On the involvement of radical oxygen species O− in catalytic oxidation of benzene to phenol by nitrous oxide

Catalytic oxidation of benzene to phenol by nitrous oxide over Fe-MFI zeolites was studied in relation to the active oxygen species taking part in the oxidation. A linear dependence of the reaction rate on the concentration of independently identified active sites generating O⁻ radicals (α sites) was obtained within a broad range of values. The dependence is interpreted as convincing evidence of the O⁻ involvement in the catalytic (not only stoichiometric) oxidation of benzene to phenol. This conclusion is of particular importance in connection with a long discussion in the literature on a possible role of O⁻ radicals in selective oxidation catalysis over V and Mo oxides. Reliable evidence of the catalytic role of O⁻ obtained with zeolites may renew general interest in the once-suggested but not recognized role of radical oxygen in oxidation over widely used metal oxide catalysts.     

利用ADCP回波强度估算河流悬移质含沙量的应用研究

通过简要介绍利用声学多普勒水流剖面仪(ADCP)回波强度估算悬移质含沙量的基本原理,结合梧州水文站的应用实例,利用ADCP的回波强度数据和现场采集的水样含沙量建立相关关系,根据相关关系由回波强度反演估算的水体悬移质含沙量验证了利用ADCP的回波强度估算悬移质含沙量的可行性。应用于梧州水文站的实践表明,左河道推算的系统误差为-0.1%,右河道推算的系统误差为1.5%。这种方法具有不扰动流场、测量剖面同步性较好、数据空间分辨率较高的优点,与传统的取样过滤称量法相比,计算效率显著提高。     

鲁北平原养鸡场周边包气带与地下水砷化合物分布规律

洛克沙胂(3-硝基-4-羟基苯胂酸)被广泛用作饲料添加剂,但大部分以原体形式随粪便排出,进入环境的洛克沙胂在微生物和光照作用下最终转化为毒性较大的As(V)和As(III)等,并在雨水或农灌的淋滤冲积下污染周边土壤、地表水和地下水。以鲁北平原某养鸡场为研究区,对鸡粪、饲料、周边表层土壤、鸡粪堆积和背景包气带垂向剖面以及地下水进行洛克沙胂及其代谢物的检测,结果饲料中洛克沙胂浓度为34mg/kg,鸡粪中HAPA(3-氨基-4-羟基苯胂酸)浓度为11 mg/kg,距离鸡场越近的表层土壤砷含量越高。三个包气带垂向剖面均以As(V)为主,As(III)含量较小。鸡粪堆积处垂向剖面上HAPA、As(V)和As(III)在土壤表层含量最高,浓度随深度增加而呈下降趋势,同时受到土壤岩性的影响,砷化合物主要的吸附层位为0~30cm与200cm以下;背景包气带垂向剖面上各砷化合物含量均明显低于鸡粪堆积处包气带垂向剖面的砷化合物含量;在鸡场内旧井中检测到浓度为165μg/kg的As(V)。结果证实鸡粪堆积导致土壤包气带、周边土壤和地下水砷含量增加,且这种污染很难消除。     

华北平原地下水资源承载力评价

华北平原地下水严重超采,并带来一系列资源环境问题,地下水资源承载力的可持续性面临严重挑战。本研究定义了地下水资源承载力的概念,提出了一种定量评价地下水承载力的新方法,并对华北平原地下水承载力进行了评价。结果表明,华北平原地区地下水资源支撑的GDP从2003年的15 608.18亿元迅速提高到2011年的37 584.9亿元,33.3%的地市位于未超采未超载区;华北平原整体及57.2%的地市均位于超采未超载区,已发生地下水超采,但通过提高用水效率,未来社会经济规模仍有发展空间;9.5%的地市位于超采超载区。最后探讨地下水资源的承载力的提高途径,主要包括增加地下水资源可利用量和提高用水效率两方面,其中提高用水效率效果更显著。     

Improved electrochemical redox performance of 2,5-dimercapto-1,3,4-thiadiazole by poly(3-methoxythiophene)

High electrocatalytic activity of an electropolymerized film of poly(3-methoxythiophene) (PMOT) is reported toward the redox reaction of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) as a promising cathode material for the lithium ion battery. Cyclic voltammetry showed improved electrochemical performance of DMcT on PMOT-coated Pt electrode, indicating accelerated redox kinetics. Moreover, charge-discharge tests exhibited higher discharge capacity and slower capacity fading of the PMOT-doped DMcT composite cathode compared with pure DMcT.     

荧光法测定N-（α-烷苯氧基）十四酰基牛磺酸钠的临界胶束浓度

研究了一类以苯氧基作疏水支链的新型阴离子表面活性剂——N-（α-烷苯氧基）十四酰基牛磺酸钠（SAPTT）水溶液的紫外吸收光谱、探针（芘）稳态荧光发射光谱及自身稳态荧光发射光谱性质．研究结果表明，荧光探针（芘）法和自身稳态荧光法可用来测定这类表面活性剂的临界胶束浓度（CMC），且测定结果与表面张力法（吊片法）接近；与荧光探针（芘）法相比，对于所研究体系，自身稳态荧光法的灵敏度和准确性均较高，所测得CMC结果与表面张力法（吊片法）能较好地吻合．     

江西浒坑钨矿含矿韧性剪切带及其^40Ar-^39Ar年代学约束

江西省浒坑钨矿是一个大型石英脉黑钨矿矿床,含矿石英脉除了块状石英脉以外,还大量发育条带状石英脉。本文针对条带状石英脉进行了专门研究,认为条带状石英脉实质上是韧性剪切带,以透入性发育的剪切面理和拉伸线理、剪切透镜体、剪切分异条带普遍发育为特色。剪切带岩石以石英质糜棱岩为主,具有丰富的塑性变形显微构造特征。显微剪切指向构造统计表明,东西向和北西向脉组的运动方式均以左旋正滑为主,近水平脉组则以正滑为主。北西向韧性剪切带的新生绢云母^40Ar-^39Ar坪年龄为140．3±1．0Ma,相应的等时线年龄为139．6±2．4Ma;而东西向韧性剪切带绢云母^40Ar-^39Ar坪年龄则比较复杂,高温阶段年龄可能受到成矿期白云母残斑的影响,中温阶段的表观年龄和总气体年龄更接近前一样品的坪年龄。据此认为韧性剪切变形的年龄为140Ma左右,韧性变形发生在成岩和成矿之后。条带状石英脉系块状石英脉韧性剪切改造而成,推测其形成主要与晚期补充岩体的斜向上侵作用有关,但更为合理的模式需要更多资料的进一步证实。     

埕岛油田馆上段沉积砂体及其夹层分布特征

通过岩矿特征、剖面结构、砂岩粒度和砂体形态分析,认为埕岛油田馆陶组上段为曲流河沉积。按砂体发育特点和成因类型划分出主河道连片砂体、河道边缘连续窄带状砂体、天然堤断续带状砂体、决口水道扇形席状砂体及废弃河道成因的透镜状砂体等5种类型。在研究区383口井精细地质研究的基础上,从不同成因储油砂体角度总结出夹层分布特征。建立了储油砂体内夹层的空间分布模式：主河道砂体内夹层分布复杂,一般底部发育钙质夹层,中部多发育物性夹层,上部为泥质夹层;河道边缘砂体主要发育泥质夹层;决口扇砂体内泥质夹层分布稳定;天然堤和废弃河道仅发育极少的钙质夹层。     

Development of Zr/ZrO<Subscript>2</Subscript> high temperature and high pressure sensors for <Emphasis Type="Italic">in-situ</Emphasis> measuring chemical parameters of deep-sea water

In order to in situ measure chemical parameters of deep-sea water and hydrothermal fluids at midocean ridge(MOR), it is necessary to use high temperature and high pressure chemical sensors.Developing new sensors is essential to measure in-situ pH and other chemical parameters(dissolved H2, dissolved H2S) of deep-sea water and hydrothermal fluids in a wide temperature range(2℃―400℃) at MOR vents.The YSZ(Yttria Stabilized Zirconia, 9%Y2O3) ceramic-based(HgO/Hg) chemical sensors possess excellent electrochemic...     

Variability of sedimentary phosphorus fractions in the western and Sandusky basins of Lake Erie

Surface sediments and three sediment cores from the western basin and one sediment core from the Sandusky basin were analyzed to document spatial and temporal changes in five phosphorus fractions and total phosphorus (TP). The areal distributions of the bioavailable fractions NaCl-Pi, NaBD-Pi, and NaOH-Pi and the refractory organic fraction Res-P were broadly consistent and contrasted with those of the detrital fraction HCl-Pi which showed that high concentrations occurred mostly in high-energy littoral zones and low concentrations largely in profundal depositional areas. The contrasting distributions were induced by interactions among tributary inputs, wave action, circulation, and biogeochemical cycling and transfer in the basin. As revealed by the Sandusky basin sediment record, the detrital fraction HCl-Pi was dominant (70% of TP) during European settlement and decreased rapidly by 28.0% in the early 1910s due largely to impoundments of the Maumee and Sandusky Rivers. While HCl-Pi has ever since remained relatively constant, NaCl-Pi, NaBD-Pi, and NaOH-Pi increased significantly between 1950 and 1970 in the two basins. However, the post-regulation sediment records differed considerably among these coring sites. There was a marked increase of TP in two cores, corresponding to recent return of eutrophication and massive harmful algal blooms but contrasting with a relatively constant, low loading into the lake. This signified the role of internal loading as derived partialy from legacy pollution. Furthermore, NaCl-Pi has increased progressively throughout all the records. We conclude that the increased levels of NaCl-Pi in surface sediments may have altered the internal loading and contributed to the resurgences of harmful algal blooms in Lake Erie.