电纺ZnO-碳复合纳米纤维制备及电容去离子研究

采用静电纺丝技术制备醋酸锌(Zn(Ac)——2)/聚丙烯腈(PAN)基复合纳米纤维,经预氧化、碳化及水洗处理后,制得含ZnO的复合碳纳米纤维(ZnO-CNF)电极.利用能量色散谱、X射线光电子能谱、透射电镜、拉曼光谱、热重分析、场发射扫描电镜、接触角测量仪和电化学技术表征纤维的结构和性能.结果表明,碳纤维内Zn元素分布均匀,且ZnO-CNF电极中Zn残余量随前驱液中Zn(Ac)2含量的变化而变化,同时Zn(Ac)——2的添加使得ZnO-CNF电极中碳石墨化程度提高且纤维表面亲水性改善.以该ZnO-CNF纤维为电极组装电容器用于电容去离子,ZnO的存在使电极电容性能得到明显改善,电容器去离子性能大大提高,最大电容脱盐量达到11.24mg/g.电容器脱盐的循环稳定性好,证明该ZnO-CNF电极的循环再生性好,有望应用于实际脱盐.     

多孔碳纤维电极材料的制备及电容去离子性能研究

由于碳纳米纤维比表面积(SSA)较低,在电容去离子(CDI)应用中,其脱盐效率并不理想。该研究采用静电纺丝技术制备了沸石咪唑酯骨架-8(ZIF-8)材料与聚丙烯腈(PAN)复合纳米纤维,并通过碳化工艺处理得到多孔碳纳米纤维电极材料。经过优化组分及碳化工艺后,所得碳纤维电极的SSA和孔体积分别高达398.74 m²/g和0.180 cm³/g。在1.2 V和1.6 V电压下,该电极对500 mg/L的NaCl溶液(50 mL)的盐吸附容量分别达21.16 mg/g和39.04 mg/g。此外,电化学测试结果显示,提高碳纳米纤维电极的孔隙率可以在一定程度上提高双电层电容,从而实现更高的离子吸附量和更稳定的储能性能。     

用于高性能超级电容器的电纺碳纤维材料（英文）

金属有机骨架(MOFs)被认为是制备纳米多孔碳材料并用于超级电容器电极的理想前体,因为它们能够从分子尺度调节材料的结构.但是,一方面MOFs衍生的碳通常表现出较低的石墨化水平,另一方面纳米多孔碳颗粒之间具有较大的界面电阻,这些影响因素会导致电极的导电性差,进而极大地限制它们的电化学性能.本研究成功将ZIF-67嵌入聚丙烯腈(PAN)的纳米线纤维中,并在碳化处理后可以独立地用于超级电容器电极.PAN纳米纤维在热解过程中能够产生高石墨化水平的碳纤维,一方面用于连接ZIF衍生的碳纳米颗粒,另一方面有利于电荷转移;ZIF-67可以提供氮掺杂的多孔碳结构用于电荷存储.这种电极在1A·g~(-1)的电流密度下可以达到124F·g~(-1)的质量比容量,并在10A·g~(-1)的10 000次循环中电容保持率大于92%.     

PAN基凝胶聚合物电解质超级电容器的研究

制备了PAN基凝胶聚合物电解质及PAN基凝胶聚合物超级电容器.采用交流阻抗法测量了凝胶聚合物电解质的离子电导率.采用交流阻抗、循环伏安、恒流充放电等测试方法研究了凝胶聚合物电解质超级电容器的性能,并对交流阻抗谱进行了模拟分析.结果表明,PAN基凝胶聚合物电解质的电导率在室温下可达7.54m s.cm-1,以活性炭为电极材料,内聚合的方式制备的PAN基凝胶聚合物电解质电容器的工作电压可达2.5V,内阻为8.92-12.6Ω.cm2,比容量达20.6 F/g(i=0.5 mA/cm2).     

基于超级电容器的TiN@CNTF电极制备及性能研究

超级电容器因其独特的性能在便携式、可穿戴电子器件领域有着很大的应用潜力。目前对超级电容器的研究主要集中在对超级电容器电极材料的研究上。碳纳米管纤维具有电导率高、力学性能好、柔韧性高等优点,是超级电容器的理想电极材料。但是,碳纳米管纤维电容量的提升被其较小的比表面积所限制。通过在碳纳米管纤维表面生长三维阵列能够有效提高碳管纤维的比表面积,从而增大电容量。因此,采用水热法,在碳纳米管纤维表面成功生长TiO2纳米阵列,并通过氨气氮化获得了TiN@CNTF电极材料。采用三电极测试TiN@CNTF电极在Na2SO4溶液中的比电容达到215.5mF/cm2,有望作为一种柔性超级电容器的负极材料得到应用。     

凝胶聚合物电解质MnO2/AC电容器的研究

采用液相氧化法制备了MnO2超级电容器电极材料,以MnO2为正极材料,活性炭(AC)为负极材料,丙烯腈作聚合物单体,碳酸二甲酯(DMC)与碳酸乙烯酯(EC)的混和液作增塑剂,高氯酸锂为支持电解质,采用内聚合法制备PAN基凝胶聚合物电解质MnO2/AC混合电容器.通过循环伏安、交流阻抗、恒流充放电等测试方法对混合电容器的电化学性能进行了测试.结果表明:混合电容器的工作电压为2.5 V,比容量为27.3 F/g(i=0.5 mA/cm2),比同电解质体系的AC/AC电容器提高约48.21%.     

电纺聚丙烯腈基活性碳纳米纤维及其亚甲基蓝吸附性能

以聚丙烯腈(PAN)和N,N-二甲基甲酰胺(DMF)为原料,通过静电纺丝-CO2活化法制备PAN基活性碳纳米纤维,探讨活化温度对活性碳纳米纤维孔结构及孔径分布的影响,并研究了所制备的PAN基活性碳纳米纤维对亚甲基蓝(MB)的吸附性能.结果表明,随着活化温度的升高,PAN基活性碳纳米纤维的比表面积(SBET)、总孔容(Vtotal)和微孔容(Vmi)均增大,当活化温度达到950℃时,SBET、Vtotal、Vαmi、Vtmi和VDmi分别高达1 484.5 m2·g-1、0.709 cm3·g-1、0.680 cm3·g-1、0.666 cm3·g-1和0.659cm3·g-1;Langmuir模型较Freundlich模型更适合描述所制备的PAN基活性碳纳米纤维对MB的吸附过程,且ACF950在(25±1)℃对MB的饱和吸附量高达270 mg·g-1.     

中空结构和豆荚结构Mn_2O_3纳米纤维的制备及电化学性能

采用静电纺丝技术结合热处理工艺制备了具有中空结构和豆荚结构的Mn_2O_3纳米纤维。利用扫描电镜、透射电镜、X-射线衍射、X光电子能谱仪和比表面测试仪对其进行表征,探讨了两种结构纤维的形成机制。在6 mol/L KOH中对两种结构Mn_2O_3纳米纤维进行循环伏安法和恒流充放电测试,结果表明,中空结构的Mn_2O_3纳米纤维由于其具有较高的比表面积,比电容可以达到198 F/g,高于豆荚状Mn_2O_3纳米纤维电极146 F/g的比电容;电极同时具有较优异的循环稳定性能。     

活化碳纳米纤维的制备

以电纺纤维素纳米纤维为原料,利用浸泡ZnCl2水溶液的化学活化法制备直径约为500nm的活化碳纳米纤维.ZnCl2将纤维素纳米纤维的脱水分解温度从339℃降低至287℃,将得炭率从15.7%提高至39.5%.活化碳纳米纤维表面形貌规整,无熔融现象;其纤维直径比未经活化盐处理的碳纳米纤维更小.     

MnO2/碳纳米球电化学超级电容器电极材料的制备与性能研究

利用水热法合成了纳米棒状的MnO_2/碳纳米球(CNPs)作为电化学超级电容器的电极材料.利用场发射扫描电镜(FESEM)、X射线衍射光谱分析(XRD)对样品的微观形貌、物相进行分析;利用循环伏安法和恒电流充放电测试材料的电化学性能.结果表明:纳米棒状MnO_2/CNPs复合材料具有良好的电化学性能.在0.1 A/g的电流密度,1 mol/L Na_2SO_4电解液中,电极材料的比电容高达305.6 F/g,远高于纯碳球的比电容(49.3 F/g),当电流密度增至5 A/g时,材料的比电容为235 F/g,比电容仍能保持76.9%.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

A computer generator for randomly layered structures

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

An Index mechanism for multi-scale view in spatial databases

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-