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.

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.

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 Tl_(2)Ba_(2)CaCu_(2)O_(8) superconducting films without thallium pellets

A new improved two-step method in fabricating Tl_(2)Ba_(2)CaCu_(2)O_(8)(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(T_(c))of the films is 105 K and the critical current density(J_(c))can achieve 1.93 MA/cm^(2) 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。

Evaluation of Interfacial Adhesion Property for Thin Hard Films with Fuzzy Method

According to nanoscratch results for the TiN film, an evaluation method for interfacial fracture toughness of thin hard films is presented with fuzzy concepts, which can account for such influential factors in scratch test as surface roughness and material imperfection. Based on configuration changes in scratching curves, the parameters RV and RF are defined as the relative ratios of tip vertical displacement and of friction coefficinet. Fuzzy features of the scratching curves are analyzed carefully. The critical load is deduced from fuzzy logic operations and used to calculate the value of interfacial fracture toughness. With this method, the interfacial fracture toughness of TiN/HSS is evaluated approximately as 4.18 MPam^1/2. Results show that the method is valid and can benefit the interfacial adhesion property investigation for thin hard films.

Observation of lateral long range order in superconducting FeTe thin films

We find that the superconductivity in the thin films of the formerly believed non-superconducting parent compound FeTe is accompanied by an emergence of second order with a correlation length of 742 nm and 258 nm at 10 K and 300 K, respectively. The structural phase transition found in iron pnictide superconductors, in non-superconducting FeTe bulk samples, and in FeSe superconducting thin films is not observed in the superconducting FeTe thin films. The interplay between superconductivity and long range order may suggest the crucial role of competition between electronic localization and itinerancy which leads to strong quantum fluctuations in the FeTe system.

Studies on the Condensed Structure of Vacuum Cast Atactic Polystyrene Films

The condensed structure of atactic-polystyrene (a - PS ) films cast from the solutions of differ- ent concentrations in dichloromethane under vacuum and atmospheric conditions was studied by differential scanning calorimetry(DSC). It was found that only under vacuum evaporating conditions did the endothermic peak in the DSC curves of a-PS films depend on the concentration of the a-PS solution. For the samples cast from the solution of concentration below 0. 010 g/mL, no endothermal peak was observed, but for those cast from the solution of concentration above 0. 020 g/mL, obvious endothermal peaks appeared. The onset of the endothermal peak is correlated with the critical overlapping concentration c' (0. 010-0. 020 g/mL), which is in agreement with the theoretically calculated one (Ccal=0.014 g/mL).

Reactive Radiofrequency Sputtering-Deposited Nanocrystalline ZnO Thin-Film Transistors

The structural and electrical properties of ZnO films deposited by reactive radiofrequency sputtering with a metallic zinc target are systematically investigated.While the as-deposited ZnO film is in a poly-crystalline structure when the partial pressure of oxygen(pO_(2))is low,the grain size abruptly decreases to a few nanometers as pO_(2)increases to a critical value,and then becomes almost unchanged with a further increase in pO_(2).In addition,the resistivity of the ZnO films shows a non-monotonic dependence on pO_(2),including an abrupt transition of about seven orders of magnitude at the critical pO_(2).Thin-film transistors(TFTs)with the nanocrystalline ZnO films as channel layers have an on/off current ratio of more than 10^(7),an off-current in the order of pA,a threshold voltage of about 4.5 V,and a carrier mobility of about 2 cm^(2)/(V.s).The results show that radiofrequency sputtered ZnO with a zinc target is a promising candidate for high-performance ZnO TFTs.

Erratum to“Fabrication of Tl_(2)Ba_(2)CaCu_(2)O_(8) superconducting films without thallium pellets

The rocking curve of Tl-2212 thin films in Fig.2 of our original paper[1]should be replaced with the following new one.Accordingly,in the fifth paragraph of Section 3 of the original paper,the statement“The full width at half maximum(FWHM)of the(0012)peak of the Tl-2212 phase is about 0.24°”should be“The full width at half maximum(FWHM)of the(0012)peak of the Tl-2212 phase is about 0.42°”.

Preparation of Y_(1-x)Ho_xBa_2Cu_3O_(7-δ) Superconductive Thin Films

Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu_3O_(7-δ)(YBCO) and half of HoBa_2Cu_3O_(7-δ)(HBCO) superconducting materials. As the distance between HBCO targetmaterial and substrate is varied , the Ho content in material is changed respectively. When the content of Ho is0. 7 (atom ratio) , the T_c>83K.

Duties of a Cinematographer in Creating a Film

The present article deals with the duties, role and methodical peculiarities of a cinematographer in creating a feature film. The development of creating artistic works in the high creative level and its process is comparatively analyzed within the progress of the Uzbek cinematography.

一种新的水平气井临界携液气流速预测模型

气井中积液现象为井筒中液体的回流和聚集,是气井中严重的生产问题之一,会导致产量降低,甚至造成停产。气井积液预测能力对于保证气井正产生产和优化相关生产工艺具有重要意义。为了及时采取适当的对策防止积液现象的发生,准确预测和识别积液点至关重要。使用空气-水混合物在管径为60 mm的管道中进行了压力为0.2 MPa和0.5 MPa时0~90°倾角的室内实验,分析了在不同角度、压力和液体流量下临界气体流量的变化,随着角度的增大,临界气量先增大后减小,倾斜段是最难携液的井段,且55°倾角是最难携液的角度。在液膜受力分析的基础上,考虑到倾斜气井井壁的液膜分布不均匀,采用SHEKHAR的最大液膜厚度分布关系式进行计算,考虑到气芯中液滴载荷和液膜夹带的平衡,建立了一种新的水平气井临界携液气流速预测模型。利用实验数据和现场数据将新模型与LUO模型、BARNEA模型和LIU模型进行比较,新模型计算结果与现场数据吻合最好,准确率为91%,表明该模型比其他积液预测模型具有更好的性能,可用于对水平气井积液的判断。

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。