Study on Spectral Structure and Photoelectric Properties of LED Healthy Light Source

LED healthy light source by using a blue LED chip to excite phosphor was prepared successfully. Four kinds of LED commercial phosphors (cyan phosphor with a peak wavelength of 498 nm, green phosphor with 520 nm, yellow-green phosphor with 546 nm, and red phosphor with 628 nm) were selected that could be excited by blue light. A series of experimental studies were carried out on the different amounts of glue, different powder-glue ratio, different combinations of phosphors, and the influence of different driving currents. Trough the optimization of the experimental scheme, we obtained a LED healthy light source spectrum with luminous efficiency higher than 124 lm/w, color rendering index higher than 80, color temperature around 4000 k. These spectra are in good agreement with the full spectrum of sunlight, and the spectral continuity and uniformity are better, which accord with the requirements of bright (dark) vision, and the proportion of the blue spectrum is less than 2.4%, which meets the high quality and healthy lighting requirements of safety and comfort.

Some results about spectral continuity and compact perturbations

In this paper, we are interested in the continuity of the spectrum and some of its parts in the setting of Hilbert spaces. We study the continuity of the spectrum in the class of operators {T}+K(H), where K(H) denote the ideal of compact operators. Also, we give conditions in order to transfer the continuity of spectrum from T to T + K, where K ? K(H). Then, we characterize those operators for which the continuity of spectrum is stable under compact perturbations.

PACKING SUBORDINACY WITH APPLICATION TO SPECTRAL CONTINUITY

By using methods of subordinacy theory, we study packing continuity properties of spectral measures of discrete one-dimensional Schrödinger operators acting on the whole line. Then we apply these methods to Sturmian operators with rotation numbers of quasibounded density to show that they have purely $\unicode[STIX]{x1D6FC}$-packing continuous spectrum. A dimensional stability result is also mentioned.

Spectral continuity, amplitude changes, and perception of length contrasts

Japanese displays a singleton/geminate contrast in obstruents and nasals, but not in glides. Patterns of emphatic gemination show that Japanese avoids creating new nasal geminates. This chapter tests hypotheses about why Japanese shows these preferences. Concerning the distinction between obstruent geminates and sonorant geminates, dispreference of sonorant geminates may exist because these geminates are easily confused with corresponding singletons. This confusability problem arises because sonorants are spectrally continuous with flanking vowels, and consequently perception of their constriction durations is difficult. Two non-speech perception experiments show that length distinctions of consonant intervals that are spectrally continuous with surrounding segments are difficult to perceive. Concerning the difference between nasal geminates and glide geminates, two further non-speech experiments show that amplitude changes facilitate discrimination and categorization of short/long contrasts. Overall, the results of the four perception experiments reported here accord well with the cross-linguistic phonological patterning of geminates.