First-principle study on the effect of high Li-2N co-doping on the conductivity of ZnO

Based on the density functional theory (DFT), using first-principles plane-wave ultrasoft pseudopotential method, the models of the unit cell of pure ZnO and two highly Li-2N co-doped supercells of Zn_0.9375Li_0.0625O_0.875N_0.125 and Zn_0.9167Li_0.0833O_0.8333N_0.1667 were constructed, and the geometry optimization for the three models was carried out. The total density of states (TDOS) and the band structures (BS) were also calculated. The calculation results showed that in the range of high doping concentration, when the co-doping concentration is more than a certain value, the conductivity decreased with the increase of co-doping concentration of Li-2N in ZnO, which agrees with the change trend of the experimental results.     

Principal component analysis of the main factors of line intensity enhancements observed in oscillating direct current plasma

Enhancement of emission line intensities by induced oscillations of direct current (DC) arc plasma with continuous aerosol sample supply was investigated using multivariate statistics. Principal component analysis (PCA) was employed to evaluate enhancements of 34 atomic spectral lines belonging to 33 elements and 35 ionic spectral lines belonging to 23 elements. Correlation and classification of the elements were done not only by a single property such as the first ionization energy, but also by considering other relevant parameters. Special attention was paid to the influence of the oxide bond strength in an attempt to clarify/predict the enhancement effect. Energies of vaporization, atomization, and excitation were also considered in the analysis. In the case of atomic lines, the best correlation between the enhancements and first ionization energies was obtained as a negative correlation, with weak consistency in grouping of elements in score plots. Conversely, in the case of ionic lines, the best correlation of the enhancements with the sum of the first ionization energies and oxide bond energies was obtained as a positive correlation, with four distinctive groups of elements. The role of the gas-phase atom-oxide bond energy in the entire enhancement effect is underlined.     

First integrals and reduction of a class of nonlinear higher order ordinary differential equations

We propose a method for constructing first integrals of higher order ordinary differential equations. In particular third, fourth and fifth order equations of the form are considered. The relation of the proposed method to local and nonlocal symmetries are discussed.     

The role of oxygen and hydrogen partial pressures on structural and optical properties of ITO films deposited by reactive rf-magnetron sputtering

Sn doped In₂O₃ films are deposited by rf-magnetron sputtering at 300 °C under Ar, Ar + O₂ and Ar + H₂ gas ambients. For the film prepared under argon ambient, electrical resistivity 6.5 × 10⁻⁴ Ω cm and 95% optical transmission in the visible region have been achieved optimizing the power and chamber pressure during the film deposition. X-ray diffraction spectra of the ITO film reveal (2 2 2) and (4 0 0) crystallographic planes of In₂O₃. With the introduction of 1.33% oxygen in argon, (2 2 2) peak of In₂O₃ decreases and resistivity increases for the deposited film. With further increase of oxygen in the sputtering gas mixture crystallinity in the film deteriorates and both the peaks disappeared. On the other hand, when 1.33% hydrogen is mixed with argon, the resistivity of the deposited film decreases to 5.5 × 10⁻⁴ Ω cm and the crystallinity remains almost unchanged. In case of reactive sputtering, the deposition rate is lower compared to that in case of non-reactive sputtering. HRTEM and first Fourier patterns show the highly crystalline structure of the samples deposited under Ar and Ar + H₂ ambients. Crystallinity of the film becomes lower with the introduction of oxygen in argon but refractive index increases from 1.86 to 1.9. The surface morphology of the ITO films have been studied by high resolution scanning electron microscopy.     

Two-Sided Optimal Bounds for Green Functions of Half-Spaces for Relativistic <Emphasis Type="Italic">α</Emphasis>-Stable Process

The purpose of this paper is to find optimal estimates for the Green function of a half-space of the relativistic α -stable process with parameter m on ℝ ^d space. This process has an infinitesimal generator of the form mI–(m ^2/α I–Δ) ^α/2, where 0<α<2, m>0, and reduces to the isotropic α-stable process for m=0. Its potential theory for open bounded sets has been well developed throughout the recent years however almost nothing was known about the behaviour of the process on unbounded sets. The present paper is intended to fill this gap and we provide two-sided sharp estimates for the Green function for a half-space. As a byproduct we obtain some improvements of the estimates known for bounded sets. Our approach combines the recent results obtained in Byczkowski et al. (Bessel Potentials, Hitting Distributions and Green Functions (2006) (preprint). ), where an explicit integral formula for the m-resolvent of a half-space was found, with estimates of the transition densities for the killed process on exiting a half-space. The main result states that the Green function is comparable with the Green function for the Brownian motion if the points are away from the boundary of a half-space and their distance is greater than one. On the other hand for the remaining points the Green function is somehow related the Green function for the isotropic α-stable process. For example, for d≥3, it is comparable with the Green function for the isotropic α-stable process, provided that the points are close enough. Research supported by KBN Grants.     

Reverse Mathematics and Grundy colorings of graphs

The relationship of Grundy and chromatic numbers of graphs in the context of Reverse Mathematics is investi‐gated (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

半无限规划的一阶最优性条件和牛顿型算法

在Fischer-Burmeister非线性互补函数的基础上,得到了半无限规划问题的一个新的一阶必要条件,并将半无限规划问题转化成一个光滑的无约束优化问题,给出了适合该问题的一个Damp-Newton算法,数值例子表明:算法结构简单,数值计算有效.     

HL-2M 装置初始等离子体放电磁场电源实时控制系统设计

为满足 HL-2M 装置初始等离子体放电参数的需求,根据磁场电源的主回路拓扑结构设计了一套实 时控制系统。系统硬件架构基于 NI PXI 与 CompactRIO 控制器,采用基于共享内存网络的千兆光纤网络传输数据, 并在本地将中控传输的控制数据处理为对应的触发脉冲,具备很强的实时性与准确性。经过首次等离子体放电实 验的验证,磁场电源实时控制系统可完全满足首次等离子体放电的需求。     

贵金属掺杂锐钛矿TiO2光催化性能的第一性原理研究

本研究采用基于密度泛函理论的第一性原理方法,对纯锐钛矿TiO2及贵金属（Ru、Pd、Pt、Ag和Au）掺杂锐钛矿TiO2的晶格结构、能带结构、电子态密度及光学性质进行了计算。结果表明：贵金属掺杂后TiO2的晶格体积都出现了不同程度的增大;Pd和Pt掺杂后TiO2体系的禁带宽度减小,Ru、Ag和Au掺杂后体系表现出了一定的金属属性,五种贵金属掺杂TiO2后吸收光谱都有红移的趋势。掺杂形成能计算表明,除Ru金属外,富氧条件下掺杂更容易实现。