نتایج جستجو برای: ir spectrum

تعداد نتایج: 289232  

Natarajan Kumaresapillai, Rengarajan Sathish Riyaz Ameer Basha

Three different Aspergillus Niger MTCC strains (872, 1785 and 2208) were used for the production of chitosan. Multivariate growth mediums in varying incubation periods were analyzed for the production. The produced chitosan was characterized by its physical appearance, moisture content (by means of gravimetric method), percentage of ash and solubility (through the Association of Official Agricu...

Abbas Ali Esmaeili Ali Morsali Malihe Javan Khoshkholgh S. Ali Beyramabadi,

Here, new N,N′-dipyridoxyl(4,4''-diaminodiphenylether) Schiff-base ligand has been synthesized and characterized by IR, 1H NMR and mass spectrometry. Also, geometry optimization and theoretical assignment of IR spectrum of the ligand have been computed by employing density functional theory (DFT) method. Two pyridine rings and benzene rings in the bridge region are not in the same plane. The ca...

2009
Yiming Yang Abhay Harpale

This paper presents an interdisciplinary investigation of statistical information retrieval (IR) techniques for protein identification from tandem mass spectra, a challenging problem in proteomic data analysis. We formulate the task as an IR problem, by constructing a “query vector” whose elements are system-predicted peptides with confidence scores based on spectrum analysis of the input sampl...

1999

An FT-IR Spectrometer is an instrument which acquires broadband NIR to FIR spectra. Unlike a dispersive instrument, i.e. grating monochromator or spectrograph, an FT-IR Spectrometer collects all wavelengths simultaneously. This feature, called the Multiplex or Felgett Advantage, is discussed in detail on page 3. FT-IR Spectrometers are often simply called FT-IRs. But for the purists, an FT-IR (...

Journal: :Physical chemistry chemical physics : PCCP 2007
Michael P Callahan Bridgit Crews Ali Abo-Riziq Louis Grace Mattanjah S de Vries Zsolt Gengeliczki Tiffani M Holmes Glake A Hill

We present resonant two-photon ionization (R2PI), UV-UV, and IR-UV double resonance spectra of xanthine seeded in a supersonic jet by laser desorption. We show that there is only one tautomer of xanthine which absorbs in the wavelength range of 36 700 to 37 700 cm(-1). The IR-UV double resonance spectrum shows three strong bands at 3444, 3485, and 3501 cm(-1), all of which we assign as N-H stre...

2009
Yiming Yang Abhay Harpale Subramaniam Ganapathy

This paper presents an interdisciplinary investigation of statistical information retrieval (IR) techniques for protein identification from tandem mass spectra, a challenging problem in proteomic data analysis. We formulate the task as an IR problem, by constructing a “query vector” whose elements are system-predicted peptides with confidence scores based on spectrum analysis of the input sampl...

Journal: :Accounts of chemical research 2007
Junrong Zheng Kyungwon Kwak M D Fayer

The experimental technique and applications of ultrafast two-dimensional infrared (2D IR) vibrational echo spectroscopy are presented. Using ultrashort infrared pulses and optical heterodyne detection to provide phase information, unique information can be obtained about the dynamics, interactions, and structures of molecular systems. The form and time evolution of the 2D IR spectrum permits ex...

Journal: :Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 2006
Hong-xia Liu Su-qin Sun Guang-hua Lv Kelvin K C Chan

In order to develop a rapid and effective analysis method for studying integrally the main constituents in the medicinal materials and their extracts, discriminating the extracts from different extraction process, comparing the categories of chemical constituents in the different extracts and monitoring the qualities of medicinal materials, we applied Fourier transform infrared spectroscopy (FT...

2007
Hakan Arslan Aydın Demircan

Geometric parameters and FT-IR spectrum of 6-bromo-8-thia-1,4epoxybicyclo[4.3.0]non-2-ene were computed by the HF, B3LYP, B3PW91 and mPW1PW91 methods in conjunction with the 6-31G(d,p) basis set. The calculated IR spectra are in a good agreement with the observed FT-IR spectrum. A general better performance of B3LYP, B3PW91 and mPW1PW91 versus HF was quantitatively characterized by using PAVF 1...

Journal: :Physical chemistry chemical physics : PCCP 2014
Adriana Huerta-Viga Sérgio R Domingos Saeed Amirjalayer Sander Woutersen

Salt bridges are important interactions for the stability of protein conformations, but up to now it has been difficult to determine salt-bridge geometries in solution. Here we characterize the spatial structure of a salt bridge between guanidinium (Gdm(+)) and acetate (Ac(-)) using two-dimensional vibrational (2D-IR) spectroscopy. We find that as a result of salt bridge formation there is a si...

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