三峡工程对库区水流水质影响预测

利用开发的三峡水库整体一维水流水质数学模型，对三峡水库建成前后的水流水质变化趋势进行预测分析。重点介绍三峡工程建成后，库区水流条件巨大变化对污染物输移转化特性和水质分布的影响。预测结果表明，三峡工程建成后，三斗坪水位175m条件下，回水区断面平均流速比建库前减小4倍左右，平均有机污染物自净降解速率和大气复氧速率比天然河道状况减小1倍。由于污染物在库区滞留时间成倍延长，有机污染物排入水库后的自净降解总量较天然河道状况增大，因而，建库后加水区内断面平均有机污染物浓度较天然河道状况明显下降，但是，断面平均溶解氧浓度与天然河道状况相比也明显降低，对于守恒类污染物，建库前后水质变化不大。因此，三峡工程对库区水质影响有利也有弊。     

蓝湿皮酶软化的特性研究

以自行研制的一种复合酶为软化剂 ,研究了 p H值、反应温度、反应时间、酶用量以及铬含量对猪蓝湿皮软化效果的影响 ,其软化效果以软化液中羟脯氨酸的浓度增量来表征。研究结果表明 :通过蓝湿皮软化来改善成品革的质量是可行的 ,而且有明显的效果 ;以软化液中羟脯氨酸的浓度来表征软化效果是一个有效的方法 ;当用该复合酶软化猪蓝湿皮时 ,最适 p H值范围为 6 .0 - 6 .5 ;反应温度在 4 0 - 6 5℃之间时 ,软化效果随温度的升高而增大 ;在 5 5℃条件下 ,该酶有很好的热稳定性 ,能长时间保持活力不衰减 ;最适酶用量为 30 0 U/ g试样 ;蓝湿皮的铬含量对软化效果有影响 ,用该方法处理的蓝湿皮 ,其铬离子质量含量一般应≤ 2 .5 %。     

铈柱撑膨润土负载Ni2P对噻吩加氢脱硫的影响

以钙钠基膨润土为原料,首先对其钠化改型得到适合制备柱撑膨润土的基质,然后使用交联法制备不同OH-含量的Ce柱撑液,进一步制备Ce-柱撑膨润土,以其为载体用浸渍法制备Ni2P/Ce-PILC加氢脱硫催化剂,并用XRD、氮气吸附和H2-TPR等方法对催化剂进行了表征,考察了不同OH-含量对Ce-柱撑膨润土的柱撑效果和催化剂活性的影响。结果表明,500℃下焙烧3 h后Ce-柱撑膨润土层间距稳定在1.4078 nm;在n(Ni):n(P)为2:1、焙烧温度为500℃(3 h)、还原温度为500℃(2 h)、反应温度为350℃的情况下,当n(OH-):n(Ce3+)为2.5:1时,制备的催化剂催化噻吩加氢脱硫的活性最高,噻吩转化率为47%。     

冲菜辛辣风味物质的顶空固相微萃取-气质联用法测定

冲菜作为一种叶芥类蔬菜产品,以其冲鼻的辛辣味而独具特色。为确定辛辣风味的物质成分,采用顶空固相微萃取-气质联用法对其挥发性风味成分进行了分析,结果显示:冲菜的主要风味物质为异硫氰酸烯丙酯、异硫氰酸环丙酯、异硫氰酸丙酯、异硫氰酸丁烯酯和异硫氰酸苯乙酯,其中异硫氰酸环丙酯为首次检测出的异硫氰酸酯类风味物质。     

Self‐Catalyzed Growth of Co,N‐Codoped CNTs on Carbon‐Encased CoSx Surface: A Noble‐Metal‐Free Bifunctional Oxygen Electrocatalyst for Flexible Solid Zn–Air Batteries

The self‐catalyzed growth of nanostructures on material surfaces is one of the most time‐ and cost‐effective ways to design multifunctional catalysts for a wide range of applications. Herein, the use of this technique to develop a multicomponent composite catalyst with CoS_x core encapsulated in an ultrathin porous carbon shell entangled with Co, N‐codoped carbon nanotubes is reported. The as‐prepared catalyst has a superior catalytic activity for oxygen evolution and oxygen reduction reactions, an ultralow potential gap of 0.74 V, and outstanding durability, surpassing most previous reports. Such superiority is ascribed, in part, to the unique 3D electrode architecture of the composite, which is favorable for transporting oxygen species and electrons and creates a synergy between the components with different functionalities. Moreover, the flexible solid Zn–air battery assembled with such an air electrode shows a steady discharge voltage plateau of 1.25 V and a round‐trip efficiency of 70% at 1 mA cm^?2. This work presents a simple strategy to design highly efficient bifunctional oxygen electrocatalysts and may pave the way for the practical application of these materials in many energy conversion/storage devices.     

超临界水氧化法处理高含量印染废水研究

采用超临界水氧化法对高含量印染废水进行试验研究,考察了废水pH、反应温度、反应压力、氧化剂用量等因素对废水COD去除率的影响.结果表明,改变废水的pH对COD去除率有显著的影响,在pH为9.1、反应温度580℃、反应压力27 MPa,过氧量200%的条件下,经处理的废水COD为47 mg·L-1,去除率达到了99.8%.使用超临界水氧化法能有效地去除印染废水的COD,达到GB 8978-96规定的一级排放标准.     

Electrochemical Monitoring of Paclitaxel‐Induced ROS Release from Mitochondria inside Single Cells

Mitochondria are believed to be the major source of intracellular reactive oxygen species (ROS). However, in situ, real‐time and quantitative monitoring of ROS release from mitochondria that are present in their cytosolic environment remains a great challenge. In this work, a platinized SiC@C nanowire electrode is placed into a single cell for in situ detection of ROS signals from intracellular mitochondria, and antineoplastic agent (paclitaxel) induced ROS production is successfully recorded. Further investigations indicate that complex IV (cytochrome c oxidase, COX) is the principal site for ROS generation, and significantly more ROS are generated from mitochondria in cancer cells than that from normal cells. This work provides an effective approach to directly monitor intracellular mitochondria by nanowire electrodes, and consequently obtains important physiological evidence on antineoplastic agent‐induced ROS generation, which will be of great benefit for better understanding of chemotherapy at subcellular levels.     

基于未确知测度理论的采矿方法优选

为选择适合贵州某金矿的最佳采矿方法,以解决该矿开采难度大与开采成本高的问题,根据矿山实际地质条件,初选出了适用于该矿体的采矿方法。将数值模拟与未确知测度理论相结合,利用数值模拟分析三种备选采矿方法的安全性,同时作为优选模型的指标。结合矿山实践经验,优选出采场生产能力等11项影响采矿方法选择的指标,利用信息熵计算各指标的客观权重,引入置信度识别准则进行评价,同时按照优越度进行排序,构建基于未确知测度理论的采矿方法优选模型。通过综合比较分析,最终确定最佳的采矿方法即下向中深孔落矿嗣后充填法,该方法可以有效解决目前开采遇到的问题,扩大矿山生产能力,降低采矿成本,提高矿山经济效益。     

Highly conductive mesoporous hierarchical carbon hollow fibers fabricated via confinement of TiO2 coating by ALD

A polysulfone (PSF) hollow fiber composed of interconnected nanofibers within its wall was employed as a template to deposit with a layer of TiO₂ by atomic layer deposition. Direct nitridation of the TiO₂-coated PSF hollow fiber at 800 and 1000°C was conducted, and a new hierarchical structure of TiO_xN_1−x and TiN@nitrogen-doped carbon hollow fibers, respectively, was formed. The PSF fiber served as the source of carbon and was directly transformed to a nitrogen-doped carbon fiber because the shape change was confined by the TiO₂ coating. In the meantime, TiO_xN_1−x or TiN was formed after the nitridation of TiO₂. X-ray photoelectron spectrometric analysis indicated that there was no chemical bonding between the nitridized coating and the carbon nanofibers. It implies that the nitridation of TiO₂ and carbonization of PSF proceed independently and simultaneously in the nitridation process. Raman spectroscopic analysis also confirmed the formation of graphitic lattice and Ti–N bonding. Electrical measurement indicated that both fibers were highly conductive, with the electrical resistivity in the order of 10⁻⁵ Ω m, which is lower than those of amorphous carbon and graphite along the direction perpendicular to the basal plane.     

Beneficial effect of yam on the amyloid β‐protein,monoamine oxidase B and cognitive deficit in mice with accelerated senescence

This study was designed to evaluate the effect of yam tuber material [Dioscorea alata L. var. purpurea (M.) Pouch.] on the amyloid β‐protein (Aβ) accumulation, monoamine oxidase (MAO) activity, cognitive ability and antioxidative defense system in senescence‐accelerated mice (SAMP8). Three‐month‐old male mice were fed with four different diets for 12 weeks: a casein diet (control group) and a casein diet supplemented with either 100, 200 or 400 g kg^?1 lyophilized yam. The results of the active shuttle avoidance test showed that the mice fed with the yam‐containing diets had significantly better learning and memory ability than the control group. All yam‐containing diet groups had lower Aβ levels and MAO B activities than the control, whereas the MAO A activity did not differ among the four diet groups. At the 400 g kg^?1 level, the yam‐containing diet group showed significantly lower concentration of thiobarbituric acid‐reactive substances (TBARS), higher total thiol level and superoxide dismutase (SOD) activity in the hippocampus than the control, but these values were not altered by the 100 and 200 g kg^?1 yam‐containing diet groups. The addition of 200 or 400 g kg^?1 yam also lowered the triglyceride levels but not the total cholesterol concentration. These results indicate that lyophilized yam could reduce brain Aβ accumulation, MAO B activity and cognitive deficits and promote the antioxidative defense system in SAMP8 mice. The improvements were in a dose‐dependent manner, possibly because the 400 g kg^?1 yam‐containing diet might contain more antioxidative phytochemicals. Copyright © 2006 Society of Chemical Industry