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91.
Amide-based polymer liquids are important for developing biological and optical colloids or nanofluids. Functionalized properties arise from specific molecular structures. In this investigation, we report model molecular configurations of a polymer liquid, 0.3 g/L poly(vinylidene fluoride) (PVF2) dissolved in liquid N,N-dimethylformamide (DMF), based on the characteristic IR vibration bands. Peculiarly, a ferroelectric β-PVF2 phase reorders on a linear configuration in support with the DMF molecules, showing a characteristic band 840 cm− 1 (CH2 rocking and CF2 asymmetric stretching) with the trans band at 1275 cm− 1. Four CO stretching bands ν10, ν11, ν12, and ν13 of 1650, 1675, 1725, and 1760 cm− 1 (bandwidth Δν½ = 180 cm− 1 in the four bands) arise in four major configurations of DMF-PVF2 pairs (or derivatives). Only one prominent ν10 band 1660 cm− 1 (Δν½ = 75 cm− 1) incurs with a shoulder ν11 of 1725 cm− 1 (Δν½ = 25 cm− 1) in two DMF configurations. A ferroelectric field cased in presence of β-PVF2 leads to enhance IR absorption by as much as an order of magnitude. It leads to converging non-bonding electron density on the amide moiety. 相似文献
92.
We have studied the peak effect (PE) phenomenon in single crystals of weakly pinned superconductors CeRu2 and 2H-NbS2. 2H-NbS2 is iso-structural and iso-electronic to 2H-NbSe2, whose similarity with CeRu2 as regards the PE representing the order-to-disorder transformation of the flux line lattice was claimed some time ago. We
report on the step change in equilibrium magnetization across the peak effect in CeRu2. We also present the vortex phase diagram of 2H-NbS2 obtained from the magnetization data, and compare the PE phenomenon in 2H-NbS2 and 2H-NbSe2. 相似文献
93.
A. K.S. Jha P. Jha S. Tyagi M. Mohan 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(3):391-398
We present relativistic close-coupling photoionization calculations of Al IV
using the Breit-Pauli R-matrix method to obtain photoionization cross-section of Al IV from the ground state and the lowest
two J=0 (even) excited
states. A multi-configuration eigenfunctions expansion of the core Al V is
employed with spectroscopic configurations 2s22p5,
2s2p6,
2s22p43s, 2s22p43p, 2s22p43d and
2s22p44s. We have included, for the first time, the lowest 68
level target states of Al V in the photoionization calculations of Al IV.
Extensive configuration interaction wavefunctions are used to describe both
the initial Al IV states and the final Al V states. Cross-sections are
compared from three level calculations including only 2s2 2p5 2Po
3/2, 1/2 and 2s 2p6
2S1/2 levels of Al
V. The present calculation using the lowest 68 target levels of Al V are
presented for the first time and should provide reasonably complete database
for practical application for photoionization cross-section for Al IV, where
high-energy cross-sections along with near-threshold photoionization cross-section is required. 相似文献
94.
The effect of multistep dc-Joule-heating thermal processing on magnetoimpedance (MI) of Fe72Al5Ga2P11C6B4 ribbons is presented. After material optimization significant increase of MI response up to value ΔZ/Z≈55% as well as sensitivity of about 6%/kA/m (for H?3–4 kA/m), were recorded in still amorphous samples at driving frequencies 2–3 MHz. On-line and post-annealing electrical resistivity together with Mössbauer spectra analysis and frequency dependence of the penetration depth were used for characterization of MI improvement. 相似文献
95.
Inhibition of Candida albicans growth was shown by lemon grass oil (LGO) and lemon grass oil vapour (LGO vapour) at 288 μg/ml and 32.7 μg/ml concentration, respectively. The assessment of cell damage by LGO and LGO vapour was done through scanning electron microscope (SEM), transmission electron microscope (TEM) and atomic force microscope (AFM) observations. SEM analysis showed complete rupture of C. albicans cells treated with LGO vapour while in those treated with LGO in broth, only shrinkage was observed. TEM study showed the alterations in morphology upon treatment with LGO while complete degradation of the Candida cells was observed in case of LGO vapour. Further three dimensional morphological changes and roughness of the cells have also been evaluated with AFM after the treatment with LGO & LGO vapour. Roughness (root mean square value) was significantly higher in control C. albicans cells (211.97 nm) than LGO (143 nm) and LGO vapour (5.981 nm) treated cells. The results for the first time demonstrate relatively higher efficacy of LGO vapours for inhibition and cellular damage of C. albicans cells as compared to the LGO in liquid phase. This suggests the potential application of LGO vapour phase against infections caused by C. albicans. 相似文献
96.
Noncollinear difference frequency mixing of dye laser and Nd:YAG second harmonic (fundamental) radiation from a commercial
laser system is employed for the generation of 2.7–5.3 μm (1.6–1.7 μm) radiations in a flux-grown KTiOAsO1 crystal. The generated radiation is used to scan the methane absorption in the fundamental (v
3) and its first overtone (2v
3) band at pressure 90 torr in a laboratory made single pass gas cell of length 33 cm. 相似文献
97.
C. Devendranath Reddy P. Mallikarjuna Reddy D. Ramasubba Reddy M. Nagalakshmamma K. Anuradha C. Naga Raju K. Darrell Berlin Kevin M. Couch Sameer Tyagi 《Journal of heterocyclic chemistry》1995,32(5):1483-1487
The synthesis of new 2,10-dichloro-6-aryloxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfides 4 was achieved in two steps with high yields from the simple materials 5,5′-dichloro-2,2′-dihydroxydiphenyl-methane (1) and thiophosphoryl chloride (2) which produced the key intermediate 2,6,10-trichloro-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfide (3) . Treatment of 3 with substituted phenols under phase transfer catalytic (PTC) conditions led to members of 4 . Long range coupling [5J(P,H) = 3.6 Hz] was observed between phosphorus and one of the bridged methylene protons in 4 . A 13C nmr analysis revealed 2J(P,O,C), 3J(P,O,C) 4J(P,O,C) and 5J(P,O,C) couplings. All 31P nmr chemical shifts for thirteen members of these new heterocycles are reported for the first time. The nmr data are not totally definitive to confirm a boat-chair as the major conformer for the central eight-membered dioxaphosphocin ring, but such a conformer is tentatively suggested as favored. 相似文献
98.
Cinelli RA Ferrari A Pellegrini V Tyagi M Giacca M Beltram F 《Photochemistry and photobiology》2000,71(6):771-776
The green fluorescent protein (GFP) has emerged, in recent years, as a powerful reporter molecule for monitoring gene expression, protein localization and protein-protein interaction. Several mutant variants are now available differing in absorption, emission spectra and quantum yield. Here we present a detailed study of the fluorescence properties of the Phe-64-->Leu, Ser-65-->Thr mutant down to the single molecule level in order to assess its use in quantitative fluorescence microscopy and single-protein trafficking. This enhanced GFP (EGFP) is being used extensively as it offers higher-intensity emission after blue-light excitation with respect to wild-type GFP. By means of fluorescence spectroscopy we demonstrate the absence of the neutral form of the chromophore and the lack of photobleaching recovery after ultraviolet light irradiation. Furthermore, we show that the EGFP spectral properties from isolated to densely packed molecules are highly conserved. From these experiments EGFP emerges as an ideal molecule for quantitative studies of intra and intercellular tagged-protein dynamics and fluorescence-activated cell sorting, but not for monitoring single-protein trafficking over extended periods of time. 相似文献
99.
Perchlorate-selective liquid membrane electrodes were developed by incorporating the ion-pair complexes of perchlorate with brucine, cinchonidine, emetine and benzyldimethyltetradecylammonium chloride (zephiramine) in nitrobenzene. The electrodes, which respond to perchlorate ion over the concentration range 1.0–5.0 × 10?4 M ClO?4, have a fast response and wide pH range. The zephiramine-perchlorate electrode was the best in terms of its fast response, wide pH range and high reproducibility of potentials. Most common inorganic and organic anions, except permanganate, do not cause significant interference. Electrodes based on brucine-, emetine- and zephiramine-perchlorate were successfully employed for the direct potentiometric determination of perchlorate in the presence of halides, sulphate, nitrate and chlorate. The cinchonidine-perchlorate electrode showed comparatively poor selectivity. 相似文献
100.
§ 1.Introduction WearegivenkindependentWishartdensitiesofthe (p +q)× (p +q)randomsymmetricpositivedefinitematricesG1,… ,Gktobeg(Gi) =Kexp -12 trR- 1i Gi Gi12 (ni- q-p- 1) ,(1 )wherei=1 ,… ,k,andRidenotesthepopulationcorrelationmatrixofthei thpopulationandKasagenericletterdenote… 相似文献