The photosystem Ⅱ （PSII） complex of photosynthetic membranes comprises a number of chlorophyll-binding proteins that are important to the electron flow. Here we report that the chlorophyll b-deficient mutant has de...The photosystem Ⅱ （PSII） complex of photosynthetic membranes comprises a number of chlorophyll-binding proteins that are important to the electron flow. Here we report that the chlorophyll b-deficient mutant has decreased the amount of light-harvesting complexes with an increased amount of some core polypeptldes of PSII, including CP43 and CP47. By means of chlorophyll fluorescence and thermolumlnescence, we found that the ratio of Fv/Fm, qP and electron transport rate in the chlorophyll b-deficient mutant was higher compared to the wild type. In the chlorophyll lPdeflclent mutant, the decay of the primary electron acceptor quinones （QA-） reoxidation was decreased, measured by the fluorescence. Furthermore, the thermoluminescence studies in the chlorophyll bdeficient mutant showed that the B band （S2/S3QB-） decreased slightly and shifted up towards higher temperatures. In the presence of dlchlorophenyl-dlmethylurea, which is inhibited in the electron flow to the second electron acceptor quinines （QB） at the PSll acceptor side, the maximum of the Q band （S2QA-） was decreased slightly and shifted down to lower temperatures, compared to the wild type. Thus, the electron flow within PSll of the chlorophyⅡ b-deficient mutant was down-regulated and characterized by faster oxidation of the primary electron acceptor quinine QA-via forward electron flow and slower reduction of the oxidation S states.展开更多
Multi-color luminescence basing on amorphous Eu^3＋/Tb^3＋ co-doped Zn-A1 hydroxides and their annealed samples were studied in detail. Results suggest that excellent red emissions due to E^u3＋ and green emissions at...Multi-color luminescence basing on amorphous Eu^3＋/Tb^3＋ co-doped Zn-A1 hydroxides and their annealed samples were studied in detail. Results suggest that excellent red emissions due to E^u3＋ and green emissions attributed to Tb^3＋ appear under the excitation of favorable wavelength for all the as- prepared amorphous samples. Moreover, the emission intensity depends on the Eu^3＋/Tb^3＋ molar ratio. The samples annealed at 300, 500, and 700 ℃ still exhibit amorphous state, and multi-color lumi- nescence kept in the samples annealed at 300 ℃, while luminescence quenched for the samples annealed at 500 and 700 ℃. However, a broad emission ranging from 450 to 650 nm occurs in some samples annealed at 900 ℃. Further, the fluorescence decay and lifetimes for the as-prepared samples and the samples annealed at 300℃ were investigated. It is found that all the decay curves of emissions due to Tb^3＋ and Eu^3＋ present characteristic double exponential function despite their different lifetimes. The present work may be a good example for developing new multi-color even white light emitting materials.展开更多
Technical polymers could be identified by means of their remarkably strong auto fluorescence. The mono-exponentially obtained time constants of fluorescence decay were applied for a rough assignment of the polymeric m...Technical polymers could be identified by means of their remarkably strong auto fluorescence. The mono-exponentially obtained time constants of fluorescence decay were applied for a rough assignment of the polymeric materials whereas bi-exponential analysis allowed a fine classification such as for special batches and for preceding contaminations. Chemically similar materials such as LDPE (low-density polyethylene), HDPE (high-density polyethylene) and UHDPE (ultrahigh-density polyethylene) could be as well identified as contaminations of mineral oil in PET (polyethylene terephthalate). Furthermore, the fluorescence spectra could be characterized by means of five Gaussian functions in the visible allowing a redundant assignment to the fluorescence lifetimes. Thus, efficient sorting of polymers was possible for high performance recycling.展开更多
合成了三种重稀土(铽、铒、钇)的2,5-噻吩二羧酸(H2L)-1,10-菲咯啉(Phen)三元配合物,通过元素分析、热分析、红外光谱法确定配合物的组成为Ln2(L)3(phen)2.4H2O。紫外光谱显示H2L和Phen在参与配位后其最大紫外吸收峰均发生红移。2,5-噻...合成了三种重稀土(铽、铒、钇)的2,5-噻吩二羧酸(H2L)-1,10-菲咯啉(Phen)三元配合物,通过元素分析、热分析、红外光谱法确定配合物的组成为Ln2(L)3(phen)2.4H2O。紫外光谱显示H2L和Phen在参与配位后其最大紫外吸收峰均发生红移。2,5-噻吩二羧酸的羧基与稀土离子以螯合双齿形式配位。Tb2(L)3(phen)2.4H2O于室温下在紫外灯的照射下发出绿色荧光,Tb2(L)3(phen)2.4H2O荧光寿命为0.24 m s。展开更多
基金Supported by the National Natural Science Foundation of China （30270124, 39970068） and the Foundation for Doctoral Programme （20020610094）.
文摘The photosystem Ⅱ （PSII） complex of photosynthetic membranes comprises a number of chlorophyll-binding proteins that are important to the electron flow. Here we report that the chlorophyll b-deficient mutant has decreased the amount of light-harvesting complexes with an increased amount of some core polypeptldes of PSII, including CP43 and CP47. By means of chlorophyll fluorescence and thermolumlnescence, we found that the ratio of Fv/Fm, qP and electron transport rate in the chlorophyll b-deficient mutant was higher compared to the wild type. In the chlorophyll lPdeflclent mutant, the decay of the primary electron acceptor quinones （QA-） reoxidation was decreased, measured by the fluorescence. Furthermore, the thermoluminescence studies in the chlorophyll bdeficient mutant showed that the B band （S2/S3QB-） decreased slightly and shifted up towards higher temperatures. In the presence of dlchlorophenyl-dlmethylurea, which is inhibited in the electron flow to the second electron acceptor quinines （QB） at the PSll acceptor side, the maximum of the Q band （S2QA-） was decreased slightly and shifted down to lower temperatures, compared to the wild type. Thus, the electron flow within PSll of the chlorophyⅡ b-deficient mutant was down-regulated and characterized by faster oxidation of the primary electron acceptor quinine QA-via forward electron flow and slower reduction of the oxidation S states.
基金Project supported by the National Natural Science Foundation of China(61564007)
文摘Multi-color luminescence basing on amorphous Eu^3＋/Tb^3＋ co-doped Zn-A1 hydroxides and their annealed samples were studied in detail. Results suggest that excellent red emissions due to E^u3＋ and green emissions attributed to Tb^3＋ appear under the excitation of favorable wavelength for all the as- prepared amorphous samples. Moreover, the emission intensity depends on the Eu^3＋/Tb^3＋ molar ratio. The samples annealed at 300, 500, and 700 ℃ still exhibit amorphous state, and multi-color lumi- nescence kept in the samples annealed at 300 ℃, while luminescence quenched for the samples annealed at 500 and 700 ℃. However, a broad emission ranging from 450 to 650 nm occurs in some samples annealed at 900 ℃. Further, the fluorescence decay and lifetimes for the as-prepared samples and the samples annealed at 300℃ were investigated. It is found that all the decay curves of emissions due to Tb^3＋ and Eu^3＋ present characteristic double exponential function despite their different lifetimes. The present work may be a good example for developing new multi-color even white light emitting materials.
文摘Technical polymers could be identified by means of their remarkably strong auto fluorescence. The mono-exponentially obtained time constants of fluorescence decay were applied for a rough assignment of the polymeric materials whereas bi-exponential analysis allowed a fine classification such as for special batches and for preceding contaminations. Chemically similar materials such as LDPE (low-density polyethylene), HDPE (high-density polyethylene) and UHDPE (ultrahigh-density polyethylene) could be as well identified as contaminations of mineral oil in PET (polyethylene terephthalate). Furthermore, the fluorescence spectra could be characterized by means of five Gaussian functions in the visible allowing a redundant assignment to the fluorescence lifetimes. Thus, efficient sorting of polymers was possible for high performance recycling.
文摘合成了三种重稀土(铽、铒、钇)的2,5-噻吩二羧酸(H2L)-1,10-菲咯啉(Phen)三元配合物,通过元素分析、热分析、红外光谱法确定配合物的组成为Ln2(L)3(phen)2.4H2O。紫外光谱显示H2L和Phen在参与配位后其最大紫外吸收峰均发生红移。2,5-噻吩二羧酸的羧基与稀土离子以螯合双齿形式配位。Tb2(L)3(phen)2.4H2O于室温下在紫外灯的照射下发出绿色荧光,Tb2(L)3(phen)2.4H2O荧光寿命为0.24 m s。
