Show: 25 50 75 100 Results

Search results: 6 out of 6

حسابات نسبيه لبعض خصائص اطياف الذرات المتوسطة والمرتفعة العدد الذري == RELATIVISTIC COMPUTATION OF SOME SPECTROSCOPIC CHARACTERISTICS OF MEDIUM AND HIGH Z - ATOMS

Author name: عدنان يوسف حسين
Supervisor name: Ra’ad A. Radhi
General topic: Physics
Specific topic: Atomic Physics
Degree: Doctorate
University: Al-Nahrain University - College Of Science - Physics Department
Language: English
University location: Baghdad
First pages:
Abstract: تم تقديم دراسة منتظمة لطريقة هارتري - فوك غير النسبيه وكذلك نسختها النسبية (ديراك - فوك) لمعدل التوزيع. بالنسبه للطريقة غير النسبية؛ فقد تم اشتقاق معادلات هارتري - فوك وبشكل مفصل واخذ بنظر الاعتبار التصحيح النسبي (تاثير الكتله - السرعه وتاثير دارون وتاثير تفاعل البرم - المداري للاكترون) وقد اعتبر كرتبه اولى للاضطراب. اما بالنسبه للطريقه النسبيه؛ فقد تم اشتقاق معادلات ديراك - فوك واخذ بنظر الاعتبار تاثير تفاعل بريت كتصحيح نسبي للتفاعل الكولومي وقد اعتبر كرتبه اولى للاضطراب. تم تقديم معادلات عناصر المصفوفه لتفاعل بريت (الحد المغناطيسي والحد الارتدادي) لمعدل التوزيع. تم تقديم النتائج لبعض خصائص الذرات في المستوى الارضي(Rb, Zr, Pd, Sn, Cs, Ba, Lu, Ir, Hg, Tl, Bi, Rn ) وتمت مقارنتها بالنتائج العمليه. التاثير النسبي على طاقات الاغلفه الذريه مهم وخصوصا على الاغلفه الداخليه 1s و2s وهذا التاثير يكون محسوسا كلما ارتفع العدد الذري. يكون تاثير بريت حوالي %2 من تاثير التصحيح النسبي (تاثير الكتله - السرعه وتاثير دارون). حسابات هارتري - فوك والتصحيح ال | A systematic study of the non - relativistic Hartree - Fock method and its relativistic version, Dirac - Fock method for the average of configuration have been presented. In the non - relativistic case, a fully derivation of the Hartree - Fock equations were presented and relativistic corrections (mass - velocity, Darwin and spin - orbit terms) are treated as first - order perturbation. For the relativistic case, Dirac - Fock equations were derived, and Breit interaction operator is used as the relativistic correction for the interelectronic Coulomb interaction, and is treated as the first - order perturbation. Expressions for the matrix elements of the Breit interaction operator (magnetic and retardation terms) are given for the average of configuration. Numerical results of some atomic properties for the ground states of (Rb, Zr, Pd, Sn, Cs, Ba, Lu, Ir, Hg, Tl, Bi, Rn ) atoms computed and compared with their corresponding experimental values. The relativistic effect on the orbital energies is important on the inner shells especially for the 1s and 2s shells and this effect becomes more pronounced as Z increases. The contribution of Breit interaction is about 2% of the relativistic shift (mass - velocity and Darwin correction). The Hartree - Fock calculations and relativistic correction gives reasonably good approximation for heavy atoms while Dirac - Fock calculation and Breit interaction gives high precision calculations

تصميم وتنفيذ متحسس لمعامل الانكسار باستخدام الالياف الضوئية البلورية PCF == DESIGN AND CONSTRUCTION OF REFRACTIVE INDEX SENSOR USING PHOTONIC CRYSTAL FIBER PCF

Author name: مريم عبد الجبار جاسم
Supervisor name: سھى موسى خورشید الاوسي
General topic: Physics
Specific topic: Atomic Physics
Degree: Master
University: Al-Nahrain University - College Of Science - Physics Department
Language: English
University location: Baghdad
First pages:
Abstract: Photonic crystal fiber (PCF) provides the availability to insert somematerials that enable the materials inside the PCF that provides thematerials to interaction with the light directly where the sensitivity releasedfrom the PCF is higher than the conventional optical fiber. Because of theimportance of the refractive index in many industrial by use it as amonitoring tools, because the clearly relationship between the temperatureand the refractive index and because the clearly sensitive of the phase ofthe liquid - crystals (LCs) where it has a range of temperature to be stay as(LCs) to the temperature and when the temperature be above this range theLCs will be liquid , The aim of the thesis is construction refractive indexsensor using photonic crystal fiber by infiltrating some different materialsof LC such as EBBA (N - (4 - Ethoxybenzylidene) - 4 - n - butylaniline) andMBBA (N - (4 - Methoxybenzylidene) - 4 - n - butylaniline) inside threedifferent kinds of a hollow core PCF (HC - PCFs) like HC - 800 - 02, HC - 1550 - 02, and HC19 - 1550 and using three different laser wavelengthswhich were; 638nm, 850nm, 1550nm. This diversification in the use oftools enable to consider different cases of designed sensor and determine itssensitivity at each case, then one can estimate the perfect cases of thedesigned sensor.It is found that the highest RI sensitivity was 173.31 dBm/RIU forthe HC19 - 1550 infiltrated with the EBBA using the laser with wavelength638nm, while the highest temperature sensitivity was 0.2505 dBm/°C forempty HC - 1550 using the laser with wavelength 1550nm.

دراسة تاثيرات حزمة ليزر هيليوم - نيون واشعة كاما علي المشعع بجسيمات الفا باستعمال بعض CR - كاشف 39 التقنيات المطيافية == Studying the Effects of He - Ne Laser Beam and Gamma Radiation on CR - 39 Detectors Irradiated by ? - particles Using Some Spectroscopy Techniques

Author name: محمد محسن نعمة
Supervisor name: ندى فاضل توفيق
General topic: Physics
Specific topic: Atomic Physics
Degree: Master
University: Al-Nahrain University - College Of Science - Physics Department
Language: English
University location: Baghdad
First pages:
Abstract: The aim of the present work was to study the effect of alpha - particles, gammarays and (He - Ne) laser beam on the track registration and optical properties of CR - 39 detectors. Twenty - four detectors divided into five groups. First group : include nine detectors were exposed to different powers of (1, 5 and 10 mW) of laser beam at times (5, 10 and 15 min) and then irradiated to alpha - particles from 226Ra source. Then it was measured following track parameters, track diameters - D, track density - ρ, and calculated the bulk etching rate - VB, track etching rate - VT, critical angle - Өc, etching efficiency - η, Sensitivity - S, etching ratio rate - V. The results show there was increased in the values of - D, ρ, VB, VT and Өc with increasing of the exposure times of laser beam at (1, 5 and 10 mW) powers, and decrease in the values of - η, S and V with increasing in the exposure time of laser beam at_1 mW power, while increasing within increase of exposed times of laser beam at (5 and 10 mW) powers. And found the appropriate etching time of CR - 39 track detector at etching time of - 4 h with NaOH etchant solation and - 6.25 N at temperature 60 oC. Second group : includes un - irradiated detector as a control. Third group : include five detectors from CR - 39 detector it was irradiated by gamma radiation from 60Co source with doses (300, 500, 800, 1200 and 1600 kGy). Fourth group : include third groups where it was exposed to laser beam at 10 mW power for 15 min. Fifth group : include nine detectors were exposed to powers - 1, 5 and 10 mW of laser beam at times (5, 10 and 15 min). The optical properties of detector were studied by using the UV - Vis. and FTIR spectroscopy.Where it was calculated the optical energy band gap and number of carbon atom to groups (Second, Third, Fourth and Fifth). The results of ultraviolet spectra show increasing in the absorbance - A of detector with increasing in the time exposure of laser beam at different powers and gamma doses, and also decreasing in the optical energy band gap and increasing in the number of carbon atom with increasing in the exposure time of laser beam at different powers and gamma doses. As for the FTIR spectra show change in the peak position of the bands detector to groups (Third, Fourth and Fifth).

دراسة خصائص انتقال لمتضمنات صوتي - ضوئي عالي السرعة والتردد == Study The Transmission Characteristic of Acousto - Optic Modulators for High Modulator Speed and High Frequency

Author name: لبابة عبد الكریم الجنابي
Supervisor name: سھى موسى خورشید الاوسي
General topic: Physics
Specific topic: Atomic Physics
Degree: Master
University: Al-Nahrain University - College Of Science - Physics Department
Language: English
University location: Baghdad
First pages:
Abstract: Acousto optics is a science that studying the light and acoustic interaction for purposes of manufacturing modulators and sensors. The technology turned to the use of acousto optic to solve the problem of transforming the communication technology from the traditional one that used the radio signal in coaxial cable into the modern one that uses the laser light in the optical fibers. Also, this enables to overcome the problem of loss and attenuations that occur in the transmission lines using the traditional technology. More sophisticated methods are suggested to help communication researches; one of the most interesting acousto optic applications are the modulators. The modulators are manufactured for specific applications, such that the input energy power and light frequency are taken in to account. The modulator of this application can achieve high accuracy with some co - operation related to the suitability of used material.In the present research, a high speed and high frequency modulator are proposed based on the concept of acousto optic interaction. The occurrence of the interaction requires existence some experimental material arranged in uniform modulator template. The analysis enables to determine the requirements of the proposed modulator design. The newly proposed idea is the use of highly transparent material that absorbed the interference associated with diffraction. Four types of materials are used to test the proposed designed modulator; they are : LiNbO3, SiO2, TeO2, and Ge, the use of such materials offer rich considerable results especially when using different light frequencies to be input into the interaction system. The proposed modulator design is computerized implemented using Comsolsoftware with predefined characteristics are determined in the stage of the analysis and requirements. As a result, different results are obtained for different use of materials and characteristics.The results are examined using validation test, which includes some performance indications. These indications are achieved by two paths : the first is the measurements of operating parameters that obtained by Comsol directly, while the latter is related to computations of efficiency that achieved programming the theoretical relations using MatLab. Actually, the measurements in the first path are documented to ensure the acceptable performance of the proposed designed modulator, whereas the computations of the second path are recorded to ensure the high performance efficiency of the proposed modulator design. In general, the achieved results were matching the state of art given in most advanced literatures, which ensure the validation of the proposed design and correct paths of performance description.The results showed that the proposed modulator design performed the modulation test with an efficiency percent of about 95%, when using LiNbO3 material in the modulator head, and this efficiency is decreases lightly when using other materials. Besides, the employed measurements and computations are nominating the use of LiNbO3 material rather than others to be used in such types of modulators due to its suitable optical features.Frequent practice tests showed that the behavior of the modulator was acceptable and it is enjoying the ability to be improved. The encouraging results gave the opportunity to suggest some developments for future work in order to strength the modulation results.

تحضير التراكيب النانوية للمركب Ba1 - xCaxTiO3 ودراسة الخواص الفيرواليكتريك == Synthesis and Characterization of Ferroelectric Ba1 - xCaxTiO3 Nanoparticles

Author name: عقيل عبد الرضا خضير عباس
Supervisor name: عماد خضير الشكرجي
General topic: Physics
Specific topic: Atomic Physics
Degree: Master
University: Al-Nahrain University - College Of Science - Physics Department
Language: English
University location: Baghdad
First pages:
Abstract: في هذه الدراسة تم تحضير المركب النانوي تيتانيت الباريوم كالسيوم Ba1 - xCaxTiO3 بقيم مختلفة لعامل التعويض (x) وهي 0, 0.25, 0.5, 0.75, 1. الطريقة المستخدمة في التحضير هي طريقة الهيدروثيرمال الكيميائية والتي تعتبر من الطرق المفضلة لتحضير تراكيب نانوية متبلورة وذات نقاوة عالية. درجة الحرارة المحددة للتحضير كانت 200 درجة مئوية والضغط كان 20 بار.الجسيمات النانوية المحضرة كان لها معدل حجم جسيمي يتراوح بين 20 الى 41 نانومتر. بعد ذلك تم كبس المساحيق بضغط قدره 127 MPa للحصول على اقراص بقطر 1 سنتيمتر. في المرحلة اللاحقة تم اجراء عملية التلبيد لهذه الاقراص بدرجة حرارة 900 درجة مئوية ولمدة اربع ساعات. معاملات التركيب البلوري والمجموعة الفراغية ومعاملات الشبيكة والحجم الجسيمي والحجم الحبيبي تم الحصول عليها من التحليلات التركيبية والشكلية مثل حيود الاشعة السينية والمجهر الالكتروني النافذ ومجهر التصوير الالكتروني. تم استعمال برامجيات خاصة مختلفة في تحليل النتائج مثل حيود الاشعة السينية والمجهر الالكتروني النافذ ومقارنتها مع النتائج الموجودة في قواعد البيانات العالمية مثل ICSD .اضهرت نتائج التحليلات اكتساب المادة طورا بلوريا متعدد باستثناء الشرط التعويضي x = 1 حيث وجد انه يميل لامتلاك طور منفرد. تم دراسة الخصائص الكهربائية المتمثلة بالقياسات العزلية الكهربائية للمركب Ba1 - xCaxTiO3 حيث تم اعتماد حالتين في هذه الدراسة, الاولى كانت تتضمن تغيير التردد وتثبيت درجة الحرارة, والثانية بتغيير درجة الحرارة مع تردد ثابت لغرض قياس ثابت العزل الكهربائي r)ɛ) ومعامل الخسارة (D) , وايضا تم قياس درجة حرارة كيوري (TC). لوحظ خلال البحث ارتفاع قياس درجة حرارة كيوري (TC) مع زيادة نسبة محتوى الكالسيوم Ca في المركب. وجد ايضا افضل قيمة لثابت العزل الكهربائي ودرجة حرارة كيوري هي عند الشرط التعويضي x = 0.25, لذلك توجد امكانية لهذه المادة للتطبيق في المتسعات وتطبيقات الانظمة الالكترونية عالية الفولتية | In this study, a nano - compound Ba1 - xCaxTiO3 (BCT) was synthesized with varying substitution x = 0.25, 0.5, 0.75, and 1. The method used for synthesis is the hydrothermal chemical process, which is preferable to produce ultrafine, pure, and crystalline nanostructures. The material was synthesized at 200 ℃ and was 20 bar pressure for 24 hours. Barium acetates, calcium acetates, and titanium tetrachloride were used as starting materials. The synthesized nanoparticles had a range of particle size (20 - 41 nm). The powder was pressed into a pellets at pressure 127 MPa to get a diameter 1 cm and thickness 2 mm. Then, these pellets were sintered at 900 ℃ for 4 hours. The parameters of the crystalline structure, space group, lattice constants, particle size and grain size were obtained from the structural and morphological, and topological analyses (i.e., XRD, TEM, and SEM). Special different software were used for analyzing, and specification of the structural and morphological results so as to make a comparison with international results and databases like ICSD. The nano powders produced has a polycrystalline structure, except at substitution (x=1), which possesses a single phase structure. Dielectric measurements for Ba1 - xCxTiO3 were achieved. Two conditions were considered in the study. The dependence of dielectric constant (ε_r) and dielectric loss (D), on temperature and frequency was measured at constant frequencies and temperatures respectively. The values of Curie temperature (TC) were determined from the dielectric measurements. It is found that the values of Curie temperature were shifted toward higher temperatures as a result of increasing the calcium ratio in the compound. The composition Ba0.75Ca0.25TiO3 (x = 0.25), reported the best results which are related to crystalline phase, morphology, dielectric constant and Curie temperature relatively, so it is recommended in capacitors and high voltage power electronic applications.

تعديل سطوح التيتانيوم وسبيكة التيتانيوم باستخدام المواد الاحيائية السيراميكية بواسطة الرشرشة بالترددات الراديوية == Surface Modification of Titanium and Titanium Alloy Using Ceramic Biomaterials by RF Sputtering

Author name: دنيا عبد الصاحب هاشم حمدي
Supervisor name: ثامر عبد الجبار جمعة | ثائر لطيف مزعل
General topic: Physics
Specific topic: Atomic Physics
Degree: Doctorate
University: Al-Nahrain University - College Of Science - Physics Department
Language: English
University location: Baghdad
First pages:
Abstract: The current in this thesis research deals with the plasma sputtering which was used to deposit single and triple layers ceramics on (cpTi) and ( Ti - 6Al - 4V) alloy. Also ,in this work the in vitro electrochemical tests , formation of HAp by biomimetic process on the coated layers by the immersion in Simulated Body Fluid(SBF) at PH equal to 7.4 and room temperature was done . The single layer TiO2and HAp , multi - layer consist of TiO2 and Al2O3 were deposited on cpTi and Ti - 6Al - 4Valloy, followed by the deposition of third layer of HAp. The deposition conditions in the RF sputtering system such as vacuum pressure, substrate temperature, power, gas type, gas flow and deposition time were fixed for the sputtering system where as the distance between the target and the substrate was varied (9 and 7 cm). Structural analysis was carried out , on the deposited layers(single and triple) using X - ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Furrier Transformation Infra - Red (FTIR), Raman Spectroscopy and X - ray Photoelectron Spectroscopy (XPS). Elemental analysis for HAp deposited in the single and triple layer was done using Energy Dispersive X - ray Spectroscopy (EDS).To investigate the biocompatibility of coatings the formed layers, were immersed in (SBF) for one month. After one month the samples were taken and anlyezed using the same structural analysis techniques used before immersion. Electrochemical investigation was carried out on the deposited layers used Open Circuit Potential (OCP),Linear Sweep Voltage(LSV) and Electrochemical Impedance Spectroscopy(EIS) in SBF. The XRD structural results show that the formation of HAp which was dominated on the phase formation on the surface of the single and triple layers. Also another Calcium - Phosphorus compound phases are found such as Tri Calcium Phosphate(TCP), Octa Calcium Phosphate(OCP) and Calcium Phosphate(CP) along with small fractionIIof the Titanium phase belong the substrate .For TiO2 single layer, XRD pat reins shows the formation of the rutile TiO2which covered the substrate surface.Elemental analysis by using EDS for the single and triple layer deposited in cpTi and Ti - 6Al - 4Valloy shows the energy transitions belong to the dominated elements, Ca and P, which contained in the HAp layer that already showed by XRD. Surface analysis by XPS for immersed samples in SBF for one month show the bonding type and the compound that formed. The XPS results confirmed the SEM observation, the FTIR and Raman results. It was found from the XPS analysis that most of the compound covers the surface are belongs to the Ca - P companies to the carboxyl groups (C - O, C - H) and this was confirmed by the XRD investigation which show the domination of (HAp) in the highest intensity (211) reflection at 2θᵒ of 31.7 for the single and triple layer coating. The XRD results also show the disappearance of the other CaP compounds after one month of immersion in SBF like TCP and CP .The increase in the HAp concentration after immersion indicates the occurrence of the biomimetic process that increases the precipitation of Ca+ and P - from the SBF and the two roots combined together to form CaP compound that increases the HAp concentration. The electrochemical parameters predicted from corrosion test show the improvement in the corrosion resistance of both cpTi and Ti - 6Al - 4Valloy after coated by shifting the OCP toward the nobel direction which was the same behaviour for the corrosion potential Ecorr, and decreases in the corrosion current Icorr and the corrosion rate CR comparing to the uncoated specimens. The (EIS) measurements conformed the improvement in the corrosion parameters result of from OCP and LSV by the very low capacitance for the coated specimens compared to that for the uncoated one which means that the single layer and triple layer protect the surface by increasing the equivalent circuit impedance block