具有白指数律重合性的GM(1,1)模型

通过分析 GM( 1 ,1 )建模机理 ,找出了 GM( 1 ,1 )模型不具有白指数律重合性的原因 ,并在此基础上 ,提出了建立 GM( 1 ,1 )模型的新方法 .新方法克服了原方法不具有白指数律重合性的缺陷 ,突破了 | a|较大时GM( 1 ,1 )模型不能应用的禁区 ,提高了建模的精度 .     

白光发光二极管的制备技术及主要特性

利用发射波长为470nm的蓝光发光二极管作为基础光源，通过荧光粉转换方法制备白光发光二极管，荧光粉主要采用稀土激活的铝酸盐Y3Al5Ol2：Ce3 (YAG)。在工作电流为15mA条件下，所研制的白光LED的法向光强为2890mcd；色坐标为x=0.29，y=0．33；显色指数为77；流明效率为14．9lm／w。研究制备了不同色温的白光LED，色温范围从2700～8000K，研究了色温与色坐标之间的对应关系。并且与国外同类产品进行比较。部分指标已经超过了国外同类产品水平。     

Fractional Brownian Motion and Sheet as White Noise Functionals

In this short note, we show that it is more natural to look the fractional Brownian motion as functionals of the standard white noises, and the fractional white noise calculus developed by Hu and Фksendal follows directly from the classical white noise functional calculus. As examples we prove that the fractional Girsanov formula, the Ito type integrals and the fractional Black-Scholes formula are easy consequences of their classical counterparts. An extension to the fractional Brownian sheet is also briefly discussed.     

Stochastic Hopf bifurcation in quasi-integrable-Hamiltonian systems

A new procedure is developed to study the stochastic Hopf bifurcation in quasiintegrable-Hamiltonian systems under the Gaussian white noise excitation. Firstly, the singular boundaries of the first-class and their asymptotic stable conditions in probability are given for the averaged Ito differential equations about all the sub-system‘s energy levels with respect to the stochastic averaging method. Secondly, the stochastic Hopf bifurcation for the coupled sub-systems are discussed by defining a suitable bounded torus region in the space of the energy levels and employing the theory of the torus region when the singular boundaries turn into the unstable ones. Lastly, a quasi-integrable-Hamiltonian system with two degrees of freedom is studied in detail to illustrate the above procedure.Moreover, simulations by the Monte-Carlo method are performed for the illustrative example to verify the proposed procedure. It is shown that the attenuation motions and the stochastic Hopf bifurcation of two oscillators and the stochastic Hopf bifurcation of a single oscillator may occur in the system for some system‘s parameters. Therefore, one can see that the numerical results are consistent with the theoretical predictions.     

White‐Light Emission Strategy of a Single Organic Compound with Aggregation‐Induced Emission and Delayed Fluorescence Properties

A novel white‐light‐emitting organic molecule, which consists of carbazolyl‐ and phenothiazinyl‐substituted benzophenone (OPC) and exhibits aggregation‐induced emission‐delayed fluorescence (AIE‐DF) and mechanofluorochromic properties was synthesized. The CIE color coordinates of OPC were directly measured with a non‐doped powder, which presented white‐emission coordinates (0.33, 0.33) at 244 K to 252 K and (0.35, 0.35) at 298 K. The asymmetric donor–acceptor–donor′ (D‐A‐D′) type of OPC exhibits an accurate inherited relationship from dicarbazolyl‐substituted benzophenone (O2C, D‐A‐D) and diphenothiazinyl‐substituted benzophenone (O2P, D′‐A‐D′). By purposefully selecting the two parent molecules, that is, O2C (blue) and O2P (yellow), the white‐light emission of OPC can be achieved in a single molecule. This finding provides a feasible molecular strategy to design new AIE‐DF white‐light‐emitting organic molecules.     

Aromatic components produced by non-Saccharomyces Cerevisiae derived from natural fermentation of grape

Aromatic components are important functional products during the wine fermentation process. In the current study, nine strains (Y10, Y5, Y21, Y2, Y19, Y16, Y3, Y13 and Y4) of non-Saccharomyces were isolated from Cabernet Sauvignon grape wine. Aromatic components from Cabernet sauvignon-fermented wine were determined the phylogenetic evolution status of different non-Saccharomyces based on 26S rDNA and D1/D2 sequence analysis and analysed by a gas chromatography–mass spectrometry analysis, and they were grouped into one category with four different yeast genus which were Meyerozyma guilliermondii, Brettanomyces naardenensis, Pichia guilliermondi and Candida fermentati. A total of 102 kinds of aroma components were detected, including 39 kinds of esters, 31 kinds of alcohols, 8 kinds of ketones, 10 kinds of alkanes, 15 kinds of acids and 4 kinds of other aroma substances.     

Determination of chlorophenols in red wine using ionic liquid countercurrent chromatography as a new pretreatment method followed by high‐performance liquid chromatography

A countercurrent chromatography method for the enrichment and cleanup of chlorophenols from food samples was successfully established by using an ionic‐liquid‐modified two‐phase solvent system composed of dichloromethane containing 2% 1‐butyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide and water. The column was firstly filled with the organic stationary phase, and then a large volume of sample was pumped into the column after it was equilibrated with pure water at the rotation speed. Finally, the trace amounts of chlorophenols extracted and enriched in the stationary phase were eluted out by an alkaline mobile phase and determined by high‐performance liquid chromatography. Under optimized conditions, the enrichment and cleanup of the chlorophenols can be fulfilled online with enrichment factors (34–65) and high recoveries (84.69–95.23%). The method has been applied to the determination of chlorophenols in real red wine samples with the limits of detection in the range of 1.89–4.21 μg/L. The present method is highly suitable for the pretreatment of large volume of aqueous sample for the determination of trace amounts of contaminants in food and environmental samples.     

黄光类水滑石的制备、表面改性及应用

采用共沉淀法合成了荧光类水滑石材料,该材料在470 nm蓝光激发下可发出黄色荧光(557 nm),采用硅烷偶联剂对其进行表面改性,探讨了表面改性对黄光类水滑石的发光性能、结构及热稳定性的影响。将改性黄光类水滑石与GaN基蓝光芯片封装后制得了白光LED。研究结果表明,改性的黄光类水滑石是制作白光LED可供选用的黄色发光材料。本文成功地将低温一步法制备得到的金属有机配合物/无机纳米杂化材料应用于LED,拓展了LED用荧光粉的选用范围。     

Full‐Color Emissive Poly(Ethylene Oxide) Electrospun Nanofibers Containing a Single Hyperbranched Conjugated Polymer for Large‐Scale,Flexible Light‐Emitting Sheets

White‐light‐emitting protocols based on organic materials have received much attention in the academic and industrial fields because of their potential applications in full‐color displays and back‐lighting units for liquid crystal displays. Here, the attempt is made to fabricate white‐light‐emitting, electrospun poly(ethylene oxide) (PEO) sheets containing controlled concentrations of a single light‐emitting material composed of a type of hyperbranched conjugated polymer (HCP). The HCPs used here have the unique property of exhibiting a variety of fluorescence colors in the electrospun matrix that is caused by the different distances between HCP chains depending on their concentrations, leading to different degrees of intermolecular energy transfer. Therefore, the emission colors of the PEO sheets can be easily manipulated by simply varying the HCP concentrations in the PEO matrix. The resulting method for fabricating nanofibers comprising light‐emitting materials in the polymer matrix has great potential for easy fabrication of cost‐effective, flexible light‐emitting system.