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11.
Adsorption of water vapour on wool provides not only textile comfort, but also convenience in transportation due to increase in its bulk density. The adsorption and desorption isotherms of water vapour for wool were determined by both volumetric technique using a Coulter Omnisorp 100CX instrument and gravimetric method employing a Cahn 2000 electronic microbalance. Adsorption isotherm fitting to B.E.T. model and hysteresis on desorption was observed. The average effective diffusion coefficient of water in wool was found to be 8.4 × 10-14 m2s-1 at 25°C from gravimetric data. The effects of packing height and air velocity on the breakthrough curves were also investigated in the wool packed columns. For pseudo first order model, k values changing between 0.33 × 10-6 – 69 × 10-6 s-1 was obtained for 2.2–6.4 cm s-1 air velocity and 0.05–0.20 m packing height ranges. 相似文献
12.
The synthesis and photoconductivity properties of the alkylthia and triethyleneoxysulfonyl substituted oxotitanium(IV) phthalocyanines (1a and 2a) are reported for the first time. The new compounds have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, electronic spectroscopy and mass spectroscopy. The mesogenic properties of these new materials were studied by differential scanning calorimetry and optical microscopy. The electrical dark conductivities (σd) and photoconductivities (σph) of deposited films of 1a and 2a were investigated in various media with different concentrations of oxygen. Molecular oxygen increases photoconductivities (σph) significantly. The photoconductivity mechanism and formation of Pc+ which is positive charge carrier under the light irradiation of the phthalocyanine molecules are demonstrated using the theoretical calculations. The geometries of the oxotitanium(IV) phthalocyanines (TiOPc) are optimized with PM3 semi-empirical method, and their visible absorption maxima are calculated with ZINDO/S method. The results agree well with the observed values. It was found that for the calculation of visible absorption of neutral and positively charged substituted TiOPc molecules using ZINDO/S method could rapidly yield excellent results. Dipole moment, HOMO, LUMO energies and atomic charges are also calculated for clarification of the oxygen effect on the photoconductivity using PM3 and ZINDO/S methods. 相似文献
13.
Methylene-bridged tetra- and octa-(13,17-dioxa nonacosane-15 sulfanyl)-substituted metal free- and Ni(II) phthalocyanines were synthesized from the corresponding phthalonitrile (3, 4) derivatives in the presence of the anhydrous metal salt (NiCl2) or a strong organic base. The new compounds were characterized by elemental analyses, UV/Vis, IR, NMR and mass spectra. The mesogenic properties of these materials were studied by differential scanning calorimetry (DSC), optical microscopy and X-ray diffraction investigations. X-ray diffraction patterns of the mesophase confirm that tetra- and octa-substituted compounds (3a–b, 4a–b) form hexagonal columnar mesophases (Colh). We indicated that addition of the methylene-bridged phthalocyanine (Pc) core can either decrease the liquid crystal phase transition temperatures or extend the liquid crystal temperature range to include room temperature. Also, the Pc compounds (3a, 3b, 4a and 4b) are liquid crystals at room temperature. These properties of the Pc complexes provide some advantages such as easily obtaining an ordered film for sensor applications. Computational modelling work was combined with X-ray diffraction investigation to validate the diameter of the phthalocyanine molecule (3b). 相似文献
14.
In this paper, we establish new Lyapunov-type inequalities for two classes of one-dimensional quasilinear elliptic systems of resonant type, which improve the recent results of Tang and He [X.H. Tang, X. He, Lower bounds for generalized eigenvalues of the quasilinear systems, J. Math. Anal. Appl. 385 (2012) 72-85] when 1 < pi < 2 for i = 1, 2, … , n. 相似文献
15.
F. Betül Kaynak Devrim
ztürk Süheyla
zbey Gültaze apan 《Journal of Molecular Structure》2005,740(1-3):213-221
The condensation products of 5-methyl-3-phenyl-1H-indole-2-carbohydrazide (1) with 2-butanone, 3-pentanone and cyclopentanone were prepared. The adducts (2a-c) were characterized by microanalysis, UV, IR, 1H NMR, 13C NMR and EI mass spectrometry. 1H NMR spectra of 2a and 2b revealed rotational restriction about the C–N bond in solution (DMSO-d6) and displayed double resonances associated with the CH3 and CH2CH3 residues of the alkylidene moieties. A variable temperature 1H NMR experiment was run on 2a to overcome the rotational barriers and thus determine the coalescence temperature but no coalescence was observed up to 77 °C. The structural analysis of 2a and 2c were also carried out by single crystal X-ray diffraction and confirmed by theoretical calculations (semiempirical PM3 and ab initio RHF/6-31G(d)). 相似文献
16.
17.
Atilla D Durmuş M Gürek AG Ahsen V Nyokong T 《Dalton transactions (Cambridge, England : 2003)》2007,(12):1235-1243
The synthesis, photophysical and photochemical properties of the tetra- and octa-poly(oxyethylene)substituted zinc (II) phthalocyanines are reported for the first time. The new compounds have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, electronic spectroscopy and mass spectra. General trends are described for photodegradation, singlet oxygen, triplet state and fluorescence quantum yields, and triplet and fluorescence lifetimes of these compounds in dimethylsulfoxide (DMSO). Photophysical and photochemical properties of phthalocyanine complexes are very useful for PDT applications. The effects of the substituents on the photophysical and photochemical parameters of the zinc(II) phthalocyanines (3a, 5a and 6a) are also reported. The singlet oxygen quantum yields (Phi(Delta)), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.60 to 0.72. Thus, these complexes show potential as Type II photosensitizers. The fluorescence of the complexes was quenched by benzoquinone (BQ). 相似文献
18.
Devrim Çakmak 《International Journal of Mathematical Education in Science & Technology》2013,44(7):964-970
In this note, by using elementary calculus on time scales, we recall the direct proof of the equivalence between Rolle's and generalized (Cauchy's) mean value theorems on time scales. 相似文献
19.
Serkan Levent Ulviye Acar Çevik Begüm Nurpelin Sağlık Özgür Devrim Can Ümide Demir Özkay 《Phosphorus, sulfur, and silicon and the related elements》2017,192(4):469-474
The present study was undertaken to synthesize some novel lipophilic piperazine and piperidinedithiocarbamates and investigate their inhibitory potencies against cholinesterase enzymes. In the synthetic studies, 44 new compounds were isolated. The structures of the synthesized compounds were confirmed by spectroscopic analyses. Enzymatic studies were carried out using modified Ellman's assay against Acetylcholinesterase (AChE) and Butrylcholinesterase (BChE) enzymes, and it was observed that some of the compounds selectively inhibit AChE. Theoretical ADME predictions were calculated for selected compounds in the series. Enzyme kinetics and molecular docking studies were performed for the most active compound C41 and nature of inhibition and interactions between enzyme and ligand were explained. 相似文献
20.
Sevdiye Atakul Savrık Devrim Balköse Sevgi Ulutan Semra Ülkü 《Journal of Thermal Analysis and Calorimetry》2010,101(2):801-806
The effect of emulsion process formulation ingredients on the morphology, structure, and properties of polyvinyl chloride
(PVC) powder has been considered in this study. PVC powder was extracted with ethanol and films were obtained by solvent casting
from tetrahydrofurane. Characterization of powders, films, and ethanol extract was performed through FTIR spectroscopy, DSC,
AFM, SEM, EDX analysis, methylene blue, and nitrogen adsorption. PVC powder was composed of spheres of a large particle size
range from 10 nm to 20 μm as shown by SEM. The specific surface area of the PVC powder was determined as 16 and 12 m2 g−1 from methylene blue adsorption at 25 °C and from N2 adsorption at −196 °C, respectively. AFM indicated the surface roughness of the films obtained by pressing the particles
was 25.9 nm. Density of PVC powder was determined by helium pycnometry as 1.39 g cm−3. FTIR spectroscopy indicated that it contained carbonyl and carboxylate groups belonging to additives such as surface active
agents, plasticizers, and antioxidants used in production of PVC. These additives were 1.6% in mass of PVC as determined by
ethanol extraction. EDX analysis showed PVC particles surfaces were coated with carbon-rich materials. The coatings had plasticizer
effect since, glass transition temperature was lower than 25 °C for PVC powder and it was 80 °C for ethanol extracted powders
as found by using differential scanning calorimetry. These additives from polymerization process made PVC powder more thermally
stable as understood from Metrom PVC thermomat tests as well. 相似文献