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Full-Text Articles in Physical Sciences and Mathematics

Studies On The Opto-Electronic Constants Of Alkali-Halide Crystals, Mahmoud A. Salem Jan 2003

Studies On The Opto-Electronic Constants Of Alkali-Halide Crystals, Mahmoud A. Salem

Turkish Journal of Physics

In this presentation, the correlation between refractive index n of alkali-halide crystals and both energy band gap E_{g} and Pauling's electronegativity difference \Delta x have been studied. The following relations are proposed for estimating the refractive index n: n^2 + C = A / E_{g} ^{1 / 2} and n^2 + C = E / (\Delta x)^{0.425}, where A, C and E are numerical constants. In addition, an interrelation between the energy band gap E_{g} and electronegativity difference \Delta x has been also proposed. The proposed relation is E_g = 4.45 (\Delta x)^{0.85}. The estimated values of the refractive index …


U(1)-Invariant Special Lagrangian 3-Folds In {\Mathbb C}^3 And Special Lagrangian Fibrations, Dominic Joyce Jan 2003

U(1)-Invariant Special Lagrangian 3-Folds In {\Mathbb C}^3 And Special Lagrangian Fibrations, Dominic Joyce

Turkish Journal of Mathematics

This is a survey of the author's series of three papers [8, 9, 10] on special Lagrangian 3-folds (SL 3-folds) in {\mathbb C}^3 invariant under the U(1)-action (z_1,z_2,z_3)e^{i\theta}z_1, e^{-i\theta}z_2,z_3), and their sequel {\mathbb C} [11] on special Lagrangian fibrations and the SYZ Conjecture. We briefly present the main results of these four long papers, giving some explanation and motivation, but no proofs. The aim is to make the results and ideas accessible to String Theorists and others who have an interest in special Lagrangian 3-folds and fibrations, but have no desire to read pages of technical analysis. Let N be …


On Locally M-Pseudoconvex A^*-Algebras, A. El Kinani Jan 2003

On Locally M-Pseudoconvex A^*-Algebras, A. El Kinani

Turkish Journal of Mathematics

We consider classical A^*-algebras in the context of locally pseudoconvex algebras. Results concerning the auxiliary topology and A^* -algebras of the first kind are given.


Photochemical Reactions Of \Alpha-Terpinene And Acenaphthene Under Concentrated Sunlight, Nesi̇be Avcibaşi, Siddik İçli̇, Andrew Gilbert Jan 2003

Photochemical Reactions Of \Alpha-Terpinene And Acenaphthene Under Concentrated Sunlight, Nesi̇be Avcibaşi, Siddik İçli̇, Andrew Gilbert

Turkish Journal of Chemistry

\alpha-Terpinene was successfully dehydrogenated to p-cymene in photocatalytic reaction with benzophenone and cupric ions under 40 suns concentrated sunlight irradiation, proving that photodehydrogenation reactions may be employed for the synthesis of fine chemicals under sunlight. Acenaphthene dehydrogenation under concentrated sunlight resulted in the minor formation of acenaphthylene and the quantitative formation of acenaphthenone when the solution was aerated. Stable benzylic-type radical intermediates are thought to lower the yield of dehydrogenation reactions.


Purification And Partial Characterization Of Catalase From Chicken Erythrocytes And The Effect Of Various Inhibitors On Enzyme Activity, Tüli̇n Aydemi̇r, Kevser Kuru Jan 2003

Purification And Partial Characterization Of Catalase From Chicken Erythrocytes And The Effect Of Various Inhibitors On Enzyme Activity, Tüli̇n Aydemi̇r, Kevser Kuru

Turkish Journal of Chemistry

Catalase plays a major role in the protection of tissues from the toxic effects of H_{2}O_{2} and partially reduced oxygen species. A nearly 136-fold enzyme purification was obtained from chicken erythrocyte by acetone precipitation, ethanol-chloroform treatment, CM-cellulose and Sephadex G-200 chromatography. The specific activity of purified enzyme was 42,556 U/mg. The molecular weight of the native chicken erythrocyte catalase was estimated at 240 kDa by gel filtration. SDS-gel electrophoresis results indicated that chicken erythrocyte catalase consists of four apparently identical subunits, with a molecular weight of around 57.5 kDa. The optical spectrum of the purified enzyme shows a Soret band …


A Novel Silver Recovery Method From Waste Photographic Films With Naoh Stripping, Nuri̇ Naki̇boğlu, Duygu Toscali, Gürel Ni̇sli̇ Jan 2003

A Novel Silver Recovery Method From Waste Photographic Films With Naoh Stripping, Nuri̇ Naki̇boğlu, Duygu Toscali, Gürel Ni̇sli̇

Turkish Journal of Chemistry

A novel, simple, fast, cheap and pollution-free method was developed for recovering the silver from waste X-ray photographic films with NaOH stripping. The method has a number of advantages because it obviates the need for burning, oxidizing, electrolysis or purifying steps. Moreover, all experiments were carried out in the same flask, unlike other techniques. Silver recovery conditions were optimized and silver a purity level of 99\% was recovered. The metal impurities (Al, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Sn) in the recovered silver were determined using the ICP-MS method. The results were compared with results in …


Studies On The Mechanism Of Base-Catalyzed Decomposition Of Bicyclic Endoperoxides, Ebru Mete, Ramazan Altundaş, Hasan Seçen, Meti̇n Balci Jan 2003

Studies On The Mechanism Of Base-Catalyzed Decomposition Of Bicyclic Endoperoxides, Ebru Mete, Ramazan Altundaş, Hasan Seçen, Meti̇n Balci

Turkish Journal of Chemistry

Kinetic studies were performed to clarify the Kornblum-Delamare reaction mechanism of bicyclic endoperoxides. Ascaridol and 1,4-diphenyl-2,3-dioxa-bicyclo[2.2.2]oct-5-ene, not having \alpha -protons, did not provide any reaction with bases. Reaction with different bases has revealed that reaction rates for the base-catalyzed decomposition of 2,3-dioxa-bicyclo[2.2.2]oct-5-ene depend strongly on the base strength. The stronger the base used, the faster the conversion rate. Reaction rate values k of endoperoxides with different skeletons were also studied with NEt_{3}. It has been noted that the strength of the base plays the dominant role in determining the rate of the reactions.


The Kinetic Study Of The Chemical Oscillating System Of 1,3-Propanediol/Acetone As The Organic Substrate, Shi-Gang Shen, Caiqin Yang, Han-Wen Sun, Jin-Huan Shan, Ying Liu Jan 2003

The Kinetic Study Of The Chemical Oscillating System Of 1,3-Propanediol/Acetone As The Organic Substrate, Shi-Gang Shen, Caiqin Yang, Han-Wen Sun, Jin-Huan Shan, Ying Liu

Turkish Journal of Chemistry

This work was primarily an experimental investigation of the bromate oscillator using 1,3-propanediol and acetone as the mixed organic substrates. The empirical equation of the induction period and oscillating period with the concentrations of the reactants and temperature were obtained. The oscillating characteristic and possible oscillation mechanism were studied.


A Study On The Fatty Acid Composition Of Fish Liver Oil From Two Marine Fish, Eusphyra Blochii And Carcharhinus Bleekeri, Zafar S. Saify, Shamim Akhtar, Khalid Mohammed Khan, Shahnaz Perveen, Syed Abdul Majid Ayattollahi, Sohail Hassan, M. Arif, Syed Moazzam Haider, Faheem Ahmad, Sazada Siddiqui, Mohammeda Zarrar Khan Jan 2003

A Study On The Fatty Acid Composition Of Fish Liver Oil From Two Marine Fish, Eusphyra Blochii And Carcharhinus Bleekeri, Zafar S. Saify, Shamim Akhtar, Khalid Mohammed Khan, Shahnaz Perveen, Syed Abdul Majid Ayattollahi, Sohail Hassan, M. Arif, Syed Moazzam Haider, Faheem Ahmad, Sazada Siddiqui, Mohammeda Zarrar Khan

Turkish Journal of Chemistry

Two species of shark found in the coastal waters Karachi (Pakistan) were studied, Eusphyra blochii (winghead snark) and Carcharhinus bleekeri (sandbar shark) for their liver oil fatty acid composition. Since liver has high lipid content and traditionally the liver oil of these species been used to relieve muscular pain and arthritis in Pakistan this study was conducted. The isolation, identification and characterization of these fatty acids were carried out by gas liquid chromatography (GLC) and a combination of the thin layer chromatography (TLC)-GLC technique. A large variation was observed between winghead shark liver oil and sandbar shark liver oil. Twenty-five …


Crystal Structure Of Cis-Bis(N,N-Dimethyl-N'-Benzoylthioureato)Palladium(Ii), Göktürk Avşar, Hakan Arslan, Hans-Jurgen Haupt, Nevzat Külcü Jan 2003

Crystal Structure Of Cis-Bis(N,N-Dimethyl-N'-Benzoylthioureato)Palladium(Ii), Göktürk Avşar, Hakan Arslan, Hans-Jurgen Haupt, Nevzat Külcü

Turkish Journal of Chemistry

In this study cis-bis(N,N-dimethyl-N'-benzoylthioureato) palladium(II) is synthesised and the crystal structure is determined by X-ray diffraction methods. It crystallises in the space group P2_{1}/c, with a = 11.943(1) Å, b = 11.713(1) Å, c = 15.345(1) Å, \beta = 93.90(1)°, and D_{calc} = 1.616 g cm^{-1} for Z = 4. The Pd(II) atom is in a four-coordinate geometry consisting of two thiocarbonyl S and two carbonyl O atoms from two ligand groups. The Pd-S and Pd-O bond lengths are 2.2313(6) and 2.0211(16) Å, respectively.


Iridoid And Phenylpropanoid Glycosides From Phlomis Samia, P. Monocephala And P. Carica, Funda Nuray Yalçin, Tayfun Ersöz, Pinar Akbay, İhsan Çaliş, Ali̇ Arslan Dönmez, Otto Sticher Jan 2003

Iridoid And Phenylpropanoid Glycosides From Phlomis Samia, P. Monocephala And P. Carica, Funda Nuray Yalçin, Tayfun Ersöz, Pinar Akbay, İhsan Çaliş, Ali̇ Arslan Dönmez, Otto Sticher

Turkish Journal of Chemistry

From the aerial parts of Phlomis samia an iridoid glucoside, shanzhiside methylester (1), and three phenylethanoid glycosides, martynoside (2), 4''-O-acetylmartynoside (3) and samioside (4), were isolated. From the overground parts of P. monocephala two iridoid glucosides, lamiide (5) and ipolamiide (6), as well as three phenylethanoid glycosides, verbascoside (= acteoside) (7), forsythoside B (8), alyssonoside (9), and one lignan glucoside, syringaresinol 4'-O-\beta -D-glucopyranoside (10), were isolated. From the aerial parts of P. carica one phenylethanoid glycoside, verbascoside (= acteoside) (7) and three phenylpropanoid monomeric glucosides, syringin (11), dihydrosyringin (12) and coniferin (13), were isolated. The structures of the isolated compounds …


Application Of A Three-Stage Sequential Extraction Procedure For The Determination Of Extractable Metal Contents In Highway Soils, Şeri̇fe Tokalioğlu, Şenol Kartal, Gökhan Bi̇rol Jan 2003

Application Of A Three-Stage Sequential Extraction Procedure For The Determination Of Extractable Metal Contents In Highway Soils, Şeri̇fe Tokalioğlu, Şenol Kartal, Gökhan Bi̇rol

Turkish Journal of Chemistry

A sequential extraction procedure, a three-step protocol proposed by the Standards, Measurements and Testing programme (SM & T--formerly BCR) of the European Union, was applied to soil samples for the determination of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn). This procedure provides measurements of extractable metals from media such as acetic acid (0.11 mol L^{-1}), hydroxylammonium chloride (0.1 mol L^{-1}) and hydrogen peroxide (8.8 mol L^{-1}) plus ammonium acetate (1 mol L^{ - 1}), which are exchangeable, reducible and oxidisable metals, respectively. Analyses were carried out using flame atomic absorption spectrometry (FAAS). The results obtained from …


Aluminum Fractionation In The Water Of Karakaya Dam Lake (Malatya, Turkey), F. Zehra Küçükbay, Mustafa Demi̇r Jan 2003

Aluminum Fractionation In The Water Of Karakaya Dam Lake (Malatya, Turkey), F. Zehra Küçükbay, Mustafa Demi̇r

Turkish Journal of Chemistry

A method was developed for the determination of trace amounts of Al species in water samples using the amberlite type XAD-4 resin. For this purpose, total dissolved Al, organically bonded Al and particulate Al in water samples taken from Karakaya dam lake (Malatya, Turkey) were determined by flame atomic absorption spectroscopy (FAAS) or graphite furnace atomic absorption spectroscopy (GFAAS) after an enrichment procedure. The total dissolved Al in the water samples was determined using 8-hydroxyquinoline as complexing reagent at pH 8 and amberlite type XAD-4 resins for the enrichment. The organically bonded Al species in the water samples were destroyed …


Purification And Characterization Of Glucose 6-Phosphate Dehydrogenase From Sheep Liver, Vedat Türkoğlu, Si̇nan Aldemi̇r, Mehmet Çi̇ftçi̇ Jan 2003

Purification And Characterization Of Glucose 6-Phosphate Dehydrogenase From Sheep Liver, Vedat Türkoğlu, Si̇nan Aldemi̇r, Mehmet Çi̇ftçi̇

Turkish Journal of Chemistry

Glucose 6-phosphate dehydrogenase (D-glucose 6-phosphate: NADP^{+} oxidoreductase, EC 1.1.1.49; G6PD) was purified from sheep liver by a simple and rapid method. The purification process consisted of two steps: preparation of the homogenate, and 2', 5'-adenosine diphosphate (ADP) Sepharose 4B affinity chromatography. Through the use of these two consecutive steps, the enzyme was purified with a yield of 35.6% and 1,920 fold, having the specific activity of 11.2 enzyme units (EU/mg protein). A K_{M} of 0.176 mM and a V_{\max} of 0.0179 EU/ml were obtained for G6-P, and 0.0194 mM and 0.0223 EU/ml for NADP^{+}. Enzymatic activity was measured spectrophotometrically according …


Preparation And Characterization Of Conducting Polybutadiene/ Polythiophene Composites, Senem Kiralp, Zuhal Küçükyavuz, Atef F. Qasrawi Jan 2003

Preparation And Characterization Of Conducting Polybutadiene/ Polythiophene Composites, Senem Kiralp, Zuhal Küçükyavuz, Atef F. Qasrawi

Turkish Journal of Chemistry

Conductive composite films of cis-1,4-polybutadiene (PBD) with polythiophene (PTh) were prepared electrochemically. Thiophene was polymerized on PBD-coated platinium electrodes. The composites with different PTh percentages showed conductivity in the order of 10^{-3} (\Omega cm)^{-1}. The characterization of the films was performed using FTIR, scanning electron microscope and differential scanning calorimetry techniques. In order to understand the dominant transport mechanism, the temperature dependence of conductivity was investigated.


Some Polyamidoxime Derivatives And Their Metal Complexes, Fatma Kari̇pci̇n, İbrahi̇m Karataş, Hali̇l İsmet Uçan Jan 2003

Some Polyamidoxime Derivatives And Their Metal Complexes, Fatma Kari̇pci̇n, İbrahi̇m Karataş, Hali̇l İsmet Uçan

Turkish Journal of Chemistry

In this paper the synthesis of six polyamidoximes from their corresponding diamines with 4,4'-methylenebis (phenylglyoxylohydroximoyl chloride) and 4,4'-methylenebis(chlorophenylgly-oxime) is presented. The average molecular weights of these organic polymers were determined. In addition, the complexes of 4,4'-methylenebis (phenylglyoxylohydroximoyl chloride) with Ni(II), Co(II) and Cu(II) salts were prepared. The structures of these compounds were identified by IR or ^{1}H NMR spectral data, elemental analyses, magnetic measurements and thermal analysis.


Synthesis Of New 4-(5-Chloro-2-Oxo-3h-Benzoxazol-3-Yl)Butanamide Derivatives And Their Analgesic And Anti-Inflammatory Properties, H. Ozan Gülcan, Serdar Ünlü, Erden Banoğlu, M. Fethi̇ Şahi̇n, Esra Küpeli̇, Erdem Yeşi̇lada Jan 2003

Synthesis Of New 4-(5-Chloro-2-Oxo-3h-Benzoxazol-3-Yl)Butanamide Derivatives And Their Analgesic And Anti-Inflammatory Properties, H. Ozan Gülcan, Serdar Ünlü, Erden Banoğlu, M. Fethi̇ Şahi̇n, Esra Küpeli̇, Erdem Yeşi̇lada

Turkish Journal of Chemistry

In this preliminary screening study for developing potent analgesic and anti-inflammatory compounds, eight new 4-(5-chloro-2-oxo-3H-benzoxazol-3-yl)butanamide derivatives were synthesized and screened for their analgesic and anti-inflammatory activities as well as gastric ulceration potential in tested animals. Their structures were elucidated by their IR, ^{1}H-NMR and elemental analysis. All of the compounds exhibited high analgesic and anti-inflammatory activities. None of the compounds except compound 2g caused gastric lesions or bleeding in tested animals.


Isolation And Structure Elucidation Of Novel Natural Products From Turkish Lichens, Süheyla Kirmizigül, Ömer Koz, Hüseyi̇n Anil, Siddik İçli̇, Ulvi̇ Zeybek Jan 2003

Isolation And Structure Elucidation Of Novel Natural Products From Turkish Lichens, Süheyla Kirmizigül, Ömer Koz, Hüseyi̇n Anil, Siddik İçli̇, Ulvi̇ Zeybek

Turkish Journal of Chemistry

Three natural products were isolated from three different Turkish lichens. Microbiological investigations were also examined of these lichens. Compound 1 is known as 2-hydroxy-4-methoxy-3,6-dimethyl benzoic acid, and is isolated from Pseudevernia furfuracea for the first time. Compounds 2 and 3 are detected as new compounds and called, 3-acetyl-4-amino-2-chloro-1- (4-hydroxy-2-methoxy- 6-methylphenyl carbonyloxy) benzene and 2-(4-methoxyphenyl)-2-(5-oxo-4-phenyl-2,5- dihydro-2-furaniliden) acetic acid; they were isolated from Evernia prunastri and Letharia vulpina, respectively. All these compounds had different skeletons. Their structures were established by chemical methods and spectroscopic techniques using IR, UV, 1D and 2D NMR and EI and (+) FAB-Mass methods.


Catalytic Spectrophotometric Determination Of Manganese In Some Medicinal Plants And Their Infusions, Kostantin L. Mutaftchiev Jan 2003

Catalytic Spectrophotometric Determination Of Manganese In Some Medicinal Plants And Their Infusions, Kostantin L. Mutaftchiev

Turkish Journal of Chemistry

The catalytic effect of manganese (II) on the oxidation of the dye 1,3-Dimethyl- 2 [4-N (N,N-dimethylamino) phenylazo] imidazolium perchlorate (BR) with potassium periodate in the presence of 1,10-phenanthroline was investigated. The reaction was followed spectrophotometrically by measuring the decrease in the absorbance of the dye at 540 nm. Under optimum conditions (5 \times 10^{-5} mol dm^{-3} BR, 2 \times 10^{-4} mol dm^{-3} potassium periodate, 1 \times 10^{-4} mol dm^{-3} 1,10-phenanthroline, 0.1 mol dm^{-3} buffer -- pH 3.0, 70 °C, 5 min) manganese (II) in the range 0.1--4.5 ng cm^{-3} can be determined by the fixed-time method with a detection limit …


Study On Papain Immobilization On A Macroporous Polymer Carrier, Liang Ding, Zihua Yao, Tong Li, Qiang Yue, Jia Chai Jan 2003

Study On Papain Immobilization On A Macroporous Polymer Carrier, Liang Ding, Zihua Yao, Tong Li, Qiang Yue, Jia Chai

Turkish Journal of Chemistry

Macroporous resin microbeads of methyl methacrylate-divinyl benzene copolymer were synthesized by radical suspension polymerization of acrolein with divinylbenzene in the presence of a pore-creating agent, petroleum ether. The microbeads had a large specific surface area and large pores covered the entire surface of the resin. This macroporous polymer carrier was aminated by hydrazine hydrate that produced a large number of amino groups on the carrier. Papain was immobilized on the porous polymer carrier by glutaraldehyde cross-linking or diazo-coupling. The factors involved in the activity recovery of the immobilized papain and the enzymic properties of the resulting immobilized papain were studied …


Phenolic, Megastigmane, Nucleotide, Acetophenon And Monoterpene Glycosides From Phlomis Samia And P. Carica, Funda Nuray Yalçin, Tayfun Ersöz, Pinar Akbay, İhsan Çaliş, Ali̇ Arslan Dönmez, Otto Sticher Jan 2003

Phenolic, Megastigmane, Nucleotide, Acetophenon And Monoterpene Glycosides From Phlomis Samia And P. Carica, Funda Nuray Yalçin, Tayfun Ersöz, Pinar Akbay, İhsan Çaliş, Ali̇ Arslan Dönmez, Otto Sticher

Turkish Journal of Chemistry

Phytochemical investigations on the aerial parts of Phlomis samia resulted in the isolation of a simple phenolic glucoside, 2,6-dimethoxy-4-hydroxyphenol-1-O-\beta -D-glucopyranoside (1); a megastigmane glucoside, phlomuroside (=3-hydroxy-5,6-epoxy-\beta -ionol-9-O-\beta -D-glucopyranoside) (2); and a nucleotide glycoside, uridine (3). From the aerial parts of P. carica, the same phenolic glucoside, 2,6-dimethoxy-4-hydroxyphenol-1-O-\beta -D-glucopyranoside (1); as well as an acetophenon glucoside, picein (4); and 2 monoterpenoid glucosides, - betulalbuside A (5) and 1-hydroxylinaloyl-6-O-\beta -D-glucopyranoside (6) - were isolated and identified. The structure elucidation of the isolates was based on spectroscopic evidence.


Application Of Ibx Method For The Synthesis Of Ketones From Carboxylic Acids, H. R. Ferhat Karabulut, Mesut Kaçan, Hasan Özyildirim Jan 2003

Application Of Ibx Method For The Synthesis Of Ketones From Carboxylic Acids, H. R. Ferhat Karabulut, Mesut Kaçan, Hasan Özyildirim

Turkish Journal of Chemistry

Methoxy phenyl propionic acid and some derivatives are converted to ketones using a new method. All classical methods to obtain ketones from carboxylic acids via acid halide consistently gave very low yields and regularly generated intermolecular cyclisation products or polymeric materials. However, high ketones yields are obtained by using the new IBX method.


Neolignan, Flavonoid, Phenylethanoid And Iridoid Glycosides From Phlomis Integrifolia, İclal Saracoğlu, Mehtap Varel, İhsan Çaliş, Ali̇ Arslan Dönmez Jan 2003

Neolignan, Flavonoid, Phenylethanoid And Iridoid Glycosides From Phlomis Integrifolia, İclal Saracoğlu, Mehtap Varel, İhsan Çaliş, Ali̇ Arslan Dönmez

Turkish Journal of Chemistry

From the aerial parts of Phlomis integrifolia Hub.-Mor. (Lamiaceae) were isolated a neolignan glucoside, dehyrodiconiferyl alcohol-4-O-\beta -D-glucopyranoside (1), an ester flavone glycoside, chrysoeriol 7-O-(3''-O-trans-p-coumaroyl)-\beta -D-glucopyranoside (2), four phenylethanoid glycosides, forsythoside B (3), verbascoside (=acteoside) (4), leucosceptoside A (5) and martynoside (6) along with an iridoid glucoside, lamiide (7). The structure elucidation of the isolated compounds was carried out by spectroscopic (UV, IR, 1D- and 2D-NMR) methods. The isolation of neolignan glucoside dehyrodiconiferyl alcohol-4-O-\beta -D-glucopyranoside (1) is reported for the first time from a Phlomis species as well as for the family Lamiaceae.


Multiply Charged Ions Produced After Deexcitation Processes For Important Elements In Astrophysics, Adel M. El-Shime, Adel A. Ghoneim, Yehia A. Lotfy Jan 2003

Multiply Charged Ions Produced After Deexcitation Processes For Important Elements In Astrophysics, Adel M. El-Shime, Adel A. Ghoneim, Yehia A. Lotfy

Turkish Journal of Physics

Selection random number method (Monte Carlo technique) is used to calculate the ion charge state distributions (CSD) and mean ion charge \bar{q} after K-, L_{I}, L_{III}- and M_{I}- shell ionization in neutral atoms and their q-fold ground state ions (q = 0 to 10) from C to Fe elements. Atomic data for radiative and non-radiative transitions and electron shake off process, which is used in the modeling vacancy cascade program, are computed with relativistic wave functions. Use of atomic data is important to accurately model vacancy cascades. To enhance the agreement between calculated and experimental values, the electron shake-off processes …


Semi-Infinite Polarized Nuclear Matter With A Seyler-Blanchard Interaction, H. M. M. Mansour, Kh. A. Ramadan Jan 2003

Semi-Infinite Polarized Nuclear Matter With A Seyler-Blanchard Interaction, H. M. M. Mansour, Kh. A. Ramadan

Turkish Journal of Physics

The surface and curvature properties of semi-infinite polarized nuclear matter (SPNM) are calculated using a modified form of the Seyler-Blanchard potential. The level density parameter is extracted from the free energy using T^{2}-approximation. Good agreement is obtained between our calculations for the level density and other parameters which characterize the surface and curvature properties of SPNM and previous theoretical estimates. PACS number(s): 21.65.+f, 21.30.Fe


Electron Transport Mechanism In Gan/Algan Hemt Structures, Si̇bel Gökden Jan 2003

Electron Transport Mechanism In Gan/Algan Hemt Structures, Si̇bel Gökden

Turkish Journal of Physics

The electron transport mechanism in GaN/AlGaN HEMT (High Electron Mobility Transistors) structures grown with MBE on sapphire substrate was investigated by using the temperature dependence of the Hall coefficient, resistivity, carrier density and Hall mobility. Hall measurements were carried out using Van der Pauw geometry. From the LO-phonon-scattering-limited component of the mobility, we obtain LO phonon energy \hbar \omega \approx 90 meV and the momentum relaxation time of \tau_{m} \approx 4 fs. Also, from the temperature dependence of the 2D carrier density, we obtain the donor activation energy E_{a} \approx 29 meV.


Null Membranes In Dyonic Black Hole Background, Alexandr Lelyakov, Sergey Nikolaevich Roshchupkin Jan 2003

Null Membranes In Dyonic Black Hole Background, Alexandr Lelyakov, Sergey Nikolaevich Roshchupkin

Turkish Journal of Physics

We consider null bosonic p-branes in curved spacetimes. The general solutions of the classical equations of motions and constraints for the null-membrane in four-dimensional dyonic black hole background are found.


Mesoscopic D-Wave Qubits: Can High-T_C Cuprates Play A Role In Quantum Computing?, Alexandre M. Zagoskin Jan 2003

Mesoscopic D-Wave Qubits: Can High-T_C Cuprates Play A Role In Quantum Computing?, Alexandre M. Zagoskin

Turkish Journal of Physics

Due to nontrivial orbital pairing symmetry, surfaces and interfaces of high-T_c superconductors support states which violate time-reversal (T-) symmetry. Such naturally degenerate states, useful as working states of a qubit, are standard for atomic or molecular-size qubit prototypes (e.g. based on nuclear spins), but exceptional for mesoscopic qubits. (In particular, they hold promise of a better scalability.) In these lectures I review the physics of T-breaking on surfaces and interfaces of high-T_c superconductors; then describe existing proposals for high-T_c based qubits and the current state of experiments; finally, I discuss the decoherence sources in the system, open questions, and future …


A Monopole Homology For Integral Homology 3-Spheres, Weiping Li Jan 2003

A Monopole Homology For Integral Homology 3-Spheres, Weiping Li

Turkish Journal of Mathematics

To an integral homology 3-sphere Y, we assign a well-defined {\mathbb Z}-graded (monopole) homology MH_*(Y, I_{\eta}(\Theta; \eta_0)) whose construction in principle follows from the instanton Floer theory with the dependence of the spectral flow I_{\eta}(\Theta; \eta_0), where \Theta is the unique U(1)-reducible monopole of the Seiberg-Witten equation on Y and \eta_0 is a reference perturbation datum. The definition uses the moduli space of monopoles on Y \times {\mathbb R} introduced by Seiberg-Witten in studying smooth 4-manifolds. We show that the monopole homology MH_*(Y, I_{\eta}(\Theta; \eta_0)) is invariant among Riemannian metrics with same I_{\eta}(\Theta; \eta_0). This provides a chamber-like structure for …


On Cofinite Subgroups Of Mapping Class Groups, Mustafa Korkmaz Jan 2003

On Cofinite Subgroups Of Mapping Class Groups, Mustafa Korkmaz

Turkish Journal of Mathematics

For every positive integer n, we exhibit a cofinite subgroup \Gamma_n of the mapping class group of a surface of genus at most two such that \Gamma_n admits an epimorphism onto a free group of rank n. We conclude that H^1 (\Gamma_n; {\mathbb Z}) has rank at least n and the dimension of the second bounded cohomology of each of these mapping class groups is the cardinality of the continuum. In the case of genus two, the groups \Gamma_n can be chosen not to contain the Torelli group. Similarly for hyperelliptic mapping class groups. We also exhibit an automorphism of …