sought in the first place, and thus is impossible. Often though, the analyst has qualitative knowledge of whether or not No1 > N02. Any knowledge of this kind can and should be put to good use. That row of which corresponds to the smallest value of Nq1 should have the largest values of the incremental molar additions. This requires abandoning the symmetric design of additions, causing the condition of ( )_1 to worsen.Nevertheless, statistical precision is gained at the expense of amplification of deterministic error. In the twocomponent example chosen, redesigning the experiment such that 1 jnc = (1/3)AZV2inc reduces the variance in N0 by approximately 50%.The above considerations suggest a procedure analogous to the Stein two-stage sampling procedure in statistics. Out of a total or rt standard additions, the first (r-s)t data points could be used to calculate a rough estimate of N0. With this, can be rechosen so that di/182 = N01/N22. In summation, the GSAM algorithm provides the obvious advantage of simultaneously estimating initial concentrations of analytes when matrix effects and mutual interference effects are present. To obtain full advantage of this technique, care must be applied in the analysis. ACKNOWLEDGMENTThe authors thank Maynarhs de Koven for helpful discussions.

We report the production of a broad band (ranging from 400 to 900 nm) white light following the monochromatic infrared light (803.5 and 975 nm) excitation of both nominally un-doped and Nd 3þ -doped Y 2 O 3 nano-powders, even up to 20% of Nd 3þ content. Experimental results indicate that such emission feature is a nano-scale phenomenon, cannot be ascribed to an overlap of sharp emission bands in the un-doped case and, even if assisted by the Nd 34 presence, is a host matrix-related process. The measured white light emission is strongly dependent on either environment pressure (a pressure threshold occurs) or pumping power. The rising patterns of the white light emission were found to increase faster for either increasing Nd 3þ content and pumping power or decreasing particle size. Notably, high correlated color temperature (2756 K), color rendering index (99), and efficiency (864 lx/W) values were measured for the un-doped sample under 803.5 nm exciting wavelength.

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We present data on broadband, white light emission from insulating hosts under intense excitation in the near infrared in host materials that are undoped, partially-doped with rare earth ions, and that contain stoichiometric concentrations of rare earth ions. Much of the emission is found to have a blackbody-like structure in the visible and near infrared region. The origin of the emission as from a blackbody is also supported by the temporal characteristics of the emission in response to turning on and off the laser, and also by the dependence of the air pressure in the chamber. However, some of the data presented cannot be explained by blackbody emission alone, so other processes are proposed to explain the observed spectra. The role of the rare earth ion dopants in enhancing the broadband emission is also considered. Over the last several years, numerous works have reported a broadband, white-light emission from insulating powders under intense, near infrared (IR) excitation. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The materials investigated are usually nano-powders of insulators, such as yttrium oxide, yttrium silicate, Al 2 O 3 , GGG, and others, either pure or doped with rare earth ions (e.g. Er, Nd, Yb, Tm) or transition metal ions (e.g. Cr). Spectral and temporal characteristics of the broadband emission suggest that it is thermal in origin. One study on the origin of the emission, conducted by Debasu et al.,16 concluded that the emission is indeed blackbody emission, with temperatures in the range of ∼1200 K-1900 K. We have studied the white-light emission phenomenon in several host materials, both doped and undoped. In this work, we present results representative of this body of work, and we consider how these results fit into the blackbody model.For lighting applications, one of the main goals is the generation of high quality, white light with highest possible efficiency. Broadband white light based on blackbody-like emission can be of very high quality, but it is never efficient, especially compared to compact fluorescent or LED-based lighting. The white light we report on here is probably no different in that regard, and so it likely will be of little usefulness as a general lighting source. One difference between these emitters and tungsten-based blackbody sources is the means by which energy is delivered to the system; the energy source is a near infrared diode laser instead of electrical power converted to Joule heating, as in a tungsten lamp.Production of white light using near IR photons can occur in different ways. One method of recent interest is the upconversion process in rare earth doped systems that depend on energy transfer and/or excited state absorption to produce emission of high-energy photons. Usually, this occurs in systems co-doped with, for example, Yb, Er and Tm, 20,21 and the emission is exclusively from the f-f transitions of the dopant ions. The white light reported on here is generated in a fundamentally different way. The energy contained in the...