有序判别分析新算法及其应用

判别分析是用已知分类数据建模对未知分类数据进行判别的方法,所用数据和分类不分顺序。要对有序又有周期数据进行判别分析,就要探索有序判别的新方法。这种方法的分类应当是有序的,并且能够排除事物发展周期性的干扰。本文介绍多元数据有序判别分析新方法的原理、建模流程、应用流程和应用实例。这种判别分析将分类建模与判别归类分开。新方法对多元数据建模时在多类模型中建立滑移的多套子模型,应用时根据应用领域的知识对样本归属作初步预估,然后程序选择相关的子模型进行判别归类。这种方法解决了由于时间序列多元数据周期性造成的样本分类颠倒问题,为时间序列数据的分类和预测开辟了新途径,在实际应用中取得了良好的效果,解决了重大难题。     

多维多目标模糊优选动态规划及其在资源分配中的应用

将目前所研究的一维模糊优选动态规划扩展为多维模糊优选动态规划。在求解多维多阶段问题时,采用遗传算法与模糊动态规划法相结合进行求解,保证了优化变量的全局最优性。在其中权系数的处理中,本文采用了主客观综合评定的方法,保证了数据的合理性及准确性。并且文中用此方法解决了多维多阶段多目标的资源分配问题。     

树脂吸附法纯化赤霉素

对比了几种大孔吸附树脂对赤霉素发酵液的吸附、解吸性能,实验发现,自制R4树脂的动态饱和吸附容量高达58.38mg/g干树脂,自制R5树脂的动态饱和吸附容量高达96.46mg/g干树脂,R5树脂的吸附容量明显高于R4,这与树脂的比表面积一致.50%(VIV)甲醇水溶液具有较好的解吸性能,收率高达95%以上,经过树脂一步吸附-解吸,赤霉素的浓度可平均提高5倍以上,集中收集最高可提高15倍以上,这对于工业化生产中,赤霉素的进一步结晶析出具有重要意义.     

Phase space reconstruction of chaotic dynamical system based on wavelet decomposition

In view of the disadvantages of the traditional phase space reconstruction method,this paper presents the method of phase space reconstruction based on the wavelet decomposition and indicates that the wavelet decomposition of chaotic dynamical system is essentially a projection of chaotic attractor on the axes of space opened by the wavelet filter vectors,which corresponds to the time-delayed embedding method of phase space reconstruction proposed by Packard and Takens.The experimental results show that,the structure of dynamical trajectory of chaotic system on the wavelet space is much similar to the original system,and the nonlinear invariants such as correlation dimension,Lyapunov exponent and Kolmogorov entropy are still reserved.It demonstrates that wavelet decomposition is effective for characterizing chaotic dynamical system.     

Effect of electric field on the electronic spectrum and the persistent current of a quantum ring with two electrons

The effect of an electric field E on a narrow quantum ring that contains two electrons and is threaded by a magnetic flux B has been investigated. Localization of the electronic distribution and suppression of the Aharonov--Bohm oscillation (ABO) are found in the two-electron ring, which are similar to those found in a one-electron ring. However, the period of ABO in a two-electron ring is reduced by half compared with that in a one-electron ring. Furthermore, during the variation of B, the persistent current of the ground state may undergo a sudden change in sign. This change is associated with a singlet--triplet transition and has no counterpart in one-electron rings. For a given E, there exists a threshold of energy. When the energy of the excited state exceeds the threshold, the localization would disappear and the ABO would recover. The value of the threshold is proportional to the magnitude of E. Once the threshold is exceeded, the persistent current is much stronger than the current of the ground state at E=0.     

Measurement of the solubility of water in 2,2-dichloro-1,1,1-trifluoroethane (HCFC 123)

A metal ebulliometer has been used to measure the solubility of water in 2,2-dichloro-1,1,1-trifluoroethane (HCFC 123) over the temperature range 297–354 K. Solubilities varied from 9.5×10⁻³ to 3.75×10⁻² (mole fraction). Activity coefficients (γ^∞) and distribution coefficients (K^∞) were estimated. The results were used to resolve a discrepancy found in the literature concerning the vapor pressure of HCFC 123.     

分子发光法研究空间位阻效应对包络物形成的影响

利用分子发光法研究了正丁醇(n-butanol,n-Bu)和苯酚(phenol,ph)存在下空间位阻效应对β-环糊精(Cyclodextrin,β-CD)和溴代萘(Bromonaphthalene,BrN)包络物形成的影响。在各自最佳实验条件下,2-BrN/β-CD/n-Bu/ph体系的室温磷光(RTP)强度不及1-BrN/β-CD/n-Bu/ph体系的三分之一;而其荧光发射光谱较1-BrN/β-CD/n-Bu/ph发射光谱红移5～10 nm,表明BrN中溴的空间位置对包络物的形成有显著的影响。两四元体系包络常数(K_f)的测定结果也进一步说明这一点。据此,讨论了上述包络物的形成机理。     

A highly-efficient method for stationary response of multi-degree-of-freedom nonlinear stochastic systems

Analytical and numerical studies of multi-degree-of-freedom(MDOF) nonlinear stochastic or deterministic dynamic systems have long been a technical challenge.This paper presents a highly-efficient method for determining the stationary probability density functions(PDFs) of MDOF nonlinear systems subjected to both additive and multiplicative Gaussian white noises. The proposed method takes advantages of the sufficient conditions of the reduced Fokker-Planck-Kolmogorov(FPK) equation when constructi...     

FIR spectra of saccharides and polysaccharides

Measurements of the FIR absorption spectra of polysaccharides and their constituent monoand disaccharides have been made between 30 and 650 cm⁻¹, using FTS. Some of the structure of the saccharides is found to show up in the polymers.