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1.
壳聚糖Cu(Ⅱ)配合物的合成及吸附性能   总被引:7,自引:1,他引:7  
目的 研究高脱乙酰度壳聚糖对Cu(Ⅱ)离子的吸附动力学,并对吸附条件进行优化。方法用红外光谱、元素分析对配合物的组成进行表征。结果壳聚糖与Cu(Ⅱ)离子的吸附配位反应符合一级反应动力学方程,25℃时其吸附反应速率常数为0.0685h^-1,吸附反应的表观活化能Ea为5.60kJ/mol。结论 壳聚糖与Cu(Ⅱ)能发生吸附反应,形成2:1(物质的量比)的配合物。  相似文献   
2.
Using the definition of vulnerability provided by the Intergovernmental Panel on Climate Change,this paper assesses the vulnerability of areas affected by Chinese cryospheric changes from 2001 to 2020 and from 2001 to 2050 in A1 and B1scenarios.Seven indices are used in the vulnerability assessment:glacial area fraction,interannual variability of permafrost depth,interannual variability of surface snow area fraction,interannual variability of surface runoff,interannual variability of surface temperature,interannual variability of vegetation growth,and interannual variability of the human development index.Assessment results show that the overall vulnerability of the studied areas in China increases from east to west.The areas in the middle and eastern parts of China are less vulnerable compared with western parts and parts of the Tibetan Plateau.The highest vulnerability values are found from 1981 to 2000,and the least ones are found from 2001 to 2050.The vulnerable areas increase from the period of 1981 to 2000 to the period of 2001 to 2050,and the less vulnerable areas decrease.The highly vulnerable areas increase from the period of 1981 to 2000 to the period of 2001 to 2020 and then decrease from the period of 2001 to 2020 to the period of 2001 to 2050.This decrease in vulnerability is attributed to the decrease in exposure and sensitivity to Chinese cryospheric changes along with a concomitant increase in adaptation.  相似文献   
3.
采用稳态和时间分辨的光谱技术对比研究了Corrole大环中插入镓(Ga)原子及环周边取代基氟原子(F)数目的增多对Corrole荧光性能的影响.稳态吸收和荧光光谱表明:Corrole环中Ga原子的插入能增强Corrole的B带和Q带吸收,而周边修饰的拉电子取代基F的增多则减小Corrole的B带和Q带吸收.Ga原子的插入大大提高了Corrole的荧光量子产率;周边修饰的拉电子取代基F的增多亦能使Corrole的荧光量子产率有所提高.瞬态发光动力学测量结果表明:环中Ga原子的插入导致了Corrole更短的荧光寿命,周边修饰的拉电子取代基F的增多反而使得Corrole的荧光寿命稍变长.分析表明:在Corrole大环中插入Ga原子既大大提高了Corrole的荧光量子产率又缩短了其荧光寿命,使得相应的辐射跃迁几率提高了10倍左右;周边修饰的拉电子取代基F的增多提高了荧光量子产率且亦增长了Corrole荧光寿命,但最终使得辐射跃迁几率略微有所增加.  相似文献   
4.
Late Miocene Red River submarine fan,northwestern South China Sea   总被引:4,自引:0,他引:4  
Wang  YingMin  Xu  Qiang  Li  Dong  Han  JianHui    Ming  Wang  YongFeng  Li  WeiGuo  Wang  HaiRong 《科学通报(英文版)》2011,56(14):1488-1494
A huge submarine fan is discovered through the research of the seismic and borehole data in the binding site of Yinggehai basin and Qiongdongnan basin in northwestern South China Sea.The fan,mainly formed during Late Miocene (Huangliu period) has an area over 10000 km 2 and maximum thickness of over 2000 m.It is characterized by a wedge-shaped oblique progradation configuration on the dip profile and a hummocky bidirectional progradation configuration on the strike profile.The core and Logging data from the well YC35-1-2 located in the front side of the fan indicate that sandy gravity flow deposits are predominant in lower Huangliu Formation and change to interbeds of sand and mud in upper Huangliu Formation.The fan is interpreted as a sand/mud-rich submarine fan in combination with the bathyal geological background of Huangliu period.A preliminary analysis of provenance indicates that neither the Guiren Uplift in the west nor the Hainan Uplift in the north can serve as the major provenance for the submarine fan.The provenance is considered to be from the Red River,based on the sedimentary facies study of the Huangliu Formation in Yinggehai basin.The fan is thus named as "Red River submarine fan".The Red River depositional system consists of the Red River submarine fan,the Red River delta,and associated submarine canyons.The discovery of the Red River submarine fan provides important information for the research of the uplift of Tibetan Plateau and the evolvement of Red River Fault Zone.Furthermore,it also points out a new direction for the deepwater hydrocarbon exploration in the northern South China Sea.  相似文献   
5.
白蛋白锌卟啉结合体光解水产氢性能   总被引:1,自引:0,他引:1  
朱永峰  何玉凤  王荣民  李岩  宋鹏飞 《科学通报》2011,56(17):1360-1366
将难溶性的锌卟啉(ZnTpHPP)与牛血清白蛋白(BSA)结合, 制得一类新型水溶性生物高分子金属卟啉配合物(BSA-ZnTpHPP). 通过紫外可见光谱(UV-Vis)、圆二色谱(CD)及非变性聚丙烯酰胺凝胶电泳(Native-PAGE)对 BSA-ZnTpHPP 的结构进行了表征, 发现二者以配位键结合, BSA与锌卟啉以较低比例结合时蛋白质二级结构保持. 考察了BSA-ZnTpHPP的光敏感性, 发现BSA-ZnTpHPP在光照条件下易变成三重激发态, 可以将电子转移给甲基紫精(MV2+). 以三乙醇胺(TEOA)为电子供体, 甲基紫精(MV2+)为电子中继体, 以BSA-ZnTpHPP/MV2+/TEOA/胶体Pt四组分体系考察了BSA-ZnTpHPP的光诱导水解产氢性能, 结果表明, 这类水溶性生物高分子金属卟啉光敏剂具有良好的光解水产氢性能.  相似文献   
6.
Seasonal variation in surface ozone and the relationship between the background ozone concentration and wind were evaluated at Zhongshan Station,Antarctica using 2008 data.The wind frequency from the station area was only 2%,while the prevailing wind frequency was much larger (79.2%).This indicates that the surface ozone observations were not affected by the human activities at the station,and therefore could be counted as background concentrations of surface ozone along Antarctic coast.The concentration of surface ozone shows a distinct annual variation with the yearly mean of 25.0 nmol mol-1 and the maximum in winter,the minimum in summer.The surface ozone concentration had a strong negative correlation with ultraviolet radiation,and the mean values during polar night were one to two times higher than those in summer.These results imply that photochemical destruction of ozone dominates over Antarctica.The ozone depletion events at Zhongshan Station were obviously related to lower temperatures and higher BrO concentrations.Backward trajectory analysis reveals that the ozone depletion events are predominately caused by the high BrO concentrations.  相似文献   
7.
无机柔性光电子技术由于具有柔性、便携、大面积等优点而受到科研人员的广泛关注,并取得了长足的进展.制备无机柔性光电子器件的技术关键是将传统刚性衬底上的纳米"构筑单元"(Building Blocks)以一种可控的、精确的、具有超高对准度的方式集成在柔性基底上.本文针对"转印"(Transfer Printing)技术中纳米"构筑单元"向柔性衬底集成时的可控转移及确定性组装(Deterministic Assembly)等难题,提出了边缘剪切转移技术,实现了柔性硅纳米带阵列在柔性基底上的制备及确定性组装.结合悬臂梁模型及有限元模拟,得出悬空硅纳米带内部在边缘剪切转移过程中所产生的应力与其厚度、宽度之间的函数关系.此外,本文还研究了不同方向硅条带在边缘剪切转移的过程中所制备硅纳米带的边缘形貌,并优化初始硅条带的方向,得到边缘平整的硅纳米带.最终,利用该技术制备出柔性衬底上的硅基光波导.  相似文献   
8.
精品课程建设是气象教育培训能力建设的一项重要教学改革工程。虚拟演播技术丰富了精品课程教学资源的制作手段,推动了优质教学资源的开发与传播。该文就虚拟演播室技术在气象精品课程中的应用做了详细的阐释,这对进一步完善精品课程的建设有重要意义。  相似文献   
9.
将传统的马科维茨模型进行了改进,引入了风险厌恶因子,对投资比例设定了上下限,进一步利用熵对风险进行了修正,并加入了专家评价对模型实行了模糊化处理。同时提出了一种自适应并行遗传算法,其运算时间短,而且随机搜索,其遗传因子能够进行自我调节,不易陷于局部最优。将该算法引入证券投资组合领域,将数据随机分为若干个小组,同时进行遗传优化,提高了运算效率。通过应用实例,求解改进的模型,计算表明自适应并行遗传算法能够准确快速地解决证券投资组合优化问题。  相似文献   
10.
Patchy distribution of high As groundwater has normally been observed in As-affected areas. Spatial and temporal evolutions help in better understanding mechanisms of As mobilization and in developing effective strategies for ensuring drinking water safety. Four multilevel samplers were installed approximately along the groundwater flow path to investigate spatial and temporal variations in groundwater As in the Hetao basin, Inner Mongolia. Both water chemistry and groundwater level were monitored for about two years. Groundwater As concentration generally showed increasing trends, and Eh values showed decreasing trends along the flow path, indicating that As was mobilized via reductive dissolution of Fe oxides. However, in evaporation discharge area, shallow groundwater As was generally lower than those upstream and downstream. In addition to evaporation, siderite and pyrite precipitations controlled groundwater As concentrations. The negative correlations between As concentration and SIpyrite (or SIsiderite) implied that siderite and pyrite precipitations wold scavenge groundwater As and lower As concentration. Temporal variation showed different trends in different locations. It may reflect replenishment of high/low As groundwater for the increase/decrease in As concentrations, resulting from water level fluctuation. The increase trends in groundwater As concentrations at depth around 15m in the discharge areas would result from the increase in the recharge of underlying groundwater (20m) with high As concentration due to enhanced evaporation in the seasons with high water levels. The investigation suggested that monitoring of groundwater As should be routinely carried out to ensure the drinking water safety in the As-affected areas.  相似文献   
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