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101.
A pulsed laser-assisted in liquid environment method has been developed successfully to synthesize size-tunable (5–12 nm) and different shapes (sphere, rod, rope) of nano II–VI semiconductor (cadmium sulfide). This method can be carried out in two ways; the first one is the top-down technique, which has been discussed in publications in the last few decades, and the other one is the bottom-up technique, which appears for the first time in this paper. X-ray diffraction, ultraviolet-visible spectroscopy, and transmission electron microscopy confirm that the nanoparticles are crystalline. The methods lead to the production of nanomaterials, which are important for photonics and biosensing applications. Both synthesized methods can be applied in all materials because of their ability to ablate almost all kinds of materials due to the ultrahigh energy density and control over the growth process by manipulating the process parameters such as intensity, wavelength, and so on. 相似文献
102.
Sebastian Milster Tobias Grünbaum Dr. Sebastian Bange Simon Kurrmann Hermann Kraus Dr. Dani M. Stoltzfus Dr. Anna E. Leung Dr. Tamim A. Darwish Prof. Paul L. Burn Prof. Dr. Christoph Boehme Prof. Dr. John M. Lupton 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(24):9474-9478
The formation of excitons in OLEDs is spin dependent and can be controlled by electron-paramagnetic resonance, affecting device resistance and electroluminescence yield. We explore electrically detected magnetic resonance in the regime of very low magnetic fields (<1 mT). A pronounced feature emerges at zero field in addition to the conventional spin- Zeeman resonance for which the Larmor frequency matches that of the incident radiation. By comparing a conventional π-conjugated polymer as the active material to a perdeuterated analogue, we demonstrate the interplay between the zero-field feature and local hyperfine fields. The zero-field peak results from a quasistatic magnetic-field effect of the RF radiation for periods comparable to the carrier-pair lifetime. Zeeman resonances are resolved down to 3.2 MHz, approximately twice the Larmor frequency of an electron in Earth's field. However, since reducing hyperfine fields sharpens the Zeeman peak at the cost of an increased zero-field peak, we suggest that this result may constitute a fundamental low-field limit of magnetic resonance in carrier-pair-based systems. OLEDs offer an alternative solid-state platform to investigate the radical-pair mechanism of magnetic-field effects in photochemical reactions, allowing models of biological magnetoreception to be tested by measuring spin decoherence directly in the time domain by pulsed experiments. 相似文献
103.
104.
Elda Nurafnie Binti Ibnu Rasid Shaza Eva Mohamad Haryati Jamaluddin Madihah Md Salleh 《Applied biochemistry and biotechnology》2014,172(4):2160-2174
Astaxanthin, a carotenoid pigment found in several aquatic organisms, is responsible for the red colour of salmon, trout and crustaceans. In this study, astaxanthin production from freshwater microalga Chlorella sorokiniana and marine microalga Tetraselmis sp. was investigated. Cell growth and astaxanthin production were determined spectrophotometrically at 620 and 480 nm, respectively. Astaxanthin was extracted using acetone and measured subsequent to biomass removal. Aerated conditions favoured astaxanthin production in C. sorokiniana, whereas Tetraselmis sp. was best cultured under unaerated conditions. C. sorokiniana produced more astaxanthin with the highest yield reached at 7.83 mg/l in 6.0 mM in nitrate containing medium compared to Tetraselmis sp. which recorded the highest yield of only 1.96 mg/l in 1.5 mM nitrate containing medium. Production in C. sorokiniana started at the early exponential phase, indicating that astaxanthin may be a growth-associated product in this microalga. Further optimization of astaxanthin production was performed using C. sorokiniana through a 23 full factorial experimental design, and a yield of 8.39 mg/l was achieved. Overall, the study has shown that both microalgae are capable of producing astaxanthin. Additionally, this research has highlighted C. sorokiniana as a potential astaxanthin producer that could serve as a natural astaxanthin source in the current market. 相似文献
105.
Salem M. A. Abbas S. Y. Darwish S. A. Helal M. H. Aish E. H. 《Russian Journal of General Chemistry》2021,91(8):1578-1583
Russian Journal of General Chemistry - Herein, novel 5-arylazosalicylaldehyde thiosemicarbazone derivatives (H2L1–12) and their copper(II) complexes have been synthesized and characterized by... 相似文献
106.
Wael Darwish Sabine Schlecht Prof. Dr. Andreas Schaper Michael Fröba Klaus Harms Werner Massa Jörg Sundermeyer Prof. Dr. 《无机化学与普通化学杂志》2009,635(8):1215-1224
Four axially substituted titanium(IV)phthalocyanines of formula trans‐[PcTi(OSiPh3)2], [PcTi{(NH)2C6H4}], [PcTi(η2‐S2)], and [PcTi=S] were prepared starting from the reactive species N,N′‐di‐4‐tolylureato(phthalocyaninato)titanium(IV). The prepared compounds were characterized by using UV/Vis‐spectroscopy, FT‐IR and raman spectroscopy, TGA, elementalanalysis and MALDI‐TOF measurements. The compound trans‐[PcTi(OSiPh3)2] crystallizes from chlorobenzene in the triclinic space group P with a = 10.4160(8) Å, b = 11.2160(8) Å, c = 13.1495(9) Å, α = 114.124(5)°, β = 99.452(6)°, γ = 96.174(6)°, and Z = 1. [PcTiS2] crystallizes from chlorobenzene in the monoclinic space group P21/n with a = 13.114(3) Å, b = 9.752(2) Å, c = 20.975(5) Å, β = 100.46(2), and Z = 4. The crystal structures of both compounds are discussed. The reactive ureato complex could also successfully be anchored onto SBA‐15 and TiOx@SBA‐15 materials using the apical ureato ligand as a good leaving group for the reaction with the silanol groups of the host material. 相似文献
107.
Mohamed Abdalla Darwish John R Graef Kishin Sadarangani 《Journal of Applied Analysis & Computation》2018,8(1):331-343
In this paper the authors study a fractional quadratic integral equation of Urysohn-Volterra type. They show that the integral equation has at least one monotonic solution in the Banach space of all real functions defined and continuous on the interval $[0,1]$. The main tools in the proof are a fixed point theorem due to Darbo and a monotonicity measure of noncompactness. 相似文献
108.
Saleem I. Qashou M. Rashad A. A. A. Darwish T. A. Hanafy 《Optical and Quantum Electronics》2017,49(7):240
Thin films of 2,9-Bis [2-(4-chlorophenyl)ethyl] anthrax [2,1,9-def:6,5,10-d′e′f′] diisoquinoline-1,3,8,10 (2H,9H) tetrone (Ch-diisoQ) were prepared by thermal evaporation technique. Structural properties of these (as-prepared and annealed at 373, 423, 473 and 523 K) films were determined by X-ray diffraction and scanning electron microscopy, which showed that the grain sizes increasing by the annealing effect. The transmittance and reflectance of all Ch-diisoQ thin films were measured in the range 200–2500 nm. Some optical constants such as optical band gap (E g ), dispersion energy (E d ), single oscillator energy (E o ) and optical dielectric constant at a higher frequency (ε ∞ ) were calculated at different annealing temperatures. The optical band gap of the samples is decreased with the increase of annealing temperatures due to the increasing of the π-dislocation. Finally, the values of the optical susceptibility, χ(3), were found to be annealing dependence. 相似文献
109.
110.
S.M. Darwish L.-G. Svensson J. Lindskog H. Solhed N.G. Jonsson 《Nuclear Physics A》1974,236(2):340-348
Earlier measurements on half-lives of the 686 keV, 625 keV and 618 keV levels in 187Re have shown remarkable disagreements. The main object of this investigation has been to remeasure these half-lives by means of the delayed coincidence method utilizing a long-lens electron-electron spectrometer. The half-lives of these levels were measured as being: 686 keV level: level: level: . 相似文献