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21.
Kandhasamy Kamaraj Tamilvanan Siva Sadagopan Sathiyanarayanan Sundarrajan Muthukrishnan Gopalachari Venkatachari 《Journal of Solid State Electrochemistry》2012,16(2):465-471
It is known that dopants present in polyaniline (PANI) play an important role in corrosion protection of mild steel since
the dopant ions form a secondary layer with iron. Since oxalate ions form a stable iron oxalate layer on mild steel, a study
has been made on the corrosion protection performance of steel by vinyl coating containing oxalate doped PANI in acid and
neutral media. Electrochemical impedance spectroscopy (EIS) studies have shown that the oxalate doped PANI is able to protect
mild steel in sodium chloride solution since the impedance values are maintained at 1010 Ω cm2 even after 100 days of exposure. 相似文献
22.
We construct an explicit intertwining operator L{\mathcal L} between the Schr?dinger group eit \frac\triangle2{e^{it \frac\triangle2}} and the geodesic flow on certain Hilbert spaces of symbols on the cotangent bundle T*X Γ of a compact hyperbolic surface X Γ = Γ\D. We also define Γ-invariant eigendistributions of the geodesic flow PSj, k, nj,-nk{PS_{j, k, \nu_j,-\nu_k}} (Patterson-Sullivan distributions) out of pairs of \triangle{\triangle} -eigenfunctions, generalizing the diagonal case j = k treated in Anantharaman and Zelditch (Ann. Henri Poincaré 8(2):361–426, 2007). The operator L{\mathcal L} maps PSj, k, nj,-nk{PS_{j, k, \nu_j,-\nu_k}} to the Wigner distribution WGj,k{W^{\Gamma}_{j,k}} studied in quantum chaos. We define Hilbert spaces HPS{\mathcal H_{PS}} (whose dual is spanned by {PSj, k, nj,-nk{PS_{j, k, \nu_j,-\nu_k}}}), resp. HW{\mathcal H_W} (whose dual is spanned by {WGj,k}{\{W^{\Gamma}_{j,k}\}}), and show that L{\mathcal L} is a unitary isomorphism from HW ? HPS.{\mathcal H_{W} \to \mathcal H_{PS}.} 相似文献
23.
Hossein A. Baghdadi Elizabeth C. Jensen Nalini Easwar Surita R. Bhatia 《Rheologica Acta》2008,47(2):121-127
We observe evidence of re-entrant behavior in dispersions of a discotic clay, laponite, with added polymer. Under basic conditions,
neat laponite forms a disordered colloidal glass. Rheologically, this phase behaves as a viscoelastic solid, and dynamic light
scattering shows evidence of non-ergodic behavior. Addition of low molecular weight poly(ethylene oxide) (PEO) melts the glass,
resulting in a low-viscosity liquid with fast dynamics. We believe this is due to a depletion force caused by excess PEO chains
in solution. A viscoelastic solid is re-formed with the addition of high molecular weight PEO, which we believe to be caused
by polymer chains bridging between laponite particles. The physics in our system is quite different from the hard sphere/nonadsorbing
polymer systems for which re-entrant glass transitions have been reported in the literature; however, we believe there may
be similarities between these phenomena. To our knowledge, this is the first evidence of a type of re-entrant behavior in
anisotropic colloids. 相似文献
24.
Malik Aijaz Ahmad Ojha Suvash Chandra Schaduangrat Nalini Nantasenamat Chanin 《Molecular diversity》2022,26(1):467-487
Molecular Diversity - Alzheimer’s disease (AD) is one of the most common forms of dementia and is associated with a decline in cognitive function and language ability. The deficiency of the... 相似文献
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In this paper, we disclose the synthesis of the dioxabicyclo[3.2.1]octane subunit of the potent antibiotic sorangicin A. The synthesis was achieved in a convergent manner in 8 steps. Regio- and stereoselective intermolecular epoxide opening, ring-closing metathesis and iodo-etherification are key steps. cis-2-Butene diol has been employed as a common staring material. 相似文献
28.
Rahul B. Chavan Nalini R. Shastri 《Journal of Thermal Analysis and Calorimetry》2018,131(3):2129-2139
Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy, and hot-stage microscopy were employed to evaluate the drug–excipient compatibility of atovaquone with commonly used tablet excipients. The DSC curves of pure drug and excipients were compared with their physical mixtures. Microcrystalline cellulose, titanium dioxide, colloidal silica, ferric oxide, lactose monohydrate, and sodium starch glycolate were compatible, while magnesium stearate, polyethylene glycol (PEG) 8000, Poloxamer 188, and hydroxypropyl methyl cellulose (HPMC) E15 showed incompatibility with the drug. Heat–cool–heat analysis of the physical and the ground mixture of later three excipients showed polymorphic transformation of atovaquone form III to form I, which occurred via amorphization with HPMC E15 and through solubilization mechanism with remaining two excipients. These outcomes were further supported by hot-stage microscopy. Results of milling experiments revealed a milling time-dependent polymorphic transformation and solubilization with HPMC E15 and PEG 8000, respectively. This study highlights the importance of compatibility assessment for selection of excipients in specific unit operations such as milling and grinding. 相似文献
29.
A novel and stereospecific synthesis of (+)-exo-brevicomin is disclosed. The key step of the reaction sequence employs the sulfinyl moiety as an intramolecular nucleophile to functionalize an alkene π-complexed to a bromonium ion. 相似文献
30.
Lyxo-phytosphingosine and erythro-sphingosine have been elaborated from a common intermediate. The key step in the reaction sequence involves stereo- and regiospecific functionalization of an olefin by intramolecular nucleophilic sulfinyl group participation. 相似文献