No abstract

Among these aforementioned types of light, blue and red light are particularly crucial for plant growth and fruit maturity. [2] Several traditional light sources for indoor plant cultivation, including incandescent lamps, high-pressure halogen lamps, and xenon lamps, have been employed; however, they have disadvantages such as high energy consumption, short work life, and spectral mismatch. [3] Therefore, light-emitting diodes (LEDs) with benefits such as reduced energy consumption, long lifespan, spectral matching, and environmental friendliness have been developed to specifically facilitate indoor plant cultivation. In addition, novel films capable of transforming light for plant growth are being currently developed; these light-conversion films directly utilize sunlight and can be employed for large-scale outdoor cultivation. Epoxy resin films containing dispersed CaAlSiN 3 :Eu 2+ particles and polyethylene films containing dispersed Sr 2 Si 5 N 8 :Eu 2+ particles are typical examples of light-conversion films for sunlightdriven plant growth. [4] Phosphors appropriate for generating light for plant growth are primarily excited by Mn 4+ , Mn 2+ , and Eu 2+ . The emission spectrum of Mn 4+ is attributed to the transitions of 2 E(t 2 3 ) → 4 A 2 (t 2 3 ) (620-750 nm), [5] and the excitation spectrum is primarily attributable to the 4 A 2 → 4 T 1 (≈350 nm) and 4 A 2 → 4 T 2 (≈455 nm) transitions. [6] However, the parity-and spin-forbidden transitions during emission and the parityforbidden transition during excitation diminish the excitation and emission, which does not favor plant growth. [7] Typical red phosphors such as YAG:Mn 4+ , [8] Sr 4 Al 14 O 25 :Mn 4+ , [9] Ca 3 Al 4 ZnO 10 :Mn 4+ , [10] and SrMgAl 10 O 17 :Mn 4+[1d] have been developed to date. Mn 2+ exhibits an emission spectrum originating from the weak crystal field located at Dq/B ≈ 1, which corresponds to the 4 T 1 ( 4 G) → 6 A 1 ( 6 S) transition in the 490-750-nm range. [11b,12] However, the extremely weak absorption of Mn 2+ in the ultraviolet and visible range results in a particularly low luminescence intensity, thereby making it unsuitable for plantgrowth-related applications. Representative phosphors include Ca 2 Sr(PO 4

The enantioselective separation of pheniramine was studied by a high-speed countercurrent chromatography method using β-cyclodextrin derivatives as a chiral selector. Several key variables, for instance, type of organic solvent and chiral selector, concentration of chiral selector, pH value of aqueous phase, and temperature on the enantioselectivity, were investigated systematically by liquid-liquid extraction experiments. Combining the results of extraction experiments and high-speed countercurrent chromatography, the most suitable conditions for separation of pheniramine enantiomers were obtained with the two-phase system that consisted of isobutyl acetate/aqueous phase, containing 0.02 mol/L carboxymethyl-β-cyclodextrin, pH 8.50 at 278.15 K. Under the optimal conditions, pheniramine enantiomer was successfully resolved after four cycles of high-speed countercurrent chromatography. By using high-performance liquid chromatography to analyze the fractions, the purities of both (+)-pheniramine and (-)-pheniramine were over 99% and the recovery of this method was up to 85-90%.

No abstract

No abstract