Study on the temperature distribution of heated falling liquid films

A 2-D theoretical model was derived to present the temperature distribution of falling liquid films flowing over a vertical heated/cooled plate with constant temperature. And the temperature gradients for different flow rates and fluids were also discussed for different liquid films. The temperature distributions for liquid films of water, ethanol aqueous solutions and glycerol aqueous solutions were experimentally investigated with a sensitive thermal imaging system. It is found that the surface temperature of a film flowing over a vertical heated solid plate has a characteristic relationship with the film flow distance. A lower flow rate of the film or a higher temperature of the wall generally leads to a higher surface temperature in the film inception. For films of glycerol aqueous solutions under the same heating conditions, a lower glycerol concentration causes a higher surface temperature of the film, due to the decrease of the liquid viscosity, whereas the ethanol concentration is found to have little influence on the temperature distribution of the film surface. Comparisons of the experimental data and the theoretical model show that the model can adequately describe the surface temperature distribution of a heated falling liquid film.     

光溅射镀膜均匀性的优化模拟

为了改善脉冲激光溅射沉积大面积薄膜的均匀性,发展了基片离轴旋转的扫描技术.根据基片离轴旋转的基本原理和等离子体羽空间余弦分布规律,建立了径向膜厚分布公式.数值模拟了各种因素对基片离轴旋转扫描沉积薄膜均匀性的影响.分析表明,优化粒子束中心与基片中心偏置距离、溅射点与基片的距离是改善基片离轴旋转扫描镀膜均匀性的主要途径.同时也考虑了电机转速、镀膜时间和激光重频的影响.通过参量优化,当均匀度要求在95％时,计算得到薄膜的最大半径超过40 mm.     

Investigation of the SiO<Subscript>2</Subscript>(Co)/GaAs heterostructures using the surface scattering of synchrotron radiation

The giant injection magnetoresistive effect has been observed in a granulated Co/SiO₂ film on a semiconductor GaAs substrate in a narrow temperature range near T = 300 K. According to the existing theory, the nature of the effect is due to the structure and physical problems of the interface layer. The spatial distribution of cobalt nanoparticles in the bulk of the Co/SiO₂ granular film and at the granular film/semiconductor substrate (GF/SS) interface has been investigated by the reflectometry and small-angle scattering of synchrotron radiation in the grazing geometry. It has been shown that the characteristic average distance between the cobalt granules in the bulk of the film is 7.3 nm. At the same time, the average distance between the granules with a vertical size of about 7.5 nm at the GF/SS interface is 32 nm. The experimental data indicate the low concentration of cobalt at the interface and the point character of the contact of the main bulk of the Co/SiO₂ film with the GaAs substrate through a relatively diluted layer of ferromagnetic cobalt granules.     

Using a nanoscale extraordinary hall effect sensor to measure the tip field of a magnetic cantilever

The spatial distribution of the magnetic field around the tip of a magnetic cantilever coated with a cobalt film 50 nm thick is investigated using an FePt extraordinary Hall effect sensor. The magnetic field’s dependence on the distance between the sensor’s surface and the MFM cantilever is measured and found to be inversely proportional to the cubic distance, as predicted in theory. The magnetic field measured on the MFM cantilever tip is found to be 0.02 T.     

Comparative study of cathode and magnetron sputtering methods for depositing Pb(TiZr)O<Subscript>3</Subscript> ferroelectric film

The radial distribution of the composition and thickness of lead zirconate titanate films deposited in several modes of magnetron and diode sputtering was measured. It was shown that the effects of deposited film resputtering with preferential lead sputtering are pronounced during ion-plasma sputtering of Pb(Zr,Ti)O₃. During magnetron sputtering, this leads to a nonuniform distribution of the film composition over the substrate, which cannot be compensated by varying the target composition. During diode sputtering with a short target-substrate distance, resputtering has no significant effect on the film composition.     

Dissipative Particle Dynamics Simulation of Microscopic Properties in Diblock Copolymer Films

利用耗散粒子动力学模拟方法研究了两嵌段共聚高分子薄膜中的一些微观性质. 结果表明：薄膜中共聚高分子链的均方根末端距2_e>^1/2、均方根回旋半径2_g>^1/2与薄膜厚度l、不同粒子间的相互作用强度a_ij、粒子与薄膜边界间的排斥作用强度a_pb均呈线性关系,而均方键长与a_ij、a_pb呈线性关系,随l增加则呈现出波浪形趋势. 2_e>^1/2与2_g>^1/2的变化趋势可以相互对应. 任一组分在薄膜中的密度分布可以通过其与薄膜边界间的相互作用来有效控制与调节.     

Modeling of near-field optical diffraction from a subwavelength aperture in a thin conducting film

A theoretical model, novel to our knowledge, to investigate the near-field optical diffraction from a subwavelength aperture in a thin conducting film is presented. A governing equation for the magnetic field distribution in an optical thin film based on the power flow theorem is derived for the first time. Thus all of the components of the electric and magnetic fields inside or outside the thin film with a subwavelength aperture embedded can be obtained by applying the Hankel transform accurately. Numerical computations are performed to illustrate the edge effect by an enhancement factor of 2.2 and the depolarization phenomenon of the transmission in terms of the distance from the film surface.     

Theoretical description of the adsorption of transition metal ions on metal surfaces with the formation of submonolayer ferromagnetic films

The influence of the temperature and ferromagnetic ordering on the adsorption of Fe, Co, and Ni transition metal ions on a copper paramagnetic substrate with the formation of a submonolayer film is described in terms of the spin-density functional theory for the first time. The conditions for the formation of magnetic monoatomic films stable with respect to island adsorption with a change in the coverage parameter Θ are revealed. Four model cases of the electron density distribution as a function of the equilibrium distance between the film and the substrate and the equilibrium thickness of the adsorption layer are considered. It is demonstrated that the inclusion of the ferromagnetic ordering substantially affects the adsorption energy and leads to its considerable increase.     

非晶硅薄膜晶体管沟道中阈值电压及温度的分布

基于氢化非晶硅薄膜晶体管(a-Si:H TFT)沟道中陷阱态的双指数分布, 区分了带尾陷阱态和深能级陷阱态的特征温度.利用源端、漏端串联电阻及沟道电阻, 将源端和漏端特征长度与有源层接触长度、SiO₂/氢化非晶硅 (a-Si:H)界面陷阱态及a-Si:H薄膜内陷阱态联系起来. 由串联电阻上电流密度相等解出沟道势. 通过泊松方程和高斯定理 得出a-Si:H TFT沟道各点的阈值电压表达式, 结果表明 沟道中某一点的阈值电压随着该点与源端距离的增大而减小. 在此基础上, 研究了自加热效应引起沟道各点温度的变化, 结果显示a-Si:H TFT在自加热效应下, 从源端到漏端各点温度变化先增大后减小, 沟道中心的温度变化最大.     

Effect of temperature oscillation on thermal characteristics of an aluminum thin film

Energy transport in aluminum thin film is examined due to temperature disturbance at the film edge. Thermal separation of electron and lattice systems is considered in the analysis, and temperature variation in each sub-system is formulated. The transient analysis of frequency-dependent and frequency-independent phonon radiative transport incorporating electron–phonon coupling is carried out in the thin film. The dispersion relations of aluminum are used in the frequency-dependent analysis. Temperature at one edge of the film is oscillated at various frequencies, and temporal response of phonon intensity distribution in the film is predicted numerically using the discrete ordinate method. To assess the phonon transport characteristics, equivalent equilibrium temperature is introduced. It is found that equivalent equilibrium temperature in the electron and lattice sub-systems oscillates due to temperature oscillation at the film edge. The amplitude of temperature oscillation reduces as the distance along the film thickness increases toward the low-temperature edge of the film. Equivalent equilibrium temperature attains lower values for the frequency-dependent solution of the phonon transport equation than that corresponding to frequency-independent solution.     

埋点靶中CH薄膜的制备工艺研究

 CH薄膜的制备是埋点靶制备的关键技术之一,本文主要研究了钨丝辅助裂解制备CH薄膜的制备工艺。研究表明蒸发舟温度和衬底温度对沉积速率影响较大,而衬底距离对沉积速率影响较小;红外光谱和质谱分析表明薄膜的主要成分是聚对二甲苯。     

Measurement of the wave characteristics of a film under the effect of external perturbations

The effect of artificial perturbations on structure formation in the water film flow over a vertical plate with a heater was studied experimentally. To measure the film thickness an eight-channel capacitance probe was used. It is shown that artificial perturbations on the liquid film surface can change the distance between rivulets from the values corresponding to the thermocapillary-wave regime of rivulet formation to the values related to the thermocapillary regime. The distance between the rivulets can be changed at Reynolds numbers higher than those corresponding to the thermocapillary regime. Artificial perturbations do not change significantly the relative amplitude of large waves, but they affect the character of amplitude dependence on the heat flux density. The work was financially supported by the Russian Foundation for Basic Research (Grants Nos. 05-08-33325-a, 06-01-00360-a) and SB RAS (Interdisciplinary Integration Project No. 111).     

Interaction of ranked copper phthalocyanine films with dry nitrogen dioxide on the basis of ESR data

The calculation procedure of the orientation distribution of molecules by the angular dependence of electron spin resonance (ESR) spectra was used to study copper(II) phthalocyanine (CuPc) films of different thickness, obtained by the molecular complex deposition on flat quartz plates. In the first stage of the deposition, the formation of the layer of the α-phase of CuPc with the predominant orientation of molecular stacks (theb-axis of the crystalline lattice) along the plate surface was formed. In the second stage, the layer with the normal disposition of molecular stacks is condensed over the first layer. The copper binuclear associates were formed during the reaction of CuPc with NO₂. The ESR spectra analysis allows us to make an assumption about the construction of associates and to calculate the distance between paramagnetic copper(II) ions. It was shown that the orientation distribution of axially symmetric CuPc associates in the film depends both on the initial film order and the conditions under which it was treated.     

Simulation of polycrystalline 3D film growth: An investigation of the evolution of grain size and texture in diamond films

An analytical method for simulating gas phase film growth has been developed and used to study the growth of diamond films during prolonged deposition, i.e. the film thickness is much larger than the lateral grain size. From a model system composed of 10⁴ grains, reliable results can be evaluated for the growth of diamond films by (111) and (001) deposition under different initial conditions and with varying growth parameters. It is demonstrated that the rate of structure evolution is sensitively influenced by the aspect ratio of diamond crystal. A near-linear proportionality between the average grain size and the thickness of films can be approximately yielded for a large film thickness which is about 10 times of the average distance of the nuclei. The proportionality constant varies for a statistical nucleation from 0.0056 to 0.43 by changing the aspect ratio. Furthermore, the orientational distribution is drastically narrowed down so that the probability of coalescence of grains with a slight orientational difference is considerably increased. Received: 28 September 2000 / Accepted: 19 February 2001 / Published online: 3 May 2001     

Non-imaging ray-tracing for sputtering simulation with apodization

Although apodization patterns have been adopted for the analysis of sputtering sources, the analytical solutions for the film thickness equations are yet limited to only simple conditions. Empirical formulations for thin film sputtering lacking the flexibility in dealing with multi-substrate conditions, a suitable cost-effective procedure is required to estimate the film thickness distribution. This study reports a cross-discipline simulation program, which is based on discrete particle Monte-Carlo methods and has been successfully applied to a non-imaging design to solve problems associated with sputtering uniformity. Robustness of the present method is first proved by comparing it with a typical analytical solution. Further, this report also investigates the overall all effects cause by the sizes of the deposited substrate, such that the determination of the distance between the target surface and the apodization index can be complete. This verifies the capability of the proposed method for solving the sputtering film thickness problems. The benefit is that an optical thin film engineer can, using the same optical software, design a specific optical component and consider the possible coating qualities with thickness tolerance, during the design stage.     

Influence of the plate inclination angle on rivulet formation and breakdown of non-isothermal liquid film

The influence of the plate inclination angle relative to the horizon on a distance between formed rivulets and breakdown of a falling water film was studied experimentally on a heater of 150×150 mm. Dependences of the distance between rivulets on the heat flux density and plate inclination angle were examined. In experiments two zones of influence of the heat flux on a distance between rivulets were revealed: at θ ≥ 20° distances between the rivulets do not depend on the heat flux, and at θ ≤ 15° they decrease with a rise of the heat flux. Data on film breakdown were generalized with consideration of evaporation effect. It is shown that there is almost no effect of inclination angle on film breakdown in the whole range of studied Reynolds numbers. The work was financially supported by the President of RF (No. NSh-6749.2006.8), Russian Foundation for Basic Research (Grants Nos. 05-08-33325-a, 06-01-00360-a) and SB RAS (Interdisciplinary integration project No. 111).     

Fabrication and structural characterization of TiO nanoparticle soft-landed on substrate by the magnetron sputtering-gas aggregation method

We have succeeded to fabricate the thin film mainly or entirely consisting of nano-crystallites TiO on a substrate at room temperature by using the magnetron sputtering combined with the gas aggregation method which has the capability to deposit grown small particles and/or clusters of the desired compound material on the substrate in soft-landed mode. The important experimental parameters to control the growth of TiO particles are identified as partial pressure of additional oxygen gas, growth-reaction distance L_td, and LN₂ cooling of growth chamber. The smallest averaged diameter of TiO nano-particles is 5.62 nm and size distribution being from 2 to 8 nm under 50 mm of L_td. The compositional uniformity is confirmed by EDS and EELS. The chemical state of the film observed by Ti 2P XPS peak confirms the primarily growth of TiO and indicates the formation of minor content of amorphous Ti_1-xO_x and/or Ti_1-xC_x particularly at the surface of the film.     

Barriola-Vilenkin黑洞Dirac场的广义Stefan-Boltzmann定律

利用薄膜模型研究Barriola-Vilenkin黑洞的热辐射,得到了黑洞的热辐射满足广义Stefan-Boltzmann定律的结论,导出的广义Stefan-Boltzmann系数不再是一个恒量,当截断距离以及薄膜厚度取定后,它是一个与黑洞视界附近的时空度规以及辐射粒子的径向平均泻流速率有关的比例系数.得到的Barriola-Vilenkin黑洞视界附近Dirac场的辐射能通量与薄层膜内辐射粒子的径向平均泻流速率成正比,与黑洞的质量平方成反比。     

脉冲高能量密度等离子体法类金刚石膜的制备及分析

利用脉冲高能量密度等离子体法在光学玻璃衬底上、在室温下成功的制备了光滑、致密、均匀的纳米类金刚石膜.工艺研究表明：放电电压和放电距离以及工作气体种类对纳米类金刚石膜的沉积起着关键作用.利用拉曼光谱、扫描电镜以及电子能量损失谱分析薄膜的形态结构表明：薄膜具有典型的类金刚石特征；纳米类金刚石膜的晶粒尺寸小于20nm甚至为非晶态；类金刚石膜中含有一定量的氮原子，随着沉积能量的升高，氮的含量增大.纳米类金刚石膜的薄膜电阻超过109Ω/cm2.对放电溅射过程进行了理论分析，结果与工艺研究的结论吻合.     

Structural,morphological and mechanical properties of niobium nitride thin films grown by ion and electron beams emanated from plasma

The influence of variation in plasma deposition parameters on the structural, morphological and mechanical characteristics of the niobium nitride films grown by plasma-emanated ion and electron beams are investigated. Crystallographic investigation made by X-ray diffractometer shows that the film synthesized at 10?cm axial distance with 15 plasma focus shots (PFS) exhibits better crystallinity when compared to the other deposition conditions. Morphological analysis made by scanning electron microscope reveals a definite granular pattern composed of homogeneously distributed nano-spheroids grown as clustered particles for the film synthesized at 10?cm axial distance for 15 PFS. Roughness analysis demonstrates higher rms roughness for the films synthesized at shorter axial distance and by greater number of PFS. Maximum niobium atomic percentage (35.8) and maximum average hardness (19.4?±?0.4?GPa) characterized by energy-dispersive spectroscopy and nano-hardness analyzer respectively are observed for film synthesized at 10?cm axial distance with 15 PFS.