An Efficient Synthesis of 4H-Benzo[g]chromene-5,10-dione Derivatives through Triethylbenzylammonium Chloride Catalyzed Multicomponent Reaction under Solvent-free Conditions

A series of 4‐aryl‐5,10‐dihydro‐4H‐benzo[g]chromene‐5,10‐dione derivatives were synthesized by a three‐component reaction with aromatic aldehyde, 2‐hydroxy‐1,4‐dihydronaphthalene‐1,4‐dione, and malononitrile catalyzed by triethylbenzylammonium chloride under solvent‐free conditions. The novel efficient method has the advantages of environmental friendliness, high yield, simple work‐up and ease of operation.     

两个修正的分子连接性指数用于有机物反磁磁化率的改进QSPR研究

为了预测有机物的摩尔反磁磁化率,基于分子图的连接矩阵和可变的原子价连接性指数δi’提出了一种可变的分子连接性指数mχ’ 及其逆指数mχ”。包含在δi’、 mχ’ 和mχ”定义式中的三个可变参数x、 a和y的最佳值可通过优化方法得到。当x=2.9、a=1.10、y=0.36时, 通过最佳子变量集合法可以构建一个良好的5参数模型。对721个有机物（训练集）,该模型的相关系数r、标准偏差s和平均绝对偏差分别是0.9930、4.96 cgs和3.74cgs。交叉验证说明,从统计学角度该模型具有良好的稳定性。另外该模型对另外360个有机物（测试集）摩尔反磁磁化率预测结果的平均绝对偏差为4.37cgs。结果表明本文的方法在预测有机物摩尔反磁磁化率方面比文献方法更有效。多元线性方法能得到比较理想的预测有机物摩尔反磁磁化率的模型。     

离子液体中13-芳基-5,7,12,14-四氢二苯并[b, i]氧杂蒽5,7,12,14(13H)-四酮衍生物的绿色高效合成

在离子液体[bmim+][BF4-]中高产率的合成了一系列13-芳基-5,7,12,14-四氢二苯并[b, i]氧杂蒽-5,7,12,14(13H)-四酮类化合物。该反应操作步骤简单,离子液体易于与产物分离,并且离子液体可以循环使用。     

Microwave-assisted Synthesis of Pyrazolo[4,3-f]quinolin-7-one Derivatives via Multi-component Reactions

A series of new pyrazolo[4,3‐f]quinolin‐7‐one derivatives were synthesized by multi‐component reactions of equimolar amount of aromatic aldehydes with 2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione and 1H‐indazol‐5‐amine in ethylene glycol without catalyst under microwave irradiation. This one‐pot protocol has the advantage of good yields, simple workup procedure and shorter reaction time.     

改进的卷积神经网络源代码相似性度量方法

源代码相似性是指不同代码段功能上的相似程度,是软件工程领域一项重要的研究问题.现有的方法主要从文本、结构两方面,利用代码的统计学特征计算相似性,其最大缺点就是无法表达代码的语义特征.为解决此类问题,提出了一种融合统计信息的卷积神经网络（statistics information for code embedding convolutional neural networks, SICE-CNN）源代码相似性检测方法.该方法首先通过词嵌入对源代码进行信息表示,获取代码的词嵌入向量信息;其次,构建CNN训练模型学习源代码文档的嵌入表示;最后,计算源代码对的余弦相似值.实验表明,该方法和一般词嵌入方法相比提高了一定的性能,能较好地检测源代码的语义相似性.     

Lanczos method for large-scale quaternion singular value decomposition

In many color image processing and recognition applications, one of the most important targets is to compute the optimal low-rank approximations to color images, which can be reconstructed with a small number of dominant singular value decomposition (SVD) triplets of quaternion matrices. All existing methods are designed to compute all SVD triplets of quaternion matrices at first and then to select the necessary dominant ones for reconstruction. This way costs quite a lot of operational flops and CPU times to compute many superfluous SVD triplets. In this paper, we propose a Lanczos-based method of computing partial (several dominant) SVD triplets of the large-scale quaternion matrices. The partial bidiagonalization of large-scale quaternion matrices is derived by using the Lanczos iteration, and the reorthogonalization and thick-restart techniques are also utilized in the implementation. An algorithm is presented to compute the partial quaternion singular value decomposition. Numerical examples, including principal component analysis, color face recognition, video compression and color image completion, illustrate that the performance of the developed Lanczos-based method for low-rank quaternion approximation is better than that of the state-of-the-art methods.

     

Global regularity of the 2D magnetohydrodynamic equations with fractional anisotropic dissipation

This paper is dedicated to establishing the global regularity for the two dimensional magnetohydrodynamic equations with fractional anisotropic dissipation when the fractional powers are restricted to some certain ranges. In addition, the global regularity results for the two dimensional magnetohydrodynamic equations with partial dissipation are also obtained. Consequently, these results bring us more closer to the resolution of the global regularity problem on the two dimensional magnetohydrodynamic equations with standard Laplacian magnetic diffusion.     

Moving mesh finite difference solution of non-equilibrium radiation diffusion equations

Numerical Algorithms - A moving mesh finite difference method based on the moving mesh partial differential equation is proposed for the numerical solution of the 2T model for multi-material,...     

On some testable conditions for excitability and transparency of a class of time-delay systems with point delays

This article is concerned with the excitability of positive linear time-invariant systems subject to internal point delays. It is proved that the excitability independent of delay is guaranteed if an auxiliary delay-free system is excitable. Necessary and sufficient conditions for excitability and transparency are formulated in terms of the parameterization of the dynamics and control matrices and, equivalently, in terms of strict positivity of a matrix of an associate system obtained from the influence graph of the original system. Such conditions are testable through simple algebraic tests involving moderate computational effort.     

从双曲α-Bloch 空间到双曲{\boldmath QK型空间上的复合算子

若φ 为单位圆盘D上的解析自映射, X为D上解析函数全体构成的Banach空间.定义X上复合算子C_φ: C_φ (f)=fοφ, 对任意 f∈X. 该文研究了从双曲α-Bloch 空间到双曲Q_K型空间上复合算子的有界性的特征. 另外, 还给出了从D_p,α 到Q_K(p, q) 空间上复合算子的有界性和紧性的特征.