Electron transfer between Eu and Tb in MMgF(4) systems

Emission of europium(II) and europium(III) have been observed in SrMgF4 : xEu, yTb phosphors which are synthesized in Ar or Ar/H-2 flow. The valence state of Eu is influenced by terbium. It is notable that the intensities of the ESR peaks corresponding to EU(2+) are regularly changed when terbium ion is incorporated. The typical Tb3d XPS spectrum belonging to Tb4+ is also found when Eu is codoped. This phenomena can be explained by electron transfer mechanism Eu3+ + Tb3+-->EU(2+) + Tb4+. And its equilibrium constant is studied by ESR technique.

Photovoltaic Properties and Quantum Size Effect in Nanocrystalline CeO2

Different size. nanocrystallines CeO2 were synthesized and their diffuse reflectance absorption spectra have heen measured. The absorption band in the region from 300 to 450 nm was assigned to the O2p-Ce2 4f transition. It was found that a strongly red-shifted broad continuum of the absorption band occured as the decrease of the partical size. We have also measured the surface photovoltage as function of wavelength by SPS technique. And the absorption band was resolved to two peaks with different photovoltaic properties. Photovoltaic quantum size effect was observed by FMSPS measurement.

A NEW KIND OF CONDUCTING POLYMER POLYPYRROLE (PPY) BR- ION CHEMICAL SENSOR

The modification of conducting polymer polypyrrole(PPy) on glassy carbon(GC)by electrcchemical technique, and the study on doping effect of Br anion and electrochemical behavior of PPy film electrode were reported.A new kind of Br~- ion selective electrode has been prepared successfully.The mechanism of the electrode potential response is based on the doping effect of anion in the conducting polymer.Effect of polymerization conditions on the potential response characteristic is investigated in dtail.The PPy...

Molecular identification of 16 Porphyra lines using sequence-related amplified polymorphism markers

Sequence-related amplified polymorphism (SRAP) is a novel molecular marker technique designed to amplify open reading frames (ORFs). The SRAP analytic system was set up and applied to Porphyra germplasm identification in this study for the first time. Sixteen Porphyra lines were screened by SRAP technique with 30 primer combinations. In the analysis, 14 primer combinations produced stable and reproducible amplification patterns in three repetitive experiments. Among the total 533 amplified fragments, 522 (98%) were polymorphic, with an average of 38 fragments for each primer combination, ranging in size from 50 to 500 bp. The 533 fragments were visually scored one by one and then used to develop a dendrogram with Unweighted Pair-Group Method Arithmetic Average (UPGMA), and the 16 Porphyra lines were divided into two major groups at the 0.68 similarity level. From the total 533 fragments, I I amplified by two primer combinations, ME1/EM1 and ME4/EM6, were used to develop the DNA fingerprints of the 16 Porphyra lines. The DNA fingerprints were then converted into binary codes, with I and 0 representing presence and absence of the corresponding amplified fragment, respectively. In the DNA fingerprints, each of the 16 Porphyra lines has its unique binary code and can be easily distinguished from the others. This is the first report on the development of SRAP technique and its utilization in germplasm identification of seaweeds. The results demonstrated that SRAP is a simple, stable, polymorphic and reproducible molecular marker technique for the classification and identification of Porphyra lines. (c) 2007 Elsevier B.V. All rights reserved.

辽东湾隐蔽油气藏地球物理识别技术研究

In China and world, more than half the recent basin discovered reserves involve lithologic hydrocarbon reservoir reserves. The major target for further hydrocarbon basin exploration is the subtle reservoir. The Liaodong Bay prospect is much important in Bohai Sea, which includes Liaoxi low uplift, Liaodong uplift, Liaoxi sag and Liaozhong sag. After dozens years’ exploration in Liaodong Bay, few unexplored big-and-middle-sized favorable structural traps are remained and most of the stock structure targets are bad for fragmentary. Thus seeking for new prospect area and making a breakthrough, have become the unique way to relieve the severe exploration condition in Liaodong Bay. Technique Route Based on the petrophysical property of target area, the seismic forward inference of typical subtle trap model is expanded with analysis of logging, seismic and geologic data. According to petrophysical characteristics and forward inference and research on seismic response of actual seismic data in target area, the optimization of geophysical technique is used in subtle trap identification and the geophysical identification technique system of subtle reservoir is formed. The Key Research ① Petrophysical Model The petrophysical parameter is the basic parameter for seismic wave simulation. The seismic response difference of rocks bearing different fluids is required. With the crossplot of log data, the influence of petrophysical parameters on rock elastic properties of target area is analyzed, such as porosity, shale index, fluid property and saturation. Based on the current research on Biot-Gassmann and Kuster-Toksoz model, the petrophysical parameter calculator program which can be used for fluid substitution is established. ② S-wave evaluation based on conventional log data The shear velocity is needed during forward inference of AVO or other elastic wave field. But most of the recent conventional log data is lack of shear wave. Thus according to the research on petrophysical model, the rock S-wave parameter can be evaluated from conventional log data with probability inverse method. ③ AVO forward modeling based on well data For 6 wells in JZ31-6 block and 9 wells in LD22-1 block, the AVO forward modeling recording is made by log curve. The classification of AVO characteristics in objective interval is made by the lithologic information. ④ The 2D parameter model building and forward modeling of subtle hydrocarbon trap in target area. According to the formation interpretation of ESS03D seismic area, the 2D parameter model building and seismic wave field forward modeling are carried on the given and predicted subtle hydrocarbon trap with log curve. ⑤ The lithology and fluid identification of subtle trap in target area After study the seismic response characteristics of lithology and fluid in given target area, the optimization of geophysical technique is used for lithology identification and fluid forecast. ⑥The geophysical identification technique system of subtle reservoir The Innovative Points of this Paper ① Based on laboratory measurement and petrophysical model theory, the rock S-wave parameter can be evaluated from conventional log data with probability inverse method. Then the fluid substitution method based on B-G and K-T theory is provided. ② The method and workflow for simulating seismic wave field property of subtle hydrocarbon trap are established based on the petrophysical model building and forward modeling of wave equation. ③ The description of subtle trap structural feature is launched. According to the different reflection of frequency wave field structural attribute, the fluid property of subtle trap can be identified by wave field attenuation attribute and absorption analysis. ④ It’s the first time to identify subtle trap by geophysical technique and provide exploration drilling well location. ⑤ The technique system of subtle reservoir geophysical identification is formed to provide available workflow and research ideas for other region of interest.

中国混汞法采金地区汞的环境地球化学研究-以陕西潼关为例

本研究选择有代表性的陕西省潼关县（小秦岭地区）采金地区作为研究对象，从环境地球化学的角度出发，研究了该地区由于受采金活动的影响后，大气、水体、土壤以及农作物中总汞和甲基汞的分布，探讨汞在采金地区环境中迁移、转化和富集的环境地球化学行为和规律，并估算了渲关县及全国在过去二十多年里，由混汞法炼金活动向环境释放汞的总量，最后对混汞法采金地区的环境管理提出可行性建一议。通过本论文的详细研究，主要得出以下结论：1．潼关县辖区大气汞的分布呈明显的空间梯度关系，炼金厂密集区大气汞含量明显高于其它地区，距离炼金厂越远，大气汞含量越低。大型炼金厂混汞提金车间内的平均大气汞浓度为18，047ng／m~3，最高达33，080ng／m~3；距离炼金厂密集区较近和较远的居民区的平均大气汞浓度分别为385ng／m~3和77ng／m~3；而一些偏远地区大气汞的平均浓度降至29ng／m~3，受炼金活动影响较 小的黄河沿岸背景区的平均大气汞浓度只有2ng／m~3。通过估算，潼关县炼金矿工汞蒸气的平均摄入量高达72，804～75，268ng／d，而当地非矿工居民（成人）每天的摄入量也有924～4，620ng。2．潼关县内泉水和井水中总汞的平均浓度有329.2ng／L，其中各形态汞的浓度都相对较高，说明金矿地区的汞背景值可能较高，且地下水也可能受到一定程度的汞污染；冷暖两季水样中溶解态汞浓度和暖季的甲基汞浓度要比泉水和井水中的溶解态汞和甲基汞浓度分别高出几倍，其它形态汞则要高出几百倍；水样中的活性汞和溶解态汞浓度表现出极显著的相关关系；冷季水样的活性汞和溶解态汞平均浓度要略高于暖季的水样，而颗粒态汞恰恰相反；两季采集的一些水样中活性汞在溶解态汞中占有较高的比例，但总汞均以颗粒态为主，大多超过50％。3．冷暖两季沉积物中平均总汞浓度分别高达151.1和44.6μg／g，甲基汞平均浓度分别为7.1和3.6ng／g，而暖季沉积物中总汞与甲基汞含量表现出极显著的相关关系；水体颗粒物和沉积物主要来源于炼金厂排出的废渣和尾矿，拥有较高的重金属（Hg、Fe、Mn和Cu）含量，且两者之间体现出一定的继承关系，但颗粒物由于粒径小，表面积大，含有机颗粒多，吸附能力强，所以其中的重金属含量要明显高于沉积物中的重金属含量；颗粒物中汞含量与Fe、Mn、Cu的含量之间均表现出极显著的相关性，而沉积物中汞含量仅与Cu含量之间有一定的相关性，与其它重金属含量的相关性不明显。4．潼关县辖区金矿石中汞的平均含量是69.2ng/g，而炼金尾矿中汞的平均含量竟高达628，4林吮，高出原矿石样中汞平均含量10，000倍，其它重金属（Fe、Mn、Cu）由于受炼金活动影响较小，其含量变化并不十分明显；黄土由于自身的特殊质地和性质，受炼金活动的干扰较小，其中的各重金属含量能够较好的反映其背景含量水平；撞关地区采集的土壤样品中总汞和甲基汞含量均要比黄土中的含量高约50倍，而其它重金属含量与黄土背景值无明显差异；土壤中甲基汞在总汞含量中所占比例较小（分布在0.001％～0.57％之间），说明潼关地区土壤中汞的甲基化水平较低。5．苔鲜样品中的高汞含量反映了采金地区较高的大气汞沉降水平；河流水藻中高含量的总汞和甲基汞体现出汞在生物体内超强的富集作用；潼关县大多数农作物样品中的汞主要来源于大气，且几乎所有样品的汞含量都严重超出国家食用标准，最高超标倍数达到60；农作物中甲基汞含量占总汞的比例在0.12％～12.34％之间波动，其中蔬菜类作物的甲基汞比例要高于粮食作物，而总体来说，作物体内的总汞和甲基汞含量之间表现出一定的负相关关系；通过估算，潼关县居民由于粮食作物（小麦）的食用每天摄入的总汞量高达54，72Ong，要高于当地居民（非矿工）通过呼吸吸入的汞蒸气量，且已超出国际上对人体汞摄入量标准的有关规定。6．潼关县水体、沉积物、土壤以及农作物中的甲基汞含量相对总汞而言，都表现了相对较低的水平，原因可能是受石英脉型金矿地区地质背景的影响，大量存在的Fe、Mn类化合物对离子态汞有着较强的束缚能力，减缓或抑制了甲基化的发生。7．通过混汞法生产黄金的产量和汞释放因子的调研和确定，估算在1980～2003年期间，全国混汞炼金行业向环境释放汞累计达1476.6t，其中约有78％进入大气；而仅潼关县就有116.5t，约占全国的7.9％：目前（1996年以后），由于混汞法工艺的改进，汞的释放量大大降低，全国混汞炼金行业平均每年释放汞约30t，憧关县平均每年有3.9t，约占全国年平均释放量的13％。

Stable tetrahedral aluminum sites in hexagonal mesoporous aluminosilicates

A unique templating approach for the synthesis of hexagonal mesoporous aluminosilicates via self-assembly of pre-formed aluminosilcate nanoclusters with the templating micella formed by cetyltrimethylammonium bromide (CTAB) is described. The obtained materials of MAS-5 are hydrothermally stable, which is shown by X-ray diffraction (XRD) analysis. Furthermore, as characterized by NMR technique, MAS-5 has stable tetrahedral aluminum sites that is the major contributions to the acidity of aluminosilicate molecular sieve, and on non-framework aluminium species in the samples was observed.

Optical Flow From 1D Correlation: Application to a Simple Time-To-Crash Detector

In the first part of this paper we show that a new technique exploiting 1D correlation of 2D or even 1D patches between successive frames may be sufficient to compute a satisfactory estimation of the optical flow field. The algorithm is well-suited to VLSI implementations. The sparse measurements provided by the technique can be used to compute qualitative properties of the flow for a number of different visual tsks. In particular, the second part of the paper shows how to combine our 1D correlation technique with a scheme for detecting expansion or rotation ([5]) in a simple algorithm which also suggests interesting biological implications. The algorithm provides a rough estimate of time-to-crash. It was tested on real image sequences. We show its performance and compare the results to previous approaches.

Asymptotic modeling of short plane-parallel high-pressure glow discharge

Here a self-consistent continuum model is presented for a narrow gap plane-parallel dc glow discharge. The set of governing equations consisting of continuity and momentum equations for positive ions, fast (emitted by the cathode) and slow electrons (generated by fast electron impact ionization) coupled with Poisson's equation is treated by the technique of matched asymptotic expansions. Explicit results are obtained in the asymptotic limit: (chi delta) much less than 1, where chi = e Phi(a)/kT, delta = (r(D)/L)(2) (Phi(a) is the applied voltage, r(D) is the Debye radius) and pL much greater than 1(Hg mm cm), where p is the gas pressure and L is the gap length. In the case of high pressure, the electron energy relaxation length is much smaller than the gap length, and so the local field approximation is valid. The discharge space divides naturally into a cathode fall sheath, a quasineutral plasma region, and an anode fall sheath. The electric potential distribution obtained for each region in a (semi)analytical form is asymptotically matched to the adjoining regions in the region of overlap. The effects of the gas pressure, gap length, and applied voltage on the length of each region are investigated. (C) 2000 American Institute of Physics. [S1070-664X(00)01302-1].

Highly accurate and efficient evaluation of randomising set index functions

Randomising set index functions can reduce the number of conflict misses in data caches by spreading the cache blocks uniformly over all sets. Typically, the randomisation functions compute the exclusive ors of several address bits. Not all randomising set index functions perform equally well, which calls for the evaluation of many set index functions. This paper discusses and improves a technique that tackles this problem by predicting the miss rate incurred by a randomisation function, based on profiling information. A new way of looking at randomisation functions is used, namely the null space of the randomisation function. The members of the null space describe pairs of cache blocks that are mapped to the same set. This paper presents an analytical model of the error made by the technique and uses this to propose several optimisations to the technique. The technique is then applied to generate a conflict-free randomisation function for the SPEC benchmarks. (C) 2003 Elsevier Science B.V. All rights reserved.

Scaled Heavy-Ball Acceleration of the Richardson-Lucy Algorithm

The Richardson-Lucy algorithm is one of the most important algorithms in the image deconvolution area. However, one of its drawbacks is slow convergence. A very significant acceleration is obtained by the technique proposed by Biggs and Andrews (BA), which is implemented in the deconvlucy function of the Image Processing MATLAB toolbox. The BA method was developed heuristically with no proof of convergence. In this paper, we introduce the Heavy-Ball (H-B) method for Poisson data optimization and extend it to a scaled H-B method, which includes the BA method as a special case. The method has proof of the convergence rate of O(k-2), where k is the number of iterations. We demonstrate the superior convergence performance of the scaled H-B method on both synthetic and real 3D images.

Use of immunosorbent-purified antigens of Fasciola hepatica in enzyme immunoassays

A monoclonal antibody specific for the T1 tegumental antigen of Fasciola hepatica was used as a solid-phase immunosorbent for the purification of T1 antigen from homogenised mature F hepatica. Material fractionated by this technique was successfully used in enzyme-linked immunoassays to detect antibodies to F hepatica in sera from sheep and cattle. Species differences in response to infection by F hepatica were demonstrated.

A critical review of labelling techniques used to quantify rhizosphere carbon-flow

The rhizosphere is a major sink for photo-assimilated carbon and quantifying inputs into this sink is one of the main goals of rhizosphere biology as organic carbon lost from plant roots supports a higher microbial population in the rhizosphere compared to bulk soil. Two fundamentally different¹⁴CO₂ labelling strategies have been developed to estimate carbon fluxes through the rhizosphere - continuous feeding of shoots with labelled carbon dioxide and pulse-chase experiments. The biological interpretation that can be placed on the results of labelling experiments is greatly biased by the technique used. It is the purpose of this paper to assess the advantages, disadvantages and the biological interpretation of both continuous and pulse labelling and to consider how to partition carbon fluxes within the rhizosphere. © 1994 Kluwer Academic Publishers.

Laser-fabricated PET-Ti Hybrid Joints for Medical Device Applications

Currently, micro-joining of plastic parts to metal parts in medical devices is achieved by using medical adhesives, For example, pacemakers, defibrillators and neurological stimulators are designed using silicone adhesive to seal the joint between the polyurethane connector module and the titanium can [1]. Nevertheless, the use of adhesive is problematic because it requires a long time to cure and has high tendency to produce leachable products which might be harmful to the human body. An alternative for directly joining plastics to metal without adhesive is therefore required. Laser transmission joining (LTJ) is growing in importance, and has the potential to gain the niche in micro-fabrication of plastics-metal hybrid joints for medical device applications. The possibility of directly joining plastics to metal by LTJ technique have been demonstrated by a number of studies in recent literature [2]. The widely-accepted understanding of LTJ between plastics and metal is that generation and rapid expansion of micro-bubbles at the plastics-metal interface exert high local pressure to press the melted plastics towards the metal surface features during the laser processing [2]. This subsequently creates the plastics-metal hybrid joint by the mechanisms of mechanical interlocking as well as chemical and physical bonds between the plastics and metal surfaces. Although the micro-bubbles can help promote the mechanical interlocking effect to increase the joint strength, the creation of bubble is a random and complex process depending on the complicated interactions between the laser intensity, thermal degradation properties of plastics, surface temperature and topographical features of metal. In an ideal situation, it is desirable to create the hybrid plastics-metal joint without bubbles. However, the mechanical performance of the hybrid plastics-metal joint without bubbles is still unknown, and systematic comparison between the hybrid joints with and without bubbles is lacking in literature. This becomes the objective of this study. In this work, the laser process parameters were carefully chosen from a preliminary study, such that different hybrid joints: with and without bubbles can be produced and compared. Biocompatible PET and commercially pure Ti were selected as materials for laser joining.