浅谈会计权益理论

本文从研究高职院校经济数学课程教育目标入手,从经济数学课程内容体系改革、教材建设改革、教学方法和考核方式改革以及数学建模活动的开展等四个方面给出经济数学课程建设和改革的实施方案。     

散体货物对敞车静侧压力的颗粒流数值模拟

以C80B敞车为研究对象,采用颗粒流程序对不同散体对敞车的静侧压力和内、外摩擦角变化时的散体侧压力沿敞车墙高的分布规律进行仿真模拟,其结果与库仑理论计算值进行比较.得出侧压力沿墙高非线性分布结果,而不是如库仑理论所计算的线性分布;侧压力的最大值位置随着内、外摩擦角的变化而上移.这种侧压力沿墙高非线性分布和侧压力最大值的位置与敞车的实际压力分布状况相符.颗粒流模拟结果指出了将离散元的方法应用于货车领域的可行性和有效性.     

Structural,optical and dielectric studies on K1‐x(NH4)xH2PO4 mixed crystals grown from z‐cut seeds

Mixed crystals of K_1‐x(NH₄)_xH₂PO₄(KADP) were grown from KDP (KH₂PO₄) dominated mixed solutions with varying molar proportion of ADP (NH₄H₂PO₄) addition. It was found that, as the increase of ADP molar concentration, the growth rate along z‐axis of KADP crystal decreased rapidly. The structure of KADP crystals was investigated by powder XRD and the lattice parameter was calculated. The results showed that the lattice parameter c of KADP crystal increased with the molar concentration of ADP. The optical homogeneity of grown KADP crystals was determined with a differential phase‐shifting interferometry. Frequency dependences of the dielectric constant and dielectric loss of KADP crystals were measured at room temperature (290 K). The dielectric constants of KADP crystals were almost invariant with the increase of frequency. In the region of 10²∼10⁴Hz, the values of the dielectric loss reduced with the increase of frequency. The piezo‐resonance coupling effect still exists in KADP crystals at room temperature, but shifted to low frequency band. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

ps-laser scribing of CIGS films at different wavelengths

Continuous growth of the thin-film electronics market stimulates the development of versatile technologies for large-scale patterning of thin-film materials on rigid and flexible substrates, and laser technologies are a promising method to accomplish the scribing processes. Lasers with picosecond pulse duration were applied in scribing of complex multilayered CuIn _x Ga_(1−x)Se₂ (CIGS) solar cells deposited on a polyimide substrate. The ablative properties of the films were examined as a function of the wavelength of laser radiation, pulse energy, and the irradiation dose. The selective removal of ITO and CIGS layers was achieved with 355 nm irradiation without any significant damage to the underlying layers in the ITO/CIGS/Mo/PI solar cell system. The 355 nm wavelength was also found to be favorable for scribing of absorber layer in a ZnO/CIGS/Mo/PI solar cell system. 266 nm radiation significantly modified the film structure due to high absorption. Extensive melt formation in the CIGS layer was found when 532 nm radiation was applied, though the trenches were smooth and crack-free.     

Investigation of patch antennas based on crossed idiosyncratic PBG structure

The method of finite difference time domain (FDTD) was used, and characteristics of the patch antenna based on drilling periodic air holes in the substrate were studied, the results indicate that the surface waves which propagate along the surface of the substrate can be suppressed by the crossed idiosyncratic PBG (photonic crystal band-gap) structure because of its effect of forbidden-band, that it can radiate most of electromagnetic waves’ energy in the substrate significantly, and that it has lower return loss (S11) compared to the conventional patch antennas, thus, a high gain is attained, its performance is improved. Due to these advantages, the use of photonic crystal patch antennas will be extended in areas such as mobile communication, satellite communication, aviation, etc.     

Improved performance of TiO2 electrodes coated with NiO by magnetron sputtering for dye-sensitized solar cells

TiO₂ electrodes are coated with NiO by DC magnetron sputtering, and their structural, optical and electrochemical performance has been investigated. X-ray diffractometry (XRD), UV-vis spectrophotometry, scanning electron microscopy (SEM), AC impedance, and linear sweep voltammetry (LSV) are used to characterize the TiO₂/NiO electrodes. Their performance is evaluated with a computer controlled electrochemical workstation in combination with three conventional electrodes. The experimental results indicate that the surface modification of TiO₂ electrodes with sputtered NiO reduces trap sites on TiO₂ and improves the electrochemical performance of dye-sensitized solar cells (DSSCs). Sputtering NiO for 7 min, which is about 21 nm thick, on 6.5 μm thick TiO₂ greatly improves the DSSC parameters, and the conversion efficiency increases from 3.21 to 4.16%. Mechanisms of the influence of the NiO coating on electrochemical performance are discussed.     

几乎不可压线弹性问题的新的Uzawa型自适应有限元方法

本文针对几乎不可压线弹性问题设计新的Uzawa型自适应有限元方法,该方法可克服"闭锁"现象·通过引入"压力"变量将弹性问题转化为一个鞍点系统,对该系统将Uzawa型迭代法和自适应有限元方法相结合,建立了Uzawa型自适应有限元方法,并给出了该算法的收敛性.该算法采用低阶协调有限元通近空间变量,选取的有限元空间对无需满足离散的BB条件.最后,数值算例验证了理论结果的正确性.     

Error bounds for linear complementarity problems of S-QN matrices

Numerical Algorithms - It is well-known that conjugate gradient algorithms are widely applied in many practical fields, for instance, engineering problems and finance models, as they are...     

Large coupling asymptotics for the entropy of quasi-periodic operators

Science China Mathematics - In this paper, we give an asymptotic estimate for the entropy, i.e., the sum of all positive Lyapunov exponents, of the quasi-periodic finite-range operator with a large...     

Periodic solutions for a type of neutral system with variable parameters

In this paper, we firstly analyze some properties of the linear difference operator $[Ax](t)=x(t)-C(t)x(t-\tau),$ where $C(t)$ is a $n\times n$ matrix function, and then using Mawhin''s continuation theorem, a first-order neutral functional differential system is studied. Some new results on the existence and stability of periodic solutions are obtained. The results are related to the deviating arguments $\tau$ and $\mu$. Meanwhile, the approaches to estimate a $prior$ bounds of periodic solutions are different from the corresponding ones of the known literature.