Recognizing TimeML events and identifying their attributes, are important tasks in natural language processing (NLP). Several NLP applications like question answering, information retrieval, summarization, and temporal information extraction need to have some knowledge about events of the input documents. Existing methods developed for this task are restricted to limited number of languages, an...

In this study, Four Wave Mixing (FWM) characteristics in photonic crystal fibers are investigated. The effect of channel spacing, phase mismatching, and fiber length on FWM efficiency have been studied. The variation of idler frequency which obtained by this technique with pumping and signal wavelengths has been discussed. The effect of fiber dispersion has been taken into account; we obtain th...

يمومع باي تيعقوم متسيس كي تقد 3 رد متسيس وردوخ يربوان ياه يم ريثأت يفلتخم لماوع زا زا تـسا مزلا لـيلد نيمه هب و دريذپ شور دومن هدافتسا وردوخ هدش نييعت تيعقوم رد تقد شيازفا تهج هشقن قيبطت ياه . متسيس رد هشقن قيبطت وردوـخ يربواـن ياـه دراد هدهع رب ار رهش هشقن يوررب وردوخ يلعف تيعقوم نييعت هفيظو . رد هـشقن قيبطت هلأسم لح يارب يبيكرت متيروگلا كي هلاقم نيا متسيس رد يم داهنشيپ وردوخ يربوان يا...

Flephedrone is an analogue of cathinone - chemically similar to ephedrine, cathine and other amphetamines. Conformations of all isomers of flephedrone have been studied at the quantum-chemical level. Calculations have been performed using DFT and MP2 methods with two basis sets - 6-31G and 6-31G(d,p). Results show that there are low energy conformers for the ortho, meta, and para isomers that a...

N,N-dioctyl-azepanium, -piperidinium and -pyrrolidinium bromides 1-3, have been obtained and characterized by FTIR and NMR spectroscopy. DFT calculations have also been carried out. The optimized bond lengths, bond angles and torsion angles calculated by B3LYP/6-31G(d,p) approach have been presented. Both FTIR and Raman spectra of 1-3 are consistent with the calculated structures in the gas pha...

sulforaphane, an isothiocyanate found in broccoli and other cruciferous vegetables. it is an antioxidantand anti-cancer agent, and reduces blood pressure, and also has anti-allergic effects.in this article, six theoretical methods have been used for calculation of physical parameters insolforaphane and several similar compounds. we calculated physical parameters like atomic charges.energy (ae) ...

enzymes catalyze many biological reactions. the rates of chemical reaction in the presence ofenzymes are, in some cases, accelerated more than 10 orders of magnitude relative to thecorresponding rates in solution.in this paper a comparison between optimized structures of two enzyme molecules in aspect ofenergy and dipole moment in different conditions including presence of metallic ion, without...

We have undertaken a DFT study of the nitride cluster fullerenes (NCFs) Ln3N@C80 for complete series fourteen lanthanides plus lanthanum by using PBE functional with Grimme’s dispersion correction (PBE-D2). tested DN and DND basis sets, which are equivalent to 6-31G 6-31G(d) Pople-type respectively. Due known convergence problems when treating lanthanide-containing systems, only set was it poss...

Potential energy (PE) curves for the intramolecular proton transfer in the ground (GSIPT) and excited (ESIPT) states of 1-hydroxy-2naphthaldehyde (1H2NA) and 2-hydroxy-3-naphthaldehyde (2H3NA) were studied using DFT/B3LYP(6-31G) and TD-DFT/ B3LYP(6-31G) level of theory, respectively. Our calculations suggest the non-viability of ground state intramolecular proton transfer for both the compounds...

The reaction mechanism of ozone (O3) addition to the double bonds of gas phase keto-limonene was investigated using ab initio methods. Two different possibilities for O3 addition to the double bond were considered and two corresponding van der Waals complexes (Complex 1 and Complex 2) were found for 1-endo and 2-endo. The rate constants were calculated using the transition state theory at the C...