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91.
Nano tetrapod based on conducting polythiophene (PTh) and tin-phosphate (SnP) were synthesized by in situ chemical oxidative polymerization. The morphology of the resulting polythiophene tinphosphate composite was characterized by elemental analysis, fourier transform infrared spectroscopy, thermogravimetric analysis, powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The physico-chemical characterization carried out on the composite showed that SnP was modified by conducting PTh with an enhancement of various properties. On the basis of highest distribution coefficient values for Hg(II), the composite was also used for the preparation of Hg(II) selective membrane electrode. The electrode showed working concentration range of 1 × 10?1 to 1 × 10?7 with Nernstian slope of 29.29 mV per decade change in concentration and the electrode may be used for wide working pH range of 4–8 having quick response time about 23 s. The life of electrode is 4 months without any notable drift in potential.  相似文献   
92.
The purpose of this study was to estimate the sedimentation rate in the Sungai Linggi estuary using the constant initial concentration of unsupported or excess 210Pb model and verified with 137Cs method. Five sediment cores were collected on 25 January 2011 using gravity corer with the inner tube of 50 cm length and 7.5 cm diameter. The total 210Pb activities in the sediment cores profile at all sampling stations were varied and upper than those obtained for supported 210Pb i.e. 226Ra, indicated disequilibrium among 210Pb and its grandparents in the 238U decay series. Meanwhile, the lower 137Cs activities were observed at all sampling stations due to no significant sources of 137Cs releases were transferred into Malaysian marine. The estimation of sedimentation rate indicated the agreement of 210Pb and 137Cs method with a general presence of deep mixing in the Sungai Linggi estuary. Therefore, the apparent sedimentation rates calculated from 210Pb profiles generally reflect the true value with the range from 0.70 to 1.97 cmyr?1. High sedimentation rate was observed at some sampling stations which are located in river channel, estuary and closer to mainland. This suggested that land-use development, agriculture activities, channelization etc. introduced a large amount of sediment loaded into those areas.  相似文献   
93.
An efficient three-step synthesis of COX-2 inhibitor inotilone from acetaldoxime is described. The structure of inotilone was elucidated via an aldol reaction between 5-methyl-3(2H)-furanone and 3,4-dihydroxybenzaldehyde. This approach describes a convenient pathway to 5-alkyl-3-furanones through isoxazole chemistry.  相似文献   
94.
Foam, as a non-Newtonian fluid, plays an important role in the underbalanced drilling technique in oil field development. The rheological properties of drilling fluids, such as foam, have a direct effect on flow characteristics and hydraulic performance. Two rheological models—the Herschel–Bulkley model and power law—were fitted to two foam systems in this study. Computational fluid dynamics (CFD) was used to simulate the effect of the rheological models on solid–liquid (cuttings transport) hydraulics in concentric and eccentric annulus during the foam drilling operation. The simulation results are compared to the experimental data from previous studies. The results of CFD using the power law model are in good agreement with experimental results in horizontal annulus with respect to the Herschel–Bulkley model with relative error less than 8%. Thus, for CFD cuttings transport for simulations in inclined and horizontal annulus, it is best to use the power law's rheological model parameters.  相似文献   
95.
Two series of new Cu(II) complexes derived from the reaction of copper acetate with the non-linear 1,2,3-triazole-based Schiff bases have successfully been synthesised. The structures of the ligands and its complexes were elucidated by elemental analysis, FT-IR, 1H-NMR and UV–visible spectroscopic techniques. The differential scanning calorimetry and polarizing optical microscopy supported the anisotropic properties of uncoordinated ligands in which the focal conic fan-shaped texture and/or broken fan-shaped texture characteristics of respective SmA and SmC phases were recorded. However, not all of their corresponding Cu(II) complexes are mesogenic. Although the iodo-substituted ligands with even parity C10H29 to C14H33 are non-stable and exhibit SmA phase which is not reproducible, the ultimate Cu(II) complexes show exclusively stable SmA phase. This observation can be ascribed to the enhanced colinearity and molecular anisotropic by the presence of Cu-N and Cu-O coordination modes. On the other hand, the comparison studies show that different positions of ortho-hydroxyl group affect the mesomorphic and thermal behaviour of ligands and Cu(II) complexes.  相似文献   
96.
Treatment of aromatic carboxylic acids and substituted toluenes with a mixture of sodium bromate and sodium hydrogen sulfite in a two-phase system gave the corresponding esters in good yield. The intermediate α-brominated toluene was formed by the in situ generated hypobromous acid. The α-bromotoluene underwent an intermolecular nucleophilic substitution reaction with aromatic carboxylic acids present in the reaction mixture to afford the corresponding esters.  相似文献   
97.
A stereoselective approach has been developed for the synthesis of cis- and trans-2-methyl-4-arylpiperidines from a common intermediate. The Ni-catalyzed hydrogenolysis of N-Boc-2-methyl-4-aryl-4-piperidinols, obtained by addition of organometallic reagents on N-Boc-2-methyl-4-piperidone, afforded the trans derivatives with up to 95% selectivity whereas the corresponding cis isomers were obtained in the presence of palladium catalysts.  相似文献   
98.
Cardiovascular diseases have always been one of the main causes of death worldwide and eventually one of the major medical concerns. Tissue engineering is promising strategies of treating cardiovascular, which can be an effective approach with the design of appropriate scaffold. In this study, to develop engineering basement membrane for endothelial differentiation with good cell attachment, we produced polycaprolactone (PCL)/poly (glycerol sebacate) (PGS)/gelatin nanofibrous scaffold via electrospinning. Attenuated total reflectance-Fourier transform infrared and the proton nuclear magnetic resonance results confirmed the chemical structure of synthesized PGS. Scanning electron microscope images of the electrospun scaffold revealed that the nanofibers are smooth, continues and uniform. Moreover, due to the presence of hydrophilic functional groups in the scaffold, the contact angle is in the appropriate range for cell adhesion especially endothelial cells. The elastic modulus and ultimate tensile stress of electrospun scaffold were calculated 1.32 ± 0.27 MPa and 1.23 ± 0.18 MPa respectively. Quantitative polymerase chain reaction was performed for evaluation of endothelial differentiation of mesenchymal stem cells cultured on standard plate and fibrous scaffold under chemical stimulation with growth factor. Specific endothelial gene expression results postulated that our modified scaffold could support and significantly promote endothelial differentiation of MSCs.  相似文献   
99.
The design of efficient heavy atom-free triplet photosensitizers (PSs) based on through bond charge transfer (TBCT) features is a formidable challenge due to the criteria of orthogonal donor-acceptor geometry. Herein, we propose using parallel (face-to-face) conformation carbazole-bodipy donor-acceptor dyads (BCZ-1 and BCZ-2) featuring through space intramolecular charge transfer (TSCT) process as efficient triplet PS. Efficient intersystem crossing (ΦΔ=61 %) and long-lived triplet excited state (τT=186 μs) were observed in the TSCT dyad BCZ-1 compared to BCZ-3 (ΦΔ=0.4 %), the dyad involving TBCT, demonstrating the superiority of the TSCT approach over conventional donor-acceptor system. Moreover, the transient absorption study revealed that TSCT dyads have a faster charge separation and slower intersystem crossing process induced by charge recombination compared to TBCT dyad. A long-lived charge-separated state (CSS) was observed in the BCZ-1 (τCSS=24 ns). For the first time, the TSCT dyad was explored for the triplet-triplet annihilation upconversion, and a high upconversion quantum yield of 11 % was observed. Our results demonstrate a new avenue for designing efficient PSs and open up exciting opportunities for future research in this field.  相似文献   
100.
Three-dimensional (3D) geopolymer printing (3DGP) technology is a rapidly evolving digital fabrication method used in the construction industry. This technology offers significant benefits over 3D concrete printing in terms of energy saving and reduced carbon emissions, thus promoting sustainability. 3DGP technology is still evolving, and researchers are striving to develop high-performance printable materials and different methods to improve its robustness and efficiency. Carbon-based nanomaterials (CBNs) with beneficial properties have a wide range of applications in various fields, including as concrete/geopolymer systems in construction. This paper comprehensively reviews the research progress on carbon-based nanomaterials (CBNs) used to develop extrusion-based 3D geopolymer printing (3DGP) technology, including dispersion techniques, mixing methods, and the materials′ performance. The rheological, mechanical, durability, and other characteristics of these materials are also examined. Furthermore, the existing research limitations and the prospects of using 3DGP technology to produce high-quality composite mixtures are critically evaluated.  相似文献   
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