Improving "color rendering" of LED lighting for the growth of lettuce

Light plays a vital role on the growth and development of plant. On the base of white light with high color rendering to the benefit of human survival and life, we proposed to improve “color rendering” of LED lighting for accelerating the growth of lettuce. Seven spectral LED lights were adopted to irradiate the lettuces under 150 μmol·m−2·s−1 for a 16 hd−1 photoperiod. The leaf area and number profiles, plant biomass, and photosynthetic rate under the as-prepared LED light treatments were investigated. We let the absorption spectrum of fresh leaf be the emission spectrum of ideal light and then evaluate the “color rendering” of as-prepared LED lights by the Pearson product-moment correlation coefficient and CIE chromaticity coordinates. Under the irradiation of red-yellow-blue light with high correlation coefficient of 0.587, the dry weights and leaf growth rate are 2-3 times as high as the sharp red-blue light. The optimized LED light for lettuce growth can be presumed to be limited to the angle (about 75°) between the vectors passed through the ideal light in the CIE chromaticity coordinates. These findings open up a new idea to assess and find the optimized LED light for plant growth

Spectral broadening of a single Ce3+-doped garnet by chemical unit cosubstitution for near ultraviolet LED

In this paper, the isostructural Mg3Al2Si3O12 was introduced into the Ce3+-doped yttrium aluminum garnet (Y3Al5O12) for synthesizing (Y1-xMgx)3Al2(Al1-xSix)3O12:Ce3+ (x = 0-0.6) solid solution phosphors. The co-substitution of the (Mg, Si)6+ pair for the (Y, Al)6+ pair leads to lattice shrinkage and then changes the spectral shape and width. The band peaking at ~450 nm shows a substantial broadening with the full width at half maximum increasing from 65 nm to 94 nm. The intensity of excitation spectrum (x = 0.5) at 400 nm is increased by 50% than that (x = 0). The near ultraviolet LED was fabricated with Y1.5Mg1.5Al3.5Si1.5O12:Ce3+ phosphors and a 400 nm chip and can emit strong white light. Therefore, by controlling the content of (Y, Al)6+ substituted by (Mg, Si)6+, the excitation spectrum of Ce3+-doped Y3Al5O12 can be tuned and applied for the near ultraviolet LEDs

Four New Furostanol Saponins from the Rhizomes and Roots of Smilax scobinicaulis and Their Cytotoxicity

Four new furostanol saponins 1–4, along with two known furostanol saponins 5 and 6 and one known spirostanol saponin 7 were isolated from the rhizomes and roots of Smilax scobinicaulis. The structures of the new saponins were elucidated as 26-O-β-D-glucopyranoside-3β,26-dihydroxy-(25R)-5α-furostan-22-methoxyl-6-one-3-O-α-L-arabinopyranosyl-(1→6)-β-D-glucopyranoside (1), 26-O-β-D-glucopyranoside-3β,26-dihydroxy-(25R)-5α-furostan-22-methoxyl-6-one (2), 26-O-β-D-glucopyranoside-3β,26-dihydroxy-(25R)-5α-furostan-20(22)-en-6-one (3), 26-O-β-D-glucopyranoside-3β,23,26-trihydroxy-(23R, 25R)-5α-furostan-20(22)-en-6-one (4) on the basis of spectroscopic analysis. The isolated saponins were evaluated for cytotoxic activity against two human cancer cell lines including Hela (cervical carcinoma) and SMMC-7221 (hepatocellular carcinoma). Compounds 1 and 7 demonstrated cytotoxicity against the tested cell lines

Site occupancy strategy for emission tunable K3HF2W1-xOF6:xMn4+ nanophosphor via ions exchange

A novel uniformly ellipsoidal K3HF2W1-xOF6:xMn4+ nanophosphor were demonstrated by ion exchange method without K2MnF6. The samples had wide excitation range from ultraviolet to visible light and tunable emission spectra from green to red were obtained which can be regulated by the emitting spectra of K3HF2WOF6 host and Mn4+. Energy transfer efficiency from [WOF6]2− to Mn4+ were improved with the increase of Mn4+. The peak position of thermal stability spectra of K3HF2WOF6 were blueshifted while Mn4+ doped samples undergoes a redshift. The crystal field strength and the Racah parameters were estimated and luminescence mechanism was explained by the Tanabe–Sugano energy level diagram of the Mn4+. Microsecond fluorescence lifetime indicates it advantages in fast react displays to avoid ghost images. The results indicate that K3HF2W1-xOF6:xMn4+ nanophosphor has potential application in display, converting phosphors for UV and blue LED and indoor plant supplyment light