Effect of drying methods on perovskite films and solar cells

The high efficiency,solution processibility,and flexibility of perovskite solar cells make them promising candidates for the photovoltaic industry[1−8].The deposition method is one of the most critical factors that affect the performance of perovskite films.Various deposition methods have been developed to make perovskite films,including spin-coating,slotdie coating.

Size Effects of the Critical Temperature in Ferroelectric Thin Films

The size effects of the critical behaviors for the systems of interacting spins are discussed extensively inliterature.In this paper,the finite-size dependence of the critical temperature and susceptibility of the ferroelectric thinfilm are investigated numerically based on the four-state Potts model with the nearest-neighbor interactions between thedipole moments.The four orientations of the domains exist in the ferroelectric film and the movement of the domainwalls determines the polarization switching process besides the boundary conditions of the film.The critical exponentsare obtained and our investigations show that the boundary conditions play the important roles for the ferroelectricproperties of the thin films and the critical behavior of the thin films strongly depends on the feature of the surface.

Critical properties of XY model dimensional layered magnetic on two- films

Using Monte Carlo simulations, we have investigated the classical XY model on triangular lattices of ultra-thin film structures with middle ferromagnetic layers sandwiched between two antiferromagnetic layers. The internal energy, the specifc heat, the chirality and the chiral susceptibility are calculated in order to clarify phase transitions and critical phenomena. Prom the finite-size scaling analyses, the values of critical exponents are determined. In a range of interaction parameters, we find that the chirality steeply goes up as temperature increases in a temperature range; correspondingly the value of a critical exponent for this change is estimated.

A Modified Lattice Model of the Reversible Effect of Axial Strain on the Critical Current of Polycrystalline REBa2Cu3O7-δ Films

The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries （GBs） in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data.

中国电影批评史上的张恨水

从电影理论和电影史的角度出发审视中国电影批评,已经成为重写电影史的重要组成部分。尽管“鸳鸯蝴蝶派”在电影批评史中占据着重要地位,但当前研究对象主要聚焦于上海的代表人物周瘦鹃等,而对于北京的代表人物张恨水的研究相对较少。为了避免电影批评史狭隘地限定在“上海电影批评史”范畴内,有必要深入研究张恨水的电影批评。尽管张恨水是一位广为人知的通俗文学作家,目前的研究更多关注于电影叙事模式和剪辑手法对他小说创作的影响,而较少涉及他的电影批评。通过对他的电影批评的深入分析可以发现,张恨水并非电影的“门外汉”,而是在社会功能、艺术表现、技术制作和市场营销等方面拥有深刻的见解。张恨水的电影批评是“鸳鸯蝴蝶派”电影批评的重要组成部分,但在思维、视角和意识等方面与上海的“鸳鸯蝴蝶派”存在一定差异。这种差异正好突显了早期中国电影的多元共生和丰富繁荣,表明中国电影并非单一受益于某一思想的影响;相反,它是在不同观点和审美标准相互平衡和影响的情况下形成的。对张恨水的电影批评进行深入分析,有助于打破以上海为中心的传统电影史书写框架,重新解读“鸳鸯蝴蝶派”电影批评的文化价值,为理解早期中国电影生态的多元性和丰富性提供新的视角。

可延展压电薄膜基底结构界面脱粘的预测与调控

调控薄膜基底结构的表面不稳定性已被成功应用于制备可延展的新型电子设备中。然而,该类电子器件在工作中需要承受外部载荷作用,致使薄膜-基底结构界面处残余应力集中,容易诱发薄膜电子器件与基底脱粘与分层。该文将从理论分析和数值仿真角度,研究压电薄膜在柔性基底表面上的失稳特性。由于压电薄膜变形具有大位移小应变的特点,该文基于非线性Euler-Bernoulli梁理论与能量最小化原理,建立压电薄膜基底结构无屈曲、褶皱、局部屈曲及全脱层屈曲模式的理论分析模型;从能量角度定量分析了薄膜-基底结构4种模式相互演变的临界条件;通过数值仿真,验证了该文解析结的有效性,定量、定性的讨论了薄膜基底结构的材料、几何参数对4种模式演变的影响。研究结果表明:改变基底弹性模量、预应变、物理场强度和界面粘附系数能够调控压电薄膜基底结构的屈曲模式;通过调控温度变化量和电压的方式,能够实现对压电薄膜基底结构的失稳特性精细化调控。该文的研究结果将为提升薄膜基底型的电子器件的稳定性及优化设计提供理论支持。

Magnetic properties and critical behavior of quasi-2D layered Cr_(4)Te_(5)thin film

Quasi-2D layered Cr4Te5 thin film has attracted great attention because it possesses the high Curie temperature close to room temperature and relatively large saturation magnetization.However,the magnetic interactions and the nature of magnetic phase transition in the Cr4Te5 film have not been explored thoroughly.In this paper,we focused on the critical behavior of its magnetic phase transition through the epitaxial Cr4Te5 film fabricated by pulsed laser deposition(PLD).The final critical exponentsβ=0.359(2)andγ=1.54(2)were obtained by linear extrapolation together with ArrottNoakes equation of state,and their accuracy was confirmed by using the Widom scaling relation and scaling hypothesis.We find that some magnetic disorders exist in the Cr4Te5 film system,which is related to Cr4Te5 critical behavior why its critical behavior is quite far from any conventional universality class.Furthermore,we also determined that the Cr4Te5 film exhibits a quasi-2D long-range magnetic interaction.Finally,the itinerant ferromagnets of Cr4Te5 films were confirmed by the Takahashi’s self-consistent renormalization theory of spin fluctuations.Our work provides a new idea for understanding the mechanism of magnetic interactions in similar 2D layered films.

20世纪20年代以前电影评论的内容生产与媒介实践

20世纪20年代以前的电影评论在内容上主要是观影印象记录、电影放映和电影审查的消息,以及对电影知识的译介;在形式上,这一时期的电影评论缺乏主体意识,具有主观化与商业性特征,文体上表现出典型的“话体”特征。从文化层面来说,早期电影评论的媒介实践,经历了从观影记录、娱乐诉求到文化启蒙的转变。

“物化”释论:当代影视艺术审美教育之思

影视美育是当下审美教育建设中的重要一环。针对观众在影视欣赏中出现的泛娱乐、消遣等现象,借鉴庄子“物化”观对审美教育的启示,强调从入乎影视文本审美动机的营造开始,重视沉浸影视文本的审美移情的训练,提高对话影视文本的审美共鸣能力,在感知影视作品的思想内容和艺术价值中获得精神的升华。启迪人们领悟艺术活动超越时空的虚拟状态,询唤物我两忘,浑然一体的沉浸式鉴赏体验,在美感中寻找共鸣,在美的体验中升华人格,助推影视艺术审美教育的建设。

一部研究日本武士电影的拓荒之作——评罗丽娅学术新作《日本武士电影研究》

《日本武士电影研究》是一部全面系统探讨日本武士电影的学术专著,也是国内外有关武士电影研究的拓荒之作。该专著首次聚焦整部日本武士电影发展史,在丰富翔实的史料基础上立论,观点鲜明,学理丰厚。该专著针对研究内容的差异使用了多元化的批评模式,体现了专著批评思维的活跃和异变。

基于项目式教学的大学生批判性思维培养

当前大学生普遍存在能掌握书本知识,却难以提出创新性问题的现状。提出以“专业综合实验”课程为依托,采用项目式教学的方法,通过拓展书本知识和运用前沿理论知识解决项目中存在的关键问题这一过程,提升学生对于所学知识的理解、分析、判断和应用的能力,进而培养其批判性思维能力。

锥形电活性聚合物薄膜作动器的力电响应研究

以一款锥形电活性聚合物薄膜作动器为研究对象,选用Ogden材料模型对作动器进行数值计算。控制外力变化,对薄膜在变形状态下的应变量、厚度及临界电场强度进行分析,研究了预拉伸对薄膜力电稳定性的影响。结果表明:外力增加会显著提高薄膜内各点的径向应变,减小膜厚,并使得临界电场强度的分布发生改变;薄膜预拉伸程度的增加,也会提高薄膜临界电场强度,使得薄膜的力电稳定性得到增强。

生态哲学观视域下COP15中国宣传片中多模态隐喻架构研究

联合国《生物多样性公约》第十五次缔约方大会(COP15)官方宣传片真实呈现了中国为全球生态文明建设所做的努力。该研究以COP15中国官方宣传片为研究对象,基于生态话语分析、多模态话语分析与认知批评话语分析三维话语分析范式,从形式、语义、语用三个维度探究多模态符号资源在构建隐喻表层架构、激活蕴含国际生态哲学观的隐喻深层架构,以及塑造中国在保护物种多样性问题上的协同作用机制,从而揭示COP15宣传片中多模态隐喻架构所凸显的符号性、认知性与社会性,为新媒体时代下多模态短片中隐喻架构动态性与情境性解构过程提供可行分析范式。

Formation of epitaxial Tl_2Ba_2Ca_2Cu_3O_(10) superconducting films by dc-magnetron sputtering and triple post-annealing method

For obtaining pure phase T12Ba2Ca2Cu3O10 （T1-2223） films with good superconducting properties, the growth technique is improved by dc magnetron sputtering and a triple post-annealing process. The triple post-annealing process comprises annealing twice in argon and once in oxygen at different temperatures. In the first low-temperature annealing phase in argon, T12Ba2CaCu2O8 （T1-2212） is obtained to effectively minimize evaporation in the next step. With the increase of temperature in the second annealing stage in argon, the previously prepared T1-2212 inter-phase is converted into T1-2223 phase. An additional annealing in oxygen is also adopted to improve the properties of T1-2223 films, each containing an optimal oxygen content value. The results of X-ray diffraction （XRD） θ-2θ scans, 09 scans and rotational φ scans show that each of the T1-2223 films has a high phase purity and an epitaxial structure. Smooth films are observed by scanning electron microscopy （SEM）. The critical temperatures Tc of the films are measured to be about 120 K and the critical current densities Jc can reach 4.0 MA/cm2 at 77 K at self field.

Two-dimensional analysis of progressive delamination in thin film electrodes

By employing the two-dimensional analysis, i.e.,plane strain and plane stress, a semi-analytical method is developed to investigate the interfacial delamination in electrodes. The key parameters are obtained from the governing equations, and their effects on the evolution of the delamination are evaluated. The impact of constraint perpendicular to the plane is also investigated by comparing the plane strain and plane stress. It is found that the delamination in the plane strain condition occurs easier, indicating that the constraint is harmful to maintain the structure stability. According to the obtained governing equations, a formula of the dimensionless critical size for delamination is provided, which is a function of the maximum volumetric strain and the Poisson’s ratio of the active layer.

Preparation and characterization of microcrack-free thick YBa_2Cu_3O_(7-δ) films

High quality epitaxial YBa2Cu3O7-δ （YBCO） superconducting films were fabricated on （00l） LaAlO3 substrates using the direct-current sputtering method. The attainment of an unusually high film thickness （up to 2.0 μm） without mi-crocracking was attributed in part to the presence of pores correlated with yttrium-rich composition in the films. The influ-ence of the film thickness on the microstructure was investigated by X-ray diffraction conventional scan （θ-2θ,ω-scan,pole figure） and high-resolution reciprocal space mapping. The films were c-axis oriented with no a-axis-oriented grains up to the thickness of 2 μm. The surface morphology and the critical current density （Jc） strongly depended on the film thickness. Furthermore,the reasons for these thickness dependences were elucidated in detail.

Fabrication of Tl2Ba2CaCu2O8 superconducting films without thallium pellets

A new improved two-step method in fabricating Tl2Ba2 CaCu2O8（Tl-2212） thin films is presented in this paper. In the first process of dc magnetron sputtering, the thallium content in the precursor film is largely increased by adjusting the ratio of thallium in the sputtering targets. After the second annealing process in the absence of additional thallium pellets or powder source, high-quality Tl-2212 thin films can be obtained. The proper content of thallium in the precursor film provides a relatively stable atmosphere to guarantee the growth of Tl-2212 film. This method avoids the repeated production of the thallium pellets in the post-annealing process, the repeatability and controllability of the experiment are greatly improved. X-ray diffraction（XRD） scans show that all of the sharp peaks of the sample films can be assigned to the（00 l） peaks of Tl-2212 phase. The highest superconducting critical temperature（Tc） of the films is 105 K and the critical current density（Jc） can achieve 1.93 MA/cm2 in zero magnetic field at 77 K for a 600 nm film.

EFFECT OF SURFACE ENERGY ON DISLOCATION-INDUCED FIELD IN HALF-SPACE WITH APPLICATION TO THIN FILM-SUBSTRATE SYSTEMS

In this work the elastic field of an edge dislocation in a half-space with the effect of surface energy has been obtained. The elastic field is then used to study the image force on the dislocation, the critical thickness for dislocation generation in epitaxial thin films with strain mismatch and the yielding strength of thin films on substrates. The results show that the image forces on the dislocation deviate from the conventional solutions when the distance of the dislocation from the free surface is smaller than several times of the characteristic length. Also due to the effect of surface energy, the critical thickness for dislocation generation is smaller than that predicted by the conventional elastic solutions and the extent of the deviation depends on the magnitude of mismatch strain. In contrast, the effect of surface energy on the yielding strength for many practical thin films can be neglected except for some soft ones where the characteristic length is comparable to the thickness.

Mean-field and high temperature series expansion calculations of some magnetic properties of Ising and XY antiferromagnetic thin-films

In this work, the magnetic properties of Ising and XY antiferromagnetic thin-films are investigated each as a function of Neel temperature and thickness for layers （n = 2, 3, 4, 5, 6, and bulk （∞） by means of a mean-field and high temperature series expansion （HTSE） combined with Pade approximant calculations. The scaling law of magnetic susceptibility and magnetization is used to determine the critical exponent γ, veff （mean）, ratio of the critical exponents γ/v, and magnetic properties of Ising and XY antiferromagnetic thin-films for different thickness layers n = 2, 3, 4, 5, 6, and bulk （∞）.

Experimental Studies on Support Systems of High Speed Motors With Flexible Squirrel-cage Support and Squeeze Film Dampers

以100kW级工作转速为45000r／min的高速永磁同步电机为实验样机，对采用鼠笼式弹性支撑和挤油膜阻尼器的滚动轴承支撑系统进行研究。分析了弹性支撑和挤压油膜阻尼器的刚度和阻尼特性，在此基础上分别计算出刚性支撑和弹性阻尼支撑时轴承一转子系统的临界转速和瞬态动力特性。最后在样机上进行对比实验，并对电机机壳振动加速度和弹性支撑笼条微应变信号进行分析。结果表明，弹性阻尼支撑可以使转子以较低的转速通过其刚体模态，同时对转子的振动起到良好的抑制作用。实验样机稳定运行在设计工作转速，其分析和实验结果为高速电机轴系设计和动力学分析提供了参考。