nanostructures-Coated External Cavity for Gain Enhancement of Rhodamine B Lasing Dye

Authors: Mohammed A. Hameed --- Omar A. Ali --- Sarmed S.M. Al-Awadi
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2018 Volume: 14 Issue: 1 Pages: 3-10
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

In this work, nanostructured silicon dioxide films were deposited by closed-field unbalanced dc magnetron sputtering technique on two sides of quartz cells containing Rhodamine B dye dissolved in ethanol with 10-5 M concentration as a random gain medium. The preparation conditions were optimized to prepare highly pure SiO2 nanostructures with a minimum particle size of about 20nm. The effect of SiO2 films as external cavity for the random gain medium was determined by the laser-induced fluorescence of this medium and an increase of about 200% in intensity was observed after the deposition of nanostructured SiO2 thin films on two sides of the dye cell.


Article
New Modified Electrodes of Graphite paste with Nano Silicon dioxide For Determination of Sildenafil citrate Drug
أقطاب محورة جديدة من عجينة الكرافيت مع ثاني أوكسيد السيليكون النانوي لتقدير عقار سترات السيلدينافيل

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Abstract

In this research, new graphite paste electrodes modified with silicon dioxide (SiO2) nano particle are constructed and used for the determination of Viagra drug (Sildenafil citrate, SILC). The electrodes are constructed by preparing ion-pair for (SILC) with phosphotungstic acid (PTA) or phosphomolybdic (PMA) acid using dibutyl phthalate (DBP) as a plasticizer. These electrodes show good sensitivity towards SILC with linear range of (1.010-7-1.010-2) M, correlation coefficient, (0.9990) and the life time (120) days for both electrodes, limit of detection (5.17710-8 and 5.02610-8) M, optimum temperature range (23-50 and 23-65)oC , slope (57.33 and 58.01) mV/decade and optimum pH range (2-6 and 2-5), for SILC-PTA and SILC-PMA electrodes respectively. These electrodes were successfully applied for determination of SILC in pure and pharmaceutical preparation form (tablets) with recovery of not less than 98% .

في هذا البحث تم بناء قطبين جديدين من عجينة الكرافيت المحور بإضافة ثاني أوكسيد السليكون النانوي واستخدم لتقدير عقار السيلدينافيل. تم تصنيع هذه الأقطاب بتحضير مزدوج أيوني للعقار مع حامض الفوسفوتنكستك أو حامض الموليبديك واستخدام ثنائي بيوتيل الفثاليت كملدن. هذه الأقطاب أعطت حساسية جيدة لعقار الفياكرا بمدى خطي (10-7- 10-2) مولاري ومعامل ارتباط 0.9990 وعمر زمني 120 يوم لكلا القطبين. أن حد الكشف كان (5.177  10-8 و 5.026  10-8) مولاري ومدى درجة الحرارة المثلى (23-50 و23-60) درجة مئوية وميل (57.55 و58.01) mV/decade ومدى الدالة الحامضية (2-6 و2-5) لكل من قطب العقار مع حامض الفوسفوتنكستك وحامض الموليبديك على التوالي. تم استخدام هذه الأقطاب بنجاح لتقدير العقار بشكله النقي وفي الحبوب باسترجاعية لاتقل عن 98%.


Article
Evaluation the Effect of Adding Silanized Silicon Dioxide Nano Filler and Carbon Nanotube Composite on Some Properties of Heat Cured Acrylic Denture Base Material
تقييم تأثير اضافة خليط اوكسيد السيكون النانوي والكاربون نانو تيوب على مادة الطقم الاكريليكية الحرارية

Author: Abdalbasit A. Fatihallah عبد الباسط أحمد فتح الله
Journal: Al-Rafidain University College For Sciences مجلة كلية الرافدين الجامعة للعلوم ISSN: 16816870 Year: 2016 Issue: 38 Pages: 1-15
Publisher: Rafidain University College كلية الرافدين الجامعة

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Abstract

The mechanical properties of polymethyl methacrylate (PMMA) are still far from ideal to fulfill the perfect mechanical requirements for dental applications. The purpose of this study was to evaluate the effect of addition of silanized silicon dioxide Nano filler (SiO2) and carbon nanotube on some properties of heat cured acrylic resin denture base material.Materials and methods: One hundred sixty (160) prepared specimens were divided into 4 groups according to the tests, each group consisted of 40 specimens and these were subdivided into 4 groups (unreinforced heat cured acrylic resin as control group),reinforced acrylic resin with (1%wt carbon nanotube and 3%wt silanized silicon dioxide) group and reinforced acrylic with(1.5%wt carbon nanotube and 5%wt silanized silicon dioxide)and reinforced acrylic with (1.5%wt carbon nanotube and 7%wt silanized silicon dioxide) .The tensile strength, transverse strength, indentation hardness(shore D), water sorption and solubility were investigated . The results were statistically analyzed using ANOVA test with LSD multiple comparisons.Results: The result of this study shows a highly significant increase in tensile strength, surface hardness, transverse strength and significant decrease water sorption and water solubility with studied groups (the addition of carbon nanotube and silanized silicon dioxide) to PMMA than control group, also the best results were obtained with acrylic resin reinforced with(1.5%wt carbon nanotube and 5%wt silanized silicon dioxide).Conclusion: The addition of a mixture of carbon nanotube (1.5%wt) and silanized nano silicon dioxide (5%wt) to PMMA acrylic resins improves its mechanical and physical properties.

تحسين صفات مادة الطقم الاكريليكية الحرارية هي من اهم مايشغل العلماء في الوقت الحاضر تم استخدمت في البحث 160 عينه قسمت الى اربع مجاميع حسب نوع الفحص احتوت كل مجموعة على 40 وتم فحص بعض الخواص الميكانيكية والفيزياوية واتضح ان خليط الكاربون نانو تيوب بنسبة 1.5% من الوزن مضاف اليه اوكسيد السيليكون النانوي بنسبة 5% من الوزن يحسن صفات مادة الطقم الاكريلي الحراري.


Article
The Effect of Si/SiO2 Interface on the Electrical Properties of MOS Device with Nano Layer Silicon Dioxide Grown by Induced Laser Oxidation
تأثير السطح البيني Si/SiO2 على الخواص الكهربائية في نبيطةMOS ذات غشاء ثنائي اوكسيد السليكون النانوي، المنمى بطريقة الاكسدة المحتثة بالليزر

Authors: Mohand M. Alyass مهند مؤيد الياس --- Laith M. Al- Taan ليث محمد الطعان
Journal: Rafidain journal of science مجلة علوم الرافدين ISSN: 16089391 Year: 2017 Volume: 26 Issue: 1A Pages: 101-112
Publisher: Mosul University جامعة الموصل

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Abstract

In this work a MOS device was fabricated with nano dioxide layer on silicon using a laser induced oxidation technique, at 600oC temperature for different times oxidation (5-20) min.FTIR spectrums were studied and analyzed for the Si (111) substrate, the Si/SiO2 interface and the SiO2 layer. The results gave a characteristic sharp peak presence at the wave number (1079 cm-1) corresponding to the level of elongation vibration (Si-O-Si) which consists the required oxide.The electrical measurement results show the response of the MOS device for the (C-V) and (I-V) characteristics. The capacity was inhomogeneous at the interface between insulator and semiconductor because of the (ac) signal harmony, as an extra-capacity created depending on the frequency, while it does not appear at frequency (f >5kHz). This determines the nature of the electronic response of the device. The different times for the oxide configuration gives a different value for the capacity that's where the capacity increases with the time of laser induction oxidation increase. The oxide thickness has an inverse relationship with the time of laser induction of the oxidation.The (I-V) characteristics show the MOS devices fabricated with oxidation time at (5,10) min has leakage current started after 0.6 volt, where the devices which oxidized for 15 min has leakage current at 0.4 volt, but the leakage current begun at 0.2 volt for the devices with 20 min oxidation time.

صُنعت في هذا البحث نبيطةMOS ذات غشاء نانوي من ثنائي أوكسيد السيلكون باستخدام تقنية الأكسدة بالحث الليزري، وعند درجة حرارة 600oC، ولأزمنة مختلفة (5-20)min وتمت دراسة طيف الارضية السيلكونية Si(111) وطيف السطح البيني Si/SiO2 وكذلك طيف الغشاء SiO2 خلال تحليل طيف الامتصاص بواسطة مطياف FTIR.بينت النتائج، وجود قمة حادة عند العدد الموجي (1079cm-1) تقابل اهتزاز الاستطالة في مستوي (Si-O-Si) حيث يكون الاوكسيد المطلوب. اظهرت القياسات الكهربائية استجابة النبيطة لخصائص (C-V) و(I-V)، وأن السعة غير متجانسة عند السطح البيني بين العازل وشبه الموصل بسبب التتناغم مع أشارة (ac) وأنتاج متسعة أضافية تعتمد على التردد، فيما لا يظهر ذلك عند الترددات (f >5kHz)، وهذا يحدد طبيعة الاستجابة الالكترونية للنبيطة. وقد تبين أن الازمنة المختلفة لتكوين الاوكسيد تعطي منحنيات مختلفة لقيمة السعة، حيث ان السعة تزداد بزيادة زمن الحث الليزري. وأيضا أن السمك ذو علاقة عكسية مع زمن الحث الليزري للاكسدة بعد الإنماء الابتدائي السريع. وكذلك بينت خواص (I-V) أن في النبائط MOS المصنعة والمنماة بزمن أكسدة عند (5,10) min يبدأ تيار التسرب فيها بعد 0.6 volt، فيما بدأ تيار التسرب بعد 0.4 volt للنماذج المؤكسدة بزمن 15min. اما النماذج المؤكسد بزمن min (20) فقد بدأ تيار التسرب عند 0.2 volt.

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