CHARGE COMPENSATION AND VALENCY STABILITY OF EU(II)-DOPED KMGF3 CRYSTAL

The spectrochemistry of Eu2+-doped perovskite KMgF3 was examined and discussed. Eu2+ can replace some of the K+ in the KMgF3 crystal, and simultaneously the corresponding cation hole can be compensated with the F- or O2- in the matrix. The emission intensity of Eu2+ due to the f --> f transition increased when Na+, Rb+ or F- was doped in KMgF3:Eu2+. Two mechanisms of charge compensation were proposed. No obvious valence change of Eu2+ occurred in KMgF3:Eu2+ after calcinating at high temperature, e.g. 900-degrees-C. It was found that the valence stability of Eu2+ improved after incorporation into the matrix.

双环己基18冠6对水/硝基苯界面离子的促进传输

Li~-和H~-因较强的亲水性,较难穿越液/液界面进行传输。本文报道了冠醚双环已基18冠6对Li~+,Na~+,Rb~-和H~-在水/硝基苯界面的促进传输行为,求得了相应促进传输过程的一系列参数,并对被传输离子在传输过程中的形态变化进行了初步的探讨。

X射线荧光光谱经验系数法分析土壤中痕量元素

本文研究了粉末直接压片,X射线荧光光谱经验系数法测定土壤中13种痕量元素V、Cr、Ga、Co、Y、Rb、Zn、Cu、Ba、Ni、Zr、Sr、P的方法。对于波长在铁K系吸收限短波侧的分析元素,采用铑靶K_α的compton散射线作内标;对于波长大于铁K系吸收限的分析元素,采用邻近谱峰散射强度作内标。方法简单快速,适合于土壤和地质样品中痕量元素的测定。

碱金属—镓族复合氟化物中 Eu~(2+)发射中心形成的过程

本文分别以 KAlF_4:Eu~(2+)和 RbGaF_4:Eu~(2+)为例,讨论了碱金属—镓族复合氟化物中 Eu~(2+)发射中心形成的过程。合成了掺 Eu~(2+)的 AMF_4(A=Na,K,Rb,Cs,M=B,Al,Ga)及 AI_(n2)F_7(A=K,Rb)。Eu~(2+)占据 AMF_4中 A~+格位。AMF_4:Eu~(2+)和 AI_nF_7:Eu~(2+)中,Eu~(2+)发射是锐峰,来源于 f→f 跃迁。Eu~(2+)进入取代格位形成发射中心的过程与中间产物(A_4MF_(?))和激活剂(EuF_2)分解条件有关。由于4f 电子受到良好屏蔽,Eu~(2+)的 f→f 发射峰位置不变。

超高灵敏显色反应及其应用的研究 Ⅶ.生命活性元素钼的高灵敏光度法

本文研究以钒(Ⅴ)作催化剂的 Mo(Ⅵ)-SCN~--RB~+-PVA_(124)超高灵敏显色体系和钼的分光光度测定条件。缔合物的吸收峰在588nm处,表观摩尔吸光系数高达2.0 x 10~7L·mol~(-1)·cm~(-1)。铜浓度在0～80ng/25ml 范围内符合比耳定律。并进一步研讨了本类显色反应的吸附机理.所制定的方法结合离子交换分离,已用于水样和麦饭石浸出液中钼的测定,结果较满意。测定下限可达0.1ppb(50ml 液样)

ABF_4: Eu~(2+)和A_2SiF_6: Eu~(2+)中Eu~(2+)的光谱结构

合成了Eu~(2+)激活的ABF_4和A_2SiF_6(A=Na、K、Rb、Cs)复合氟化物磷光体,得到了与ASTM一致的结晶学数据,在这些体系中都观察到了Eu~(2+)的f→跃迁锐峰发射,其中NaBF_4:Eu~(2+)和Na_2SiF_6:Eu~(2-)中Eu~(2+)所处基质晶格的配位数较低。

土壤中铜、锌、铷、钇的X射线荧光光谱分析

本文叙述了以非相干散射和相干散射之比为内标,低压聚乙烯镶边垫底、粉末直接压片、X射线荧光光谱法测定土塘中痕量Cu、En、Rb、Y的方法,具有简便、准确、快速的优点。

超高灵敏显色反应及其应用的研究——Ⅳ.生命活性元素锌的高灵敏光度法

本文研究了Zn~(2+)-SCN~--RB~+-PVA_(124)超高灵敏显色体系及锌的分光光度测定条件。缔合物的吸收峰在607nm处,表观摩尔吸光系数达2.6×10~6L·mol~(-1)·cm~(-1)。Zn~(2+)浓度在0～0.5μg/25ml范围内符合比耳定律。测得缔合物的组成比Zn~(2+):RB~(+)为1:30。初步研讨了显色反应的机理。方法有较好的选择性,可不经预分离,成功地用于水样,麦饭石浸出液、花粉和发样中痕量锌的测定。

C440/C540/Saf-T三元混合染料体系的荧光光谱研究

选择适当的混合染料溶液作为染料激光器的工作物质,近年来,已有一些文献报导,但大都局限于二元混合染料体系。对于三元混合染料体系国外也曾有过少量报导,诸如C102/R110/RB,C102/RB/CV,C2/C6/R6G,R6G/CV/NB等。或多或少地得到了三个波长

罗丹明类碱性染料中取代基对染料高氯酸缔合物稳定性的影响

本文研究了用苯为萃取剂时四种罗丹明类碱性染料中取代基对染料高氯酸缔合物稳定性和可萃性的影响,结果表明,随着取代基体积的增大,憎水基的引入和增重、碱性的减弱以及染料阳离子正电性的增加,均能使缔合物的稳定性和可萃性增加,其顺序为:BRB>ERB>R_6G>RB。

Expression of human epidermal growth factor gene in cyanobacteria

The human epidermal growth factor (hEGF) is a small single-chain polypeptide of 53 amino acid residues. It can stimulate the proliferation of many cell types, mainly those of epidermal and epithelial tissues both in vivo and in vitro. A vector pRL-hEGF was constructed using plasmids pRL-489 and pUC-hEGF. The synthetic hEGF gene was recombined into the downstream of strong promoter psbA in plasmids pRL-489. Then, the vector was introduced into Synechococcus sp. PCC 7002 and Anabaena sp. PCC 7120 by triparental conjugative transfer. The transformation was confirmed by PCR amplification. The pRL-hEGF is thought to be retained as a plasmid form in the transgenic Anabaena sp. PCC 7120, since it can be recovered. However, it has been integrated into the chromosome of Synechococcus sp. PCC 7002 as there is no duplication origin in the pRL-hEGF in this cyanobacterium. and plasmid cannot be isolated from the Synechococcus sp. PCC 7002 either. The radioimmunoassay (RIA) proved that the hEGF gene has been expressed as the protein existed in these two strains of transgenic cyanobacteria, and the hEGF protein in Anabaena sp. PCC 7002 could be secreted into the medium.

Three-stage transformation of chlorophyll transient fluorescence pattern under sustained dehydration and the discovery of critical water content in seaweeds

The chlorophyll fluorescence kinetics of marine red alga Grateloupia turutunt Yamada, green alga Ulva pertusa Kjellm and brown alga Laminaria japonica Aresch during natural sustained dehydration were monitored and investigated. The pulse amplified modulation (PAM) system was used to analyze the distinct fluorescence parameters during thallus dehydration. Results proved that the fluorescence kinetics of different seaweed all showed three patterns of transformation with sustained water loss. These were: 1) peak kinetic pattern (at the early stage of dehydration fluorescence enhanced and quenched subsequently, representing a normal physiological state). 2) plateau kinetic pattern (with sustained water loss fluorescence enhanced continuously but quenching became slower, finally reaching its maximum). 3) Platform kinetic pattern (fluorescence fell and the shape of kinetic curve was similar to plateau kinetic pattern). A critical water content (CWC) could be found and defined as the percentage of water content just prior to the fluorescence drop and to be a significant physiological index for evaluation of plant drought tolerance. Once thallus water content became lower than this value the normal peak pattern can not be recovered even through rehydration, indicating an irreversible damage to the thylakoid membrane. The CWC value corresponding to different marine species were varied and negatively correlated with their desiccation tolerance, for example. Laminaria japonica had the highest CWC value (around 90%) and the lowest dehydration tolerance of the three. In addition, a fluorescence "burst" was found only in red algae during rehydration. The different fluorescence parameters F-o, F-v and F-v, F-m were measured and compared during water loss. Both F-o and F-v increased in the first stage of dehydration but F-v/F-m. kept almost constant. So the immediate response of in vivo chlorophyll fluorescence to dehydration was an enhancement. Later with sustained dehydration F-o increased continuously while F-v decreased and tended to become smaller and smaller. The major changes in fluorescence (including fluorescence drop during dehydration and the burst during rehydration) were all attributed to the change in F-o instead of F-v This significance of F-o indicates that it is necessary to do more research on F-o as well as on its relationship with the state of thylakoid membrane.

冲绳海槽西南端中全新世以来的沉积特征及其物源与环境意义

作为大陆向大洋的过渡带，由于享有得天独厚的沉积环境，具有独特的构造特征以及与黑潮主流之间的密切关系，一直以来，冲绳海槽都是中外学者研究的重点靶区。2005年5月，由我国与法国联合主持的IMAGES 航次在台湾东北海域获取MD05-2908柱状岩芯（24º48.04′N,122 º29.35′E,水深为1275米），该柱状岩芯为一34.17米长高质量的连续沉积记录，岩性以深灰色粘土质粉砂为主，含水量较高，粘性、可塑性强，含有数层厚度不等的夹层。岩芯年龄模式依据17个AMS 14C定年数据建立，岩芯底部年代约6.8ka，为中全新世以来的沉积。在实验室对样品按照2cm的间隔进行分割后分别进行了粒度分析、粘土矿物提取与测试、碎屑矿物提取与鉴定、常微量元素和稀土元素分析等实验。 粒度分析结果显示，MD05-2908岩芯沉积物粒度垂向上总体比较均一，以细颗粒的粘土与粉砂质为主，但不同层位也稍有差别，表现为底部层位粒度较粗，含砂量较高，说明底部沉积环境比较复杂。粘土粒级（<2µm）矿物主要由四种粘土矿物和少量石英、长石碎屑组成。其中，粘土矿物相对含量变化中，伊利石（～68％）与绿泥石（～17%）构成主要成分，含有蒙皂石（～10％）和高岭石（～5％）。结合台湾东北外海表层沉积物的研究，利用粘土矿物伊利石/蒙皂石和绿泥石/高岭石比值得出岩芯粘土矿物主要为陆源碎屑粘土矿物，其源岩主要为台湾中央山脉的变质岩与台湾东部的沉积岩。重矿物分析共选取了41个层位，对63~250μm粒级的样品在实体镜和偏光显微镜下进行鉴定，结果显示，岩芯重矿物主要由绿泥石（29%）、普通角闪石（22%）、白云石（10%）、黑云母（8%）、绿帘石（7%）、白云母（7%）、褐铁矿（5%）等组成。稳定矿物少，矿物成熟度低。碎屑矿物风化程度低，磨蚀不明显，分选较差，表明沉积物来自于近源，后期改造作用不明显。常量元素分析结果表明，SiO2 、Al2O3和Fe2O3是岩芯沉积物中的最主要组分，这三种组分占沉积物总量的82%左右。 整个岩芯自下而上各常量组分变化不大，其平均值与东海陆架沉积物基本接近。微量元素变化比较明显， Ba、Cr、Cu、Zn元素的含量比东海陆架沉积物中的含量要高，而Sr的含量明显低于东海陆架。对常微量元素的R型因子分析表明，常量元素SiO2、Al2O3、Fe2O3、MgO和K2O，微量元素Cr、Cu、Ni、Zn、Pb、Rb和Mn可代表陆源物质；常量元素CaO和微量元素Sr、Ba可代表生物源物质。岩芯沉积物以陆源物质为主，生源物质的贡献起次要作用。岩芯沉积物中稀土元素总量平均为169.87×10-6，并且轻稀土含量均高于重稀土，LREE/HREE平均值为10.14，表明了轻稀土对稀土总量的贡献远高于重稀土，沉积物富集轻稀土，反映了沉积物的陆源特征。 岩芯MD05-2908中全新世以来平均5m/ka的高沉积速率主要源于丰富的物质供应和适宜的沉积环境。岩芯细粒级沉积物中，地球化学特征表明沉积物主要来源于陆源碎屑物质，粘土矿物特征与台湾东部陆源物质相同；粗粒级沉积物中，重矿物含量及矿物特征也表明岩芯沉积物粗颗粒组分主要来自于近源沉积。台湾宜兰境内的兰阳溪每年携带约一千万吨冲积物入海成为研究区重要的物质来源。由于受到黑潮的强烈影响，逆时针涡流及底层反向流的存在是岩芯高沉积速率重要控制因素。因此，利用动力分选的粉砂组分可以用来示踪古洋流强度，结果显示，6.8ka以来黑潮的强弱波动频繁，并表现出一定的旋回性变化，频谱分析表明，其具有的千年尺度周期（1500a）、百年尺度周期（604a、242a、192a、153a、133a）与十年尺度周期（22a）的周期性变化均与太阳辐射量变化有密切关系，因此，黑潮的强弱变化在大背景上是由太阳活动所控制的。 根据测年资料可以识别出岩芯存在5期快速堆积事件，这与区域性降水增加有关，降雨量增加导致陆源物质输入的增加。另外，岩芯位于大陆斜坡区，附近存在有三支海底峡谷，并且地震活动频繁，沉积在宜兰陆架及东海陆架处的浅海沉积物由于受到地震、风暴等活动的影响而受扰动崩塌、因重力作用而向低处输送，产生二次侵蚀并经由海底峡谷搬运到冲绳海槽南段堆积,使得沉积环境更为复杂，但同时也为冲绳海槽提供了丰富的物质供应。