有限外尺度对大气湍流统计特征测量的影响

有限外尺度影响下的相位结构函数和孔径平均的斜率相关函数的表达式,结果表明有限的大气外尺度对大气流流统计特征的测量有很大的影响,尤其对大尺寸的望远镜和子孔径更是如此。基于科尔莫戈罗夫模型的大气相位结构函数和相干长度仅仅是本文推导结果的近似。对结果的分析表明,测量得到的对大气湍流科尔莫戈罗夫模型的偏离有可能是大气外尺度的影响,而不完全是真正的偏离。     

数学机械化在转子系统分析中的应用

以转子－轴承系统中两圆盘转子为研究对象,在计及陀累力矩的条件下,通过对两圆盘转子临界转速与振型参数的分析,对吴消去法在转子动力学研究中的应用做了初步探索,将吴消去法的特征列思想 Maple软件的符号计算功能相结合,实现了对两圆盘转子临界转速与振型参数的解析计算与分析。     

杆的初应力及识别

提出用数值特征描写杆中初应力的方法,建立初应力位形上的小变形动力学方程,由此讨论初应力对杆小变形力学行为的影响与用受初应力影响的附加变形来识别和测定初应力的数值特征的途径。     

最大特征根的极值六角链

定义了六角链的一种翻转-粘贴运算, 利用这一运算, 证明了Gutman 猜想.这一证明思想也可用于证明关于Hosoya指标和Merrifield-Simmons 指标的极值六角链的结果.     

关于矩阵相似中变换矩阵的一般形式

本利用Jordan标准形理论,给出了矩阵相似中的变换矩阵的一般表达形式。     

The reliability of measurements on electron energy distribution function in silane rf glow discharges

Electron energy distribution function (EEDF) is a key parameter of plasmas, which is directly proportional to the second derivative of the probe I-V characteristics. Because of an amplifying effect of unavoidable noises in the experimental probe I-V curves during the derivation process, the experimental I-V curves should be smoothed before performing the numerical derivation. This paper investigates the effect of adjustable factors used in the smoothing process on the deduced second derivative of the I-V curves, and an optimum group of the adjustable factors is selected to make the rms deviation of the smoothed I-V curves from the measured curves less than 1%. A simple differentiation circuit is designed and used to measure the EEDF parameter straightforwardly. It is the first time, so far as we know, to measure the EEDF parameters simultaneously by means of both numerical and circuit derivative methods under the same discharge conditions and on the same discharge equipment. The deviation between two groups of mean electron energy E and electron density n_e obtained by the above different methods is within about 7%. This apparently improves the reliability of the measurements of the EEDF parameters.     

Cell image recognition with radial harmonic Fourier moments

Various types of moments have been utilized to recognize image patterns in a number of applications. Multi-distortion invariant－radial harmonic Fourier moments were investigated in the recognition of cell smear images. Image recognition experiments showed that radial harmonic Fourier moments are not only highly concentrated image features but also have a good property of antidistortion and antinoise. They may be used in fast and accurate automatic cell recognition.     

Theoretical investigation of incomplete ionization of dopants in uniform and ion-implanted 4H-SiC MESFETs

The effects of incomplete ionization of nitrogen in 4H-SiC have been investigated. Poisson's equation is numerically analysed by considering the effects of Poole--Frenkel, and the effects of the potential on $N^+_\dd$ (the concentration of ionized donors) and $n$ (the concentration of electrons). The pinch-off voltages of the uniform and the ion-implanted channels of 4H-SiC metal-semiconductor field-effect transistors (MESFETs) and the capacitance of the gate are given at different temperatures. Both the Poole--Frenkel effect and the potential have influence on the pinch-off voltage $V_{\rm p}$ of 4H-SiC MESFETs. Although the $C$-$V$ characteristics of the ion-implanted and the uniform channel of 4H-SiC MESFETs have a clear distinction, the effects of incomplete ionization on the $C$-$V$ characteristics are not significant.     

Ni(OH)_2电极材料的XRD和Raman光谱表征

用 XRD和 Raman光谱等方法对几种典型球形 Ni( OH) 2 电极材料进行了表征 ,并分析了材料的表观形貌、掺杂元素和微观结构等对其充放电性能的影响 .结果表明 ,有较好填充性和充放电性能 Ni( OH) 2 电极材料所具有的特征为 ,颗粒的球形好且结晶完好 ,晶粒较小 ,较大的晶格参数 c,并在 51 0和 3596cm- 1 处可以生成 Raman光谱峰 ;而 XRD和 Raman光谱方法则是评价 Ni( OH) 2 电极材料性能的有效手段 .     

Ni(OH)2电极材料的XRD和Raman光谱特征

掺杂元素;Ni(OH)2电极材料的XRD和Raman光谱特征