نتایج جستجو برای: double bond

تعداد نتایج: 306165  

Journal: :journal of dentistry, tehran university of medical sciences 0
beheshteh malekafzali associate professor, department of pedodontics, shahid beheshti university of medical science dental school, tehran, iran. amir ghasemi hassan torabzadeh reza hamedani nekoo tadayon

multiple adhesive coating is a controversial topic, especially in primary dentition that should be clarified. we evaluated the effect of multiple consecutive adhesive resin coatings on the microshear bond strength (μsbs) of composite resin to primary tooth dentin utilizing a filled (adper single bond plus) and an unfilled (adper single bond) adhesive resin.thirty extracted primary canines were ...

Journal: :iranian journal of mathematical chemistry 2013
h. tavakol h. mohammadi s. a. aslanzadeh

in the present work, dft calculations are employed to obtain the optimized structures of 4-acyl pyrazolone tautomers (19 tautomers) using b3lyp/6-311++g** calculations. inaddition, molecular parameters, ir frequencies and relative energies are extracted for alltautomers. the existence of aromatic ring, keto tautomer (versus enol tautomer), n-h bond(versus c-h bond) and c=n double bond (versus n...

جلالی‌اسدآبادی, سعید, جوانبخت, سمانه,

Single and double equilibrium bond lengths of the fcc-C60 crystal were calculated in the absence and presence of the endohedral C atom as an impurity doped into each C60 cluster, i.e., fcc-C@C60, by means of fully-relaxed self-consistent calculations within the density functtional theory (DFT) employing the full potential-augmented plane waves plus local orbital (FP-APW+lo) method. The result s...

Journal: :Journal of mass spectrometry : JMS 2002
Eduardo C Meurer Marcos N Eberlin

Gas-phase reactions of acylium ions with alpha,beta-unsaturated carbonyl compounds were investigated using pentaquadrupole multiple-stage mass spectrometry. With acrolein and metacrolein, CH(3)-C(+)(double bond)O, CH(2)(double bond)CH-C(+)(double bond)O, C(6)H(5)-C(+)(double bond)O, and (CH(3))(2)N-C(+)(double bond)O react to variable extents by mono and double polar [4 + 2(+)] Diels-Alder cycl...

Journal: :Applied and environmental microbiology 1986
A Verhulst G Parmentier G Janssen S Asselberghs H Eyssen

Eubacterium lentum (33 strains) isomerized the 12-cis double bond of C(18) fatty acids with cis double bonds at C-9 and C-12 into an 11-trans double bond before reduction of the 9-cis double bond. The 14-cis double bond of homo-gamma-linolenic acid was isomerized by 29 strains into a 13-trans double bond. The same strains isomerized the 14-cis double bond of arachidonic acid into a 13-trans dou...

Journal: :Environmental science. Processes & impacts 2017
Xiang Luo Xianhai Yang Xianliang Qiao Ya Wang Jingwen Chen Xiaoxuan Wei Willie J G M Peijnenburg

Reaction with hydroxyl radicals (˙OH) is an important removal pathway for organic pollutants in the aquatic environment. The aqueous reaction rate constant (kOH) is therefore an important parameter for fate assessment of aquatic pollutants. Since experimental determination fails to meet the requirement of being able to efficiently handle numerous organic chemicals at limited cost and within a r...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور مرکز - دانشکده علوم پایه 1389

هدف: سنتز ایندول های سیکلو پنتن شده می باشد. روش تحقیق: ساخت پیوند های کربن- کربن در ترکیباتی که دارای ممانعت فضایی زیادی می باشند یکی از مسائلی می باشد که همواره توجه شیمیدانان را به خود جلب نموده است. بنابراین هدف، در این پروژه بررسی مکانیسم واکنش گرمایی حلقوی شدن ترکیب 2- (آلنیل) فنیل آزید، ( که منجر به تشکیل ایندول سیکلوپنتن شده میشود) با استفاده از شیمی محاسباتی می باشد. لازم به ذکر است...

Journal: :Dalton transactions 2015
Jian Yuan Cheryl J Bourgeois Arnold L Rheingold Russell P Hughes

Reductive activation of an α-fluorine in the perfluoroalkyl complexes Cp*(L)(i)Ir-CF2RF using Mg/graphite leads to perfluorocarbene complexes Cp*(L)Ir[double bond, length as m-dash]CFRF (L = CO, PMe3; RF = CF3, C2F5, C6F5). New complexes E-Cp*(PMe3)Ir[double bond, length as m-dash]CFC2F5 and E-Cp*(CO)Ir[double bond, length as m-dash]CFC6F5 have been characterized by single crystal X-ray diffrac...

2009
Martial Boggio-Pasqua Michael A. Robb Gerrit Groenhof

We have performed excited-state dynamics simulations of a Photoactive Yellow Protein chromophore analogue in water. The results of the simulations demonstrate that in water the chromophore predominantly undergoes single-bond photoisomerization, rather than double-bond photoisomerization. Despite opposite charge distributions in the chromophore, excited-state decay takes place very efficiently f...

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