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The optical absorption spectra of EuCl3 in aqueous and acidic solutions were measured in the visible anduv regions of the spectrum. The concentration as well as the temperature of the solutions were varied to establish an accurate
free-ion energy level scheme of Eu3+. The energy levels were assigned on the basis of a correlation between the calculated and the experimentally observed transition
energies and associated band intensities. 相似文献
4.
R. Malik S. Lamba R. K. Kotnala S. Annapoorni 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,74(1):75-80
Magnetic nanoparticle systems are characterized by several competing effects like anisotropy, an inherent disorder, the long
range dipolar and the short range exchange interactions due to clustering effects. The sensitivity of the observed static
and dynamical properties of these systems like the blocking temperature, the hysteresis and the susceptibility, to the methods
of preparation, annealing and the resulting morphology is a manifestation of this. However, given the complexity of the system,
it is often difficult to isolate the effects which might be dominant in a particular sample, which has a direct bearing on
the desired applications. In this paper we report the effects of anisotropy, interactions and particle concentration on the
temperature dependent remanence and coercivity through a numerical simulation on an array of single domain magnetic particles
which incorporates all the above mentioned factors. Our results show that it is possible to distinguish between purely anisotropic
systems and interacting systems with these measurements. In confirmation of our simulation results we also present the experimental
results on the remanence and coercivity of nanomagnetic nickel ferrite composites. 相似文献
5.
Tadej Dolenec Sbreveivana Lambasbrevea Matej Dolenec 《Isotopes in environmental and health studies》2013,49(1):77-85
Analyses of nitrogen stable isotopes in the marine sea grass Posidonia oceanica were used to investigate the influence of fish farming on the coastal ecosystem of Vrgada Island in the Murter Sea, Central Adriatic. The results show a statistically significant 15N enrichment (up to 4.7‰ at p?<?0.005) in P. oceanica leaf and shoot tissues from fish cage sites with respect to the unaffected offshore reference site of Lumbarda Reef Flat (Kornati Islands). Heavy nitrogen enrichment was also detected in other benthic organisms analysed during this study and is attributed to the absorption and assimilation of 15N-enriched fish farm derived nitrogen waste. 相似文献
6.
Nagarajan S Nagarajan R Braunhut SJ Bruno F McIntosh D Samuelson L Kumar J 《Molecules (Basel, Switzerland)》2008,13(11):2704-2716
Catechins, naturally occurring flavonoids derived from wine and green tea, are known to exhibit multiple health benefits. Epigallocatechin gallate (EGCG) is one of the most widely investigated catechins, but its efficacy in cancer therapy is still inconsistent and limited. The poor stability of EGCG has contributed to the disparity in the reported anti-cancer activity and other beneficial properties. Here we report an innovative enzymatic strategy for the oligomerization of catechins (specifically epicatechin) that yields stable, water-soluble oligomerized epicatechins with enhanced and highly specific anti-proliferative activity for human breast cancer cells. This one-pot oxidative oligomerization is carried out in ambient conditions using Horseradish Peroxidase (HRP) as a catalyst yielding water-soluble oligo(epicatechins). The oligomerized epicatechins obtained exhibit excellent growth inhibitory effects against human breast cancer cells with greater specificity towards growth-inhibiting cancer cells as opposed to normal cells, achieving a high therapeutic differential. Our studies indicate that water-soluble oligomeric epicatechins surpass EGCG in stability, selectivity and efficacy at lower doses. 相似文献
7.
Barbara DeSantis AnnaLaura Iamiceli RinaldoMarini Bettolo LuisaMaria Migneco Rita Scarpelli Giorgio Cerichelli Giancarlo Fabrizi Doriano Lamba 《Helvetica chimica acta》1998,81(12):2375-2387
The factors responsible for the diastereoselective formation of the 6-endo-hydroxybicyclo[2.2.2]octan-2-one by acid-catalyzed intramolecular aldol reaction of 3-oxocyclohexaneacetaldehydes have been investigated. This study, carried out on (1SR,4RS,6RS)-6-hydroxybicyclo[2.2.2]octan-2-one 1a , (1SR,4RS,6SR)-6-hydroxybicyclo[2.2.2]octan-2-one 1b , and 3,3-(ethylenedioxy)cyclohexaneacetaldehyde 2a , allowed to demonstrate the absence of intramolecular H-bonding in 1a as a stabilizing factor, and to ascertain the presence of unfavorable steric interactions in 1b . 相似文献
8.
Raman spectra of Cs2ZnI4 single crystal have been measured in different scattering orientations covering the successive phase transitions down to 68 K. Two second order anomalies at around ice temperature (270 K) and at ~ 92 K are observed. The anomaly around ice temperature exhibits the features of a normal-incommensurate transition evidenced by softening of a low-lying lattice phonon whose frequency decreases as the transition temperature is approached from below whereas the latter one appears to arise from usual structural distortions. 相似文献
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Abhishek Kumar Subhalakshmi Nagarajan Ke Yang Robinson Anandakathir Jagdeep Singh Ramaswamy Nagarajan 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):963-966
A novel, one step and simple methodology for the fabrication of submicron scale silver patterns is demonstrated. The photosensitivity of an organic silver salt has been utilized for this purpose of fabrication. The silver-organometallic compound is converted to metallic silver selectively in the illuminated regions. Surface morphology was studied by scanning electron microscopy (SEM). Energy dispersion spectroscopy (EDS) shows the presence of silver in the developed film. X-ray photoelectron spectroscopy (XPS) confirms the formation of metallic silver. Feature sizes of the order of 200 nm have been achieved using this technique. 相似文献