沉积氧压对RuVO2合金薄膜结构及MIT特性的影响研究

本工作采用脉冲激光沉积法,以c-Al_2O_3为衬底,金属钌(Ru)镶嵌金属钒(V)圆片作为靶材,高纯氧气为反应气体,在不同沉积氧压下制备出一系列RuVO_2合金薄膜.采用XRD、XPS、紫外-可见-近红外光谱仪、四探针测试仪等表征了薄膜的结构、成分及光电性能.实验结果表明:在不同沉积氧压下,薄膜均沿(010)晶面高度取向生长,薄膜的摇摆曲线半高宽在0. 050°～0. 091°之间,薄膜具有良好的结晶质量.低氧压(1. 5 Pa)下制备的RuVO_2薄膜成分严重偏离化学计量比而含有大量O空位缺陷.随着沉积氧压增大,薄膜化学成分接近化学计量比2∶1;在大于2. 4 Pa氧压条件下制备的薄膜都表现出显著的MIT特性,薄膜相变温度在50～55℃之间,在相变前后电阻率发生3个数量级的突变,同时对红外光展现出良好的调制能力,最高可达17%.氧压太高将降低薄膜沉积速率而不利于薄膜生长.     

氧压对PLD技术制备0.935Bi_(1/2)Na_(1/2)TiO_3-0.065BaTiO_3-0.01Al_6Bi_2O_(12)薄膜的影响

压电薄膜具有优异的铁电、压电和介电性能,被广泛的应用于存储器、微传感器和微驱动器等领域中.目前脉冲激光沉积技术(PLD)成为一种新兴的薄膜制备技术,沉积薄膜的质量容易受到衬底温度、氧压、靶材与衬底距离、激光能量等方面的影响.本文基于0.935Bi_(1/2)Na_(1/2)TiO_3-0.065BaTiO_3-0.01Al_6Bi_2O_(12)(简称为BNBT-0.01AB)薄膜,利用PLD制备技术研究了不同氧压(15Pa,30Pa)对沉积的薄膜结构与性能的影响.结果表明:在30Pa下沉积得到的薄膜产生了(l00)方向的择优取向生长,晶粒呈立方块状,有效压电系数d*33为103pm/V;15Pa下沉积得到的薄膜为随机取向,晶粒呈片状,有效压电系数d*33为69pm/V.本研究结果为选择合适的沉积参数提供了有利的参考.     

氧压对用PLD法制备的ZnO薄膜的特性影响

通过脉冲激光沉积方法在不同的氧压中制备ZnO 薄膜.用X射线衍射(XRD)谱、原子力显微镜(AFM)及光学透过率谱表征了薄膜的结构和光学特性.XRD谱和AFM显示在生长压力为2Pa时获得了较好的结晶薄膜,随着氧压的提升薄膜表面平整,晶粒均匀.光学透过率谱显示在生长压力为5Pa时有较好的光学特性.     

磁控溅射参数对钛酸锶钡薄膜生长及介电性能的影响

使用射频磁控溅射系统在Pt/SiO_2/Si基片上沉积了Ba_(0.6)Sr_(0.4)TiO_3(BST)薄膜,研究了溅射过程中氧氩比与溅射总气压对BST薄膜生长过程及介电性能的影响。通过XRD衍射仪、原子力显微镜等对在不同条件下制备出的薄膜样品进行了性能测试和分析。结果表明:增加氧氩比能够增加薄膜表面晶粒尺寸,提升薄膜的结晶度,增加薄膜的介电常数并降低介电损耗,但同时也会降低薄膜的沉积速率;增加溅射气压会导致薄膜表面晶粒尺寸减小、结晶度降低,薄膜的沉积速率随着溅射气压的增加呈现先增加后降低(溅射气压大于2Pa时)的趋势。     

激光分子束外延ZnO薄膜的缺陷发光研究

利用激光分子束外延方法在温度为573 K的单晶硅(100)衬底上制备了不同氧压条件下的氧化锌薄膜,对其结构和光学特性进行了研究.结果表明:所有的ZnO薄膜都具有很好的C轴择优取向.在氧压为1 Pa时,薄膜紫外发光最强,半高宽最窄(101 meV).变温发光光谱表明:当温度从80 K升至室温时,制备氧压为1 Pa的薄膜未发现可见光发射;而制备氧压为30 Pa的薄膜随着测量温度的降低,出现了可见光发射,并且随着测量温度的降低,与氧空位、氧占位和氧替锌位相关的缺陷发光峰出现红移,而与氧替锌位发光峰相近的锌位缺陷发光峰出现蓝移.     

沉积气压对磁控溅射ZrO2薄膜光性能的影响

为了探究沉积气压对ZrO₂薄膜光学特性的影响规律，以玻璃和硅片为基底，利用射频磁控溅射的方法在不同沉积气压下制备ZrO₂薄膜样品.通过分光光度计测定薄膜在可见光波段的透射光谱，利用椭圆偏振谱仪表征薄膜的折射率、消光系数、厚度等光学参量，利用原子力显微镜观测薄膜表面的微观结构等.结果表明：(1)薄膜的沉积速率随沉积气压的增大而减小，沉积气压为0.4 Pa时沉积速率最大，为0.033 nm/s，沉积气压为1.0 Pa时沉积速率最小，为0.011 nm/s；(2)当沉积气压为1.0 Pa时，200～1 000 nm波段薄膜的平均透射率和折射率均最高，分别为82.71%和2.35，表现出良好的透光性；(3)沉积气压对薄膜消光系数的影响较小；(4)不同沉积气压下制备薄膜的表面粗糙度也不同，沉积气压为1.0 Pa时薄膜的粗糙度最低，为5.5 nm，沉积气压为0.6 Pa时薄膜的粗糙度最高，为25.2 nm.     

氧分压对Zn0.99Mn0.01O稀磁薄膜结构和磁学特性的影响

采用脉冲激光沉积技术在Al2O3衬底上制备了Mn掺杂的ZnO稀磁薄膜.通过不同氧压下所制备样品的微观结构、光学性质和铁磁特性分析,研究了氧分压对Zn0.99Mn0.01O稀磁薄膜微观结构和磁学特性的影响.结果表明,所沉积薄膜均具有良好的c轴择优取向.在氧分压为5 Pa时得到的(002)衍射峰半高宽最小,但薄膜的室温铁磁...     

氧分压对磁控溅射BST薄膜及其介电性能的影响

为了应用平板式射频磁控溅射设备制备出良好介电性能的钛酸锶钡(BST)纳米薄膜,研究了溅射过程中不同氧分压(pO2)对沉积薄膜的化学成分、结晶性、表面形貌、电学性能的影响.实验结果表明:纯氩无氧气氛沉积的BST纳米薄膜化学成分符合化学计量比,经750℃、30 min氧气保护热处理后,呈现出BST材料固有的钙钛矿相,有较高的介电常数(rε=700)和较低的漏电流密度(1.9μA/cm2);氧氩混合气氛沉积的BST纳米薄膜,由于氧负离子反溅射作用,使薄膜的化学成分偏离化学计量比,经相同热处理后,不能形成相应的晶体结构,导致薄膜的rε下降、漏电流密度提高,介电性能变坏;pO2的变化对沉积薄膜的化学成分影响不大.     

溅射气压对ZnO薄膜生长、发光性能和结构的影响

沉积缺陷少、晶粒高度c轴择优生长的ZnO薄膜是制备短波发光器件和压电谐振传感器的关键问题之一.以ZnO为靶材,采用射频磁控溅射法在玻璃衬底上制备纳米ZnO薄膜,实现了室温下强的紫外受激发射和弱的深能级发射.通过对薄膜表面形貌的观测, 以及对X射线衍射(XRD)谱和室温光致发光(PL)谱的分析,研究了不同溅射气压对ZnO薄膜生长、结构和发光性能的影响.结果显示溅射气压在1.9 Pa-3.5 Pa之间,晶粒直径先增大后减小,在2.6 Pa时晶粒生长到最大;在3.2 Pa时薄膜单一取向性最优,以此推断最佳的溅射气压在2.6 Pa-3.2 Pa之间.实验在玻璃衬底上制备出了XRD衍射峰半高宽仅为0.12°的、高度c轴择优生长的ZnO薄膜.     

高质量外延VO_2薄膜制备及其金属-绝缘体相变特性研究

采用脉冲激光沉积法,在c面蓝宝石衬底上,以VO_2陶瓷作为烧蚀靶材,高纯氧气作为反应气体,固定衬底温度600℃,通过改变生长氧压制备VO_2薄膜.利用X线衍射仪、原子力显微镜、四探针测试仪测试,系统研究生长氧压对VO_2薄膜晶体结构、表面形貌、金属-绝缘体相变(MIT)特性的影响.实验结果表明:生长氧压1.2 Pa时,薄膜(020)晶面摇摆曲线半高宽低至0.061°,结晶质量高;薄膜表面平整光滑;薄膜相变温度接近68℃,金属-绝缘体转变特性显著,电阻率有4个数量级变化.     

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-