| In green plants, photosynthesis takes place in chloroplasts. After chlorophyll molecules absorbed sunlight, photosynthesis uses solar energy to synthesize carbohydrate from carbon dioxide and water. Green plants contain two types of chlorophyll molecules, chlorophyll-a and chlorophyll-b, that differ slightly in structure and in the wavelength of light they can absorb. The various studies confirmed mat only blue and red components in sunlight could be efficiently absorbed by chlorophyll-a and chlorophyll-b. Therefore a large portion of solar energy could not be used directly by green plants, particularly the ultraviolet and green components in sunlight. A possible way to increase the productivity of green plants is to convert the ultraviolet or green component in sunlight into blue or red. Such strategy will become more and more realistic as the increase of the world population. There have been evidences that the greenhouse made by the plastic film containing special photoluminescent materials may considerably increase the yield and quality of the products. However, the extensive use of me plastic greenhouse may bring about the environmental problem; thus it is necessary to consider the light-conversion glasses for permanent greenhouses.Glass is one of the oldest synthetic materials with such precious properties as transparency, solidity, the ability to endure erosion and heat It also has good properties of electricity and optics and is able to be made into products of various shapes and sizes by means of figuration and machining.The rare earth ions have plenty of energy levels. Various special glasses,such as x-ray-to-light conversion glass, long lasting luminescence glass, can be prepared by doping with rare earth ions in matrix. In the system of alkaline earth rare earth borate, there are two different kinds of positive ions, and europium element has two kinds of valence states: Eu2+ and Eu3*. In this parjer,aA2O-bMO-(c-x-y)La2O3-dB2O3-xEu2O3-yGd2O3(AMLBEG) glassesare synthesized, it is found that the glasses have the function converting ultraviolet light into blue and red component and converting green to red component. This is a new kind of light- conversion material for agriculture.1. The Technological Process of Syntheses and Methods of Measurement for Borate Glasses Doped with Rare Earth IonsThe borate glasses doped with rare earth ions were prepared with conventional high temperature process. The starting materials were thoroughly mixed and heated from room temperature to 500 for 30min. Then the temperature was increased to and maintained at 800 for 30min and at 1200 for about 2~3h. Then the glassy liquids were poured on stainless plate and cooled slowly to room temperature. After quenching to room temperature, the glass samples were cut and polished into pieces with size of 20 5mm. All the samples are transparent with slight red color. Some of samples were prepared by high temperature process under an N2 +H2 or CQ2 reducing atmosphere in a horizontal carbon furnace.X-ray powder diffractions were measured for the samples by The D/max-RA x-ray powder diffraction analytical instrument. The UV-Vis absorption spectra were measured on a PE- A, 17 spectrophotometer. Photolurninescence spectra were recorded on RF-5301PC and PE 50B fluorescence spectrophotometer. The ESR spectra were obtained using a X-band spectrometer (JES-FE1XG), the resonance frequency of its cavity was 9.442GHZ.2. Luminescent Properties of the MO -RE2O3-B2O3 (M=Mg, Ca, Sr, Ba; RE=La, Eu, Gd) Glass17MO-(8-x-y)La2O3-75B2O3-Eu2O3-yG4O3(MLBEG> M= Mg2+, Ca2+, Sr2+, Ba2+) glasses were prepared with the conventional high temperature process. The study of luminescent spectra and ESR reveal mat in this system, mere have existed two valence states for europium ions: Eu2+ and Eu3+. The broad emission band peaking at 430nm correspond to the 5d -Remission transition of Eu2+ ions, the sharp emission bands peaking at 592, 616, 650 and 750mn correspond to the 5D0...
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