一个2+1维可积方程的代数几何解

该文从1+1维的孤子方程出发,构造出一个2+1维在Lax意义下可积的方程.接着这个2+1维可积方程被分解为可解的常微分方程.随后引入超椭圆Riemann曲面和Abel-Jacobi坐标把流进行了拉直.再利用Riemannθ函数给出了这个2+1维方程的代数几何解.     

A note on allocation of portfolio shares of random assets with Archimedean copula

This paper further studies the single-period portfolio allocation of risk assets under the assumption that random returns having increasing utility and Archimedean copula. The shares of risk assets in the optimal allocation are proved to be ordered when marginal returns have the likelihood ratio order, and sufficient conditions for the joint density of returns of a multivariate risk to be arrangement increasing is built as well.     

有机发光二极管的光致磁电导效应

制备了结构为ITO/CuPc/NPB/Alq₃/LiF/Al的常规有机发光二极管, 之后对器件采用波长为442 nm和325 nm的激光线进行照射产生激子, 并在小偏压下(保证器件没有开启)对激子的演化过程进行控制, 同时测量器件的光致磁电导(photo-induced magneto-conductance, PIMC). 实验发现, 不同于电注入产生激子的磁电导效应, PIMC在正、反小偏压下表现出明显不同的磁响应结果. 当给器件加上正向小偏压时, 器件的PIMC在0-40 mT范围内迅速上升; 随着磁场的进一步增大, 该PIMC增加缓慢, 并逐渐趋于饱和. 反向小偏压时, 器件的PIMC随着磁场也是先迅速增大(0-40 mT), 但达到最大值后却又逐渐减小. 通过分析外加磁场对器件光生载流子微观过程的影响, 采用'电子-空穴对'模型和超精细相互作用理论对正向偏压下的PIMC进行了解释; 反向偏压下因各有机层的能级关系, 为激子与电荷相互作用提供了必要条件, 运用三重态激子与电荷的反应机制可以解释PIMC出现高场下降的实验现象.     

Heterogeneous copper‐catalyzed oxidative coupling of oxime acetates with sodium sulfinates: An efficient and practical synthesis of β‐keto sulfones

An efficient and practical route to β‐keto sulfones has been developed through heterogeneous oxidative coupling of oxime acetates with sodium sulfinates by using an MCM‐41‐supported Schiff base‐pyridine bidentate copper (II) complex [MCM‐41‐Sb,Py‐Cu (OAc)₂] as the catalyst and oxime acetates as an internal oxidant, followed by hydrolysis. The reaction generates a variety of β‐keto sulfones in good to excellent yields. This new heterogeneous copper (II) catalyst can be easily prepared via a simple procedure from readily available and inexpensive reagents and exhibits the same catalytic activity as Cu (OAc)₂. MCM‐41‐Sb,Py‐Cu (OAc)₂ is also easy to recover and is recyclable up to eight times with almost consistent activity.     

Analysis of phenolic acids and flavonoids in leaves of Lycium barbarum from different habitats by ultra‐high‐performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry

The leaves of Lycium barbarum (LLB) have been utilized as crude drugs and functional tea for human health in China and Southeast Asia for thousands of years. To control its quality, a rapid and sensitive ultra‐high‐performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry method was established and validated for the first time for simultaneous determination of 10 phenolic acids and flavonoids (including neochlorogenic acid , protocatechuic aldehyde, p‐hydroxybenzoic acid, chlorogenic acid, cryptochlorogenic acid, caffeic acid, p‐coumaric acid, ferulic acid, rutin and kaempferol‐3‐O‐rutinoside) in LLB. The separation was performed on an Acquity UPLC C₁₈ chromatographic column (100 × 2.1 mm internal diameter, 1.7 μm particle size) with 0.1% formic acid in water (A)–acetonitrile (B) as the mobile phase under gradient elution. Multiple reaction monitoring mode was adopted to simultaneously monitor the target components. The developed method was fully validated in terms of linearity (r² ≥ 0.9860), precision (RSD ≤ 6.58%), repeatability (RSD ≤ 6.60%), stability (RSD ≤ 6.17%), recovery (95.56–108.06%, RSD ≤ 4.64%) and limit of detection (0.021–0.664 ng/mL) and limit of quantitation (0.069–2.210 ng/mL), and then successfully applied to evaluate the quality of 64 batches of LLB collected from 41 producing areas in four different provinces of China. The results showed that the LLB, especially collected from Inner Mongolia regions, were rich in the phenolic acids and flavonoids. Rutin, kaempferol‐3‐O‐rutinoside and chlorogenic acid are the predominant compounds contained in LLB. The above findings will provide helpful information for the effective utilization of LLB.     

人工神经网络应用于维生素B族4组分同时测定

应用人工神经网络原理，采用Levenberg-Marquardt BP算法，对于吸收光谱严重重叠的维生素B1，B2，B6和烟酰胺4组分同时进行含量测定。四者的平均回收率分别为100％，98％，96％，100％。该方法用于复合维生素B片剂中B1，B2，B6和烟酰胺的同时测定，获得较满意的结果。实验表明，该方法与现有的算法相比具有训练速度快、预测结果准确度高等特点，有望能成为多组分分析的有效方法之一。     

Tunable Oxygen Activation for Catalytic Organic Oxidation: Schottky Junction versus Plasmonic Effects

The charge state of the Pd surface is a critical parameter in terms of the ability of Pd nanocrystals to activate O₂ to generate a species that behaves like singlet O₂ both chemically and physically. Motivated by this finding, we designed a metal–semiconductor hybrid system in which Pd nanocrystals enclosed by {100} facets are deposited on TiO₂ supports. Driven by the Schottky junction, the TiO₂ supports can provide electrons for metal catalysts under illumination by appropriate light. Further examination by ultrafast spectroscopy revealed that the plasmonics of Pd may force a large number of electrons to undergo reverse migration from Pd to the conduction band of TiO₂ under strong illumination, thus lowering the electron density of the Pd surface as a side effect. We were therefore able to rationally tailor the charge state of the metal surface and thus modulate the function of Pd nanocrystals in O₂ activation and organic oxidation reactions by simply altering the intensity of light shed on Pd–TiO₂ hybrid structures.