Multiple morphologies and their transformation of a polystyrene-block-poly(4-vinylpyridine) block copolymer

We report the multiple morphologies and their transformation of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) in low-alkanol solvents. In order to improve the solubility of polystyrene block in alcohol solvents, the solution of block copolymer sample was treated at a higher temperature, and then the influence of rate of decreasing temperature on multiple morphologies (including spheres, rods, vesicles, porous vesicles, large compound vesicles, and large compound micelles) was observed. The transformation of spheres to rods, to tyre-shaped large compound micelles, and to sphere-shaped large compound micelles was also realized. The formation mechanisms of the multiple morphologies and their transformation are discussed briefly.

In-situ Fourier transform infrared spectroelectrochemistry as a probe of the glassy carbon electrode chemically modified by nickel (II)-cyanometallates

A new nickel (II)-cyanometallates modified on glassy carbon electrode was prepared by a new method and studied by cyclic voltammetry and in situ Fourier transform infrared (FTIR) spectroelectrochemistry. It was found that the NiHCF film existed in two forms: Ni2Fe(II)-(CN)(6) and M2NiFe(II)(CN)(6), Fe(CN)(3)(6-) codeposited in the NiHCF film existing in free cation or bridged-bond state depended on the property of the cations in electrolyte: in NaCl and LiCl solution, it is in bridges-bonded, but in HCl and KCl, it is free.

六氰亚铁酸镍修饰玻碳电极的现场红外光谱电化学研究

报道了一种制备六氰亚铁酸镍玻碳修饰电极(NiHCF/GC)的电化学方法,并用循环伏安(CV)和现场红外光谱电化学(FTIRs)方法对该修饰电极进行了研究.结果表明该电极上的NiHCF修饰膜有两种结构:Ni_2Fe(Ⅱ)(CN)_6和M_2NiFe(Ⅱ)(CN)_6,M为碱金属离子.M_2NiFe(CN)_6结构具有阳离子选择性,而阳离子对Ni_2Fe(Ⅱ)(CN)_6电化学反应的影响是间接的.FTLRs研究还表明在膜制备过程中Fe(CN)_6~(4-)发生了共沉积,其存在形式与支持电解质中阳离子的性质有关:在Na~+和Li~+溶液中,主要以桥式结构存在;而在K~-和H~-溶液中,主要为离子对形式.

Identification of 27 Porphyra lines (Rhodophyta) by DNA fingerprinting and molecular markers

Twenty-seven Porphyra lines, including lines widely used in China, wild lines and lines introduced to China from abroad in recent years, were screened by random amplified polymorphic DNA (RAPD) technique with 120 operon primers. From the generated RAPD products, 11 bands that showed stable and repeatable RAPD patterns amplified by OPC-04, OPJ-18 and OPX-06, respectively were scored and used to develop the DNA fingerprints of the 27 Porphyra lines. Moreover, the DNA fingerprinting patterns were converted into computer language expressed with two digitals, 1 and 0, which represented the presence (numbered as 1) or absence (numbered as 0) of the corresponding band, respectively. Based on the above results, computerized DNA fingerprints were constructed in which each of the 27 Porphyra lines has its unique fingerprinting pattern and can be easily distinguished from others. Software named PGI (Porphyra germplasm identification) was designed for identification of the 27 Porphyra lines. In addition, seven specific RAPD markers from seven Porphyra lines were identified and two of them were successfully converted into SCAR (sequence characterized amplification region) markers. The developed DNA fingerprinting and specific molecular markers provide useful ways for the identification, classification and resource protection of the Porphyra lines.

Estimation of suspended sediment concentrations using Pulse-coherent Acoustic Doppler Profiler (PCADP)

The objective of the study is to investigate the suitability of using Pulse-coherent Acoustic Doppler Profiler (PCADP) to estimate suspended sediment concentration (SSC). The acoustic backscatter intensity was corrected for spreading and absorption loss, then calibrated with OBS and finally converted to SSC. The results show that there is a good correlation between SSC and backscatter intensity with R value of 0.74. The mean relative error is 22.4%. Then the time span of little particle size variation was also analyzed to exclude the influence of size variation. The correlation coefficient increased to 0.81 and the error decreased to 18.9%. Our results suggest that the PCADP can meet the requirement of other professional instruments to estimate SSC with the errors between 20% and 50%, and can satisfy the need of dynamics study of suspended particles.

Typhoon effects on DOC dynamics in a phosphate-limited reservoir

To explore typhoon effects on dissolved organic carbon (DOC) dynamics, field investigations (tributary and dam site) and laboratory experiments (bioassay and DOC consumption) were conducted in a subtropical reservoir. A tributary survey indicated that after typhoon disruption, upstream areas were the sources of phosphate (P) but not DOC for the dam site located downstream. Bioassay experiments verified P-limitation on bacteria and phytoplankton during summer stratification, and bacteria showed a faster response than algae to added P. Experiments indicated that DOC consumption was determined by the availability of P. The 4 yr typhoon period (June-September) data of the dam site denoted that DOC concentration (27 to 270 mu M C) and its rate of change (-13 to 24 mu M C d(-1)) varied more dramatically in the weak (2006 and 2007) than in the strong (2004 and 2005) typhoon years. The negative correlation of DOC with the ratio of bacterial production (BP) to primary production (PP) in the euphotic zone (0 to 10 m) signified the interactive effects of auto- and heterotrophic processes on DOC variation. In the aphotic zone, the variation of DOC could be ascribed to the change of BP, which showed a positive correlation with P concentrations. This study documents that DOC concentration in the studied system varied at multiple time scales. Such variation can be explained by the decoupling between BP and PP, which is believed to be a function of the limiting nutrient's availability. More importantly, this study suggests that the P supply introduced by strong typhoons might have substantiated a tighter coupling between BP and PP, so that the amplitude of DOC oscillation during the summer period was effectively reduced.

川西獐牙菜与抱茎獐牙菜中酮的高效液相色谱分析

采用反相高效液相色谱法同时分离和测定了龙胆科獐牙菜属的川西獐牙菜和抱茎獐牙菜中几种酮的含量.色谱柱为Kromasil C_(18)(250 mm * 4.60 mm i.d., 5 μm),流动相为甲醇-0.1%的磷酸水溶液(体积比为73∶27),流速1 mL/min,检测波长260 nm,柱温20 ℃.实验结果表明,该方法具有很好的线性关系与精密度,方法简单、准确、实用性强.

甘肃阳山金矿同位素地球化学特征及矿床成因

甘肃文县阳山金矿的探明黄金储量已达308t，平均品位4.74g/t，是我国地质勘查储量最大的金矿床。该矿床产于西秦岭造山带，是一个同碰撞形成的类卡林型金矿床，矿体受EW向韧脆性剪切带控制，赋矿围岩为泥盆系碳质千枚岩-板岩-碳酸盐-硅质岩和侵入其中的花岗斑岩脉。流体成矿过程包括：形成石英-绢云母-黄铁矿组合的早阶段，形成石英-黄铁矿-毒砂-方铅矿等多金属组合的主成矿阶段，形成碳酸盐-辉锑矿-石英网脉的晚阶段。 与矿体关系较为密切的花岗斑岩富集LILE 和 LREE, 亏损 Ba, Sr, Nb, Ta, P 和Ti，ΣREE＝54.35～124.01 μg/g ，(La/Yb)N=9.72～27.80，δEu=0.70～0.89， ISr值为0.70806～0.71756，平均0.71107；εNd(t)平均-3.4；Nd模式年龄（T2DM）平均1.34（Ga）。表明花岗斑岩岩浆应源自成熟度较低的中元古代基底地壳物质。花岗斑岩的(206Pb/204Pb)220Ma、(207Pb/204Pb)220Ma和(208Pb/204Pb)220Ma的平均值分别为17.875、15.604和38.296，与秦岭微陆块的中元古代基底和碧口地体碧口群的Pb同位素组成一致。考虑到前人获得碧口群的年龄为1.235～1.367Ga，而秦岭微陆块沿勉略缝合带向南仰冲到碧口地体之上，我们认为由碧口群等组成的俯冲板片的变质脱水熔融作用导致了阳山金矿带花岗斑岩的形成。因此，阳山金矿带的花岗斑岩是扬子与华北大陆中生代碰撞造山过程中形成的同碰撞花岗岩类。 最新的S，Sr和Pb同位素研究表明：热液成矿早阶段的黄铁矿的34S值范围介于-15.5‰~6.59‰之间，总体离散性比较大，显示沉积地层来源的特征，硫同位素组成属离散型，不具有岩浆主导的成矿的塔式效应。花岗岩中黄铁矿硫同位素范围很集中，34S值处于-1.47‰～2.12‰之间，本区花岗斑岩不可能为成矿物质的主要来源。矿石硫化物的初始锶同位素比值范围较大（0.70877～0.71697，平均为0.71258），显示成矿物质并非单一来源，考虑到花岗斑岩先于矿床形成，只在后期构造作用的岩体部分成矿的地质事实，少量矿石中的低锶同位素比值黄铁矿有可能来自作为围岩的花岗斑岩，也可能来自基底物质。矿石硫化物Pb同位素206Pb/204Pb=17.552～18.853，平均18.260；207Pb/204Pb=15.574～15.928，平均15.685；208Pb/204Pb=37.894～39.293，平均38.680，变化范围比较大。μ=9.46~10.06，平均为9.65，ω值介于36.96～42.21，显示了铅源的物质成熟度较高，要求最佳物源是浅变质化学-碎屑沉积建造，恰好与本区泥盆构造层为浅变质细碎屑岩夹薄层灰岩系的特征一致，部分低Sr和Pb同位素比值的成矿物质可能来自于作为围岩的花岗斑岩和/或者基地物质。 总结前人阳山金矿床的H-O-C同位素体系的研究得出，初始成矿流体来源于碳酸盐地层或相似岩石建造的变质或/和改造脱水，成矿流体系统从早到晚、从深到浅，由变质热液演变为大气降水热液。与本文得出的结论一致。 总而言之， 阳山金矿矿成矿流体的来源早期具有变质水特征，应来自赋矿地层或相似岩性组合的改造或变质脱水作用，晚阶段大气水为主的流体性质。成矿物质主要来自于赋矿围岩。流体经过作为部分围岩的花岗斑岩时从中萃取少部分成矿物质，而导致了少部分的低锶、铅同位素的矿石硫化物组成。 在中生代扬子板块北缘（包括碧口地块）向南秦岭陆陆碰撞过程中，扬子北缘板片沿勉略断裂向北俯冲到南秦岭之下，下插板片增温增压，发生变质、脱水和部分熔融。碰撞中期，构造背景由挤压向伸展转变，减压增温的环境导致大量变质流体沿深大断裂向上运移，不断萃取围岩中大量成矿元素，并将成矿元素搬运至有利于流体聚集、成矿物质卸载的空间，使成矿物质富集成矿。阳山金矿床定位于泥盆系构造层中，成矿时代为190Ma左右，紧随花岗斑岩侵入作用（220Ma左右），主成矿作用发生于碰撞作用由挤压-伸展转变期的减压增温环境。成岩、成矿模式与CMF模式吻合。 阳山超大型金矿是世界罕见的碰撞造山带内类卡林型金矿床，其地质地球化学特征复杂、独特，流体性质主要与造山型金矿一致，矿床地质主要与卡林型金矿一致，部分特征兼与造山型和卡林型两类矿床之间，花岗斑岩本身成矿的特点又为阳山所特有，总体具有造山型向卡林型金矿过渡的性质。因此建议以“秦岭式”或“阳山式”类卡林型金矿床代表与阳山金矿具有类似成矿背景及地球化学性质的矿床。