花形Fe3O4-Au纳米复合材料的制备及催化性能研究

首先利用共沉淀法合成了三维花形Fe_3O_4纳米颗粒,再利用种子沉积法在其表面负载了不同颗粒尺寸的Au纳米颗粒,最终制备了花形Fe_3O_4-Au纳米复合材料.利用X射线衍射仪(XRD)对样品的结构进行了分析,利用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对样品的形貌进行了表征.并以有机染料罗丹明B(Rh B)作为目标物,对Fe_3O_4-Au纳米复合材料的催化性能进行了研究.结果表明,由于6 nm的Au纳米颗粒具有更多的活性位点和更高的电子传输效率,因此负载6 nm Au纳米颗粒的花形Fe_3O_4-Au纳米复合材料呈现出更显著的催化性能.     

再沉淀法制备DPA纳米粒子

采用再沉淀法,以CTAB为稳定剂和软模板,制备了有机小分子9,10-二苯基蒽(DPA)的纳米粒子.考察了CTAB的浓度对生成的DPA纳米粒子的尺寸和形貌的影响.结果表明,加入CTAB有利于制备形貌规则和尺寸均匀的DPA纳米粒子.CTAB浓度较高条件下制备的DPA粒子为带状形貌,带宽约为300 nm左右,片长约为6μm,厚度约为几十纳米.     

CTAB与BDA对45号钢镀锌层耐腐蚀性的影响

采用CTAB(十六烷基三甲基溴化铵)与BDA(苄叉丙酮)作为添加剂在45号钢上进行镀锌,研究这2种添加剂对镀锌层耐腐蚀性的影响。通过利用SEM、XRD对镀锌层形貌和晶体结构、晶粒尺寸进行比较,利用塔菲尔极化曲线以及交流阻抗等测试方法对镀锌层耐腐蚀性能进行比较。结果表明,CTAB、BDA的添加改变了镀锌层的表面形貌,晶粒尺寸由微米尺寸变为纳米尺寸,晶面(110)为择优取向,提高了镀层的耐腐蚀性能;同时添加CTAB与BDA所得到的镀层形貌紧凑、平整,耐腐蚀性能最好。     

不同元素添加对CoPt纳米颗粒结构和磁性的影响

利用溶胶—凝胶法制备Co Pt,Co Pt-Ag,Co Pt-Si O2,Co Pt-Cu磁性纳米颗粒.并利用X射线衍射仪(XRD),透射电子显微镜(TEM)和振动样品磁强计(VSM)对所制备的样品进行了结构,形貌和磁性的表征.XRD结果表明700℃时Co Pt,Co Pt-Ag,Co Pt-Si O2,Co Pt-Cu磁性纳米颗粒均为面心四方结构(FCT)的L10相.TEM结果表明Co Pt-Si O2较Co Pt,Co Pt-Ag,Co Pt-Cu的颗粒尺寸小,说明了Si O2的添加抑制了Co Pt磁性纳米颗粒的尺寸生长.VSM结果显示Co Pt-Ag,Co Pt-Cu,Co Pt-Si O2较Co Pt的矫顽力大,说明一定量的Ag,Cu,Si O2的添加更能促进Co Pt纳米颗粒磁性的增长.     

高分子稳定的水溶性铂氧化物纳米颗粒的制备

利用铂氯化物的水解反应,制备出聚乙烯吡咯烷酮(PVP)稳定的水溶性二氧化铂纳米颗粒.此法所得的产物颗粒小,粒径分布窄,稳定,室温下放置几个月无沉淀.用紫外-可见光谱检测纳米颗粒的形成过程,用X-射线光电子能谱(XPS)和透射电子显微镜(TEM)对样品的成分、形貌、尺寸进行了表征,并考察了PVP的浓度以及体系的酸碱度对形成二氧化铂颗粒粒径的影响.     

改性纳米羟基锡酸锌的制备及表征

用共沸蒸馏方法制备了纳米ZnSn(OH)6颗粒,然后在共沸蒸馏纳米ZnSn(OH)6-正丁醇的体系中,直接加入硬脂酸制备了改性纳米ZnSn(OH)6颗粒.用XRD、TEM、FTIR和TG/DTA等对这种纳米颗粒的形貌和结构进行了表征,所得表面改性纳米ZnSn(OH)6的大小为60~80nm.并对改性机理进行了初步探讨.把改性纳米颗粒加在软质PVC中,和微米级产品相比,其氧指数提高17.8%.     

基底材料对嵌入型Fe_3O_4纳米颗粒的应变场影响

埋嵌型纳米颗粒在生长的过程中会受到周围基质材料对其施加的应力作用,应力的大小不仅会对纳米颗粒的晶格结构和物理性能产生影响,还与纳米颗粒的尺寸大小息息相关.因此,研究埋嵌在不同薄膜材料中的纳米颗粒生长过程中的应变场分布对于调控纳米颗粒的物理性能有着重要的意义.该文利用脉冲激光沉积和快速退火技术成功地制备了分别镶嵌在非晶氧化铝薄膜、非晶氧化镥薄膜和非晶二氧化硅薄膜中的Fe_3O_4纳米颗粒,并利用透射电子显微镜观察这些球形纳米颗粒.为了研究纳米颗粒的尺寸与应力大小之间的关系,采用有限元算法分别模拟仿真了这些纳米颗粒的应变场分布,并对结果进行了系统的分析.研究发现:Fe_3O_4纳米颗粒在不同薄膜材料生长过程中均受到非均匀偏应变作用,而且纳米颗粒的尺寸及应变场分布与纳米颗粒周围基质材料的杨氏模量和泊松比密切相关.在不同基质材料中生长的纳米颗粒所受到的应变场分布也有所不同,这为调控纳米颗粒的晶格结构和形貌以及物理性能提供了一个新思路.     

印制电子技术中纳米铜导电墨水的研制

以次磷酸钠(NaH_2 PO_2·H_2O)为还原剂,硫酸铜(CuSO_4·5H_2O)为前驱体,十六烷基三甲基溴化铵(CTAB)为表面活性剂,聚乙烯吡咯烷酮(PVP)为保护剂,在一缩二乙二醇(DEG)有机液相溶液中采用化学还原法成功地制备了铜纳米颗粒.采用XRD、TEM、SEM、纳米粒度仪及IR对所制备的铜纳米颗粒的结构、形貌、粒径大小及表面物质进行表征.结果表明制备的纳米铜粒子为球型颗粒,分散较好,尺寸较为均匀,平均粒径约为27 nm,并且具有立方晶型结构,其表面被有机物包覆.涂布纳米铜导电墨水的样品,其在高于250℃的温度下烧结60min后得到导电铜薄膜.温度在300℃烧结后,导电铜薄膜更加致密,可以推测铜薄膜的导电性能会增加.     

纳米CeO2粉体的合成及结构表征

以三氯化铈(Ⅲ)为原料,氢氧化钠为矿化剂,通过水热法制备了形貌可控的CeO2粉体.采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对合成的样品进行物相和形貌分析.同时,实验还研究了水热反应条件对产物形貌和粒度分布的影响.XRD测试结果表明,通过水热法在温度为120℃条件下,反应6h即可得到纳米粒子,且随着时间的延长其晶粒变大,而表面活化剂CTAB的加入对纳米粒子的影响不大.SEM和TEM图显示表明,在120℃下,反应120h得到的CeO2为纳米立方体颗粒,其粒径为(10-50) nm.     

升温速率对CoFe2O4纳米颗粒性能的影响

利用热分解法制备CoFe₂O₄纳米颗粒,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)和振动样品磁强计(VSM)等方法分析样品的晶体结构、微观形貌和磁性能,研究样品制备过程中不同升温速率对样品微观形貌和磁学性能的影响.结果表明,提高升温速率可增加晶核生长动力,有利于样品的晶粒生长,从而增大样品的饱和磁化强度和矫顽力.     

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-