Clustered detection

Similar experiments exist to correlate the resonances of different types of nucleus, e.g. C with H, provided that some suitable couplings are present, such as It is necessary to apply pulses at both the relevant frequencies and it is also desirable to be able to detect either nucleus, to resolve different peak clusters. Detection tlirough the nucleus with the higher frequency is usually called reverse-mode detection and generally gives better sensitivity. The spectrum will have the two different chemical shift scales along its axes... 

Paul-Hayase H, Rosseneu M, Robinson D, Van Bervliet JP, Deslypere JP, Humphries SE. Polymorphisms in the apolipoprotein (apo) AI-CIII-AIV gene cluster Detection of genetic variation determining plasma apo AI, apo CIII and apo AIV concentrations. Hum Genet. 1992, 88 439 446. 

Besides the nearby cluster detections (z O.l) that are using simple galaxy density criteria, the combination of such galaxy densities over the sky and of the shape of the galaxy luminosity function allows cluster detections up to 1... 

Figure 3.4. Cluster detection efficiency for blind redshift surveys down to 1=24. Solid line is for a 100% complete survey, dotted line is for a 50% complete survey. Dashed line is for a 33% complete survey down to 1=22.5.

Department, Rensselaer Polytechnic Institute, Troy, NY, 1999. Clusterability Detection and Initial Seed Selection in Large Data Sets. 

GFNM is a one-level (or horizontal) clustering procedure. It may be used to detect spherical or ellipsoidal clusters. The shape of the clusters detected by this procedure is influenced by the matrix M. If M = I il... 

May occur as large bands, small and diffiisely scattered areas, and/or as individual fibers or fiber clusters detectable only with a microscope. 

Prom this relation, we also can estimate the sensitivity of the method. As an example, for a typical limit of measurable absorption losses of 0.5 X 10 and a cross section of 0.1 A (t3rpical for transitions in metal clusters) detectable cluster coverages are in the range of 5 x 10 °cm ( 0.005% ML). This is indeed orders of magnitudes better than for conventional surface science techniques in laboratory conditions (XPS, UPS, FTIR, etc.). 

Smeeton T. M., Kappers M. J., Barnard J. S., Vickers M. E., Humphreys C. J. Electron-beam-induced strain within InGaN quantum wells False indium cluster detection in the transmission electron microscope Appl. Phys. Lett. 83, 5419 (2003). 

Cavity ring down (CRD) spectroscopy, having proven to be a very sensitive method for detecting molecular species in a wide variety of environments, has also been applied to the mid infrared vibrational spectroscopy of hydrogen-bonded clusters of water " and alcohols.As a direct absorption method, it can be used to quantitatively measure important molecular properties, such as absorption cross sections and coefficients. Knowing these properties, as a function of cluster size and structure, is useful in making the connection to the condensed phase. The sensitive detection of methanol clusters, as shown in Fig. 13, is of considerable importance. These particular measurements nicely complement the action spectra of methanol clusters, detected by depletion of mass-detected signal via vibrational predissociation. 

Fig. 1.40 Excitation spectra of Lis clusters detected by photoionization of the excited states (a) no mass selection (b) spectrum of the Lis = Li Li Li isotopomer (c) spectrum of Lis = Li Li Li, recorded with doubled sensitivity [95]...

For some metal ions, such as high-spin Co° (5=3/2) or iron-sulfur clusters, the electron spin relaxation time is strongly temperature dependent. If the relaxation time becomes too short, then the signal becomes so broad that the signal is essentially undetectable. For many high-spin Co complexes and iron sulfur clusters, detection of an EPR signal requires temperatures in the liquid helium range. 

This ligand is useful for inorganic species as well. Irradiation at 532 nm of gold nanoparticles (average size 1 nm) encapsulated inside CB7 in water underwent electron ejection to form positive gold clusters (detected as a long-lived transient, x>1.2ms). Such clusters were active for the catalytic dimerization of phenylacetylene and to minimize the spurious decomposition of H2O2 otherwise promoted by Au CB7 in the dark. ... 

N. V. Lokshin, L.R. Chuprikov, A.V. Discrimination Effects in Inorganic Ion-Cluster Detection by Secondary-Electron Multiplier in Mass Spectrometry Experiments. Rapid Commun. Mass Spectrom. 1990,4,9-12. 

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