例证法与代数簇的包含关系

1986年,洪加威教授发展吴文俊机器证明理论,提出了一类平面几何定理的例证法,这一方法依赖于 Ritt-吴整序原理和吴文俊教授关于升组不可约分解的构造性理论.我们发现例证法适用于证明所有等式型几何定理,即吴几何中的定理.本文应用吴和洪的方法叙述等式型几何定理的例证法,并考虑代数簇的包含关系.目前的讨论仅停留在理论上,这种方法能否用来证明非平凡的几何定理还有待于进一步研究和尝试.     

黑龙江省税务系统珠算协会召开第三届理事会

黑龙江省税务系统珠算协会三届理事会议于4月7日至8日在哈尔滨市召开。出席会议的领导同志有;黑龙江省国家税务局副局长苍万琦同志、黑龙江省地方税务局副局长李树义同志、黑龙江省珠算协会副会长孙     

一类微分方程问题的机器处理

在微分方程的理论与应用研究中，一般来说，大多数方程的解都不能显式表出，因此研究解的性态，诸如稳定性、周期性等成为微分方程研究的中心课题，但在不少情形，这种研究由于复杂的计算而被迫终止。我们依据吴文俊机械化方法，讨论一类微分方程问题，用我们编制的机器处理系统，可以判定这类微分方程的运动稳定性，并能给出供研究极限环的判定量。     

Recombination-induced voltage-dependent photocurrent collection loss in CdTe thin film solar cell

Recently, the efficiency of CdTe thin film solar cell has been improved by using new type of window layer Mg_xZn_1-xO (MZO). However, it is hard to achieve such a high efficiency as expected. In this report a comparative study is carried out between the MZO/CdTe and CdS/CdTe solar cells to investigate the factors affecting the device performance of MZO/CdTe solar cells. The efficiency loss quantified by voltage-dependent photocurrent collection efficiency (η_C(V')) is 3.89% for MZO/CdTe and 1.53% for CdS/CdTe solar cells. The higher efficiency loss for the MZO/CdTe solar cell is induced by more severe carrier recombination at the MZO/CdTe p—n junction interface and in CdTe bulk region than that for the CdS/CdTe solar cell. Activation energy (E_a) of the reverse saturation current of the MZO/CdTe and CdS/CdTe solar cells are found to be 1.08 eV and 1.36 eV, respectively. These values indicate that for the CdS/CdTe solar cell the carrier recombination is dominated by bulk Shockley—Read—Hall (SRH) recombination and for the MZO/CdTe solar cell the carrier recombination is dominated by the p—n junction interface recombination. It is found that the tunneling-enhanced interface recombination is also involved in carrier recombination in the MZO/CdTe solar cell. This work demonstrates the poor device performance of the MZO/CdTe solar cell is induced by more severe interface and bulk recombination than that of the CdS/CdTe solar cell.     

多项式组的特征分解

任一多项式理想的特征对是指由该理想的约化字典序Grobner基G和含于其中的极小三角列C构成的有序对(G,C).当C为正则列或正规列时,分别称特征对(G,C)为正则的或正规的.当G生成的理想与C的饱和理想相同时,称特征对(G,C)为强的.一组多项式的(强)正则或(强)正规特征分解是指将该多项式组分解为有限多个(强)正则或(强)正规特征对,使其满足特定的零点与理想关系.本文简要回顾各种三角分解及相应零点与理想分解的理论和方法,然后重点介绍(强)正则与(强)正规特征对和特征分解的性质,说明三角列、Ritt特征列和字典序Grobner基之间的内在关联,建立特征对的正则化定理以及正则、正规特征对的强化方法,进而给出两种基于字典序Grobner基计算、按伪整除关系分裂和构建、商除可除理想等策略的(强)正规与(强)正则特征分解算法.这两种算法计算所得的强正规与强正则特征对和特征分解都具有良好的性质,且能为输入多元多项式组的零点提供两种不同的表示.本文还给出示例和部分实验结果,用以说明特征分解方法及其实用性和有效性.     

Lotka-Volterra系统LaSalle不变集的结构

本文利用吴文俊提出的,现通称为Ritt-吴整序的原理,发展文献[3]的计算机辅助证明方法,确定了七维Lotka-Volterra食物链系统的LaSalle不变集,从而解决了这类系统的全局稳定性问题.     

基于氧化镍背接触缓冲层碲化镉薄膜太阳电池的研究

采用电子束蒸发法制备了NiO薄膜,并对其作为碲化镉薄膜太阳电池背接触缓冲层材料进行了相关研究.NiO缓冲层的加入使得碲化镉太阳电池开路电压显著增大.通过X射线光电子能谱测试得到的NiO/CdTe界面能带图表明NiO和CdTe的能带匹配度很好.NiO是宽禁带P型半导体材料,在电池背接触处形成背场,减少了电子在背表面处的复合,从而提高电池开路电压.通过优化NiO薄膜厚度,制备得到转换效率为12.2%、开路电压为789 mV的碲化镉太阳电池.研究证实NiO是用来制备高转换效率、高稳定性碲化镉薄膜太阳电池的一种极有前景的缓冲层材料.     

Low temperature ferromagnetic properties of CdS and CdTe thin films

The magnetic property in a material is induced by the unpaired electrons. This can occur due to defect states which can enhance the magnetic moment and the spin polarization. In this report, CdS and CdTe thin films are grown on FTO glass substrates by chemical bath deposition and close-spaced sublimation, respectively. The magnetic properties, which are introduced from oxygen states, are found in CdS and CdTe thin films. From the hysteresis loop of magnetic moment it is revealed that CdS and CdTe thin films have different kinds of magnetic moments at different temperatures. The M–H curves indicate that from 100 K to 350 K, CdS and CdTe thin films show paramagnetism and diamagnetism, respectively.A superparamagnetic or a weakly ferromagnetic response is found at 5 K. It is also observed from ZFC/FC curves that magnetic moments decrease with temperature increasing. Spin polarized density functional calculation for spin magnetic moment is also carried out.