A New Isopropenyl Benzofuran-type Tetramer from Ligularia stenocephala

A new isopropenyl benzofuran-type tetramer was isolated from the roots of ligularia stenocephala and its structure was established by spectroscopic methods.     

Singular integral operators and norm ideals satisfying a quantitative variant of Kuroda's condition

A norm ideal C is said to satisfy condition (QK) if there exist constants 0<t<1 and 0<B<∞, such that ∥X^[k]∥_C?Bk^t∥X∥_C for every finite-rank operator X and every k∈N, where X^[k] denotes the direct sum of k copies of X. Let μ be a regular Borel measure whose support is contained in a unit cube Q in Rⁿ and let K_j be the singular integral operator on L²(Rⁿ,μ) with the kernel function (x_j-y_j)/|x-y|², 1?j?n. Let {Q_w:w∈W} be the usual dyadic decomposition of Q, i.e., {Q_w:|w|=?} is the dyadic partition of Q by cubes of the size 2^-?×?×2^-?. We show that if C satisfies (QK) and if ∥∑_w∈W2^|w|μ(Q_w)ξ_w⊗ξ_w∥_C^′<∞, where C^′ is the dual of C⁽⁰⁾ and {ξ_w:w∈W} is any orthonormal set, then K₁,…,K_n∈C^′. This is a very general obstruction result for the problem of simultaneous diagonalization of commuting tuples of self-adjoint operators modulo C.     

含纳米棒银溶胶的制备及其光谱性质研究

以CTAB表面活性剂胶束为模板用化学还原法制备出含有银纳米棒的银胶体,用透射电镜(TEM)对颗 粒形貌进行了表征.UV Vis吸收谱显示,含银纳米棒溶胶有两个吸收蜂,其中长波长吸收峰位置随胶粒长径比增 加迅速红移和宽化.用多尺寸统计平均的Mie散射模型计算了纳米棒银胶体的吸收谱,较好地解释了长波长吸收 峰的宽化.以此胶体为衬底材料,测量了染料分子的表面增强拉曼散射(SERS),结果显示,SERS强度随胶体中 所含纳米棒长径比的增加呈现先显著增强后缓慢减弱的变化规律,用电磁增强理论对有关现象进行了分析.     

Multi-color display and its model for a white OLED combined with optical color filters

A bright white organic light-emitting diode (OLED) has been successfully fabricated in which a greenish-white emitting host Bis-(2-(2-hydroxyphenyl) benzothiazole)zinc (Zn(BTZ)₂) is doped with an orange-red fluorescent dye 5,6,11,12-tetraphenylnaphthacene (rubrene). The pure white light emission with CIE coordinates of (0.341, 0.334) is achieved at the driving voltage of 20 V, and the corresponding luminance and external quantum efficiency are 4000 Cd/m² and 0.63%. On the other hand, the pure red, green, and blue (RGB) emissions are obtained from the white OLED combined well with RGB custom-built optical color filters (CFs) with peaks at 616, 556, and 456 nm, respectively. Moreover, based upon the color mixture principles, we build a model of multi-color display mixed by the pure RGB emissions under the controllable bias.     

Determination of sulpiride in human urine using excitation-emission matrix fluorescence coupled with second-order calibration.

This paper proposes a new and effective approach for the quantitative analysis of sulpiride, a significant antipsychotic drug, in human urine samples by the incorporation of excitation-emission matrix (EEM) fluorescence and second-order calibration methodologies based on the alternating fitting residue (AFR) and self-weighted alternating trilinear decomposition (SWATLD) algorithms. With the application of a second-order advantage, the proposed strategy could be utilized for a direct concentration determination of sulpiride with a simple pretreatment step, even in the presence of serious natural fluorescent interferences. The average recoveries of sulpiride in complex urine samples by using AFR and SWATLD with an estimated component number of three were 101.2 +/- 2.1 and 94.4 +/- 0.7%, respectively. Moreover, the accuracy of the two algorithms was also evaluated through elliptical joint confidence region (EJCR) tests as well as the figures of merit, such as sensitivity (SEN), selectivity (SEL) and limit of detection (LOD). The experimental results demonstrated that both algorithms, as promising quantitative alternatives, have been satisfactorily applied to the determination of sulpiride in human urine, but the performance of AFR was slightly better than that of SWATLD.     

含Eu3+离子的Na2O-K2 O-SiO2-Al2O3系统玻璃的制备及其变温发射光谱与结构特性

通过高温熔融法制备了含Eu^3 离子的Na2O-K2O-SiO2-Al2O3系统玻璃。在488nm波长光的激发下，系统地研究了上述玻璃从77K到700K温度范围的变温发光特征。发现总的荧光强度首先随温度的升高而大幅度升高，然后随温度的升高而减少，用声子辅助吸收与热激活过程及温度淬灭效应定性地解释了上述强度的变化，同时测量与分析了Eu^3 离子的晶格场参量。结果表明，Eu^3 离子与氧离子的距离随着温度升高而变短，而Eu^3 离子的配位数不随温度而变化。     

新型噁二唑有机电致发光小分子光电性质研究

通过升降温差热分析(DSC)曲线、偏光显微镜、紫外吸收光谱、电化学行为曲线以及多层器件等,研究了噁二唑衍生物小分子的电学和光学性质,发现其同时具有液晶性、电子和空穴传输性、发光性等优良性能.引进R-OXD(En)层后的多层器件在低于3 V时就能得到可见光发射,在7 V时可以得到光亮度为1000 cdm^-2.此系列小分子可降低有机电致发光器件开启电压,提高发光亮度和发光效率,是一种非常具有吸引力的有机电致发光小分子.     

Minimal Martingale Measures for Discrete-time Incomplete Financial Markets

Abstract In this note, we give a characterization of the minimal martingale measure for a general discrete-time incomplete financial market.Then we concretely work out the minimal martingale messure for a specificdiscrete-time market model in which the assets'returns in different times are independent.     

A novel binucleating macrocyclic ligand with two alcohol pendants

A novel binucleating 24‐membered macrocyclic ligand, 6,20‐bis(2‐hydroxy­ethyl)‐3,6,9,17,20,23‐hex­aza­tri­cyclo­[23.3.1.1^11,15]triaconta‐1(29),11(30),12,14,25,27‐hexaene (L), was synthesized and crystallized as the tetra­hydro­bromide salt, i.e. 6,20‐bis(2‐hydroxy­ethyl)‐6,20‐di­aza‐3,9,17,23‐hexa­azoniatri­cyclo­[23.3.1.1^11,15]­triaconta‐1(29),11(30),­12,14,25,27‐hexaene tetrabromide tetrahydrate, C₂₈H₅₀N₆O₂⁴⁺·­4Br^?·4H₂O. A crystallographic inversion center is located in the macrocyclic cavity and the two hydroxy­ethyl pendants are on opposite sides of the macrocyclic plane. The benzene rings of the macrocycle are parallel to each other and a π–π‐stacking interaction exists between the benzene rings of adjacent macrocycles, which are separated by 3.791 (9) Å. An infinite intermolecular hydrogen‐bond network stabilizes the crystal.