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101.
A.S. Shalabi A.M. El Mahdy M.M. Assem H.O. Taha W.S. Abdel Halim 《Molecular physics》2014,112(1):22-34
Molecular electronic structure calculations, employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methodologies, have been carried out to improve the performance of the synthesised dye YD2-o-C8 which is characterised by 11.9%–12.7% efficiencies. We aimed to narrow the band gap of YD2-o-C8 to extend the light-harvesting region to near-infrared (NIR). This was done by incorporating Cd instead of Zn onto the porphyrin ring and elongating the length of π-conjugation by adding ethynylene link and anthracene unit, so that the performances of the suggested cells could be expected to exceed the 11.9%–12.7% efficiencies with TiO2, ZnO2, and WO3 oxide electrodes. The effects of modifying the central metal and elongating the length of π-conjugation on cell performance are confirmed in terms of frontier molecular orbital (FMO) energy gaps, density of states (DOS), molecular electrostatic potentials (MEPs), non-linear optical (NLO) properties, ultraviolet–visible (UV–vis) electronic absorption, and 1H nuclear magnetic resonance chemical shifts. Increasing the length of π-conjugation of the D–π–A dyes leads to increasing the DOS near Fermi levels, more active NLO performance, strong response to the external electric field, delocalisation of the negative charges near the anchoring groups, deep electron injection, suppressing macrocycle aggregation, active dye regeneration, and inhibited dye recombination. The calculated band gap/eV of the present DMP-Zn is correlated with the experimental (E1/2(oxidation)–E1/2(reduction)/V) potentials of the identical YD2-o-C8. A co-sensitiser is suggested for NIR sensitisation (550–950 nm) to increase the power-to-conversion efficiency beyond 14%. 相似文献
102.
Adnan M. Hussein R. A. Bakar K. Kadirgama K. V. Sharma 《Heat and Mass Transfer》2014,50(11):1553-1561
The car radiator heat transfer enhancement by using TiO2 and SiO2 nanoparticles dispersed in water as a base fluid was studied experimentally. The test rig is setup as a car radiator with tubes and container. The range of Reynolds number and volume fraction are (250–1,750) and (1.0–2.5 %) respectively. Results showed that the heat transfer increases with increasing of nanofluid volume fraction. The experimental data is agreed with other investigator. 相似文献
103.
Kennedy RD Halim M Khan SI Schwartz BJ Tolbert SH Rubin Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(24):7418-7433
The relationship between the size of the substituents of aryl groups in a series of fifteen 6,9,12,15,18-pentaaryl-1-hydro[60]fullerenes and the solid-state structures and packing motifs of these compounds has been analyzed. Pentaarylfullerenes have a characteristic "badminton shuttlecock" shape that causes several derivatives to crystallize into columnar stacks. However, many pentaarylfullerenes form non-stacked structures with, for example, dimeric, layered, diamondoid, or feather-in-cavity relationships between molecules. Computational modeling gave a qualitative estimate of the best shape match between the ball and socket surfaces of each pentaarylfullerene. The best match was for pentaarylfullerenes with large, spherically shaped para-substituents on the aryl groups. The series of pentaarylfullerenes was characterized by single-crystal X-ray diffraction. A total of 34 crystal structures were obtained as various solvates and were categorized by their packing motifs. 相似文献
104.
Ersen Beyatl? Solmaz Naghizadeh Adnan Kurt Alphan Sennaroglu 《Applied physics. B, Lasers and optics》2012,109(2):221-225
We report a low-threshold continuous-wave Tm:YAG laser that can be excited near 785?nm with low-cost, single-mode AlGaAs laser diodes. Low-threshold operation was achieved using a tightly focused, astigmatically compensated x-cavity containing a 2-mm-thick Tm:YAG crystal with 5?% Tm3+ concentration. Two linearly polarized single-mode diodes operating at 785.8?nm were polarization coupled to end pump the resonator. With a 6?% output coupler, as high as 32?mW of output power could be obtained at 2016?nm with 184?mW of incident pump power. The output could be further tuned in the 1935?C2035?nm range. Slope efficiency measurements indicated that cross-relaxation was very effective at this doping level. With a 2?% output coupler, lasing could be obtained with as low as 32.3?mW of pump power. In the limit of vanishing output coupling, the incident threshold pump power could be reduced to as low as 25?mW. To our knowledge, this is among the lowest lasing thresholds reported to date for continuous-wave, room-temperature thulium lasers. 相似文献
105.
Sania Pervaiz Muhammad Akhyar Farrukh Rohana Adnan Fahim A. Qureshi 《Journal of Saudi Chemical Society》2012,16(1):63-67
The kinetics of the reaction between vitamin C (l-ascorbic acid) and ferric chloride hexahydrate was investigated in acidic medium at pH 3 spectrophotometrically. The order of the reaction was established by applying different methods, such as initial rate method, integration method and half-life method. The results obtained from each method were correlated with each other and consistency in all methods was observed. The order of the reaction with respect to each reactant was found first and the overall second order was recommended for the reaction. 相似文献
106.
R Hamzah MA Bakar M Khairuddean IA Mohammed R Adnan 《Molecules (Basel, Switzerland)》2012,17(9):10974-10993
A structural study of epoxidized natural rubber (ENR-50) and its cyclic dithiocarbonate derivative was carried out using NMR spectroscopy techniques. The overlapping 1H-NMR signals of ENR-50 at δ 1.56, 1.68-1.70, 2.06, 2.15-2.17 ppm were successfully assigned. In this work, the 13C-NMR chemical shift assignments of ENR-50 were consistent to the previously reported work. A cyclic dithiocarbonate derivative of ENR-50 was synthesized from the reaction of purified ENR-50 with carbon disulfide (CS2), in the presence of 4-dimethylaminopyridine (DMAP) as catalyst at reflux temperature. The cyclic dithiocarbonate formation involved the epoxide ring opening of the ENR-50. This was followed by insertion of the C-S moiety of CS2 at the oxygen attached to the quaternary carbon and methine carbon of epoxidized isoprene unit, respectively. The bands due to the C=S and C-O were clearly observed in the FTIR spectrum while the 1H-NMR spectrum of the derivative revealed the peak attributed to the methylene protons had split. The 13C-NMR spectrum of the derivative further indicates two new carbon peaks arising from the >C=S and quaternary carbon of cyclic dithiocarbonate. All other 1H- and 13C-NMR chemical shifts of the derivative remain unchanged with respect to the ENR-50. 相似文献
107.
Muhammad Akhyar Farrukh Chin-Kiat Thong Rohana Adnan Mohd Amirrul Kamarulzaman 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(13):2041-2048
In this work, we report the formation of leaf-like ZnO nanoflakes by anodization of zinc foil in a mixture of ammonium sulfate and sodium hydroxide electrolytes under various applied voltage and concentration of sodium hydroxide. The morphology and structure of ZnO nanoflakes were investigated by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. In addition, the photocatalytic activity of the prepared nanoflakes zinc oxide was evaluated in the photodegradation of organic dye methylene blue (MB) solution under UV irradiation. It was found that zinc oxide prepared under high concentration of sodium hydroxide and high voltage showed better performance in the photodegradation of methylene blue. 相似文献
108.
Synthesis of D-mannitol substituted ether-linked bis-1,2,3-triazoles as models of gemini surfactants
Adnan Ibrahim Mohammed Zaid Hassan AbboudAtheer Hamed Odda Alghanimi 《Tetrahedron letters》2012,53(38):5081-5083
Readily available and low cost D-mannitol was converted into 1,2,5,6-di-O-isopropylidene-D-mannitol (1) in the presence of acetone and zinc chloride. Williamson etherfication of 1 with propargyl bromide afforded the bisalkyne 2 in a very good yield. 1,3-Dipolar cycloaddition of 2 with four different alkyl azides using click conditions gave four novel bistriazoles 3a-d. Removal of the acetal groups of 3a-d afforded the deprotected bistriazoles 4a-d in excellent yields. Products 3 and 4 represent models of gemini surfactants. 相似文献
109.
Adnan S. Abu‐Surrah Tony Debaerdemaeker Wolfgang Huhn Bernhard Rieger Martti Klinga Timo Repo Markku Leskel 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(2):e42-e43
In the title compound, [Pd(CH3)2(C27H26P2)]·0.5C7H8, the Pd atom is at the centre of an approximately square‐planar arrangement of two P atoms and two methyl groups. The P—Pd—P angle [93.19 (3)°] is significantly larger than that in the corresponding dichloride complex [Pd(dppp)Cl2]. The toluene molecule is disordered across an inversion centre. 相似文献