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2009

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Articles 6961 - 6990 of 7616

Full-Text Articles in Physical Sciences and Mathematics

Production Of Ybco Superconductor Sample By Powder-In-Tube Method (Pitm); And Effect Of Cd And Ga Doping On The System, Serkan Alagöz Jan 2009

Production Of Ybco Superconductor Sample By Powder-In-Tube Method (Pitm); And Effect Of Cd And Ga Doping On The System, Serkan Alagöz

Turkish Journal of Physics

In this study, YBa_2Cu_3O_{7-\delta} and Y_{0.5}X_{0.5}Ba_2Cu_3O_{7-\delta} (x = Ga, Cd) compounds are produced by Powder-In-Tube Method and electrical and physical characteristics of those samples were investigated. Following 3, 5 and 9 tons pressure applied to three sample groups (YBa_2Cu_3O_{7-\delta}, Y_{0.5}Cd_{0.5}Ba_2Cu_3O_{7-\delta}, Y_{0.5}Ga_{0.5}Ba_2Cu_3O_{7-\delta}), samples were examined via X-Ray diffraction, resistivity and SEM measurement. Considerable changes in Crystallographic properties of the YBCO samples, produced by using Powder-In-Tube Method for different pressure values, were observed. Under different magnetic fields conditions, resistance of the YBCO samples was measured and it was seen that samples had very pure and homogenous structure. Ga doping into YBCO composition …

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Electrical Characterization And Relaxation Behavior Of Lithium-Indium-Phosphate Glasses Via Impedance Spectroscopy, M. V. N. V. D. Sharma, A. V. Sarma, R. Balaji Rao Jan 2009

Electrical Characterization And Relaxation Behavior Of Lithium-Indium-Phosphate Glasses Via Impedance Spectroscopy, M. V. N. V. D. Sharma, A. V. Sarma, R. Balaji Rao

Turkish Journal of Physics

Phosphate glasses with various compositions of lithium oxide and indium oxide were synthesized by melt quenching technique. The glass forming ability parameter K_{gl} was characterized by differential thermal analysis. The electrical measurements for all the glass samples were carried out in the frequency range of 10 Hz to 10^{6} Hz and at a temperature range of 393-513 K by the Impedance spectroscopy. Frequency dependent conductivity follows the power law. The ac conductivity increases with temperature following the Arrhenius law. Master curve in the scaling analysis suggesting the temperature independent conduction relaxation mechanism.

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Generation Of Ultrafast Bright And Dark Pulse On Silicon Chip With Integrated Mach-Zehnder Interferometer Configuration, Jianwei Wu, Fengguang Luo Jan 2009

Generation Of Ultrafast Bright And Dark Pulse On Silicon Chip With Integrated Mach-Zehnder Interferometer Configuration, Jianwei Wu, Fengguang Luo

Turkish Journal of Physics

In this paper we propose and simulate ultrafast femtosecond bright and dark pulses, obtained simultaneously at the same center wavelength, based on silicon-on-insulator (SOI) waveguides in Mach-Zehnder interferometer (MZI) configuration; the ultrafast pulsed pump is injected into one MZI's arm and a continuous wave component (CW) is divided equally into the two MZI arms. Numerical results show that properties of the generated bright and dark pulses are strongly dependent on the launching optical powers of both the pump pulse and CW carriers, and on the waveguide length.

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Composition Dependent Of Dielectric Properties In Se_{100-X}Pb_X Glassy Alloys, Jyoti Sharma, Santosh Kumar Jan 2009

Composition Dependent Of Dielectric Properties In Se_{100-X}Pb_X Glassy Alloys, Jyoti Sharma, Santosh Kumar

Turkish Journal of Physics

In this paper we report the composition dependent of dielectric properties in Se_{100-x}Pb_x (x = 0, 2, 4, 6 and 10) glassy alloys. The temperature and frequency dependence of the dielectric constants and the dielectric losses in the above glassy systems in the frequency range 1 kHz-5 MHz and temperature range 300-340 K have been measured. It has been found that dielectric constant and the dielectric loss both are highly dependent on frequency and temperature and also found to be increased with increasing concentration of Pb in pure amorphous Se. The results have been interpreted in terms of increase in …

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Study Of Second-Class Currents Effects On Polarization Characteristics In Quasi-Elastic Neutrino (Anti-Neutrino) Scattering By Nuclei, Adamou Ousmane Manga, Almoustapha Aboubacar Jan 2009

Study Of Second-Class Currents Effects On Polarization Characteristics In Quasi-Elastic Neutrino (Anti-Neutrino) Scattering By Nuclei, Adamou Ousmane Manga, Almoustapha Aboubacar

Turkish Journal of Physics

The differential cross section of quasi-elastic neutrino scattering by nuclei is computed. The numerical analysis of energy dependence of the spin asymmetry, the angular electron-neutrino (e\nu) correlation and the charge asymmetry coefficients shows that the relative contribution of the second-class current (SCC) tensor form factor can reach some tens of percents in the case of particular values of final nuclei alignment and polarization.

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Behavior Of Transition Amplitude And Evolution Of The Energy Of Quantum Kicked Rotator, Abdolrasoul Gharaati Jan 2009

Behavior Of Transition Amplitude And Evolution Of The Energy Of Quantum Kicked Rotator, Abdolrasoul Gharaati

Turkish Journal of Physics

I give certain analytical properties of quantum kicked rotators, both theoretic and observed from computation. I give an expression for the wave function between two successive impulses. An element of the transition matrix, the matrix that takes the wave function from one impulse to another, exponentially falls away from the main diagonal. The decay parameter is given for a few special cases of a periodic potential. Finally, the transition matrix is used to derive the time evolution of the energy for periodic cases and for fundamental resonances. The empirical expressions of Dorizzi et al. are compatible with our analytical results.

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^{207}Pb-^{206}Pb, ^{40}Ar-^{39}Ar And Fission-Track Geothermochronology Quantifying Cooling And Exhumation History Of The Kaman-Kırşehir Region Intrusions, Central Anatolia, Turkey, Durmuş Boztuğ, Özlem Güney, Matt Heizler, Raymond J. Jonckheer, Marion Tichomirowa, Nazmi̇ Otlu Jan 2009

^{207}Pb-^{206}Pb, ^{40}Ar-^{39}Ar And Fission-Track Geothermochronology Quantifying Cooling And Exhumation History Of The Kaman-Kırşehir Region Intrusions, Central Anatolia, Turkey, Durmuş Boztuğ, Özlem Güney, Matt Heizler, Raymond J. Jonckheer, Marion Tichomirowa, Nazmi̇ Otlu

Turkish Journal of Earth Sciences

The Kaman-Kırşehir region intrusions were generated in a post-collisional extensional setting following Cenomanian-Turonian docking of an oceanic island arc, comprising the supra-subduction zone (SSZ) Central Anatolian ophiolite (CAO), onto the Tauride-Anatolide Platform (TAP). These granitoids have been named, from N to S, the Çamsarı quartz syenite, Hamit quartz syenite, Bayındır nepheline-cancrinite syenite, Durmuşlu nepheline-nosean-melanite syenite porphyry and Baranadağ quartz monzonite. They intrude the crustal metasediments of the Central Anatolian Crystalline Complex (CACC) and CAO and are unconformably overlain by Upper Paleocene to Lower-Middle Eocene sediments. The single-zircon ^{207}Pb-^{206}Pb evaporation age of the Çamsarı unit is 95.7±5.1 Ma; those of the …

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Lead And Sulfur Isotope Studies Of The Koru (Çanakkale, Turkey) Lead-Zinc Deposits, Gülcan Bozkaya, Ahmet Gökçe Jan 2009

Lead And Sulfur Isotope Studies Of The Koru (Çanakkale, Turkey) Lead-Zinc Deposits, Gülcan Bozkaya, Ahmet Gökçe

Turkish Journal of Earth Sciences

Koru (Çanakkale) barite-bearing lead-zinc deposits are typical examples of the lead-zinc deposits occurring in the Tertiary volcanic rocks which crop out in the Biga Peninsula. Volcanic rocks around the investigated deposits are distinguished as Eocene Akçaalan andesite, Oligocene Adadağı pyroclastics, Miocene Dededağ dacite and Plio-Quaternary Karaömerler basalt. The investigated deposits are hosted by Adadağı pyroclastics and show two different mineralization styles such as stockwork ore veinlets in the upper parts and ore veins along the fault zones in WNW-ESE direction, in the lower parts. Sphalerite, galena, pyrite, chalcopyrite, quartz, barite and calcite are the main minerals and they are accompanied …

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Perturbation Of Closed Range Operators, Mohammad Sal Moslehian, Ghadir Sadeghi Jan 2009

Perturbation Of Closed Range Operators, Mohammad Sal Moslehian, Ghadir Sadeghi

Turkish Journal of Mathematics

Let T, A be operators with domains D(T) \subseteq D(A) in a normed space X. The operator A is called T-bounded if Ax \leq a x +b Tx for some a, b\geq 0 and all x \in D(T). If A has the Hyers--Ulam stability then under some suitable assumptions we show that both T and S: = A+T have the Hyers--Ulam stability. We also discuss the best constant of Hyers--Ulam stability for the operator S. Thus we establish a link between T-bounded operators and Hyers--Ulam stability.

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The Integrated Biomedical Science Graduate Program At The University Of South Carolina, Richard Hunt Jan 2009

The Integrated Biomedical Science Graduate Program At The University Of South Carolina, Richard Hunt

Journal of the South Carolina Academy of Science

No abstract provided.

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Temperature Changes Resulting From A Gaalas Laser In The Decontamination Of A Failing Dental Implant, Adam B. Oppenheimer Jan 2009

Temperature Changes Resulting From A Gaalas Laser In The Decontamination Of A Failing Dental Implant, Adam B. Oppenheimer

Journal of the South Carolina Academy of Science

No abstract provided.

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Where Do Mouse Embryos Thrive Best? Comparison Of Mammalian Embryo Development Under Varying Laboratory Environments, Yvonne K. Kao, H. Lee Higdon Iii, Ph.D, Jennifer E. Graves-Herring , M.S., William R. Boone Ph.D Jan 2009

Where Do Mouse Embryos Thrive Best? Comparison Of Mammalian Embryo Development Under Varying Laboratory Environments, Yvonne K. Kao, H. Lee Higdon Iii, Ph.D, Jennifer E. Graves-Herring , M.S., William R. Boone Ph.D

Journal of the South Carolina Academy of Science

No abstract provided.

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Crustal Thermal Properties Of The Central Pontides (Northern Turkey) Deduced From Spectral Analysis Of Magnetic Data, Nafi̇z Maden Jan 2009

Crustal Thermal Properties Of The Central Pontides (Northern Turkey) Deduced From Spectral Analysis Of Magnetic Data, Nafi̇z Maden

Turkish Journal of Earth Sciences

The Pontides can be divided tectonically into three main sectors: Eastern, Central, and Western Pontides. Each of these represents an amalgamated tectonic mosaic consisting of remnants of oceanic, continental, and island arc segments. The Eastern and the Western Pontides meet in the Central Pontides, where they are structurally mixed and form a tectonic knot. The Central Pontides of northern Turkey is one of the best exposed segments of the southern margin of Eurasia adjacent to the Tethys Ocean. The study area also extends to parts of the Sakarya and Kırşehir continents. Magnetic spectral analysis, which has been used to estimate …

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Optically Stimulated Luminescence To Date Coastal Dunes And A Possible Tsunami Layer On The Kavak Delta (Saros Gulf, Nw Turkey), Ahmet Evren Ergi̇nal, Nafi̇ye Kiyak Güneç, Hasan Özcan Jan 2009

Optically Stimulated Luminescence To Date Coastal Dunes And A Possible Tsunami Layer On The Kavak Delta (Saros Gulf, Nw Turkey), Ahmet Evren Ergi̇nal, Nafi̇ye Kiyak Güneç, Hasan Özcan

Turkish Journal of Earth Sciences

Optically stimulated luminescence (OSL) dating was used to determine the timing of initial dune formation and reconstruct the evolution of coastal dunes that developed on the Kavak Delta, Saros Gulf, Turkey. Along a 500-m-long representative transect, dune sands were extracted from foredune, semistable (grey) dune, stable (dark) dune and dune-swamp boundary defined by a scarp 50-75 cm high. The data obtained showed that dune drift initiated 670 years ago. A pumice layer 15-20-cm-thick interbedded with marine clay and sand showed an OSL age of 340 years coinciding with underlying dune sand. XRF analysis showed that pumices were of similar composition …

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A Convenient Synthesis Of 2-Azido And 2-Thiocyanato-2,3-Unsaturated Cyclic Ketones, Mesut Boz, Ömer Zai̇m, Hi̇lal Esen Jan 2009

A Convenient Synthesis Of 2-Azido And 2-Thiocyanato-2,3-Unsaturated Cyclic Ketones, Mesut Boz, Ömer Zai̇m, Hi̇lal Esen

Turkish Journal of Chemistry

2-Azido and 2-thiocyanato-2,3-unsaturated ketones were synthesized by utilizing functionalization of 5- or 6-membered cycloalkane-1,2-diones, namely diosphenols, with dimethylthiocarbomoyl chloride, which activates the system towards reaction with nucleophiles in acidic conditions. Replacement of the enolic oxygen of the diosphenols with azide and thiocyanate may be achieved by treating their dimethylthiocarbamates with sodium azide or potassium thiocyanate in boiling acetonitrile/acetic acid.

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Synthesis And Antimicrobial And Antitumor Activity Of Some New [1,2,4] Triazole-5-One Derivatives, Yasemi̇n Ünver, Esra Düğdü, Kemal Sancak, Mustafa Er, Sengül Alpay Karaoğlu Jan 2009

Synthesis And Antimicrobial And Antitumor Activity Of Some New [1,2,4] Triazole-5-One Derivatives, Yasemi̇n Ünver, Esra Düğdü, Kemal Sancak, Mustafa Er, Sengül Alpay Karaoğlu

Turkish Journal of Chemistry

4-[Arylidene-amino]-3-thiophen-2-ylmethyl-4,5-dihydro[1,2,4]triazole-5-one compounds (3a-g) with Schiff base character were obtained from the reaction of 4-amino-3-thiophen-2-ylmethyl-4,5-dihydro-1H-[1,2,4]triazole-5-one (2) with various aldehydes. 1-(2-Oxo-2-phenyl-ethyl)-4-[arylidene-amino]-3-thiophen-2-ylmethyl-4,5- dihydro-1H-[1,2,4]triazole-5-ones (4a-g) were synthesized from the reaction of corresponding compounds 3a-g with bromoacetophenone. 1-(2-Hydroxy-2-phenyl-ethyl)- 3-thiophen-2-ylmethyl-4-[aryl-amino]4,5-dihydro-1H-[1,2,4]triazole-5-ones (5a-g) and 1-(2-hydroxy-2-phenyl-ethyl)-3-thiophen-2-ylmethyl-4-[arylidene-amino] 4,5-dihydro-1H-[1,2,4]triazole-5-ones (6b,d,e) were obtained from the selective reduction of 1-(2-oxo-2-phenyl-ethyl)-4-[arylidene-amino]-3-thiophen-2ylmethyl- 4,5-dihydro-1H-[1,2,4] triazole-5-ones (4) with NaBH_4. They were characterized by IR, H-NMR,^{13}C-NMR, and elemental analyses. Compounds 2, 3a, 3c, 3g, 4f, 5b, and 5g showed good antifungal activity against yeast-like fungi. Compounds selected by the National Cancer Institute (NCI, USA) were investigated for antitumor activity.

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Quantitative Structure--Retention Study Of Some 2,4-Dioksotetrahydro- 1,3--Thiazole Derivatives Using The Partial Least Squares Method, Tatjana Djakovic-Sekulic, Costel Sarbu, Nada Perisic-Janjic, Zagorka Lozanov-Crvenkovic Jan 2009

Quantitative Structure--Retention Study Of Some 2,4-Dioksotetrahydro- 1,3--Thiazole Derivatives Using The Partial Least Squares Method, Tatjana Djakovic-Sekulic, Costel Sarbu, Nada Perisic-Janjic, Zagorka Lozanov-Crvenkovic

Turkish Journal of Chemistry

Thin-layer chromatography on rice starch support and aqueous ammonia--organic modifier (methanol, dioxane, and acetone) mobile phases was used to study the effect on retention of the chromatographic system and the physicochemical properties of twelve 2,4-dioxotetrahydro-1,3-thiazoles. A multivariate approach to the retention behaviour of the investigated compounds with 3 quite different organic solvents was used to explain the interactions between the 1,3-thiazoles and the mobile phases. Partial least-squares (PLS) regression was used to quantify differences between the observed data and recognize the molecular properties with the greatest effect on retention for each modifier. Good correlation was obtained between experimental and calculated …

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The Effect Of Electrocatalytic Activity And Crystal Structure Of Pbo_2 Surfaces On Polyphenylene Oxide (Ppo) Production In Acetonitrile, Serdar Abaci, Atti̇la Yildiz Jan 2009

The Effect Of Electrocatalytic Activity And Crystal Structure Of Pbo_2 Surfaces On Polyphenylene Oxide (Ppo) Production In Acetonitrile, Serdar Abaci, Atti̇la Yildiz

Turkish Journal of Chemistry

The crystallographic nature of PbO_2 films was changed by optimizing the electrolysis conditions in an electrodeposition solution of PbO_2. These PbO_2 films were then used to prepare PPO films. It was determined that \alpha and \beta modifications, and relative degrees of crystallinity had profound effects on the electrocatalytic performance of PbO_2 films in the production PPO films.

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Voltammetric Determination Of Ascorbic Acid And Dopamine Simultaneously At A Single Crystal Au(111) Electrode, Zekerya Dursun, Levent Peli̇t, Isao Taniguchi Jan 2009

Voltammetric Determination Of Ascorbic Acid And Dopamine Simultaneously At A Single Crystal Au(111) Electrode, Zekerya Dursun, Levent Peli̇t, Isao Taniguchi

Turkish Journal of Chemistry

A single-crystal Au(111) electrode was used for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) in a phosphate buffer solution at pH 6.9. The single-crystal Au(111) electrode displayed excellent electrocatalytic activity for DA and AA oxidation in comparison to a Au disk electrode. Although the anodic peaks of both reagents overlapped on the Au disk electrode, the anodic peak potentials of DA and AA in their mixture were well separated since the peak potential of AA was shifted to more negative values by cyclic and differential pulse voltammetry. The oxidation peak current increased linearly with the concentration of …

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Synthesis And Biological Activity Of 4-(4-Hydroxybenzylidene)-2- (Substituted Styryl) Oxazol-5-Ones And Their O-Glucosides, Vijay Taile, Kishor Hatzade, Pravin Gaidhane, Vishwas Ingle Jan 2009

Synthesis And Biological Activity Of 4-(4-Hydroxybenzylidene)-2- (Substituted Styryl) Oxazol-5-Ones And Their O-Glucosides, Vijay Taile, Kishor Hatzade, Pravin Gaidhane, Vishwas Ingle

Turkish Journal of Chemistry

The 4-(4-hydroxybenzylidene)-2-methyl oxazol-5-ones 1 were treated with various aldehydes in the presence of acetic acid to form 4-(4-hydroxybenzylidene)-2-(substituted styryl) oxazol-5-ones 2a-i, which were glucosylated using \alpha-acetobromoglucose as a glucosyl donor to afford 4-(4-o-\beta-d-tetra-o-acetyl-glucoxybenzylidene)-2- (substituted styryl) oxazol-5-ones 3a-i, which were deacetylated using zinc acetate in absolute methanol to form 4-(4-o-\beta-d-glucoxybenzylidene)- 2-(substituted styryl) oxazol-5-ones 4a-i. The compounds showed good antimicrobial and antifungal activity.

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Synthesis, Characterization, And Antibacterial Effect Of 4-Methoxy-2-(5-H/Me/Cl/No_2-1h-Benzimidazol-2-Yl)- Phenols And Some Transition Metal Complexes, Aydin Tavman, Serkan İki̇z, Arzu Funda Bağcigi̇l, N. Yakut Özgür, Seyyal Ak Jan 2009

Synthesis, Characterization, And Antibacterial Effect Of 4-Methoxy-2-(5-H/Me/Cl/No_2-1h-Benzimidazol-2-Yl)- Phenols And Some Transition Metal Complexes, Aydin Tavman, Serkan İki̇z, Arzu Funda Bağcigi̇l, N. Yakut Özgür, Seyyal Ak

Turkish Journal of Chemistry

4-Methoxy-2-(5-H/methyl/chloro/nitro-1H-benzimidazol-2-yl)-phenol(HL_X; X=1-4) ligands and HL_1 complexes with Fe(NO_3)_3, Cu(NO_3)_2, AgNO_3, and Zn(NO_3)_2 were synthesized and characterized. The structures of the compounds were confirmed on the basis of elemental analysis, molar conductivity, magnetic moment, FT-IR, UV-visible, and ^1H- and ^{13}C-NMR. Antibacterial activity of the free ligands, their hydrochloride salts, and the complexes was evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimum inhibitory concentration (MIC) dilution method, against 9 bacteria, and the results were compared with penicillin-G and oxytetracycline. It was observed that HL_1, [Ag(HL_1)](NO_3), and [Cu(L_1)_2](H_2O)_2 are effective on S. epidermidis, S. aureus, and …

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H_2{So}_4-Silica As An Efficient And Chemoselective Catalyst For The Synthesis Of Acylal From Aldehydes Under Solvent-Free Conditions, Seied Ali Pourmousavi, Zahra Zinati Jan 2009

H_2{So}_4-Silica As An Efficient And Chemoselective Catalyst For The Synthesis Of Acylal From Aldehydes Under Solvent-Free Conditions, Seied Ali Pourmousavi, Zahra Zinati

Turkish Journal of Chemistry

A variety of aldehydes react with acetic anhydride in the presence of a catalytic amount of H_2SO_4-silica to afford the corresponding 1,1-diacetates (acylals) in excellent yields. Ketones are not affected under the reaction conditions. The advantages are the simplicity of the acylation procedure, and the relatively non-toxic nature of the catalyst as well as its easy availability and low cost.

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Synthesis, Characterization, And Optical Properties Of Novel 2,5-Bis[4-(2-(-Arylvinyl)Phenyl]-1,3,4-Oxadiazoles, Dao-Hang He, Yong-Chuang Zhu, Zhuo-Ru Yang, Ai-Xi Hu, Gao Cao Jan 2009

Synthesis, Characterization, And Optical Properties Of Novel 2,5-Bis[4-(2-(-Arylvinyl)Phenyl]-1,3,4-Oxadiazoles, Dao-Hang He, Yong-Chuang Zhu, Zhuo-Ru Yang, Ai-Xi Hu, Gao Cao

Turkish Journal of Chemistry

Six novel 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles were synthesized by introducing 1,3,4-oxadiazole moiety into the stilbene skeleton. The synthesis route included the cyclization of p-toluic acid and hydrazine hydrate catalyzed by polyphosphoric acid (PPA), bromination of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), esterification, and the Wittig-Horner reaction. All the title compounds were characterized by ^1H-NMR, MS, and elemental analysis. UV-Vis absorption and fluorescence emission spectra in THF solution were investigated; the compounds may have potential for use in organic optical materials.

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Application Of Fam Ligands In The Metal-Promoted Catalytic Enantioselective Synthesis Of Organic Compounds, Özdemi̇r Doğan, Philip P. Garner, Adnan Bulut Jan 2009

Application Of Fam Ligands In The Metal-Promoted Catalytic Enantioselective Synthesis Of Organic Compounds, Özdemi̇r Doğan, Philip P. Garner, Adnan Bulut

Turkish Journal of Chemistry

Novel ferrocenyl substituted aziridinyl methanol (FAM) ligands were synthesized and successfully used in metal-promoted catalytic enantioselective azomethine ylide cycloadditions, diethylzinc additions to enones, alkynylzinc additions to aldehydes, diethylzinc additions to aldehydes, and Henry reactions. These reactions are summarized in this report.

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One-Pot Synthesis Of Amidoalkyl Naphthols Using Nahso_4.Sio_2 As An Efficient And Recyclable Heterogeneous Catalyst, Hamid Reza Shaterian, Hossein Yarahmadi, Majid Ghashang Jan 2009

One-Pot Synthesis Of Amidoalkyl Naphthols Using Nahso_4.Sio_2 As An Efficient And Recyclable Heterogeneous Catalyst, Hamid Reza Shaterian, Hossein Yarahmadi, Majid Ghashang

Turkish Journal of Chemistry

An efficient synthesis of amidoalkyl naphthols using silica supported sodium hydrogen sulphate as heterogeneous catalyst under a thermal solvent-free green procedure is described. This simple protocol offer advantages such as shorter reaction times, simple work-up, excellent yield, and recovery and reusability of the catalyst.

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Performance Analysis For Direct 2-Propanol Fuel-Cell Based On Pt Containing Anode Electrocatalysts, Ni̇yazi̇ Alper Tapan, Ezgi̇ Öztürk Jan 2009

Performance Analysis For Direct 2-Propanol Fuel-Cell Based On Pt Containing Anode Electrocatalysts, Ni̇yazi̇ Alper Tapan, Ezgi̇ Öztürk

Turkish Journal of Chemistry

Direct 2-propanol cell performance based on Pt containing anode electrocatalyst was evaluated. Cell performance, open circuit voltage, maximum current density, and maximum power density were measured at various alcohol concentrations and cell temperatures. 2-propanol fuel cell shows the highest performance at 1 M concentration and 80 °C operating temperature. The highest practical efficiency (at the maximum power density) was found at 2 M 2-propanol concentration and 60 °C operating temperature. Parameter estimation was performed by non-linear least squares method using the Levenberg Marquardt algorithm. According to the parametric analysis, cross-over current was minimum for 0.5 M 2-propanol concentration at 40 …

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Chemical Constituents And Mushroom Tyrosinase Inhibition Activity Of Chloroxylon Swietenia Leaves, G. Venkatateswara Rao, K. Sambasiva Rao, Tiruganasambandham Annamalai, Narayanasamy Radhakrishnan, Triptikumar Mukhopadhyay Jan 2009

Chemical Constituents And Mushroom Tyrosinase Inhibition Activity Of Chloroxylon Swietenia Leaves, G. Venkatateswara Rao, K. Sambasiva Rao, Tiruganasambandham Annamalai, Narayanasamy Radhakrishnan, Triptikumar Mukhopadhyay

Turkish Journal of Chemistry

From the leaves of Chloroxylon swietenia DC., 5 known secondary metabolites, namely 6, 8-diprenylumbelliferone (1), bergaptan (2), isopimpinellin (3), tritriacontanol (4), and isoquercetrin (5), were isolated from a folklore medicinal plant. Three compounds were isolated for the first time from this genus. The structures of these compounds were elucidated by UV, IR, 1D and 2D NMR techniques. Different fractions from the leaves of C. swietenia were investigated for their tyrosinase inhibition activity.

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2,2'-Binaphthylene Phosphorochloridite (Binol-Pcl) As A Bulky And Efficient Reagent For The Conversion Of Primary And Secondary Alcohols Into Iodides, And Tertiary Alcohols Stereo- And/Or Regioselectively Into Olefin(S), Nader Noroozi-Pesyan, Jabbar Kalaphy, Hossein Khani-Meinagh Jan 2009

2,2'-Binaphthylene Phosphorochloridite (Binol-Pcl) As A Bulky And Efficient Reagent For The Conversion Of Primary And Secondary Alcohols Into Iodides, And Tertiary Alcohols Stereo- And/Or Regioselectively Into Olefin(S), Nader Noroozi-Pesyan, Jabbar Kalaphy, Hossein Khani-Meinagh

Turkish Journal of Chemistry

Primary and secondary alcohols were transformed in high yield to corresponding iodides by 4-chloro-3,5-dioxaphosphacyclohepta [2,1-\alpha; 3,4-\alpha'] dinaphthalene (BINOL-PCl) at room temperature. The tertiary alcohols formed corresponding alkenes by stereo- and/or regioselective elimination reactions. (E)-1,2-Diphenyl-1-propene and 2,3-diphenyl-1-propene were stereoselectively obtained from 1,2-diphenyl-2-propanol, as representative. No (Z)-1,2-diphenyl-1-propene was observed. 2-Methyl-1-phenylcyclopentene and 3-methyl-2-phenylcyclopentene were regioselectively obtained from 2-methyl-1-phenylcyclopentanol. ^{13}C chemical shifts for the \alpha-methylene carbon of some alkyl iodides empirically calculated through a very simple additive relationship lead to similar or even better values than the reported values. All primary alkyl iodides showed the iodine heavy atom effect on the \alpha-methylene carbon chemical …

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Zeolite Catalyzed Efficient Synthesis Of Perimidines At Room Temperature, Akbar Mobinikhaledi, Naser Forughifar, Nemat Bassaki Jan 2009

Zeolite Catalyzed Efficient Synthesis Of Perimidines At Room Temperature, Akbar Mobinikhaledi, Naser Forughifar, Nemat Bassaki

Turkish Journal of Chemistry

Arylperimidines, 3(a-l), were synthesized in good yields by cyclocondensation reaction of 1,8-diaminonaphthalene and aromatic aldehydes in the presence of NaY zeolite as a catalyst. The simple environmentally benign nature, reusability of the catalyst, and the easy work-up reaction are some of the advantages of this protocol.

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Comparison Of Photochromic Properties And Thermal Stabilities Of Fulgide, Fulgimide, And Benzimidazole[1,2-A]Pyrrolidine-2-One Derivatives, Mahmut Köse, Ersi̇n Orhan Jan 2009

Comparison Of Photochromic Properties And Thermal Stabilities Of Fulgide, Fulgimide, And Benzimidazole[1,2-A]Pyrrolidine-2-One Derivatives, Mahmut Köse, Ersi̇n Orhan

Turkish Journal of Chemistry

New thermally stable photochromic fulgimides and benzimidazole[1,2-a]pyrrolidin-2-one derivatives of furylfulgide and thienylfulgide were prepared and their photochromic properties were investigated. Thermal stabilities of some of the new isomers in an alcoholic solution and in PMMA (poly(methyl methacrylate)) polymer films, and pyrolytic behaviors in inert atmosphere with TGA were compared. The colored form of fulgimide and that of benzimidazole[1,2-a]pyrrolidin- 2-one derivatives showed large bathochromic shifts for visible absorption maximum compared with the colored form of corresponding fulgides. The imides and benzimidazole[1,2-a]pyrrolidin-2-one derivatives of fulgide displayed better thermal stability than corresponding fulgides.

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