溶胶-凝胶法制备纳米荧光粉Y4Al2O9:Eu3+的初步研究

用溶胶-凝胶法(sol-gel)制备了纳米荧光粉Y4Al2O9: Eu3+,用X射线粉晶衍射对其进行了物相鉴定,表明在900℃已经得到纯相的Y4Al2O9产物,并用透射电镜对其进行形貌和衍射分析,分析结果证明得到的产物为纳米粉末态晶体,产物Y4Al2O9:Eu3+粒径均匀,大致在20～50nm之间,平均粒径为30nm.并用荧光光度计对其荧光光谱进行了研究,光谱表明Eu3+在Y4Al2O9晶格中占据两种不同的位置.用λ =254nm的紫外光激发Y4Al2O9:Eu3+时,产生两条发光谱带,即由于5 D 0→7 F 1的跃迁产生在峰值λ =590nm处的橙色发光带,和5 D 0→7 F 2跃迁在峰值λ =610nm处的红色发光带.     

三峡库区不同垂直带森林土壤大孔隙染色实验

降雨过程中森林土壤大孔隙内优先流的发生,是森林植被调蓄径流和保持水土的主要方式。利用染色示踪法,对三峡库区宜昌大老岭-邓村地区不同垂直带内森林土壤大孔隙特征进行了实验研究。结果表明,山地植被-土壤类型的梯度变化使不同垂直带内土壤大孔隙数量差异显著,在土壤垂直剖面内呈现不同分布模式。亚高山阔叶林覆盖的山地棕壤下,土壤剖面染色面积比达62.3%,染色区域主要集中在根系发达的腐殖质层,染料下渗深度较浅。低山针叶林黄壤剖面染色比例低于亚高山阔叶林棕壤,但染料下渗深度较深可达69.5 cm,腐殖质层、淋溶淀积层和母质层间染色比例无显著差异。中山灌丛幼林黄棕壤剖面染色比例和染料下渗深度较小,腐殖质层染色比例显著高于淋溶淀积层,母质层几乎无染色现象。与森林土壤相比,低山弃耕坡地的染料下渗深度和染色面积比显著减小,染色区域集中在耕作表层。植物根孔、母质裂隙、土壤发育程度和土地耕作是造成山地不同垂直带间土壤大孔隙结构差异的主要因素。     

Tracer tests in fractured rocks with a new fluorescent dye—pyrene-1,3,6,8-tetra sulphonic acid (PTS) / Tests de traçage en roches fracturées avec un nouveau produit fluorescent—l'acide pyrène 1.3.6.8 tétra sulfonique (PTS)

Abstract

Two multi-tracer tests were performed in fissured rocks accessible in underground laboratories to examine a new fluorescent dye: pyrene-1,3,6,8-tetra sulphonic acid (PTS). The first test was carried out at the Lindau Rock Laboratory (LRL), Germany, in a highly permeable ore dike, and the second, at the Grimsel Test Site (GTS), Switzerland, in a heterogeneous granite fault zone (AU 126). At the LRL new tracer was injected together with uranine in a convergent flow field (monopole test), and slightly different tracer breakthrough curves were observed according to different diffusion coefficients of both tracers. The matrix porosity calculated with the aid of the one-dimensional (1-D) single-fissure dispersion model (SFDM) agrees well with that found in earlier tracer tests and with measurements performed on core samples. At the GTS, the PTS tracer was applied together with pyranine in two-well injection–withdrawal (dipole) tests. Both tracers yielded identical tracer concentration curves, which confirm their conservative behaviour. Mathematical simulations performed with the aid of a 3-D numerical model (FRAC3DVS) yielded equally good fits for different sets of parameters, independent of whether matrix porosity was included or neglected. That lack of unique solution and the difficulty in observing the influence of matrix diffusion result from a wide distribution of the transit times of particular streamlines, which is characteristic for injection–withdrawal tests. However, both tracer tests clearly indicated that the new tracer (PTS) behaves conservatively at high pH values and can be successfully used for groundwater labelling.     

X射线荧光法在桂北金矿勘查中的应用

介绍了X射线荧光法工作原理及其在金矿勘查的物理基础和寻找金矿依据,通过在桂北金矿区勘查的应用,表明了该方法可缩小找金矿的靶区,确定隐伏金矿体位置,划分金矿体的边界,达到缩短找矿周期的目的.     

光照及营养盐对3种赤潮甲藻吞噬营养行为的影响

通过在室内批量培养实验中添加活体藻类及荧光标记藻类(Fluorescent Labled Algae,FLA)的方式,研究不同光照及营养盐条件下3种赤潮甲藻米氏凯伦藻(Karenia mikimotoi)、链状亚历山大藻(alexandrium catenella)及东海原甲藻(Prorocentrum donghai...     

菲尔德斯半岛3种金发藓植株的同步辐射X射线荧光分析

为了研究南极不同苔藓植株及其器官间的元素组成和分布的差异 ,我们利用同步辐射X射线荧光对菲尔德斯半岛 3种金发藓植株进行了重元素分析。这 3种植物是高山金发藓(Polytrichumalpinum) ,桧叶金发藓 (P .juniperinum)和极地金发藓 (P .alpestre)。它们所含的元素种类大致相同 ,主要有K、Ca、Mn、Fe、Cu、Zn和Sr等 ,这说明在菲尔德斯半岛 3种金发藓植株的生境条件是相似的。但是 ,在Polytrichumalpinum叶内 ,K峰远大于Ca ,Ca峰大于Fe ;在P .juniperinum植物叶片中 ,K峰大于Ca ,而Ca峰接近于Fe ;在P .alpestre叶内 ,K、Ca和Fe峰几乎相等。通过对P .alpestre不同部位进行X荧光分析 ,并用荧光计数法表示元素相对含量 ,我们发现各部位间的元素含量差异很大。在顶芽处 ,K的含量最高 ,K/Ca比等于 1 .30 ,而其他部位的K/Ca比均小于 1。在假根部位 ,Mn的含量在所有部位中是最高的 ,并且Mn/Fe比值最大 ,为 0 .2 1。在老叶片和假根部位 ,Cu/Zn比分别等于 1 .2 0和 1 .84,而其他部位的Cu/Zn比均小于 1。特别是这两个部位还出现了Br元素 ,这可能与器官的衰老有关。     

A Fast and Indriect Fluorescent Antibody Assay for the Vibro in Large Yeelow Croaker Pseudosciaena Crocea (Richardson)

A fast and indirect fluorescnet antibody assay for the Vibrio alginolyticus and V.Parahaemolyticus infecting the large yellow croaker has been developed.The specific antisera for the two strains of vibrio were prepared with New Zealand rabbit and the antiserum and cross-reactive efficacy was tested by coagulation in tube.It showed that the goat anti-rabbit IgG had been labeled by fuorescence isothiocyanate(FITC).The results showed that positive reactions were 100% for the large yellow croaker Pseudosciaena crocea with typical symptom of vibrio infection,while the positive reaction to the pathogen in healthy yellow croakers reached 40%,but seemed negative for aquaculter water.The results demonstrated that this fast and indirect fluorescent antibody assay can be used not only to test the vibrio pathogen in diseased yellow croaker but also in infected animals with no symptom.     

Determination of Trace Copper （Ⅱ） in Water Samples by Kinetic-spectrophotometry

A new kinetic-spectrophotometric method is proposed for the determination of copper （ Ⅱ ）. The method is based on the catalytic effect of copper （ Ⅱ ） on the oxidation of weak acid brilliant blue dye （RAWL） by hydrogen peroxide. The copper （ Ⅱ ） can be determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ = 626 nm using the fix-time method. The optimum reaction conditions are as follows： pH 7.20, buffer solution NaOH-KH2PO4, RAWL （200 mgL-1） 5.00 mL, H2O2 （30%） 0.50 mL, reaction temperature 80 ？？ and reaction time 20 min. The linear range of this method is between 0 μg L^-1 and 12 μg L^-1 and the limit of detection is 0.011 μg L-1, the relative standard deviation （RSD） in five replicate determinations for 2 and 8 μg L-1 copper （ Ⅱ ） are 3.2% and 2.3%, respectively. Twenty ions do not interfere in the determination of copper （ Ⅱ ）. The method has been applied satisfactorily to the determination of copper （ Ⅱ ） in freshwater samples （tap water and Yellow River water from Lijin, Shandong, China） and seawater samples （from the South China Sea）, the recovery rates are 98.0%, 102.5% and 96.0%, respectively.     

A Fast and Indirect Fluorescent Antibody Assay for the Vibrio in Large Yellow Croaker Pseudosciaena crocea (Richardson)

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曲折海湾中潮汐和环流的数值研究

The Shacheng Bay(SCB) is one of the most complex coastal bays in southeast China and due to the fact of complicated geometry and dynamic coastal processes, it is considered as a challenging area for the numerical simulation of its hydrodynamic characteristics. The most advanced finite volume ocean model, finite-volume coastal ocean model(FVCOM), has adopted to simulate this hydrodynamic system, where tidal currents, tidal residual current and dye diffusion processes were studied and analyzed quantitatively. The validation of this numerical model matches well with various observation data, including elevation and current data. The misfit of a tidal elevation has a relative standard error of 3.66% and 4.67% for M2 and S2 tide components. The current validation shows a good match with an average error of 10 cm/s and 8° in the speed major axis and its direction respectively between the simulation and the measurement. This proves the robustness and reliability of this model. It is also found that the cape effect is significant and important in this system. The dye diffusion simulations show a 53 d flushing period for the whole inner bay waterbody. The results are of its first kind for understanding the hydrodynamic system in the SCB and they can provide helpful and trustful scientific information for others.