非饱和土中镉离子传输模型参数反演

使用自行设计的的真空实验装置,采用一维实验室土柱实验方法在不同实验条件下进行了15组实验,并基于实验所得的穿透曲线,使用梯度正则化方法反演得到了镉离子在8种葡萄牙土样和1种比利时土样中相应的传输模型参数.同时通过数值模拟实验验证了梯度正则化方法的有效性和可靠性,进而证明所得结果是有效的.

Preparation And Optical Properties Of Cdte/Cdo Center Dot Nh(2)O Core/Shell Nano-Composites In Aqueous Solution

The deposition of CdO center dot nH(2)O On CdTe nanoparticles was studied in an aqueous phase. The CdTe nanocrystals (NCs) were prepared in aqueous solution through the reaction between Cd2+ and NaHTe in the presence of thioglycolic acid as a stabilizer. The molar ratio of the Cd2+ to Te2- in the precursory solution played an important role in the photoluminescence of the ultimate CdTe NCs. The strongest photoluminescence was obtained under 4.0 of [Cd2+]/[Te2-] at pH similar to 8.2. With the optimum dosage of Cd(II) hydrous oxide deposited on the CdTe NCs, the photoluminescence was enhanced greatly. The photoluminescence of these nanocomposites was kept constant in the pH range of 8.0-10.0, but dramatically decreased with an obvious blue-shifted peak while the pH was below 8.0. In addition, the photochemical oxidation of CdTe NCs with cadmium hydrous oxide deposition was markedly inhibited.

Preparation and optical properties of CdTe/CdO center dot nH(2)O core/shell nano-composites in aqueous solution

The deposition of CdO center dot nH(2)O On CdTe nanoparticles was studied in an aqueous phase. The CdTe nanocrystals (NCs) were prepared in aqueous solution through the reaction between Cd2+ and NaHTe in the presence of thioglycolic acid as a stabilizer. The molar ratio of the Cd2+ to Te2- in the precursory solution played an important role in the photoluminescence of the ultimate CdTe NCs. The strongest photoluminescence was obtained under 4.0 of [Cd2+]/[Te2-] at pH similar to 8.2. With the optimum dosage of Cd(II) hydrous oxide deposited on the CdTe NCs, the photoluminescence was enhanced greatly. The photoluminescence of these nanocomposites was kept constant in the pH range of 8.0-10.0, but dramatically decreased with an obvious blue-shifted peak while the pH was below 8.0. In addition, the photochemical oxidation of CdTe NCs with cadmium hydrous oxide deposition was markedly inhibited.

Formation, thermal, optical and physical properties of GeS2-Ga2S3-AgCl novel chalcohalide glasses

Novel GeS2-Ga2S3-AgCl chalcohalide glasses had been prepared by melt-quenching technique, and the glass-forming region was determined by XRD, which indicated that the maximum of dissolvable AgCl was up to 65 mol%. Thermal and optical properties of the glasses were studied by differential scanning calorimetry (DSC) and Visible-IR transmission, which showed that most of GeS2-Ga2S3-AgCl glasses had strong glass-forming ability and broad region of transmission (about 0.45-12.5 mu m). With the addition of AgCl, the glass transition temperature, Tg decreases distinctly, and the short-wavelength cut-off edge (lambda(vis)) of the glasses also shifts to the long wavelength gradually. However, the glass-forming ability of the glass has a complicated evolutional trend depended on the compositional change. In addition, the values of the Vickers microhardness, H (v) , which decrease with the addition of AgCl, are high enough for the practical applications. These excellent properties of GeS2-Ga2S3-AgCl glasses make them potentially applied in the optoelectronic field, such as all-optical switch, etc.

Novel erbium-doped TeO2-based oxysulfide glasses: thermal and spectroscopic properties

Er3+-doped TeO2-based oxysulfide glasses have been prepared in argon atmosphere in carbon crucibles. The thermal analysis and spectroscopic properties of Er (3+) have been considered in terms of sulfide influence. As a function of composition, we have principally measured optical absorption, spontaneous emission and lifetime measurements. Judd-Ofelt theory was introduced to calculate bandwidth and emission cross-section. The results show the product FVMM x sigma(c) increase from 476.8 8 to 635.04 10(-21) cm(2) nm evidently with the addition of 10 mol% PbS into tellurite glass, which indicates a perfect effect on spectra property of Er3+ ions. (C) 2004 Elsevier B.V. All rights reserved.

Yb:Y2O2S的粉体制备和光谱性质

通过助熔剂固相反应法制备了5%Yb掺杂的硫氧化钇(Y2O2S)粉体。通过对其漫反射光谱和荧光光谱的测量，估算得Yb3+离子在Y2O2S晶格中的晶场分裂。由光谱数据计算得Yb3+离子的2F7/2能级在Y2O2S中的分裂值为709cm-1，适合于Yb3+离子的准三能级的激光运转。由5％Yb：Y2O2S的发射光谱拟合得出其峰位，峰高及峰宽。为了比较，相关的5％Yb：YAG的数据也被给出。

I.小麦非叶器官碳酸酐酶活性与定位分析II.镉毒害导致芦苇胚性细胞死亡的激素调控研究

第一部分： 通过生理测定和化学染色分析了冬小麦品种小堰54和京411的叶片和非叶片组织的碳酸酐 酶活性。叶片碳酸酐酶活性(CA)在挑旗时期达到最大值，之后减少到最小，而在饱粒期又呈 增加趋势。从灌浆期到饱粒期，颖片和内稃的CA活性均减少，而外稃和种皮的CA活性均增加。在饱粒期，小堰54的叶片、颖片、外稃和种皮CA活性均高于京411。组织化学染色表明，CA主要分布在旗叶的叶肉细胞叶绿体中，也分布在非叶片组织颖片、外稃和内稃的叶肉和维管束鞘细胞的胞质中。这些结果表明，小麦非叶组织叶肉和维管束鞘细胞的胞质中的CA可能对饱粒期冬小麦的C4光合途径起作用。饱粒期小堰54的C02传递到Rubisco酶速率和抗旱性较京411高。 第二部分： 以继代培养的芦苇胚性细胞为材料，利用台盼兰拒染法检测了悬浮细胞死亡过程，并利用石蜡切片法及苏木精染色法观察了不同浓度镉对芦苇细胞的毒害作用。1000μM的CdCl2迅速导致芦苇悬浮细胞死亡，200μM的CdClz在接种后第5天引起悬浮细胞死亡，100μM的CdCl2在接种后第7天引起悬浮细胞死亡，≤50μM的CdClz在接种后7天不引起悬浮细胞死亡。同时对不同浓度镉处理的芦苇胚性细胞的内源植物激素和可溶性蛋白质进行分析，≤50μM的镉浓度显著地降低胚性细胞内IAA、ZR、GA3和GA4的含量，却提高ABA的含量，抑制可溶性蛋白质的合成：≥100μM的镉浓度显著地提高IAA、ZR、GA3和GA4的含量，却降低ABA的含量，促进可溶性蛋白质的合成。这些结果表明，镉的毒害至少包括镉浓度决定的两种细胞死亡机制，高浓度的镉(1000μM)引起的细胞死亡应当为坏死，而100μM的镉引起植物悬浮细胞发生程序性死亡。在较高浓度(≥100μM)的镉处理下，芦苇细胞内内源IAA、ZR、GA3和GA4的浓度较高，可能调控可溶性蛋白质的合成而促进细胞发生程序化死亡。

植物对重金属砷和镉胁迫适应的分子机理初探

随着现代工业的发展，重金属污染日趋严重。重金属污染引发的环境和健康问题在许多国家都有报道，我国的重金属污染状况也不容乐观。土壤和水体中的重金属污染可以通过食物链进入人体，对人类健康造成很大的危害，如诱发癌症 和畸胎等。 植物修复是一种利用植物对重金属或有机污染物的超富集能力清除或减低污染的环境生物技术。植物修复的生物学机制的研究为这项技术走向实用化奠定了基础。植物修复近期的进展可能来自于可更有效地富集重金属的植物品种的选择、土壤条件的改善等;但长远看来，植物修复技术的巨大进步将取决于新的可更好地抵抗重金属或降解有机毒物的基因的鉴定和克隆，并通过转基因技术创造一批新的植物品种，如可迅速大量富集重金属的高生物量的用作环境净化的植物，以及可排拒重金属吸收的粮食、蔬菜和水果等作物。 本研究针对砷污染的植物修复机制，以超富集砷的凤尾蕨属植物——蜈蚣草为试材取得了如下进展： 1． 以从砷污染地区采集的蜈蚣草（Pteris vittataL．）为植物材料，利用抑制消减杂交(SSH)分离了经砷诱导处理与其对照间表达有差异的cDNA片段，以期得到与砷富集密切相关的基因。其中筛选到的一个cDNA片段与ABC transporter (ATP-binding cassette transporter)有较高的同源性。通过RACE方法对该基因进行了克隆，并进行了初步的结构和功能分析。结果表明所获得的PvABCTl (Accession No. AY496966)为一全长cDNA，长度为2165 bp，其中开读框架为1791 bp，编码597个氨基酸。该基因所编码的蛋白中含有2个ABC transporter特性结构域，1个ATP-binding cassette和2个ATP/GTP结合位点(P-loop)，没有明显的跨膜区。 2． 对蜈蚣草在砷胁迫下PvABCT1基因的表达模式进行了研究。转录水平分析表明PvABCT1的表达受砷的诱导。进一步通过PvABCTl-GFP融合基因在洋葱细胞中的表达进行亚细胞定位，结果显示该基因可能定位于细胞质中。 3． 为了研究所克隆的PvABCT1基因的功能，本研究构建了PvABCT1的酵母表达载体，把该基因转入因ACR3基因缺失而对砷敏感的酵母突变株。酵母功能互补实验表明PvABCT1不仅不能与ACR3基因功能互补，反而使酵母对砷的敏感性增加，同时酵母细胞中的砷含量较未转化的酵母细胞增加。即在转入PvABCT1后，酵母细胞吸收了更多的砷。这暗示该基因与蜈蚣草中砷的高吸收有关。 针对食品重金属污染问题，本研究探讨了减低蔬菜对重金属吸收的方法及其 作用机理，取得了如下进展： 1．研究了钙离子和镧离子对镉离子胁迫下生菜种子萌发和植株生长的影响，结果表明在种子萌发时外施4 mM CaCI2或0.04 mg/L La(N03)3均可提高生菜对重金属镉的抗性。 2．通过检测0.5 mM CdCl2胁迫下生菜植株中的镉含量以及外施钙离子或镧离子后相应的镉含量，发现4 mM CaCl2可以增加镉胁迫下生菜植株中镉的积累;而0.04 mg/L La(N03)3可以降低镉胁迫下生菜植株中镉的积累。 3．对生菜中植物络合素合酶基因进行了克隆，通过RT-PCR分析以及植物络合素( phytochelatins，PCs)的检测，探讨了外施钙离子或镧离子对镉胁迫下生菜植株中植物络合素合酶基因在转录水平的表达量、植物络合素含量以及镉的积累三者之间的关系。结果表明：4 mM CaCl2可以提高镉胁迫下生菜植株中植物络合素合酶基因在转录水平的表达以及植物络合素的含量，增加镉的积累;而0.04 mg/L La(N03)3虽然同样可以提高植物络合素合酶基因在转录水平的表达以及植物络合素的含量，却能降低镉胁迫下生菜植株中镉的积累。这暗示外施钙离子可以促进用于重金属污染环境修复的植物对重金属的吸收，而外施镧离子可以用于降低叶菜类蔬菜中重金属镉的积累。