三明治结构薄膜GMI效应的频率特性

利用一定边界条件下的Maxwell方程、Landau-Lifshitz方程和欧姆定律,解出了三明治结构薄膜的阻抗公式,式中包含了各向异性和交换作用等因素.利用MATLAB进行了数值计算,得出三明治薄膜阻抗与外磁场和频率的关系曲线.结果表明中间夹高导电材料的三明治薄膜的巨磁阻抗效应比单层磁性薄膜大,铁磁层为横向各向异性时阻抗的峰值将出现在外磁场与各向异性场相等的位置,并存在某一最佳频率使阻抗达最大值.     

非晶FeCuNbSiB多层膜的巨磁阻抗效应

研究在250℃退火温度下非晶FeCuNbSiB薄膜的巨磁阻抗效应.X-ray谱和Mossbauer谱显示样品为非晶状态.导电层的厚度为2 μm,磁性层的厚度为1 μm.三明治结构的最大阻抗效应为20%.为了提高巨磁阻抗效应,在两磁性层之间加入了绝缘层SiO2,在250℃退火温度下最大阻抗效应为62%.随着驱动电流频率的增大,磁阻抗效应曲线由随磁场的单调下降变为出现峰的结构.     

非晶FeCuNbSiB多层膜的巨磁阻抗效应(英)

研究在250℃退火温度下非晶FeCuNbSiB薄膜的巨磁阻抗效应.X-ray谱和Mössbauer谱显示样品为非晶状态.导电层的厚度为2μm，磁性层的厚度为1μm.三明治结构的最大阻抗效应为20%.为了提高巨磁阻抗效应，在两磁性层之间加入了绝缘层SiO₂，在250℃退火温度下最大阻抗效应为62%.随着驱动电流频率的增大，磁阻抗效应曲线由随磁场的单调下降变为出现峰的结构.     

磁性多层膜磁特性的蒙特卡罗模拟

利用Monte Carlo模拟方法研究了样品的尺寸、交换耦合相互作用、各向异性对磁性多层膜的磁特性的影响。重点研究磁性多层膜的维度特性及其相变，当磁性层厚度减小时，系统从三维转变为二维，居里温度减小，M（T）呈线性的维度效应。Bloch系数B与磁相互作用J及平均配位数Z有很大的关系，B正比于^-Z^-3/2及J^-3/2。模拟结果与用自旋波激发理论和平均场理论计算的结果相吻合，且较好地解释了实验事实。     

Ti(t)/Co(54nm)/Ti(t)纳米薄膜的制备和磁特性

应用对靶磁控溅射法在玻璃基底上制备了Ti(t)/Co(54nm)/Ti(t)(t=5,10,15,20,25nm)纳米薄膜,研究了非磁性Ti层厚度对样品磁特性的影响.实验结果显示,Ti(5nm)/Co(54nm)/Ti(5nm)样品的垂直膜面矫顽力高达159kA·m-1.研究表明,如此高的矫顽力主要源于样品晶粒的磁晶各向异性.另外,非磁性Ti原子的扩散在一定程度上减小了磁性颗粒间的交换相互作用,导致出现大的矫顽力.     

任意方向磁化磁各向异性单晶YIG薄膜中静磁波色散特性

考虑退磁场、单轴磁各向异性和立方磁各向异性,导出了在(110)面内与膜面法向[111]成任意角度磁化的单晶YIG薄膜的静磁波色散方程,并用该方程计算出了0°～90°范围内的静磁共振模式,与实验结果符合得较好.本文的理论和实验结果进一步完善了单层磁性薄膜的静磁模共振理论.     

真空蒸镀法制备巨磁阻抗材料

采用真空蒸镀法在玻璃基片上制备具有巨磁阻抗效应的单层FeS iB薄膜.通过改变驱动电流方向和外磁场方向,得到4种测量巨磁阻抗效应的方式.通过比较发现,只有当外加磁场和单轴磁各向异性方向垂直时才有比较明显的巨磁阻抗效应的出现,并比较了磁各向同性和磁各向异性FeS iB薄膜的巨磁阻抗效应.验证了用真空蒸镀法能够制备具有巨磁阻抗效应材料的可行性.     

溅射工艺对NiFe/Cu复合丝结构和性能的影响

利用射频磁控溅射法分别采用连续溅射和间歇溅射工艺制备了Ni80Fe20/Cu复合结构丝。通过扫描电镜和X射线衍射等手段研究了溅射模式对复合丝微观结构的影响.结果表明：间歇溅射使镀层之间形成明显的界面,镀层结晶度增加,晶粒较大.利用巨磁阻抗效应和磁滞回线手段分析了样品的磁性能,发现实验中溅射的磁性层具有良好的软磁性能,复合丝呈现出较大的巨磁阻抗效应.当采用间歇溅射工艺时,由于复合丝的镀层中存在明显界面,内、外磁层的磁化行为不同,出现两个各向异性场.该样品经退火后,释放了一部分内部应力,软磁性能提高,阻抗效应增强,且内、外磁层磁性能趋于一致.     

Cu层厚度对NiFe/Cu/Co 的巨磁电阻效应影响

用磁控射频溅射法制备了NiFe/Cu/Co多层膜;研究了薄膜的磁特性和磁电阻特性与中间层Cu厚度的关系.在适当的Cu层厚度下 (大约为2 nm),制备出了具有很好自旋阀巨磁阻效应的多层膜.研究表明,在弱磁场下,薄膜的磁电阻回线的斜率与原来的磁化过程有关,因此该薄膜材料可以用于巨磁电阻存储器中.     

Co-Al-O磁性纳米颗粒膜微波磁性研究

通过实验研究和理论计算模拟研究Co-Al-O磁性纳米颗粒膜的微波磁性.首先采用双靶反应磁控溅射工艺制备Co-Al-O磁性纳米颗粒膜,探讨工艺条件对薄膜微波磁谱的影响;然后,利用Landau-Lifshitz-Gilbert方程和Bruggeman有效媒质理论,计算模拟主要磁参量变化对磁性纳米颗粒膜磁谱的影响.研究结果表明:增大Co靶溅射功率,可使磁性颗粒间因分布电容效应引起的涡流损耗增加,从而使磁谱的共振线宽增大;阻尼系数增大导致磁导率频谱的共振线宽增人趋势与实验结果基本一致.     

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