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751.
Carrasco S Nasr MB Sergienko AV Saleh BE Teich MC Torres JP Torner L 《Optics letters》2006,31(2):253-255
Broadband light generation is demonstrated by noncollinear spontaneous parametric downconversion with a cw pump laser. By use of a suitable noncollinear phase-matching geometry and a tightly focused pump beam, downconverted signals that feature a bell-shaped spectral distribution with a bandwidth approaching 200 nm are obtained. As an application of the generated broadband light, submicrometer axial resolution in an optical coherence tomography scheme is demonstrated; a free-space resolution down to 0.8 microm was achieved. 相似文献
752.
Intein-mediated protein splicing is a self-catalytic process in which the intervening intein sequence is removed from a precursor protein and the flanking extein segments are ligated with a native peptide bond. Splice junction proximal residues and internal residues within the intein direct these reactions. The identity of these residues varies in each intein, as groups of related residues populate conserved motifs. Although the basics of the four-step protein splicing pathway are known, mechanistic details are still unknown. Structural and kinetic analyses are beginning to shed some light. Several structures were reported for precursor proteins with mutations in catalytic residues, which stabilize the precursors for crystallographic study. Progress is being made despite limitations inherent in using mutated precursors. However, no uniform mechanism has emerged. Kinetic parameters were determined using conditional trans-splicing (splicing of split precursor fragments after intein reassembly). Several groups concluded that the rate of the initial acyl rearrangement step is rapid and Asn cyclization (step 3) is slow, suggesting that this latter step is rate limiting. Understanding the protein splicing pathway has allowed scientists to harness inteins for numerous applications. 相似文献
753.
S. Darwish S.Y. Al-Tel M.M. Abu-Teir R.M.-L. Kitanah A.A. Legrouze A.M. Saleh 《Solid State Sciences》2009,11(2):544-548
Systematic spectroscopic measurements of the spectral lines in MnF2 have been carried out in the temperature range 10–300 K. Observations of exciton and exciton–magnon sidebands in the fine structures of the 6A1g → 4A1g, 4Eg (4G) state of Mn+2 ions are reported at low temperatures for MnF2. The fine structure of the C-band is mainly attributed to spin multiplicity in the ordered state. In addition, the pure exciton bands have been identified and the ratios for the separation energies between these lines are fitted with the ratios expected form Lande interval rule. 相似文献
754.
A class of non-linear singular integral equations with Hilbert kernel and a related class of quasi-linear singular integro-differential
equations are investigated by applying Schauder's fixed point theorem in Banach spaces.
相似文献
755.
Saleh M. Al‐Mousawi Mohammad A. Mohammad Mohamad H. Elnagdi 《Journal of heterocyclic chemistry》2001,38(4):989-991
While 3(5)‐aminopyrazole reacts with enaminonitrile to yield pyrazolo[1,5‐a]pyrimidines, 3‐amino‐5‐pyrazolone reacts with the same reagents to yields pyrazolo[3,4‐b]pyridines. 相似文献
756.
Effective Heuristics for the GPS Survey Network of Malta: Simulated Annealing and Tabu Search Techniques 总被引:1,自引:0,他引:1
A GPS network can be defined as a set of stations, co-ordinated by a series of sessions formed by placing receivers on the stations. This paper shows how to search for the best order in which to observe these sessions giving the cheapest schedule. The complexity of observing GPS networks increases with their size and become highly difficult to solve effectively. To obtain good methods to solve this problem a new area of research is implemented. This area is based on developed heuristic techniques that provide an optimal or near optimal solution for large networks. Comparing their outcome in terms of solution quality and computational effort proves the performance of the developed techniques. 相似文献
757.
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759.
Khushbakhat Khan Muhammad Saeed Sameer A. Awad Muhammad Younas Khan Eman M. Khalaf Muhammad Saleh Zaman Vaneeza Aiman Tasmia Irshad Hadia Ahsan 《中国化学会会志》2023,70(1):46-57
The recent study enlightens the synthesis and characterization of zirconia (ZrO2), Fe-doped ZrO2 (Fe@ZrO2), and Ni-doped ZrO2 (Ni@ZrO2) catalysts having new-fangled morphology with tuned band gap as photocatalysts for degradation of textile wastewater dyes methylene blue (MB), malachite green (MG), and their mixtures. SEM imaging of Fe@ZrO2 and Ni@ZrO2 is interestingly varied from ZrO2 as well as doping of transition metals greatly affects the morphology of composites. The optimization study depicts that the pH, time (min) and catalyst amount (g) have a direct relation with degradation efficiency, while the dye concentration (mg/L) has an indirect relation as well. The photocatalytic studies depict that the degradation of MB and MG follows oxidation pathway via hydroxyl radicals (OH•) and holes. Reusability of catalysts corresponds to a little decrease in degradation efficiency in the first two cycles and decreases to about ∼10% (Ni@ZrO2) and ∼12% (Fe@ZrO2) in next three cycles. 相似文献
760.
Balkis Al‐Saleh Mervat Mohammed Abdel‐Khalik Elham Darwich Ossama Abdel‐Motaleb Salah Mohammed Hilmy Elnagdi 《Heteroatom Chemistry》2002,13(2):141-145
The reactivity of benzotriazolylacetone toward a variety of carbon and nitrogen electrophiles is reported. Several novel azolylbenzotriazoles as well as benzotriazolyl‐cinnolines have been synthesized. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:141–145, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10009 相似文献