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241.
A sodium ion conducting composite polymer electrolyte (CPE) prepared by solution-caste technique by dispersion of an electrochemically
inert ceramic filler (SnO2) in the PEO–salt complex matrix is reported. The effect of filler concentration on morphological, electrical, electrochemical,
and mechanical stability of the CPE films has been investigated and analyzed. Composite nature of the films has been confirmed
from X-ray diffraction and scanning electron microscopy patterns. Room temperature d.c. conductivity observed as a function
of filler concentration indicates an enhancement (maximum) at 1–2 wt% filler concentration followed by another maximum at
∼10 wt% SnO2. This two-maxima feature of electrical conductivity as a function of filler concentration remains unaltered in the CPE films
even at 100 °C (i.e., after crystalline melting), suggesting an active role of the filler particles in governing electrical
transport. Substantial enhancement in the voltage stability and mechanical properties of the CPE films has been noticed on
filler dispersion. The composite polymer films have been observed to be predominantly ionic in nature with t
ion ∼ 0.99 for 1–2 wt% SnO2. However, this value gets lowered on increasing addition of SnO2 with t
ion ∼ 0.90 for 25 wt% SnO2. A calculation of ionic and electronic conductivity for 25 wt% of SnO2 film works out to be ∼2.34 × 10−6 and 2.6 × 10−7 S/cm, respectively. 相似文献
242.
We report on the observation of some unusual electronic patterns on a graphite surface using scanning tunneling spectroscopy
(STM). We attribute these patterns to different types of strain near the surface. One such pattern seen on a particular layer
comprises of two-dimensional spatially varying super-lattice and one-dimensional fringes. This pattern is present in a finite
region of a layer on the surface confined between two carbon fibers. We attribute this spatially varying super-lattice structure
to the shear strain generated in the top layer due to the restraining fibers. We have also developed a model with the Moirè
rotation hypothesis that gives us a better insight into such largescale spatially varying patterns. We have been able to model
the above-observed pattern. We also report another pattern near a defect, which we attribute to the change in density of states
due to the physical buckling of the top graphite layer. Part of this buckled layer is found to be buried under another layer
and this region shows a reversed contrast and thus supporting our idea of buckling. We also performed tunneling spectroscopy
measurements on various regions of these patterns which show significant variations in the density of states.
相似文献
243.
Adamson P Andreopoulos C Arms KE Armstrong R Auty DJ Ayres DS Baller B Barnes PD Barr G Barrett WL Becker BR Belias A Bernstein RH Bhattacharya D Bishai M Blake A Bock GJ Boehm J Boehnlein DJ Bogert D Bower C Buckley-Geer E Cavanaugh S Chapman JD Cherdack D Childress S Choudhary BC Cobb JH Coleman SJ Culling AJ de Jong JK Dierckxsens M Diwan MV Dorman M Dytman SA Escobar CO Evans JJ Harris EF Feldman GJ Frohne MV Gallagher HR Godley A Goodman MC Gouffon P Gran R Grashorn EW Grossman N Grzelak K 《Physical review letters》2008,101(13):131802
This Letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum-mechanical oscillations of neutrino flavor with mass splitting |Deltam2| = (2.43+/-0.13) x 10(-3) eV2 (68% C.L.) and mixing angle sin2(2theta) > 0.90 (90% C.L.). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight: namely, neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard-deviation levels, respectively. 相似文献
244.
Abdullah Mohammed Al-Majid M. Ali Mohammad Shahidul Islam Saeed Alshahrani Abdullah Saleh Alamary Sammer Yousuf M. Iqbal Choudhary Assem Barakat 《Molecules (Basel, Switzerland)》2021,26(20)
A new series of di-spirooxindole analogs, engrafted with oxindole and cyclohexanone moieties, were synthesized. Initially, azomethine ylides were generated via reaction of the substituted isatins 3a–f (isatin, 3a, 6-chloroisatin, 3b, 5-fluoroisatin, 3c, 5-nitroisatin, 3d, 5-methoxyisatin, 3e, and 5-methylisatin, 3f, and (2S)-octahydro-1H-indole-2-carboxylic acid 2, in situ azomethine ylides reacted with the cyclohexanone based-chalcone 1a–f to afford the target di-spirooxindole compounds 4a–n. This one-pot method provided diverse structurally complex molecules, with biologically relevant spirocycles in a good yields. All synthesized di-spirooxindole analogs, engrafted with oxindole and cyclohexanone moieties, were evaluated for their anticancer activity against four cancer cell lines, including prostate PC3, cervical HeLa, and breast (MCF-7, and MDA-MB231) cancer cell lines. The cytotoxicity of these di-spirooxindole analogs was also examined against human fibroblast BJ cell lines, and they appeared to be non-cytotoxic. Compound 4b was identified as the most active member of this series against prostate cancer cell line PC3 (IC50 = 3.7 ± 1.0 µM). The cyclohexanone engrafted di-spirooxindole analogs 4a and 4l (IC50 = 7.1 ± 0.2, and 7.2 ± 0.5 µM, respectively) were active against HeLa cancer cells, whereas NO2 substituted isatin ring and meta-fluoro-substituted (2E,6E)-2,6-dibenzylidenecyclohexanone containing 4i (IC50 = 7.63 ± 0.08 µM) appeared to be a promising agent against the triple negative breast cancer MDA-MB231 cell line. To explore the plausible mechanism of anticancer activity of di-spirooxindole analogs, molecular docking studies were investigated which suggested that spirooxindole analogs potentially inhibit the activity of MDM2. 相似文献
245.
Nida Ali Farooq-Ahmad Khan Kayode Muritala Salawu Rimsha Irshad Almas Jabeen Chun-Lei Zhang Muhammad Iqbal Choudhary Xin-Min Liu Yan Wang 《Molecules (Basel, Switzerland)》2022,27(4)
Two new ursane-type triterpenoids, named Polyanside A (1) and B (2), along with eleven known compounds (3–13), were isolated and elucidated from Maranthes polyandra (Benth.) Prance. The structures of these compounds were elucidated based on chemical evidence and multiple spectroscopic data. Isolated compounds were evaluated for anti-cancer, anti-inflammatory activities, and cytotoxicity on a normal human cell line (BJ). None of them showed activity and cytotoxicity. The hexane fraction was analyzed by GC-MS, resulting in the identification of forty-one compounds. This is the first comprehensive study on the phytochemistry of M. polyandra. 相似文献
246.
247.
Polycrystalline samples of KVO3, a member of the pyroxene structural family have been synthesised with high-temperature solid-state reaction technique. Preliminary
structural and spectroscopic and detailed dielectric properties have been studied in different conditions. No dielectric anomaly
or hysteresis loop has been observed in a wide temperature range (30°C to 450°C). Basic structural and spectroscopic (IR and
Raman) studies suggest that at room temperature, KVO3 is centrosymmetric as reported earlier. This and other observations do not support the recent report of ferroelectric phase
transition in the compound. 相似文献
248.
249.
Decomposition of H2O2 over Pd (5%)/carbon in an aqueous sulfuric acid solution at different acid concentrations (0-10 mol/L) and temperatures (281-313
K) in a magnetically stirred glass reactor has been investigated. The catalytic activity, activation energy and frequency
factor for the decomposition decrease with increasing acid concentration; the decrease in the activation energy is, however,
very small.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
250.