Influence of the size of ultrafine CaCO3 powder on PP crystallization

The effects of CaCO3 on the crystallization behavior of polypropylene (PP) were studied by means of DSC and WAXD. The average sizes of the CaCO3 powders used were 0.1 mum (UC) and 0.5 mum (GC), respectively. The PP/CaCO3 composites at compositions of 1 phr and 10 phr were investigated. The results showed that the addition of CaCO3 reduced the supercooling, the rate of nucleation and the overall rate of crystallization (except for the 10 phr UC/PP sample). The crystallinity of PP was increased and the size distribution of the crystallites of alpha -PP; was: broadened. On the other hand,the crystallization rate of 10 phr UC/PP is 1.5 times higher than that of neat PP. It has an overall rate of crystallization 2 times as much as that of the neat PP and has the maximum crystallinity. The sizes of crystallites and the unit cell parameters of alpha -PP were varied by the addition of CaCO3. beta -PP was formed by addition of Ge and was not detected by addition of UC. The differences of crystallization behaviors of PP might be attributed to the combined effects of the content and size of CaCO3 filled.

Luminescent centers of EU2+ in BaMgAl10O17 phosphor

Two kinds of luminescent centers an observed in BaMgAl10O17:Eu2+ phosphor. Influence of flux on luminescence of Eu2+ in the phosphor is discussed in detail. There exists Eu2+ (F-) center (a luminescent center with 277 nm excitation band and 386 nm emission band) due to the substitution of F- ions for O2- ions, Effective energy transfer from Eu2+ (F-) to Eu2+ (O2-) (a luminescent center with 334 nm excitation band and 450 nm emission band) is observed. The quenching concentration of Eu2+ in BaMgAl10O17 is raised by 0.20 mole per mole host due to forming of new luminescent center Eu2+ (F-). (C) 2001 Elsevier Science Ltd. All rights reserved.

The luminescence of the phosphor Sr2ZrO4 with one-dimensional chains structure

A new type of phosphor Sr2ZrO4 with one-dimensional structure was prepared by solid reaction and its luminescence is seen at room temperature. The excitation and emission spectra were measured and display broad maximum at 354 nm and 386 nm respectively. The mechanism of this luminescence is ascribed to charge transfer.

The reduction of Eu3+ in SrB6O10 prepared in air and the luminescence of SrB6O10 : Eu

The reduction of Eu3+ to Eu2+ in SrB6O10 prepared in air by a high-temperature solid state reaction was studied. The luminescent properties of Eu2+ in this matrix show f-d broad band emission peaking at about 386 and 432 nm at room temperature. A charge compensation mechanism is proposed as a possible explanation. The luminescence of Eu3+ with f-f transitions was studied in this sample and reflected that the Eu3+ ion occupied a site with non-centro-symmetry. The ESR spectrum was used to detect the existence of Eu2+ in the samples. (C) 1998 Elsevier Science S.A.

用超微电极研究二茂铁等物质在聚电解质聚乙二醇·高氯酸锂中的伏安行为

用超微电极研究了聚电解质聚乙二醇·高氯酸锂（ＰＥＧ·ＬｉＣｌＯ４）的电化学性能。用伏安法研究了气体、有机小分子、温度、支持电解质、聚合链长的影响。结果表明，有机小分子有增塑效应；物质的扩散速率随温度的上升而增加，随支持电解质中阳离子半径增大而增加，随聚合物链长增加而减小。用粘度和自由体积理论解释了此现象。定性地描述了电子自交换对扩散的贡献。

同多酸和杂多酸修饰微电极的电化学研究 Ⅶ.磷钒钼杂多酸薄膜修饰微电极和杂多酸/聚苯胺薄膜修饰微电极的制备和电化学性质

本文详细描述了磷钒钼杂多酸（PV2Mo10）极薄膜修饰碳纤维（CF）微电极和PV2Mo10／聚苯胶（PAn）薄膜修饰微电极的制备及其电化学性质。

粗糙化银电极上氰基钴胺素的电化学行为

比较研究氰基钴胺素在光滑和粗糙化银电极上的电化学行为，发现在光滑银电极上氰基钴胺素的还原为一个二电子过程，而在粗糙化银电极上则为两个一电子过程．其原因是由于粗糙化银电极对氰根的强吸附作用．

ELECTROCHEMISTRY AND IN-SITU IR MICROSPECTROELECTROCHEMISTRY IN A VERSATILE THIN-LAYER REFLECTION FOURIER-TRANSFORM IR MICROSPECTROELECTROCHEMICAL CELL

A simple, convenient and versatile thin layer reflection Fourier transform IR microspectroelectrochemical (FTIRMSEC) cell has been described and characterized. Electrochemistry and in situ FTIR microspectroscopy were studied by using the hexacyanoferrate redox couple in aqueous sulphate solution, indicating that this type of cell is characteristic of both micro- or ultramicroelectrode and thin layer spectroelectrochemistry. Furthermore, the application of this FTIRMSEC cell to IR for characterization of the products of electrochemical reactions was carried out for the oxidation of (mesotetraphenylporphinato)manganese(III) perchlorate in dichloromethane + tetrabutylammonium perchlorate solution. Finally, the advantages and problems of this type of cell compared with a conventional optically transparent thin layer FTIR spectroelectrochemical cell were discussed.

多元校正-紫外-可见分光光度法同时测定铬(Ⅵ)和铬(Ⅲ)

本文研究在pH3.0～4.0,70～80℃加热条件下,Cr(Ⅱ)与EDTA形成紫色络合物,其最大吸收波长为537.5nm,而在此条件下,Cr(Ⅵ)几乎不与EDTA反应,利用Cr(Ⅱ)络合物和Cr(Ⅵ)离子本身吸收光谱间的差异,借助于最小二乘(K—矩阵)法解析两物种吸收光谱的重叠问题,进而建立了多波长同时光度测定Cr(Ⅱ)和Cr(Ⅵ)的方法,用于合成试样、电镀废液及废铬酸洗液中Cr(Ⅵ)和Cr(Ⅱ)的同时测定,获得满意结果.

5-α-(磷酸基)苄基-2-甲基-4-羟基咪唑衍生物的电子轰击质谱研究

由于在农药方面的广泛应用,新的有机磷化合物不断被合成。质谱是研究其结构的重要手段之一。总结不同类型有机磷化合物的质谱裂解规律将有助于识别未知的有机磷化合物。本文所研究的5—α—[磷酸基]苄基—2—甲基—4—羟基咪唑衍生物是合成的新型除草剂,质谱未见报道。本工作在低分辨EI谱的基础上,根据高分辨精确质量测量和B/E、B_2/E联动扫描亚稳离子测定数据,研究了该类化合物的质谱断裂机理。着重讨论了该类化合物的共同质谱特征,如:P—C,P—N键的断裂;产物离子的开环反应;产物离子的H重排反应和失去CO的反应等。为该类化合物的结构研究提供依据。

Construction and characterization of a bacterial artificial chromosome library of marine macroalga Porphyra yezoensis (Rhodophyta)

A large-DNA-fragment library is necessary for research into the Porphyra genome. In this study, a bacterial artificial chromosome (BAC) library of Porphyra yezoensis was constructed and characterized. The library contains 54,144 BAC clones with an average insert size of about 65 kb and fewer than 0.7% of clones without large inserts. Therefore, its capacity is more than 6.6 P. yezoensis genome equivalents, and the probability of recovering any nuclear DNA sequence from the library is higher than 99%. The library shows good fidelity and stability. A putative trehalose-6-phosphate synthase (TPS) gene was successfully screened out from the library. The above results show that the library is useful for gene cloning and genomic research in P. yezoensis.

QTL Mapping for Frond Length and Width in Laminaria japonica Aresch (Laminarales, Phaeophyta) Using AFLP and SSR Markers

In Laminaria japonica Aresch breeding practice, two quantitative traits, frond length (FL) and frond width (FW), are the most important phenotypic selection index. In order to increase the breeding efficiency by integrating phenotypic selection and marker-assisted selection, the first set of QTL controlling the two traits were determined in F-2 family using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers. Two prominent L. japonicas inbred lines, one with "broad and thin blade" characteristics and another with "long and narrow blade" characteristics, were applied in the hybridization to yield the F-2 mapping population with 92 individuals. A total of 287 AFLP markers and 11 SSR markers were used to construct a L. japonica genetic map. The yielded map was consisted of 28 linkage groups (LG) named LG1 to LG28, spanning 1,811.1 cM with an average interval of 6.7 cM and covering the 82.8% of the estimated genome 2,186.7 cM. While three genome-wide significant QTL were detected on LG1 (two QTL) and LG4 for "FL," explaining in total 42.36% of the phenotypic variance, two QTL were identified on LG3 and LG5 for the trait "FW," accounting for the total of 36.39% of the phenotypic variance. The gene action of these QTL was additive and partially dominant. The yielded linkage map and the detected QTL can provide a tool for further genetic analysis of two traits and be potential for maker-assisted selection in L. japonica breeding.

海底地形的SAR影象仿真与反演

本文旨在建立SAR水下地形探测的理论和应用的基本框架。研究内容包括：1. 水下地形的SAR成象机制 采用Bragg散射理论与海面微尺度波高频谱的饱和谱形式相结合，建立了后向散射截面与海面微尺度波流调制作用间的函数关系，该函数为雷达相关项与大尺度海流对海面微尺度波的调制作用项之积，该调制项包含海底地形的信息。2. 建立水下地形的SAR影象仿真模型，定性和定量地解释SAR影象的类地形条纹以及SAR在不同的水文条件下对水下地形的可视性 以二维深度平均的海流模式或三维σ坐标的海流模式计算流场，结合风波即可计算出大尺度海流对海面微尺度波的调制作用项，文中记为函数G，并称计算所得的G值灰度影象为SAR的仿真影象。通过仿真模型可以研究不同微尺度波波向、流向及地形梯度方向情况下SAR影象对海底地形变化的可视性，结果表明，当海流流向、地形梯度方向和微尺度波波向三者平等时，SAR影象中的类地形牲的可视性最好。随着这三个方向夹角逐渐增大，可视性逐渐降低，当其中两个方向垂直时，类地形特征消失或变得很弱。较大的流速可以增强类地形影象的对比度，这在SAR影象中存在背景噪声时是重要的。3. SAR水深反演的反问题的提法与解法以及反演模型的反演精度分析通过SAR探测海底地形可以归为已知雷达后向散射截面或G值求水深的数学物理反问题，本文的反演模型由G 值函数表达式和二维深度平均的海流运动方程组以及适当的初边值条件构成。由于该反问题的边界条件的提法为超定的，所以其解设计为求目标泛涵的最小偏差解，反演算法为最速下降法。该算法不受反演大小的限制，具有较好的收剑性和解的存在性，但解依赖于初猜值的选择。当反演区域内部分点的水深已知时，这些数据可以很容易地融合在最小偏差解的算法中，从面加快收敛速度，提高计算精度。利用仿真模式所给出的SAR影象证实了该反问题的求解方法是可行的，且具有较高的计算精度。通过反演模型进行的数值试验表明： 1）微尺度波波向、流向和地形梯度方向对反演精度有明显影响。三个方向平等时反演精度最高，当其中任两向垂直时，都会成为反演的盲点。这是由反演模式本身的奇性所决定的。虽然三向夹角不同时，反演精度有变化，但在大多数情况下，反演值与真值地形波动的位置，形状和幅度等都具有很好的一致性。只有当其中两向接近垂直时，才出现较大的差异或反演失效；2）虽然一定流速的存在是反演的基础，但流速的大小对反演精度影响并不大；3）本反演系统对G值误差和反演未知量的初猜值的误差以及波向角选取误差都有较强的容差能力；但对水深边值误差较敏感，要求其精度较高；4）由于反演模式需要水深的初猜值，所以需要知道反演区域的平均水深，一个好的初猜值可以加速算法的收敛，而一个较差的初猜值则可能引起较大的误差，一船说来，平均水深就已经可以获得较高精度的结果。4. 仿真和反演模型的一个实例研究 本文以北海（the North Sea)的一张 Seasat SAR 影象和该区域的海图水深为例，采用所建立的仿真模型和反演模型对这张SAR影象上的类地形明暗条纹进行了成功的仿真，也通过SAR影象数据经过数据处理和反演，求出了影象区域的水深，反演水深数据和实际海底沙脊吻合较好。研究结果初步验证了海底地形结构的SAR影象仿真与反演的可行性。本文的研究表明，只要SAR影象在低海况下拍摄，且有精确的定位，再加上对SAR影象所覆盖海区的粗精度的水深和边界水深的已知条件，就可以在对该海区进行潮流模拟的基础上用反演模式来获取高空间分辨率的水深资料。

Seasonal and interannual variability of primary and export production in the South China Sea: a three-dimensional physical-biogeochemical model study

To investigate the seasonal and interannual variations in biological productivity in the South China Sea (SCS), a Pacific basin-wide physical - biogeochemical model has been developed and used to estimate the biological productivity and export flux in the SCS. The Pacific circulation model, based on the Regional Ocean Model Systems (ROMS), is forced with daily air-sea fluxes derived from the NCEP (National Centers for Environmental Prediction) reanalysis between 1990 and 2004. The biogeochemical processes are simulated with a carbon, Si(OH)(4), and nitrogen ecosystem (CoSiNE) model consisting of silicate, nitrate, ammonium, two phytoplankton groups (small phytoplankton and large phytoplankton), two zooplankton grazers (small micrograzers and large mesozooplankton), and two detritus pools. The ROMS-CoSiNE model favourably reproduces many of the observed features, such as ChI a, nutrients, and primary production (PP) in the SCS. The modelled depth-integrated PP over the euphotic zone (0-125 m) varies seasonally, with the highest value of 386 mg C m (-2) d (-1) during winter and the lowest value of 156 mg C m (-2) d (-1) during early summer. The annual mean value is 196 mg C m (-2) d (-1). The model-integrated annual mean new production (uptake of nitrate), in carbon units, is 64.4 mg C m (-2) d (-1) which yields an f-ratio of 0.33 for the entire SCS. The modelled export ratio (e-ratio: the ratio of export to PP) is 0.24 for the basin-wide SCS. The year-to-year variation of biological productivity in the SCS is weaker than the seasonal variation. The large phytoplankton group tends to dominate over the smaller phytoplankton group, and likely plays an important role in determining the interannual variability of primary and new production.