NdB2Cu3O7-x/YBa2Cu3O7-y高温超导薄膜的稳定性研究

采用脉冲激光沉积方法 ,在钇稳定氧化锆 (YSZ)衬底上制备了YBa2 Cu3 O7-y高温超导薄膜和NdB2 Cu3 O7-x/YBa2 Cu3 O7-y双层高温超导薄膜。X射线衍射分析结果表明 ,NdB2 Cu3 O7-x/YBa2 Cu3 O7-y双层膜在结晶度、表面光滑平整度和稳定性方面优于YBa2 Cu3 O7-y薄膜 ;电阻温度曲线测量结果表明 ,NdB2 Cu3 O7-x/YBa2 Cu3 O7-y双层膜的转变温度为 87.6 6K ,转变宽度为 0 .34K ;YBa2 Cu3 O7-y薄膜的则分别为 86 .6 4K和 0 .95K。与YBa2 Cu3 O7-y薄膜相比 ,NdB2 Cu3 O7-x/YBa2 Cu3 O7-y双层膜稳定性更高 ,在超导电子器件领域更具有应用潜力。     

NdB2Cu3O7—x／YBa2Cu3O7—y高温超导薄膜的稳定性研究

采用脉冲激光沉积方法，在钇稳定氧化锆（YSZ）衬底上制备了YBa2Cu3O7-y高温超导薄膜和NdB2Cu3O7-x/YBa2Cu3O7-y双层高温超导薄膜。X射线衍射分析结果表明，NdB2Cu3O7-x/YBa2Cu3O7-y双层膜在结晶度、表面光滑平整度和稳定性方面优于YBa2Cu3O7-x薄膜；电阻－温度曲线测量结果表明，NdB2Cu3O7-x/YBa2Cu3O7-y双层膜的转变温度为87.66K，转变宽度为0.34K;YBa2Cu3O7-y薄膜的则分别为86.64K和0.95K。与YBa2Cu3O7-y薄膜相比，NdB2Cu3O7-x/YBa2Cu3O7-y双层膜稳定性更高，在超导电子器件领域更具有应用潜力。     

La部分替代Y对YBa2Cu3O7-δ氧传感器性能的影响

在Al2O3衬底上制备了Y1-xLaxBa2Cu3O7-δ(0≤x≤0.15)厚膜,研究了La部分替代Y对YBa2Cu3O7-δ氧传感器性能的影响和x=0.05样品的电阻与温度和氧分压的关系.与未掺杂膜相比较可看出,各组样品仍然表现出YBCO的基本性质,其中Y0.95La0.05 Ba2Cu3O7-δ样品表现出较高的灵敏度和较短的恢复时间,是替代 YBa2Cu3O7-δ作为氧传感器的良好的材料.     

添加剂对电泳法制备YBa2Cu3O7-δ超导涂层的影响

第二代高温超导带材YBa2Cu3O7-δ(YBCO)具有高载流能力、高不可逆场、低交流损耗和高转变温度,成为当前的热点研究对象.采用低成本的电泳沉积技术在Hastelloy合金上成功制备了YBCO超导层.添加剂对电泳液的稳定性及涂层性能有着重要影响.实验研究了添加剂(种类选择及添加量)与YBCO超导层的关系.结果表明,添加005gPVB时所制备的样品具有较好的超导电性,其临界电流密度可达100A/cm2(0T,77K).     

去除难降解有机废水COD用高效多相催化剂的研究

以超细 γ- Al2 O3 为载体 ,担载 Cu O,制备去除有机废水 COD用高效超细 γ- Al2 O3 /Cu O催化剂 ,采用 TEM和XRD对粒子形态进行表征 .以水溶性偶氮染料活性艳红 X- 3 B为处理对象 ,采用不同载体制备催化剂 ,考察其催化效率 ,结果表明超细 γ- Al2 O3 /Cu O催化剂的效率最高 .     

高温超导体GdBa_2(Cu_(1-x)Fe_x)_3O_(7-δ)中Fe的位置与价态的确定

利用~(57)Fe的穆斯堡尔效应对高温超导氧化物GdBa_2Cu_3O_(7-8)进行研究,分析Fe的价态与环境.Fe在氧化物中存在四个亚晶位(Fe(A),Fe(B),Fe(C),Fe(D)),其中Fe(A),Fe(B)和Fe(C)占据氧化物中Cu(1)的位置,只是氧配位不同;Fe(D)占据Cu(2)的位置.     

在硅基材料上用Sol-gel法制备涂层测定氧扩散系数研究

提出一种测定氧扩散系数新方法.用Sol-gel法制备了Y2O3/SiO2均匀致密的薄膜,能成功解决其它方法无法得到的冶炼所得到的熔体,光学椭偏测定氧化层的膜厚.探讨了氧在薄膜中的扩散,在Wagner理论基础上,用数学方法表达在掺杂SiO2薄膜氧扩散系数与氧化层膜厚的关系.     

电子束蒸发Al2O3/SiO2复合薄膜电学性能的研究

利用离子辅助电子束蒸发技术,在玻璃基底上以交替沉积的方式制备了A12O3/SiO2叠层复合薄膜,单层介质膜膜厚分别选取54和16 nm,总厚度为560 nm.采用步进法测试得到金属电极/复合绝缘膜/金属电极(MIM)结构的I-V特性曲线,具体成分为CrCuCr/(Al2O3/SiO2)8/CrCuCr,相应的厚度为80...     

BaCo_(0.7)Fe_(0.2)Nb_(0.1)O_(3-δ)钙钛矿型混合导体透氧膜的性能

混合导体固体透氧膜与POM制氢工艺相耦合,可以较大幅度地降低制氢成本.由于透氧膜在高温、强还原性气氛下工作,仅仅具有较高的透氧能力并不能满足实际应用需求,还必须具有较高的化学稳定性.通过O2-TPD,CO2-TG及透氧实验研究了两种透氧能力最高的膜材料BaCo0.7Fe0.2Nb0.1O3-δ及Ba0.5Sr0.5Co0.8Fe0.2O3-δ.研究发现,由于Ba0.5Sr0.5Co0.8Fe0.2O3-δ钙钛矿中A位的Sr2+被Ba2+取代及B位的Co4+部分被Nb5+取代,有效地提高了BaCo0.7Fe0.2Nb0.1O3-δ钙钛矿材料的化学稳定性.     

Cu/SO_4~(2-)/TiO_(2-)Al_2O_3催化剂的制备及其催化性能研究

采用共沉淀法制备复合载体TiO2-Al2O3,并采用SO42-进行改性,然后负载上铜,制成Cu/SO42-/TiO2-Al2O3催化剂.借助红外光谱、X射线衍射等方法,研究该催化剂性能与结构的关系.催化性能的测试结果表明:Cu/SO42-/TiO2-Al2O3对于富氧条件下丙烯选择性还原NO反应具有良好的催化活性和水热稳定性,在275℃能使NO转化率高达83%.添加Ti不影响-γAl2O3的晶相结构,添加SO42-能与钛形成具有超强酸的结构,从而能够有效促使Cu/SO42-/TiO2-Al2O3催化性能的提高.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that