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491.
The optical and electrical behavior was investigated of a symmetric liquid crystal (LC) cell: ITO–silane–LC–silane–ITO. The silane layer induces a perfect homeotropic alignment of the molecules of the studied electroclinic liquid crystal (ELC) material, BDH 764E. A field-induced transition from the perfect homeotropic to planar orientation in the chiral smectic C (SmC*) and smectic A (SmA) phases of the ELC was observed. Optical and dielectric studies were performed for both alignment (geometry) modes. The field-induced transition from the homeotropic to planar orientation was studied vis-à-vis the high negative dielectric anisotropy obtained in the studied material. Such an ELC with large negative dielectric anisotropy and perfect homeotropic alignment may have important implications for modern LC display technology. 相似文献
492.
We investigate the effect of dopant (boron ‘B’–nitrogen ‘N’) position and density on electronic transport properties of a BN co-doped silicon carbide nanotube (SiCNT). The results show an increase in conductance when both BN impurities are far in space from each other. Orbital delocalization and appearance of new electronic states around Fermi level contribute to the current when this spacing is increased. On the other hand, a reduction in SiCNT conductivity was observed when BN dopant density was increased. This is attributed to the electronic states moving away from the Fermi level and orbital localization at higher bias voltages. 相似文献
493.
Naveen Mukhtar Abdul Malik Naheed Riaz Kiran Iqbal RasoolBakhsh Tareen ShamsunNahar Khan SarfrazAhmad Nawaz Juveria Siddiqui M.Iqbal Choudhary 《Helvetica chimica acta》2004,87(2):416-424
Pakistolides A and B, novel dimeric β‐(glucosyloxy)benzoates were isolated from Berchemia pakistanica and assigned structures 1 and 2 on the basis of extensive NMR studies. In addition, the known compounds 7,5′‐dimethoxy‐3,5,2′‐trihydroxyflavone (=3,5‐dihydroxy‐2‐(2‐hydroxy‐5‐methoxyphenyl)‐7‐methoxy‐4H‐1‐benzopyran‐4‐one), 4′,5‐dihydroxy‐3,6,7‐trimethoxyflavone (=5‐hydroxy‐2‐(4‐hydroxyphenyl)‐3,6,7‐trimethoxy‐4H‐1‐benzopyran‐4‐one), 5,6‐dihydroxy‐4,7‐dimethoxy‐2‐methylanthracene‐9,10‐dione, and 1,3,4‐trihydroxy‐6,7,8‐trimethoxy‐2‐methylanthracene‐9,10‐dione were reported for the first time from the genus Berchemia. Both 1 and 2 showed significant α‐glucosidase and lipoxygenase inhibitory activities, while 2 also showed antioxidant potential. 相似文献
494.
In this paper we define a sequence space using Orlicz functions. We give certain properties and inclusion relations between
known sequence spaces and new sequence space. 相似文献
495.
Vasant R. Choudhary Kailash Y. Patil Suman K. Jana 《Journal of Chemical Sciences》2004,116(3):175-177
Montmorillonite K-10 clay supported InCl3 is a highly active catalyst for the acylation of aromatic alcohols and phenols with different acyl chlorides. This catalyst
can be reused in reactions a number of times without very significant loss of catalytic activity 相似文献
496.
Fe-Mg-hydrotalcite (Mg/Fe = 3) anionic clay with or without calcination (at 200–800‡C) has been used for the benzylation of
toluene and other aromatic compounds by benzyl chloride. Hydrotalcite before and after its calcination was characterized for
surface area, crystalline phases and basicity. Both the hydrotalcite, particularly after its use in the benzylation reaction,
and the catalyst derived from it by its calcination at 200–800‡C show high catalytic activity for the benzylation of toluene
and other aromatic compounds. The catalytically active species present in the catalyst in its most active form are the chlorides
and oxides of iron on the catalyst surface. 相似文献
497.
In this paper we define a sequence space using Orlicz functions. We give certain properties and inclusion relations between known sequence spaces and new sequence space. 相似文献
498.
A facile, SbCl3-catalyzed, one-pot, tandem Friedel–Crafts/lactonization reaction of phenols and mandelic acids has been developed under solvent-free conditions to afford 3-aryl benzofuran-2(3H)-ones in good to high yields (52–90%). Additionally, the utility of 3-aryl benzofuran-2(3H)-ones is demonstrated by using them as precursors in the synthesis of a new class of spirocyclic benzofuran-2-ones using classical synthetic methodologies. 相似文献
499.
Molecular structure investigation and biological evaluation of Michael adducts derived from dimedone
Assem Barakat Abdullah M. Al-Majid Mohammad Shahidul Islam Ismail Warad Vijay H. Masand Sammer Yousuf M. Iqbal Choudhary 《Research on Chemical Intermediates》2016,42(5):4041-4053
Trimolecular salt Michael adducts 2a–c were synthesized in excellent yields up to 92 % via one-pot multicomponent reactions in an aqueous medium. The chemical structures of compounds 2a–c were characterized by X-ray single-crystal diffraction techniques. Calculations of the density functional theory for the synthesized compound were performed. The stability of the products was deduced by TGA analysis. Compounds 2a–c were screened in vitro for different bio-assays such as thymidine phosphorylase inhibition assay, urease inhibition assay, β-glucuronidase inhibition assays and cytotoxicity against PC-3 and HeLa cell lines. 相似文献
500.
Hemant Kumar Priti Priya Nena Singh Mukesh Kumar Binod Kumar Choudhary Lokendra Kumar Indu Shekhar Singh Nitish Kumar 《Applied biochemistry and biotechnology》2016,180(7):1345-1360
Euryale ferox Salisbury is an important aquatic food plant cultivated largely in eastern India. E. ferox is a monotypic genus, and breeding programmes have mostly relied on the variability present in the primary gene pool. Knowledge of the genetic structure of the population is limited, and there are very few reports available on the genetic diversity of E. ferox. In this study, comprehensive research on the genetic diversity of 16 germplasms of E. ferox was carried out using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. Out of 320 RAPD and 95 ISSR primers screened initially, 61 primers (40 RAPD and 21 ISSR) gave reproducible bands and were selected for further work. Amplification of the 40 RAPD primers gave 533 polymorphic bands with an average of 13.32 polymorphic bands per primer. The percentage of polymorphism ranged from 37.5 to 100, with an average of 88.3 %. The 21 ISSR primers produced 259 bands, of which 214 were polymorphic, with an average of 10.19 polymorphic bands per primer. The percentage of polymorphism using ISSR primers ranged from 50 to 100, with a mean of 82.6 %. Jaccard’s coefficient ranged from 0.45 to 0.69 (RAPD), 0.50 to 0.77 (ISSR) and 0.48 to 0.71 (RAPD and ISSR). Molecular characterization of different germplasms of E. ferox not only is essential for its conservation but also can be used in further breeding programmes. 相似文献