Search results for "NAK"
showing 10 items of 469 documents
Biphenyl macrolactams in anion complexation. Selective naked-eye fluoride recognition
2004
Two colorimetric anion sensors 1 and 2 allow for the selective differentiation of fluoride in the presence of other anions. Two different types of species have been observed in the complexation process, one of them is a co-ordination complex and the other is a salt generated by ligand deprotonation. The deprotonation reaction induces a conformational change, giving rise to a symmetrical species. This species is responsible for colour development. Ligand 3 has a similar structure and does not give rise to any colour modification due to presence of the dimethylamino groups in the biphenyl moiety. The X-ray structure of ligand 2 is also reported and compared with that of ligand 1, that had bee…
The Influence of Spatial Correlation and Severity of Fading on the Statistical Properties of the Capacity of OSTBC Nakagami-m MIMO Channels
2009
This paper deals with the analysis of statistical prop- erties of the capacity of spatially uncorrelated orthogonal space- time block coded (OSTBC) Nakagami-m multiple-input multiple- output (MIMO) channels. We have derived exact closed-form expressions for the probability density function (PDF), cumula- tive distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the channel capacity. We have also investigated the statistical properties of the approximated capacity of spatially correlated OSTBC Nakagami-m MIMO channels. The results are studied for different values of the fading parameter m, corresponding to different fading conditions. It is observed …
Successive specification ofDrosophilaneuroblasts NB 6-4 and NB 7-3 depends on interaction of the segment polarity geneswingless,gooseberryandnaked cu…
2001
The Drosophila central nervous system derives from neural precursor cells, the neuroblasts (NBs), which are born from the neuroectoderm by the process of delamination. Each NB has a unique identity, which is revealed by the production of a characteristic cell lineage and a specific set of molecular markers it expresses. These NBs delaminate at different but reproducible time points during neurogenesis (S1-S5) and it has been shown for early delaminating NBs (S1/S2) that their identities depend on positional information conferred by segment polarity genes and dorsoventral patterning genes. We have studied mechanisms leading to the fate specification of a set of late delaminating neuroblasts,…
On the statistical properties of the capacity of OSTBC Nakagami-lognormal MIMO channels
2010
This article presents a thorough statistical analysis of the capacity of orthogonal space-time block coded (OSTBC) Nakagami-lognormal (NLN) multiple-input multipleoutput (MIMO) channels. The NLN channel model allows to study the joint effects of fast fading and shadowing on the statistical properties of the channel capacity. We have derived exact analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the capacity of NLN MIMO channels. It is observed that an increase in the MIMO dimension1 or a decrease in the severity of fading results in an increase in the mean channel capa…
The Influence of the Severity of Fading and Shadowing on the Statistical Properties of the Capacity of Nakagami-Lognormal Channels
2008
This paper deals with the study of the statistical properties of the capacity of Nakagami-lognormal (NLN) channels for various fading environments. Specifically, the impact of shadowing and the severity of fading on the channel capacity is investigated. We have derived analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the channel capacity. These results are analyzed for different levels of shadowing and for various fading conditions, corresponding to different terrestrial environments. It is observed that the severity of fading and shadowing has a significant influence …
Electric field induced alignment-orientation conversion in diatomic molecules: analysis and observation for NaK
1999
This article reports the observation of the molecular fluorescence circularity under irradiation with linearly polarised light. This alignment-orientation conversion phenomenon arises as a result of partial transformation from alignment of the ensemble of 1 P state molecular angular momenta into their orientation under the effect of non-linear dc Stark effect. Circularity rate up to 0.12 was observed in D 1 P! X 1 S fluorescence of 23 Na 39 K molecules in agreement with the theoretically predicted value.
Studies of rotational level Λ-doubling by rf-optical double resonance spectroscopy: application to NaK D1Π
1997
Abstract We report here the application of optical-radio frequency double resonance spectroscopy for individual rotational levels of the NaK D 1 Π state. Lambda doubling constant q values for five ν′, J ′ levels are obtained. These data are combined with measurements of dc e - f Stark-mixing-induced changes in optical spectra, and the electric dipole moment d p in the D 1 Π state is determined.
Protection against chemical submission: naked-eye detection of γ-hydroxybutyric acid (GHB) in soft drinks and alcoholic beverages
2020
Two new oxazole derivatives, able to detect γ-hydroxybutyric acid (GHB) in soft drinks and alcoholic beverages, by color and fluorescence changes, are reported.
A new selective fluorogenic probe for trivalent cations.
2012
[EN] A new selective chromo-fluorogenic probe for Fe 3+, Cr 3+ and Al 3+ is reported. Detection limits are in the ¿M range and the fluorogenic sensing ability could be observed by the naked eye when illuminated with UV-light. No response is observed with divalent cations. © 2012 The Royal Society of Chemistry.
Chromogenic Detection of Nerve Agent Mimics by Mass Transport Control at the Surface of Bifunctionalized Silica Nanoparticles
2010
Chemical warfare (CW) agents are toxic chemicals that have been used in several terrorist attacks in recent years. Among CW species, nerve agents are probably the most dangerous; their high toxicity and facile synthesis underscores the need to detect these lethal compounds with quick, reliable procedures. Analytical methods based on enzymatic assays and physical measurements have generally been used to detect these hazards. However, these protocols usually have limitations such as low selectivity, poor portability, and a certain level of complexity. In recent years, several chromogenic and fluorogenic sensors, and reagents for the detection of nerve agents have been described. For instance,…