Spectroscopic evidence for triplet excitation energy transfer among carotenoids in the LH2 complex from photosynthetic bacterium <Emphasis Type="Italic">Rhodopseudomonas palustris</Emphasis>

The LH2 complex from Rhodopsudomonas (Rps.) palustris is unique in the heterogeneous carotenoid compositions. The dynamics of triplet excited state Carotenoids (³Car* has been investigated by means of sub-microsecond time-resolved absorption spectroscopy both at physiological temperature (295 K) and at cryogenic temperature (77K). Broad and asymmetric T _n ←T ₁ transient absorption was observed at room temperature following the photo-excitation of Car at 532 nm, which suggests the contribution from various carotenoid compositions having different numbers of conjugated C=C double bonds (N_c=c). The triplet absorption bands of different carotenoids, which superimposed at room temperature, could be clearly distinguished upon decreasing the temperature down to 77 K. At room temperature the shorter-wavelength side of the main T_n04T₁ absorption band decayed rapidly to reach a spectral equilibration with a characteristic time constant of ∽1 μs, the same spectral dynamics, however, was not observed at 77 K. The aforementioned spectral dynamics can be explained in terms of the triplet-excitation transfer among heterogeneous carotenoid compositions. Global spectral analysis was applied to the time-resolved spectra at room temperature, which revealed two spectral components peaked at 545 and 565 nm, and assignable to the T_n04 T₁ absorption of Cars with Nc=c=11 and Nc=c=13, respectively. Surprisingly, the decay time constant of a shorter-conjugated Car, i.e. 0.72 ώs (aerobic) and 1.36 ώs (anaerobic), is smaller than that of a longer-conjugated Car, i.e. 2.12 us (aerobic) and 3.75 ώs (anaerobic), which is contradictory to the general rule of carotenoids and relative polyenes. The results are explained in terms of triplet-excitation transfer among different types of Cars. It is postulated that two Cars with different conjugation lengths coexist in an α, β-subunit in the LH2 complex.     

Study on antimony oxide self-assembled inside HZSM-5

Sb/ZSM-5 was obtained by solid-state reaction with the mixture of Sb₂O₃ and zeolite HZSM-5 under a dry nitrogen flow at 773 K. Characterization of the treated zeolite was undertaken with XRD, ²⁷Al MAS NMR, BET, TGA and FT-IR. The results revealed that part of the antimony oxides migrated into the channels of zeolite, and decreased the Brönsted acid sites in Sb/ZSM-5 remarkably. The other part of antimony oxides together with the amorphous alumino-silicate in the products distributed on the external surface of zeolite ZSM-5 and modified it, while the framework of ZSM-5 in crystal phase was retained. The structure of occluded antimony oxide inside the channels of ZSM-5 was studied by XRD Rietveld method. The result showed that their structure can be described as a chain of non-perfect [Sb₅O₅(H₂O)₂]_n⁵ⁿ⁺, which is parallel to the straight channel of ZSM-5. There is about 0.6 [Sb₅O₅(H₂O)₂]⁵⁺ unit in every cell of the ZSM-5 on an average.     

复合蛋白锌在儿科疾患方面的应用

儿童缺锌是较普遍的社会现象，济南泉城微量元素生命研究所研制的复合蛋白锌系采用生物技术转化而得到的一种蛋白复合物，属生物合成的有机微量元素，经急性和长期毒性试验均未发现毒副作用，经检测不含兴奋剂，用于临床后，对纠正偏食厌食，反复呼吸道感染和智力低下等近千例儿童疾患，显示了可喜的临床效果，证明是优质有机补锌剂。     

Crystal Structure and Characterization of a Large Polyoxotungstate (NH4)21{La(H2O)5[Ni(H2O)]2As4W40O140}·53H2O

The heteropolytungstate (NH4)₂₁{La(H₂O)₅[Ni(H₂O)]₂As₄W₄₀O₁₄₀}·53H₂O is obtained by the reaction of Na₂₇[NaAs₄W₄₀O₁₄₀]· 60H₂O with NiCl₂·6H₂O, La(NO₃)₃·6H₂O and NH₄Cl at pH‐4.5. The structure and chemical composition are determined by X‐ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are a = 1.9551(3) nm, b = 2.4156(4) nm, c= 3.7068(6) nm, β = 91.505(3)°, V = 17.500 (5) nm³, monoclinic crystal system with space group P2₁/n, Z = 4, R₁ = 0.0573, wR₂ = 0.0717 [I >2<s?(I)], R₁, = 0.2463 and wR₂ = 0.1199 (all data). [La(H₂O)₅] {Ni(H₂O)}₂AS₄W₄₀O₁₄₀ has C₂, symmetry. IR spectra of the ligand [NaAs₄W₄₀O₁₄₀]^27‐ and its three complexes were discussed.     

荧光光谱法研究十六烷基三甲基溴化铵与牛血清白蛋白的相互作用

十六烷基三甲基溴化铵;牛血清白蛋白;结合反应;热力学参数;荧光光谱     

A ONE-STEP SURFACE MODIFICATION PROCEDURE TO PEG-GRAFTED NANO-TITANIA

PEG （Polyethylene Glycol）-grafted nano-titania has been obtained in a one-step procedure using hexamethylene diisocyanate as the coupling agent and dibutyltin dilaurate as the catalyst in toluene at 80℃ and characterized qualitatively by FTIR and quantitatively by elemental analysis and thermogravimetric analysis. A comparison of nano-titania with two other commonly used inorganic nanoparticles, nano-silica and nano-alumina, is made, revealing that reactivity order is nano- silica 〉 nano-alumina 〉 nano-titania in view of PEG grafting. Possible mechanism of PEG grafting is also discussed.     

有机溶剂与水溶液引入电感耦合等离子体电子密度和电子温度轴向分布的比较

为了研究有机ICP最佳分析条件与水溶液ICP明显不同的原因,本文在不同的等离子体操作条件下测量了Hβ486.133nm Stark变宽,分别计算了有机溶剂和水溶液引入1CP轴向的n_e和Te值,并进行了比较。有机溶剂引入ICP时,在固定的功率,观测高度及载气流量下其轴向ne和Te均比用水溶液引入时低一些。有机ICP的优异分析性能只有在比水溶液ICP有较高的入射功率和较低的载气流量条件下才能展现出来。     

1-苯基-3-甲基-4-苯甲酰基-5-吡唑酮与甲基膦酸二(1-甲基庚基)酯对Pb(Ⅱ)、Cd(Ⅱ)和Cu(Ⅱ)的萃取机理研究

本文用两相滴定法研究了1-苯基-3-甲基-4-苯甲酰基-5-吡唑酮(PMBP,简写为HA)与甲基膦酸二(1-甲基庚基)脂(P_(350),简写为B)对Pb~(2+)、Cd_(2+)和Cu~(2+)离子在不同的有机溶剂中的萃取机理.(?)定了萃合物的组成分别为:MA_2(M=Pb~(2+)、Ca~(2+)、Cu~(2+));MA_2·HA(M=Cd~(2+));MA_2·B(M=Pb~(2+)、Cd~(2+))和MA_2·2B(M=Cd~(2+)),同时求得了相应的萃合常数β值.     

一种新颖一维铅碘聚合物[(Pb_2I_5)(L-H~ )·2DMF]_n(L=Piperazine)的自组装合成和晶体结构(英文)

0IntroductionIncreasinginterestisfocusedonthestudyofmagnetic,electronicandoptoelectronicpropertiesoflow鄄dimensionalorganic鄄inorganichybridcompoun鄄ds[1~3].Studiesshowthatcomplexconsistingoforganicandinorganiccomponentshavegreatpotentialforthecreationoff…     

高聚物固体电解质聚氧化乙烯－溴化铜复阻抗谱及介电常数的静水压效应

采用分子量５００万的聚氧化乙烯和无水溴化铜，通过混溶蒸发法制备成高聚物固体电解质Ｐ（ＥＯ）ｎ－ＣｕＢｒ２薄膜，并在０．１～３００ＭＰａ范围不同的流体静水压下详细测量其复平面阻抗谱，分别得到在不同压力下离子电导率和介电常数与测量频率的关系．进一步解谱准确地求出Ｐ（ＥＯ）ｎ－ＣｕＢｒ２（ｎ＝１２、１６）薄膜离子电导率和介电常数的静水压效应，并结合Ｘ－光物相分析，根据离子迁移通道的物理图象和高聚物的极化机构进行了初步的讨论．添加２０％的增塑剂碳酸丙烯酯，较大改进了压力下的导电性．１２０～３００ＭＰａ的离子电导率提高一个数量级