四氯合锌酸1,10-癸二铵配合物的晶体结构

合成了[NH_3(CH_2)_(10)NH_3]ZnCl_4配合物(简称DDAZn),用X射线衍射法研究了它的晶体结构,晶体属三斜晶系,空间群为P1,晶胞参数为:α=0.7296(1),b=1.0110(3),c=1.2814(4)nm;α=90.84(2),β=101.17(2),γ=92.52(2)°;Z=2.该配合物为层型结构.由单个四面体阴离子ZnCl_4~(2-)构成的阴离子层被夹在烷基铵阳离子层之间,形成“夹心面包”型体系.在层之间的烷基铵链在垂直于层的方向上倾斜排列.

1-甲基-1,4,7,10-四氮杂环十二烷镧配合物的合成及晶体结构

合成了1-甲基-1,4,7,10-四氮杂环十二烷(L)配体。在乙腈中培养了La(L)(CH_3CN)-(H_2O)(CF_3SO_3)_3配合物单晶,测定了其红外光谱和质子核磁共振谱。用X射线衍射方法测定了配合物的晶体结构,该晶体属于单斜晶系,P2_1/n空间群,a=0.9700(2)nm,b=1.5966(2)nm,c=1.9085(1)nm,β=104.71(3)°,V=2.8588(50)nm~3。配合物中镧为9配位,其配位多面体为扭曲的单帽四方反棱柱体。

STRUCTURE OF CIS-DIAQUABIS(1,10-PHENANTHROLINE)ZINC SULFATE HEXAHYDRATE

[Zn(C12H8N2)2(H2O)2]SO4.6H2O, M(r) = 665.98, triclinic, P1BAR, a = 10.070 (4), b = 12.280 (3), c = 13.358 (2) angstrom, alpha = 109.12 (2), beta = 92.58 (2), gamma = 110.85 (2)-degrees, V = 1433.9 (7) angstrom 3, Z = 2, D(x) = 1.54 g cm-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 10.1 cm-1, F(000) = 692, T = 293 K, R = 0.044 for 3985 observed reflections. The Zn atom is coordinated in a distorted octahedral geometry by four N atoms from two 1,10-phenanthroline (phen) ligands and two water molecules. The intermolecular ring-stacking interactions between the phen ligands occur in two forms: infinite chains and discrete dimers. Hydrogen bonds further stabilize the structure.

Eu~(3+)离子在晶体KY_3F_(10)、YPO_4及YVO_4中的角重迭晶场参数计算

本文运用角重迭模型首次对Eu~(3+)离子在KY_3F_(10)S、YPO_4及YVO_4晶体中的四个角重迭参数e_σ、e_π、e_δ、e_φ进行了计算。结果表明,所得规律与文献[1]基本相符,并且e_σ和e_φ两个参数对能级的劈裂和移动也有着不可忽略的作用。

水溶性聚合物和两亲聚合物——10.两亲聚合物PAMC_(16)S的自组装有序膜

用自组装技术在金(纯金和经阳极氧化的金)表面上获得了新型两亲聚合物PAMC_(16)S的有序膜。用接触角测试,XPS谱和电化学分析等方法对自组装膜进行了表征。根据膜表面的润湿性,金表面的自组装膜是疏水的,亲水的磺酸基团连于金表面,而疏水的碳氢链从表面伸展出。XPS实验结果支持金表面上单层膜的疏水结构。聚合物单层膜复盖的金电极起到含有针孔缺陷的阻膈型电极的作用。单层膜在法拉第反应中显示很强的吸附稳定性,说明聚合物LB膜在潜在应用中有其特有的特点。

稀土钼硅杂多酸根配合物K_(10)H_3[Pr(SiMo_(11)·O_(39))_2]·18H_2O的合成及晶体结构

本文采用低温技术,在—90℃的干燥氮气保护下,收集标题化合物晶体的衍射数据,用重原子法解出结构。P2_1/n空间群,a=17.504(2),b=27.323(5),c=21.616(4),β=104.49(2)°,z=4.8320个衍射参与精修,最后的R值为0.088。中心离子Pr(Ⅲ)同2个钼硅杂多酸根中的8个氧原子键合,形成正方反棱柱配位多面体。Pr—O的平均键长为2.44(2)。钼硅杂多酸根配体具有缺位的α型Keggin结构。

(Ce,Gd,Mn)MgB_5O_(10)磷光体的合成及其发光

本文采用固相反应的方法合成了一系列(Ce,Gd,Mn)MgB_5O_(10)磷光体。观察到合成温度、灼烧时间、原料配比对磷光体的形成和发光亮度有重要影响。X射线衍射分析表明,磷光体结构与LaMgB_5O_(10)相同,属单斜晶系、空间群P2_(1/c)。用EPR确定了磷光体中锰离子为二价。测定了(Ce_(0.2)La_(0.2))MgB_5O_(10),(Gd_(0.7)La_(0.3))MgB_5O_(10),(Mn_(0.05)La_(0.95))MgB_5O_(10),(Ce_(0.2)Mn_(0.05)La_(0.75))MgB_5O_(10),(Gd_(0.95)Mn_(0.05))MgB_5O_(10)、(Ce_(0.2)Gd_(0.8))MgB_5O_(10)和(Ce_(0.2)Gd_(0.75)Mn_(0.05))MgB_5O_(15)等磷光体的光谱。根据光谱数据讨论了(Ce_(0.2)Gd_(0.75)Mn_(0.05))MgB_5O_(10)磷光体中能量传递过程为:Ce~(3+)→Mn~(2+),Gd~(3+)→Mn~(2+)以及Ce~(3+)→Gd~(3+)→Mn~(2+),其中Ce~(...

K_5LnLi_2F_(10)(Ln=La,Gd,Y)的合成和Ce~(3+)在其中的发光

在Ar气氛中,采用高温固相反应法合成了K_5LnLi_2F_(10)(Ln=La,Ce,Gd,Y)化合物。X射线衍射图表明:除K_5YLi_2F_(10)外,均具有与K_5NdLi_2F_(10)(KNLF)相同的结构。计算了K_5LnLi_2F_(10)(Ln=La,Ce,Gd)的晶胞参数和晶胞体积,它们随着La~(3+),Ce(3+),Gd~(3+)的离子半径减小而有规律地减小。测定了K_5Ce_?Ln_(1-?)Li_2F_(10)化合物的激发光谱和荧光光谱。发现Ce~(3+)的激发波长和发射波长随着La~(3+),Gd~(3+),Y~(3+)离子的改变几乎不变,并对这种现象进行了讨论。

TWO SPECIFIC CAUSES OF CELL MORTALITY IN FREEZE-THAW CYCLE OF YOUNG THALLI OF PORPHYRA YEZOENSIS (BANGIALES, RHODOPHYTA)1

Porphyra yezoensis Ueda is an important marine aquaculture crop with single-layered gametophytic thalli. In this work, the influences of thallus dehydration level, cold-preservation (freezing) time, and thawing temperature on the photosynthetic recovery of young P. yezoensis thalli were investigated employing an imaging pulse-amplitude-modulation (PAM) fluorometer. The results showed that after 40 d of frozen storage when performing thallus thawing under 10 degrees C, the water content of the thalli showed obvious effects on the photosynthetic recovery of the frozen thalli. The thalli with absolute water content (AWC) of 10%-40% manifested obvious superiority compared to the thalli with other AWCs, while the thalli thawed at 20 degrees C showed very high survival rate (93.10%) and no obvious correlation between thallus AWCs and thallus viabilities. These results indicated that inappropriate thallus water content contributed to the cell damage during the freeze-thaw cycle and that proper thawing temperature is very crucial. Therefore, AWC between 10% and 40% is the suitable thallus water content range for frozen storage, and the thawing process should be as short as possible. However, it is also shown that for short-term cold storage the Porphyra thallus water content also showed no obvious effect on the photosynthetic recovery of the thalli, and the survival rate was extremely high (100%). These results indicated that freezing time is also a paramount contributor of the cell damage during the freeze-thaw cycle. Therefore, the frozen nets should be used as soon as time permits.

Toxicity and protective efficiency of cryoprotectants to flounder (Paralichthys olivaceus) embryos

With the purpose of finding an ideal cryoprotectant or combination of cryoprotectants in a suitable concentration for flounder (Paralichthys olivaceus) embryo cryopreservation, we tested the toxicities, at culture temperature (16 degrees C), of five most commonly used cryoprotectants-dimethyl sulfoxide (Me2SO), glycerol, methanol (MeOH), 1,2-propylene glycol (PG) and ethylene glycol (EG). In addition, cryoprotective efficiency to flounder embryos of individual and combined cryoprotectants were tested at -15 degrees C for 60 min. Five different concentrations of each of the five cryoprotectants and 20 different combinations of these cryoprotectants were tested for their protective efficiency. The results showed that the toxicity to flounder embryos of the five cryoprotectants are in the following sequence: PG < MeOH < Me2SO < glycerol < EG (P < 0.05); whereas the protective efficiency of each cryoprotectant, at -15 degrees C for a period of 60 min, are in the following sequence: PG > Me2SO approximate to MeOH approximate to glycerol > EG (greater symbols mean P < 0.05, and approximate symbols mean P > 0.05). Methanol combined with any one of the other cryoprotectants gave the best protection, while ethylene glycol combined with any one of the other cryoprotectants gave the poorest protection at -15 degrees C. Toxicity effect was concentration dependent with the lowest concentration being the least toxic for all five cryoprotectants at 16 degrees C. For PG, MeOH and glycerol, 20% solutions gave the best protection at -15 degrees C; whereas a 15% solution of Me2SO, and a 10% solution of EG, gave the best protection at -15 degrees C. (c) 2004 Elsevier Inc. All rights reserved.

Product monitoring and quantitation of oligosaccharides composition in agar hydrolysates by precolumn labeling HPLC

Since the discovery of multiple bioactivities for agarobiose oligomers, a quantitative method has been in great need to monitor the agarobiose oligomers. This report demonstrates that agarobiose oligomers can be separated with high resolution in HPLC after introducing a-naphthylamine into compounds. Agarobiose oligomers ranged from biose to decaose were isolated by Sephadex column. HPLC analysis indicated that each oliomer could be quantified with good linearity and a low detection limit of 0.1-4 mug/ml. The chromatographic profiles of agaro-oligosaccharides with different hydrolysis modes (hydrochloride, citric acid, solid acid, and hydroxyl radical degradation) showed that agarobiose could be obtained more than 57.8% using solid acid mediated hydrolysis, while hydrochloride acid could degrade agar into a series of agaro-oligosaccharides from biose to decaose. The yield of oligosaccharides was low if hydrolyzed by citric acid. The Fenton degradation can increase the speed of hydrolysis, but the product was complex. (C) 2004 Elsevier B.V. All rights reserved.

He, Ne and Ar isotopic composition of Fe-Mn crusts from the western and central Pacific Ocean and implications for their genesis

The noble gas nuclide abundances and isotopic ratios of the upmost layer of Fe-Mn crusts from the western and central Pacific Ocean have been determined. The results indicate that the He and Ar nuclide abundances and isotopic ratios can be classified into two types: low He-3/He-4 type and high He-3/He-4 type. The low He-3/He-4 type is characterized by high He-4 abundances of 191x10(-9) cm(3.)STP(.)g(-1) on average, with variable He-4, Ne-20 and Ar-40 abundances in the range (42.8-421)x10(-9) cm(3.)STP(.)g(-1), (5.40-141)x10(-9)cm(3.)STP(.)g(-1), and (773-10976)x10(-9) cm(3.)STP(.)g(-1), respectively. The high He-3/He-4 samples are characterized by low He-4 abundances of 11.7x10(-9) cm(3.)STP(.)g(-1) on average, with He-4, Ne-20 and Ar-40 abundances in the range of (7.57-17.4)x10(-9) cm(3.)STP(.)g(-1), (110.4-25.5)x10(-9) cm(3.)STP(.)g(-1) and (5354-9050)x10(-9) cm(3.)STP(.)g(-1), respectively. The low He-3/He-4 samples have He-3/He-4 ratios (with RIRA ratios of 2.04-2.92) which are lower than those of MORB (R/R-A=8 +/- 1) and Ar-40/Ar-36 ratios (447-543) which are higher than those of air (295.5). The high He-3/He-4 samples have He-3/He-4 ratios (with R/R-A ratios of 10.4-12.0) slightly higher than those of MORB (R/R-A=8 +/- 1) and Ar-40/Ar-36 ratios (293-299) very similar to those of air (295.5). The Ne isotopic ratios (Ne-20/Ne-22 and Ne-21/Ne-22 ratios of 10.3-10.9 and 0.02774-0.03039, respectively) and the Ar-38/Ar-36 ratios (0.1886-0.1963) have narrow ranges which are very similar to those of air (the Ne-20/Ne-22, Ne-21/Ne-22, Ar-38/Ar-36 ratios of 9.80, 0.029 and 0.187, respectively), and cannot be differentiated into different groups. The noble gas nuclide abundances and isotopic ratios, together with their regional variability, suggest that the noble gases in the Fe-Mn crusts originate primarily from the lower mantle. The low He-3/He-4 type and high He-3/He-4 type samples have noble gas characteristics similar to those of HIMU (High U/Pb Mantle)- and EM (Enriched Mantle)-type mantle material, respectively. The low He-3/He-4 type samples with HIMU-type noble gas isotopic ratios occur in the Magellan Seamounts, Marcus-Wake Seamounts, Marshall Island Chain and the Mid-Pacific Seamounts whereas the high He-3/He-4 type samples with EM-type noble gas isotopic ratios occur in the Line Island Chain. This difference in noble gas characteristics of these crust types implies that the Magellan Seamounts, Marcus-Wake Seamounts, Marshall Island Chain, and the Mid-Pacific Seamounts originated from HIMU-type lower mantle material whereas the Line Island Chain originated from EM-type lower mantle material. This finding is consistent with variations in the Pb-isotope and trace element signatures in the seamount lavas. Differences in the mantle surce may therefore be responsible for variations in the noble gas abundances and isotopic ratios in the Fe-Mn crusts. Mantle degassing appears to be the principal factor controlling noble gas isotopic abundances in Fe-Mn crusts. Decay of radioactive isotopes has a negligible influence on the nuclide abundances and isotopic ratios of noble gases in these crusts on the timescale of their formation.

Crystal structure of (5R,10R)-2,7-dibromo-3,8-dihydroxy-5,10-dimethoxy-5,10-dihydrochromeno[5,4,3-cde]chromene sesquihydrate, C16H12Br2O6 center dot 1.5H(2)O

C16H15Br2O7.5, orthorhombic, P2(1)2(1)2 (no. 18), a = 18.483(2) angstrom, b = 9.413(1) angstrom, c = 10.072(1) angstrom, V = 1752.3 angstrom(3), Z = 4, R-gt(F) = 0.083, wR(ref)(F-2) = 0.202, T= 293 K.