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1.
对经不同离子交换的聚苯乙烯阳离子交换树脂进行了高温炭化处理 ,制备成具有高度分散状态的金属炭复合材料。考察了将这些金属炭复合材料作为二次锂离子电池炭电极的电化学行为。实验结果表明 ,掺杂不同离子的炭电极具有充、放电的不可逆性 ,其充、放电容量也有明显的差别。采用聚苯乙烯阳离子交换树脂制备二次锂离子电池炭电极材料时 ,炭化处理的温度并不是越高越好。在一定温度范围内 ,低温处理样品的充、放电容量反而高于高温处理样品  相似文献   

2.
以Ni^2 改性的聚苯乙烯阳离子交换树脂和聚苯胺树脂为炭化预聚体,制备出了锂离子电池炭负极材料,考察了炭化制备工艺对炭负极材料充电放电性能的影响。实验结果表明,采用Ni^2 改性的聚苯乙烯阳离子交换树脂和聚苯胺树脂制备锂离子电池炭负极材料时,炭化处理并不是越高越好,而是在一定温度范围内,低温处理样品的充电放电容量反而比高温处理样品的要高;在还原性气氛中炭化处理样品的充电放电容量明显高于惰性气氛中炭化处理的样品。实验数据还表明,在相同处理条件下,树脂炭化产物的粒度越小,制备出的锂离子电池炭负极材料的充电放电容量就越大。  相似文献   

3.
以Ni2 改性的聚苯乙烯阳离子交换树脂和聚苯胺树脂为炭化预聚体 ,制备出了锂离子电池炭负极材料 ,考察了炭化制备工艺对炭负极材料充电放电性能的影响。实验结果表明 ,采用Ni2 改性的聚苯乙烯阳离子交换树脂和聚苯胺树脂制备锂离子电池炭负极材料时 ,炭化处理温度并不是越高越好 ,而是在一定温度范围内 ,低温处理样品的充电放电容量反而比高温处理样品的要高 ;在还原性气氛中炭化处理样品的充电放电容量明显高于惰性气氛中炭化处理的样品。实验数据还表明 ,在相同处理条件下 ,树脂炭化产物的粒度越小 ,制备出的锂离子电池炭负极材料的充电放电容量就越大  相似文献   

4.
制备了Ni~(2+)离子掺杂的聚苯乙烯阳离子交换树脂,并对其进行碳化处理,分析了树脂 碳化产物的组成和结构,同时还考察了树脂碳化产物作为二次锂离子电池碳电极材料时的电 化学性能.实验结果表明:Ni~(2+)离子掺杂的聚苯乙烯阳离子交换树脂碳化产物与相同条件下处 理的未掺杂离子的树脂碳化产物相比,氢、氧含量有所提高,而硫含量则有所降低;Ni~(2+)离子掺 杂提高了聚苯乙烯阳离子交换树脂碳化产物的石墨化程度,并且促进了碳化产物中层片石墨 微晶结构的增长和有序排列;Ni~(2+)离子掺杂有效的提高了树脂碳化产物作为锂离子电池碳负极 材料的电化学性能.与未掺杂离子的树脂碳化产物相比,Ni~(2+)离子掺杂的树脂碳化产物组装的 锂离子电池充放电容量平均提高了约20(mA·h)/g,同时还显著降低了电池第一次充放电时的 不可逆性.  相似文献   

5.
制备了Ni^2+离子掺杂的聚苯乙烯阳离子交换树脂,并对其进行碳化处理, 树脂碳化产物的组成和结构,同时还考察了树脂碳化产物作为二次锂离子电池碳电极材料时的电化学性能。实验结果表明:Ni^2+离子掺杂的聚苯乙烯阳离子交换树脂碳化产物与相同条件下处理的未掺杂离子的树脂碳化产物相比,氢、氧含量有所提高,而硫含量则有所降低;N^2+离子掺杂提高了聚苯乙烯阳离子交换树脂脂碳化产物的石墨化程度,并且促进了碳化  相似文献   

6.
稻壳制备锂离子电池负极材料的研究   总被引:2,自引:1,他引:1  
研究了升温速率、热解温度、碱浓度对稻壳制备锂离子电池负极材料的结构和电化学性能的影响.利用差热-热重(DT-TGA)分析、元素分析、X射线衍射(XRD)等测试手段对不同条件处理后的炭材料进行表征,通过电化学分析其充、放电性能.结果表明:该材料属于无定形炭材料,首次充电容量为678.0 mA·h/ g,首次放电容量为239.0 mA·h/ g,十次循环以后容量基本稳定,可逆容量保持在206.1 mA·h/ g左右.  相似文献   

7.
以二乙烯基苯(DVB)为交联剂、偶氮二异丁腈(AIBN)为引发剂、聚乙烯吡咯烷酮(PVP)为模版剂,通过自组装,制备聚苯乙烯微球。经过氧化和高温炭化转换成硬炭微球。考察了硬炭微球作为锂离子负极材料的电化学性能。结果表明硬炭微球的首次放电比容量为505 mA·h/g,40次循环后保持在304 mA·h/g。  相似文献   

8.
测试分析了酚醛树脂碳化产物组装的锂离子充放电性能,实验结果表明,树脂碳化产物作为锂离子电池碳电极材料时,其碳化处理温度有一个最佳温范围,酚醛树脂碳化产物的最佳温度在700℃左右,树脂碳化产物的比表面积是影响电池充放电性的重要因素,碳化产物的比表面积越大,电池的充放电量就越高,电池充放电量与充放电电流密度成反比。  相似文献   

9.
以煤焦油为原料在天然石墨球表面包覆一层中间相炭制备复合炭材料,研究中间相炭、天然石墨球和复合炭材料作为锂离子二次电池炭负极材料的电化学性能,并考察不同温度热处理得到的复合炭材料的电化学性能。研究结果表明:复合炭材料同时具有中间相炭及天然石墨球的优点;随着热处理温度的升高,复合炭材料的充放电容量有所降低,于700℃处理2 h的性能最佳,首次充电容量达378 mA.h/g,首次充放电效率为91.3%。复合炭材料在Li/C扣式电池中的循环性能得到提高,50个循环后容量保持率为96%。  相似文献   

10.
有机高分子树脂碳化过程中结构基团的变化   总被引:5,自引:0,他引:5  
用红外光谱法对不同温度下处理的酚醛和聚苯乙烯阳离子交换树脂碳化物的结构基团进行了测试分析,实验结果表明,酚醛树脂苯环上的氢虽然在碳化过程中不断减少,但经1000℃碳化处理后仍有少量氢联接在苯环结构上,主要以单个或两个相邻的形式存在苯环之中,多氢相邻形式较少。在碳化过程中,聚苯乙烯阳离子交换树脂的苯环结构和稀烃基团比磺酸基团稳定,两种树脂中的苯环结构随着随碳化处理温度的升高逐渐形成多苯稠环结构,在1000℃下碳化处理时,苯环之间相互连接成多苯筒环结构的速度比较缓慢,特别是聚苯乙烯阳子交换树脂的苯环结构基团变化也较缓慢,碳化产物的石墨化程度较低。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
19.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

20.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

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