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1 - Experimental results of thep+d⇌3He+γ reactions up to 450 MeV
Ali Akbar Mehmandoost-Khajeh-DadAbstractAbstractExperiments on proton-deuteron radiative capture and the inverse reaction, the photo-disintegration of 3He, performed since 1963, up to the intermediate energies are reviewed. Differential cross sections in the center-of-mass system for the radiative cap أکثرAbstractAbstractExperiments on proton-deuteron radiative capture and the inverse reaction, the photo-disintegration of 3He, performed since 1963, up to the intermediate energies are reviewed. Differential cross sections in the center-of-mass system for the radiative capture (θγc.m.=90°) and the inverse reaction (θpc.m.=90°) as a function of photon energy are presented. The experimental data are compared with a calculation based on CD-Bonn+Δ with the hadronic potential including Coulomb and relativistic 1N current corrections. This study demonstrates a success for time-reversal invariance for the electromagnetic interaction, except for 35 تفاصيل المقالة -
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2 - Number-projected isovector neutron-proton pairing effect in odd mass nuclei
Amine Berbiche Mohamed Fellah Nassima H AllalAbstractA formalism which enables one to strictly conserve the number of particles when taking into account the isovector pairing correlations is presented in the case of odd mass nuclei. With this aim, we had to first establish the expression of the projector for such أکثرAbstractA formalism which enables one to strictly conserve the number of particles when taking into account the isovector pairing correlations is presented in the case of odd mass nuclei. With this aim, we had to first establish the expression of the projector for such systems. Expressions of the ground state and its energy have been exhibited. The model has been numerically tested in the framework of a schematic model.PACS21.60.-n; 21.30.Fe تفاصيل المقالة -
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3 - Number projected isovector neutron–proton pairing effect in odd-mass nuclei
Amine Berbiche Mohamed Fellah Nassima H. AllalAbstractA formalism which enables one to strictly conserve the number of particles when taking into account the isovector pairing correlations is presented in the case of odd-mass nuclei. With this aim, we had to first establish the expression of the projector for such أکثرAbstractA formalism which enables one to strictly conserve the number of particles when taking into account the isovector pairing correlations is presented in the case of odd-mass nuclei. With this aim, we had to first establish the expression of the projector for such systems. Expressions of the ground state and its energy have been exhibited. The model has been numerically tested in the framework of a schematic model. تفاصيل المقالة -
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4 - Beam shaping assembly study for BNCT facility based on a 2.5 MeV proton accelerator on Li target
J. G. FantidisAbstractA new study for a boron neutron capture therapy irradiation facility, based on a 2.5 MeV proton accelerator on a thick Li target as neutron converter, is presented here. The beam shaping assembly (BSA) modeling has been performed with the use of the MCNP5 Monte أکثرAbstractA new study for a boron neutron capture therapy irradiation facility, based on a 2.5 MeV proton accelerator on a thick Li target as neutron converter, is presented here. The beam shaping assembly (BSA) modeling has been performed with the use of the MCNP5 Monte Carlo code. The fast (i.e., > 10 keV) neutron component yielded by the 7Li(p,n)7Be reaction is slowed down through TiF3 neutron spectrum shifter, while to obtain a high-quality epithermal neutron beam at the beam port exit additional layers for thermal neutrons removal and shielding of gamma rays were used. Moreover, 60Ni and Ti6Al14V were selected to filter out and further remove the residual fast neutron component, while cadmium was chosen as thermal neutrons absorber, and bismuth was selected for gamma rays shielding. The therapeutic effectiveness of the proposed BSA was evaluated by performing a set of dose-equivalent distribution calculations in a standard Snyder head phantom. The simulation results show that the proposed BSA modeling meets all the recommended by IAEA criteria and provides one possible technical choice for an accelerator-based BNCT irradiation facility in a hospital environment. تفاصيل المقالة -
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5 - Quantum mechanics investigation of acid dissociation constant of carboxylic acids in aqueous solution
M. Khaleghian Gh. R. GhashamiAccording to the Bronsted definition, any compound which has a hydrogen atom is an acid, since itmay be lost as a proton. A thermodynamical cycle is proposed to calculate absolute pKa values forBronsted acids in aqueous solution. The equilibrium of dissociation of a Bro أکثرAccording to the Bronsted definition, any compound which has a hydrogen atom is an acid, since itmay be lost as a proton. A thermodynamical cycle is proposed to calculate absolute pKa values forBronsted acids in aqueous solution. The equilibrium of dissociation of a Bronsted acid depends onthe interaction of the acid and its conjugate base with solvent molecules. There fore the pKa valuedepends on the solvent medium. The polarizable continuum model (PCM) was used to describe thesolvent, and absolute pKa values were computed for different compounds: HCOOH, CH3COOH,C6H5COOH, FCH2COOH and CH3CH2COOH. The model of furnishes pKa values was in goodagreement with the experimental results for some classes of compounds. The quantum Mechanics(QM) calculations were carried out with the GAUSSIAN 98 program based on HF/6-31+G** level. تفاصيل المقالة -
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6 - Solvent effects on protonation and complexation of histidine with molybdenum (VI) at different aqueous solutions of methanol
Farrokh Gharib Nayyer Farkhad-AaliThe formation constants of the species formed in the systems H+ + Mo(VI) + histidine and H+ +histidine have been determined at different aqueous solutions of methanol (0 - 45 % v/v) at 25 °C andconstant ionic strength (0.1 mol dm-3 sodium perchlorate), using a combi أکثرThe formation constants of the species formed in the systems H+ + Mo(VI) + histidine and H+ +histidine have been determined at different aqueous solutions of methanol (0 - 45 % v/v) at 25 °C andconstant ionic strength (0.1 mol dm-3 sodium perchlorate), using a combination of spectrophotometricand potentiometric techniques. The composition of the complex species was determined by thecontinuous variations method (Job). It was shown that molybdenum (VI) forms a mononuclear 1:1complex with histidine of the type MoO3L- at pCH 5.8. The protonation of histidine and the formationconstant of the formed complex species in various media were analyzed in terms of Kamlet, Abboud,and Taft (KAT) parameters. Single-parameter correlation of the formation constant versus (hydrogen-bond donor acidity), (hydrogen-bond accepter basicity) and * (dipolarity/polarizability)are poor in all solutions, but dual-parameter correlation represents significant improvement withregard to the single or multi-parameter models. Linear correlation is observed when the experimentallog KS values are plotted versus the calculated ones while the KAT parameters are considered.Finally, the results are discussed in terms of the effect of solvent on protonation and complexation. تفاصيل المقالة -
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7 - Spectrophotometric Determination of Protonation Constants of T ry p to ph an at Different Ionic Strengths and Various Ionic Media
Al' Shamel Masumeh Asgharian Farrokh GitaribThe prtnonation constant values of tryptophan were studied at 25 C. different ionic strengths. 0.1-1.0 moldm", and various ionic media of NaCIO, and N4N01, using a combination of spectrophotometrie andpotentiometric techniques. The general vend for the two protonation c أکثرThe prtnonation constant values of tryptophan were studied at 25 C. different ionic strengths. 0.1-1.0 moldm", and various ionic media of NaCIO, and N4N01, using a combination of spectrophotometrie andpotentiometric techniques. The general vend for the two protonation con Slant Vai net of tryptophan is in theorder of NaC104 > NaNO3 in different ionic media. The dependence of protonation constants on ionicstrength and ionic media were taken into account; using a Debye-Huckel type equation (molarconcentration scale) and the SIT (specific ion interaction theory) approach (udal concentration scale).Differences in protonation constants in thc various supporting electrolytes were also interpreted anddiscussed. تفاصيل المقالة -
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8 - Solvent Effects on Tautomeric and Microscopic Protonation Constants of Glycine in Different Aqueous Solutions of 1,4-Dioxane
M. S. Mojarrad A. Shamel F. GharibThe acid-base equilibria of glycine have been studied in different aqueous solutions of 1,4-dioxane(0-50 % by v/v) using potentiometric method. In this study, the macro and micro protonationconstants of the amino acid and its tautomeric constant have been determined at أکثرThe acid-base equilibria of glycine have been studied in different aqueous solutions of 1,4-dioxane(0-50 % by v/v) using potentiometric method. In this study, the macro and micro protonationconstants of the amino acid and its tautomeric constant have been determined at 25 °C and constantionic strength 0.1 mol dm-3 (NaCl). The protonation and the tautomeric constants of glycine indifferent binary mixtures were analyzed in terms of Kamlet, Abboud and Taft (KAT) parameters.Single-parameter correlations of the constants versus α (hydrogen-bond donor acidity), β (hydrogenbondacceptor basicity) and π* (dipolarity/polarizability) are poor in all solutions. Multi-parametercorrelations show better results, but dual-parameter correlations represent significant improvementswith regard to the single- and multi-parameter models. Linear correlation is observed when theexperimental protonation constant values are plotted versus the calculated ones, while the KATparameters are considered. Finally, the results are discussed in terms of the effect of the solvent onprotonation and tautomeric constants. تفاصيل المقالة -
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9 - The Effect of Hydrogen Bonding and π–π Stacking to Stabilization of 3D Networks of a New Proton Compound, (a-6-mpyH)(Hpyzd) H2O
R. Mohammadinasab M. Tabatabaee M. A. Seyed SadjadiA new proton transfer compound, formulated as (Hamp-6-pic)(Hpyzd) ∙H2O (1), has been synthesized from the reaction of pyrazine-2,3-dicarboxylic acid (H2pyzd) and 2-amino-6-methyl pyridine (amp-6-pic), in 1:1 molar ratio. Extensive O−H×××O, N&minu أکثرA new proton transfer compound, formulated as (Hamp-6-pic)(Hpyzd) ∙H2O (1), has been synthesized from the reaction of pyrazine-2,3-dicarboxylic acid (H2pyzd) and 2-amino-6-methyl pyridine (amp-6-pic), in 1:1 molar ratio. Extensive O−H×××O, N−H×××N and O−H×××O hydrogen bonds involving (Hamp-6-pic)+ cation, (Hpyzd)- anion and co-crystal water molecule٫ static electronic٫ and π…π stacking interactions form a three-dimensional network. تفاصيل المقالة -
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10 - Interaction of Thallium (I) with Cytidine 5-Monophosphate in Different Ionic Strengths and Various Media
Farhoush i Kian Farrokh GharibThe formation constants of the species formed in the systems H+ + cytidine 5-monophosphate (CMP)and H+ + cytidine 5-monophosphate + Tl (I) ion have been determined in aqueous solution in a widepH range of 1.5 to 10.5 at 25 °C and different ionic strengths ranging أکثرThe formation constants of the species formed in the systems H+ + cytidine 5-monophosphate (CMP)and H+ + cytidine 5-monophosphate + Tl (I) ion have been determined in aqueous solution in a widepH range of 1.5 to 10.5 at 25 °C and different ionic strengths ranging from 0.1 to 1.5 moldm-3NaClO4, NaNO3, and NaCl using potentiometric-spectrophotometric technique. The composition ofthe complexes was specified and was shown that thallium ion forms mononuclear two 1:1 complexeswith CMP. The general trend for the protonation constants of CMP and its complexes with thallium(I) are in the order of NaClO4> NaNO3> NaCl in different ionic media. The dependence of formationconstants on ionic strength are described by a Debye-Huckel type equation and interpreted for thevarious supporting electrolytes. تفاصيل المقالة -
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11 - Study of pH influence on the stability of 175th codon of P53 genes by computational and modeling methods
Nastaran Asghari MoghaddamP53 tumor suppressor gene, also known as “genome guardian” is mutated in more than half of allkind of cancers. In this study we have investigated the controls of environmental pH for P53 genemutation in point of specific sequence which is prone to mutagenesi أکثرP53 tumor suppressor gene, also known as “genome guardian” is mutated in more than half of allkind of cancers. In this study we have investigated the controls of environmental pH for P53 genemutation in point of specific sequence which is prone to mutagenesis. The most probable cancerousmutations occur as point mutations in exons 5-8 of P53 gene. The 175th codon of P53 is the thirdmost mutated codon in this gene. By experimental research, it is revealed that acidic pH raised therate of cancer and mutation in 175 CGC codon of P53 gene. It to some extent is due to protonation ofthis three nucleotide codon. Mutation in this codon changes the encoding amino acid andsubsequently produces a protein which has oncogenic features instead of tumor suppressorcharacteristics of original p53 protein. In current study, we perform investigation on the impact ofprotonation on stability of codon 175CGC in this gene. We used HyperChem software for answeringto our mentioned goal above. Our results suggested a reliable answer about the effect of protonationon mentioned codon and its stability. From theoretical point of view, acidity can decrease theinstability of this specific codon. Along with the experimental investigations, our results can to someextent elaborate acidic pH competency to cause mutation. تفاصيل المقالة -
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12 - Quantum-chemical modeling of the stacking mechanism for the 1H-4H proton transfer in pyridine derivatives. A DFT study
Jumber Kereselidze Marine Kvaraia George MikuchadzeThe stacking mechanism of the 1H-4H proton transfer in 4-pyridone, 4-pyridinthione and p-aminopyridineare constructed. For quantitative description of this process by means of the quamtumchemicalmethod density functional theory (DFT) the activation energy (<E#), reac أکثرThe stacking mechanism of the 1H-4H proton transfer in 4-pyridone, 4-pyridinthione and p-aminopyridineare constructed. For quantitative description of this process by means of the quamtumchemicalmethod density functional theory (DFT) the activation energy (<E#), reaction energy (<E)and tautomeric equilibrium constant (KT) has been calculated. The results of calculations have shown,that the values of the energetical and kinetical characteristics, from the point of view of chemicalreactions, in reasonable limits varies, that allows one to make the conclusion in favour of competenceof the offered stacking mechanism for the 1H-4H proton transfer in pyridine derivatives. It is a newone-stage synchronous and unique mechanism for the 1H-4H proton transfer. تفاصيل المقالة -
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13 - FT-IR and NMR Spectroscopic Investigation and Hybrid Computational DFT/HF Analysis on the Molecular Structure of NSPD
Mohammad Mahdi Akbarzadeh Khirollah Mehrani Shahriar Ghammamy Vahideh Hadigheh RezvanCompound (N,N-bis (salicylidene) 1,2-diaminophenylene) was prepared by condensation of ethanolsolution of 2-Hydroxybanzaldehyde and 1,2-diaminophenylene. The compound was characterized by1H NMR, infrared spectroscopy (FT-IR) data and analytical data. The geometrical par أکثرCompound (N,N-bis (salicylidene) 1,2-diaminophenylene) was prepared by condensation of ethanolsolution of 2-Hydroxybanzaldehyde and 1,2-diaminophenylene. The compound was characterized by1H NMR, infrared spectroscopy (FT-IR) data and analytical data. The geometrical parameters andenergies have been obtained from Density Functional Theory (DFT) B3LYP method and Hartree-Fock (HF) method with 3-21G* (6D, 7F) basis sets calculations. In the first instance, the full geometryoptimization of the studied molecule was performed at the gradient corrected density functional levelof theory using the hybrid B3LYP method based on Becke’s three parameters functional of DFT andGauge Including Atomic Orbital (GIAO). HF/3-21G* (6D, 7F) calculations on B3LYP geometrieswere done for all the reactants and HOMO-LUMO energy gaps. The force fields calculated with theB3LYP functional yield infrared spectra in very good agreement with the experiment. All of thesecalculations were performed using Gaussian 03 program. تفاصيل المقالة -
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14 - Solvent Effect on Protonation Constants of L-alanine and Alanine Methyl ester in Different Aqueous Solutions of 1,4-Dioxane
Mehry Seyed Mojarad Somaryn Farrokh GharibThe protonation constants of alanine and alanine methyl ester were determined in different aqueous solutions of 1,4-dioxane containing (0-50% v/v), using a potentiometric method at 25o C and constant ionic strength 0.1 mol.L-1 (NaCl). The protonation constants were anal أکثرThe protonation constants of alanine and alanine methyl ester were determined in different aqueous solutions of 1,4-dioxane containing (0-50% v/v), using a potentiometric method at 25o C and constant ionic strength 0.1 mol.L-1 (NaCl). The protonation constants were analyzed in terms of Kamlet, Abboud and Taft (KAT) parameters. The results show that the effect of β is higher in comparison with the other parameters (α and π*). Single-parameter correlation of the constants versus α, β, and π* are poor in all solutions. But multi-parameter correlation represents significant improvements with regard to the single- parameter models. تفاصيل المقالة -
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15 - Synthesis of Sulfonated Polystyrene/acrylate–ionic Liquid (Si-SPS/A–IL) Hybrid Membranes for Methanol Fuel Cells
Mohammad Galehassadi Alireza KhaniIn this paper, the silicon-containing sulfonated polystyrene/acrylate–ionic liquid (Si-SPS/A–IL)hybrid membranes was prepared to obtain the proton exchange membrane (PEM) materials withhigh methanol barrier and good selectivity. The Si-SPS/A–IL hybrid أکثرIn this paper, the silicon-containing sulfonated polystyrene/acrylate–ionic liquid (Si-SPS/A–IL)hybrid membranes was prepared to obtain the proton exchange membrane (PEM) materials withhigh methanol barrier and good selectivity. The Si-SPS/A–IL hybrid membranes characterized asthe function of IL to evaluate their potential as PEMs in direct methanol fuel cells (DMFCs).Fourdifferent Hybrid material with different properties have been synthesized and named from I toIV.The potential of the membranes in direct methanol fuel cells (DMFCs) is characterizedpreliminarily by studying their thermal stability, ion-exchange capacity, water uptake, methanoldiffusion coefficient, proton conductivity and selectivity (proton conductivity/methanol diffusioncoefficient). All the hybrid membranes exhibit good thermal stability and reasonable water uptake.IV and V membranes have a low methanol diffusion coefficient, while II and III membrane havegood proton conductivity. In addition, the selectivity values of hybrid membranes increase withincreasing IL content and V membrane shows the best selectivity (1.14×105Ss cm−3). These resultssuggest that the Si-SPS/A–IL hybrid membranes are possible candidate materials for PEMs inDMFC applications. تفاصيل المقالة -
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16 - بررسی ساختار مولکولی و الکترونی ترکیب جدید انتقال پروتون بر پایه 2و6-پیریدین دی کربوکسیلیک اسید و پیریدین–3–کربوکسامید: سنتز و محاسبه های نظریه تابعی چگال
محمد چهکندی محمود ابراهیمیترکیبهای انتقال پروتون از انتقال پروتون بین دو گونه دهنده و گیرنده پروتون بوجود می آید. سنتز موفقیت آمیز این ترکیبها بستگی به انتخاب درست و دقیق پروتون دهنده و پروتون پذیرنده دارد. از این رو کربوکسیلیک اسیدها را بعنوان پروتون دهنده و آمین-ها و آمیدها را بعنوان پروتو أکثرترکیبهای انتقال پروتون از انتقال پروتون بین دو گونه دهنده و گیرنده پروتون بوجود می آید. سنتز موفقیت آمیز این ترکیبها بستگی به انتخاب درست و دقیق پروتون دهنده و پروتون پذیرنده دارد. از این رو کربوکسیلیک اسیدها را بعنوان پروتون دهنده و آمین-ها و آمیدها را بعنوان پروتون پذیرنده انتخاب میکنند و این به دلیل افزایش نیروی برهمکنش بین دو قطعه کاتیونی و آنیونی میباشد. در این پژوهش بلورهای بیرنگ لیگاند جدید انتقال پروتون از واکنش بین 2و6- پیریدین دی کربوکسیلیک اسید (2,6–pydc = pyridine–2,6–dicarboxilic acid) و پیریدین-3-کربوکسامید(py–3–cm = pyridine–3–carbocxamide) تهیه و ساختار آن به کمک FTIR، UV–Vis و آنالیز عنصری شناسایی شد. در ادامه ساختار پیشنهادی ترکیب انتقال پروتون سنتز شده2,6–pydc(py–3–cm) برای انجام محاسبههای نظریهی تابعی چگال (DFT) در سطح B3LYP/6–311+G(d, p) انتخاب شد. محاسبههای بهینه سازی، فرکانس، انتقالهای الکترونی در طیف سنجی مرئی‒ فرابنفش، انرژی اوربیتالهای مرزی و NBO برای لیگاند 2,6–pydc (Py–3–cm) به کمک نرم افزار گوسین 09 انجام شد. مقایسه نوارهای زیر قرمز لیگاند انتقال پروتون سنتز شده و گونه-های اولیه دهنده و پذیرنده پروتون، تشکیل پیوند هیدروژنی بین مولکولی در لیگاند را تائید می کند. با مقایسه طیفهای تجربی و طیف-های نظری میتوان نتیجه گرفت که لیگاند جدید انتقال پروتون تشکیل شده که همخوانی خوبی بین این طیف ها دیده می شود. طیف محاسبهای انتقال های الکترونی این لیگاند، نشان دهنده ی انتقالهایILCT بین گونهی دهنده و پذیرنده پروتون با ویژگی n (p)/π → π* است. پیوندهای هیدروژنی O−H···N و C−H···O ترکیب انتقال پروتون مورد بحث را به میزان kcal mol–136و67- پایدار کرده است. تفاصيل المقالة -
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17 - بررسی نظری تشکیل پیوندهای C-C و C-N کاتالیزور شده توسط کمپلکس مس (I)
فاطمه زرکوب علیرضا آریافرداز محاسبات نظریۀ تابعی چگالی برای بررسی مکانیسم کاتالیزوری مس (I) جهت تشکیل پیوندهای کربن–کربن و کربن-نیتروژن توسط هتروآرنها در حضور آریل هالید و آلکیل هالید استفاده شد.محاسبات ما نشان داد مکانیسم واکنش با پروتون زدایی روی پیوند فعال (X-H (X=C,N آغاز می شود. با ع أکثراز محاسبات نظریۀ تابعی چگالی برای بررسی مکانیسم کاتالیزوری مس (I) جهت تشکیل پیوندهای کربن–کربن و کربن-نیتروژن توسط هتروآرنها در حضور آریل هالید و آلکیل هالید استفاده شد.محاسبات ما نشان داد مکانیسم واکنش با پروتون زدایی روی پیوند فعال (X-H (X=C,N آغاز می شود. با عبور از حالت گذار پنج عضوی و برهمکنش اتم نیتروژن هتروآرن با فلز مس، سطوح انرژی در مرحلۀ پروتون زدایی بهطور چشمگیری پایین میآید. سپس با اضافه شدن آریل هالید C(sp2)-X به محصول فعالسازی، مکانیسم از مسیر همزمان، بهصورت واکنش افزایش اکسایشی به فلز مس پیش رفت. درحالیکه آلکیل هالیدها C(sp3)-X مکانیسمی متفاوت از آریل هالیدها دارند و مکانیسم کلی واکنش هستهدوستی دومولکولی است. اما در تشکیل پیوندهای کربن–کربن مکانیسم بهصورت هستهدوستی دومولکولی از طریق واکنش افزایش اکسایشی فلز مس و در تشکیل پیوندهای کربن-نیتروژن، مکانیسم هستهدوستی دومولکولی از طریق واکنش جفت شدن کربن-نیتروژن است. ما نشان دادیم، تغییر خصلت اسیدی در پیوند فعال (X-H (X=C,N تغییری در سرعت کلی واکنش ایجاد نمیکند و مرحلۀ تعیینکننده سرعت مرحلۀ اضافه شدن آریل یا آلکیل هالید است. همچنین مسیرهای محتمل برای تشکیل پیوندهای کربن–کربن، کربن-نیتروژن را بررسی و مسیرهایی با پایینترین سطح انرژی پیشنهاد دادیم که موضوع قابلتوجه مطالعات آزمایشگاهی، سنتز ترکیبات آلی و دارویی است. تفاصيل المقالة -
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18 - Excited State Proton Transfer Process In The 2-hydroxy –N-Salicylidene Schiff Base
Vali Alizadeh Ahmad Jamali moghadamThe Excited state reaction coordinates and the consequent energy profiles of a new Schiff Base N- Salicylidene-2-Bromoethylamine (NSBA) have been investigated at the CC2 level of theory. The electron-driven proton transfer and torsional deformation have been identified أکثرThe Excited state reaction coordinates and the consequent energy profiles of a new Schiff Base N- Salicylidene-2-Bromoethylamine (NSBA) have been investigated at the CC2 level of theory. The electron-driven proton transfer and torsional deformation have been identified as the most important photochemical reaction coordinates. The potential energy profiles of the ground and the lowest excited singlet state are calculated. In contrast to the ground state, the excited state potential energy profile shows a barrier-less dissociation pattern along the O–H stretching coordinate which verifies the proton transfer reaction at the S1 (ππ*) state. The calculations indicate S1/S0 conical intersections (CIs) which provide non-adiabatic gates for radiation-less decay to the ground state. At the CI, barrier-free reaction coordinates direct the excited system to the ground state of enol-type minimum. According to calculation results, a trans- keto type structure obtained from photoexcitation of the enol, can be responsible for the photo chromoic effect of title compound. Furthermore, our results confirm the suggestion that aromatic Schiff Bases are potential candidates for optically driven molecular switches. تفاصيل المقالة -
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19 - Photo switching of Salicylidene methyl Furyl amine: A Theoretical Photo dynamics Study
Vali Alizadeh Ahmad Jamali moghadamPotential energy surfaces (PES) for the ground and excited state intramolecular proton transfer (ESIPT) processes in N-salicilydene methyl furylamine(SMFA)have been studied usingCC2 level of theory. Our calculations suggest thenon-viability of ground state intramolecula أکثرPotential energy surfaces (PES) for the ground and excited state intramolecular proton transfer (ESIPT) processes in N-salicilydene methyl furylamine(SMFA)have been studied usingCC2 level of theory. Our calculations suggest thenon-viability of ground state intramolecular proton transfer. Excited states PES calculations support the existence of ESIPT process in SMFA.The calculated results show that the intramolecular hydrogen bond were formed in the S0 state, and upon excitation, the intramolecular hydrogen bonds between - OH group and nitrogen atom would be strengthened in the S1 state, which can facilitate the proton transfer process effectively. The calculations indicate two S1/S0 conical intersections (CIs) which provide radiation-less decay to the ground state. At the CIs, two barrier-free reaction coordinates direct the excited system to the ground state of enol-type minimum.The keto-type S1 state attained by barrier less proton transfer is found to be unstable via a torsional motion, which provides fast access to a S1−S0 conical intersections. From the conical intersection, a barrier less reaction path directs the system back to the enol-type minimum of the S0 potential energy surface, thus closing the photocycle. تفاصيل المقالة -
حرية الوصول المقاله
20 - Role of Relativistic Quantum Theory in Hadron Radiation Therapy
Seyede Nasrin HoseiniMotlagh Neda Farhangkhah Mohammad Ghasemi ShabankarehIn recent years, the attention of scientists has been drawn to laser accelerators because they have a smaller size and more power than RT accelerators. But to upgrade these laser accelerators for hadron therapy, the theory governing these accelerators needs more investi أکثرIn recent years, the attention of scientists has been drawn to laser accelerators because they have a smaller size and more power than RT accelerators. But to upgrade these laser accelerators for hadron therapy, the theory governing these accelerators needs more investigation. The present paper represents the theory of laser-driven accelerators. Also, for the first time, we calculated the quantum relativistic important parameters such as the effective atomic number, z_eff, β=v⁄c , parameter, the density effect, δ⁄2, the shell effect,〖∆L〗_shell, Barkas effect, L_Barkas , Lynard Sorensen, effect, 〖∆L〗_LS, the standard perturbation function, L_stand, the first order general term of quantum perturbation theory, L_Pert, for proton and carbon beams in different energies versus the depth of penetration in the different human tissues using Maple programming, and our numerical results show that since the physical and chemical properties of carbon and hydrogen ions are not the same and carbon is heavier than hydrogen, carbon and hydrogen ion beams in hadron therapy do not have the same behavior inside the different human tissues. تفاصيل المقالة -
حرية الوصول المقاله
21 - Improvement of Fuel Cells Dynamic Response in Micro-Grids Using Ultra Capacitors
Pouria Maghouli Hossein RefahiFuel Cells do not respond to higher frequency contents of load changes due to their inherent large time constants; thus, if any disturbance occurs in the system loading, it would cause negative effects on power quality of the system. This is especially of high importanc أکثرFuel Cells do not respond to higher frequency contents of load changes due to their inherent large time constants; thus, if any disturbance occurs in the system loading, it would cause negative effects on power quality of the system. This is especially of high importance in microgrids which contain critical loads with low inertia requirements. Sudden changes in load points could cause significant frequency and voltage variations. Hence, proper measures such as energy storage systems should be taken into microgrids for improving their stability. In this paper, a new method based on Ultra-Capacitor (UC) with bidirectional converter has been proposed to solve this drawback of fuel cells. The UC is used to modify the system's frequency response with a fast and efficient controller. The proposed method is simulated for a sample test system in MATLAB/SIMULINK environment and results are presented to illustrate its performance. Based on the results, the system can manage its frequency and voltage variations effectively by the proposed configuration. تفاصيل المقالة -
حرية الوصول المقاله
22 - یونش شیمیایی اسید آمینه والین در فشار اتمسفر با طیف سنج تحرک یونی مجهز به منبع یونش تخلیه کرونا
منیژه توضیحی نسیم نجفلو حامد بهرامیدر این پژوهش، یونش شیمیایی اسید آمینه والین در فشار اتمسفری از راه برهم کنش آن با یونهای هیدرونیم و آمونیم با طیف سنج تحرک یونی مجهز به منبع یونش تخلیه کرونا بررسی شد. نتیجه ها نشان داد که در حضور هیدرونیم به عنوان یون واکنشگر و آمونیم به عنوان دوپه کننده، یونش اسید آم أکثردر این پژوهش، یونش شیمیایی اسید آمینه والین در فشار اتمسفری از راه برهم کنش آن با یونهای هیدرونیم و آمونیم با طیف سنج تحرک یونی مجهز به منبع یونش تخلیه کرونا بررسی شد. نتیجه ها نشان داد که در حضور هیدرونیم به عنوان یون واکنشگر و آمونیم به عنوان دوپه کننده، یونش اسید آمینه والین از راه پروتونه شدن آن و تکه تکه شدن مولکول پروتونه شده و نیز تشکیل یون های افزایشی صورت می گیرد. دست کم شش گونه یونی به عنوان فراورده شناسایی شد. در طیف تحرک یونی والین دو نشانک به ترتیب به والین پروتونه شده و دوپار متقارن با مرز پروتون نسبت داده شد. تعیین دو نشانک دیگر از راه مقایسه طیف تحرک یونی والین و ایزوبوتیل آمین صورت گرفت. با معادله ارتباط جرم-تحرک بر پایه دو جرم استاندارد دو نشانک دیگر شناسایی شد. یکی از آن ها به یک خوشه یونی که از پیوند تکه یونی به مولکول خنثی والین به دست آمده، نسبت داده شد و دیگری به یک کربوکاتیون ناشی از تکه تکه شدن والین پروتونه از راه حذف آب مرتبط شد. با مطالعه تحول زمانی یون های فراورده و واکنشگر و نیز تغییر دمای محفظه دستگاه، منشاء پیشنهادی نشانک ها تایید شد. به این ترتیب بدون نیاز به جفت شدن دستگاه طیف سنج تحرک یونی به دستگاه طیف سنج جرمی، شناسایی فراورده های یونش انجام شد. تفاصيل المقالة -
حرية الوصول المقاله
23 - Conformational Study of some novel Methoxy Half-Analogues of Michler’s Ketone by NMR
Naghi Saadatjou Geoffrey HallasOne series of half-analogues of Michler’s ketone containing one or more terminal methoxysubstituents with variable tertiary amino groups have been used in this study. NMR spectralresults for the parent ketones confirm earlier findings that ortho proton shifts are أکثرOne series of half-analogues of Michler’s ketone containing one or more terminal methoxysubstituents with variable tertiary amino groups have been used in this study. NMR spectralresults for the parent ketones confirm earlier findings that ortho proton shifts are apparentlyindependent from steric effects in derivatives of Michler’s ketone because the ring current andcarbonyl-induced shifts are self-canceling. تفاصيل المقالة
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