Design and Synthesis of a Ruthenium(II) Complex-Based Luminescent Probe for Highly Selective and Sensitive Luminescence Detection of Nitric Oxide

Nitric oxide (NO) is one of the most important intercellular signaling molecules, and plays important roles in various biological systems. In this work, a unique Ru^II complex, tris[(5-(4-methylamino-3-aminobenzylamino)-1,10-phenanthroline)] ruthenium(II) hexafluorophosphate [Ru(MAA-phen)₃][PF₆]₂, has been designed and synthesized as a luminescent probe for the detection of NO in aqueous media. The complex itself is almost non-luminescent, but can specifically react with NO under the aerobic conditions to afford its highly luminescent triazole derivative in aqueous media, [Ru(MTA-phen)₃]²⁺ (MTA-phen: methyl-trazolebenzylamino-1,10-phenanthroline), accompanied by a 302-fold increase in luminescence intensity at 598 nm with a 130 nm Stokes shift. The luminescence response of [Ru(MAA-phen)₃]²⁺ to NO is rapid, highly specific without interferences of other reactive oxygen/nitrogen species, and highly stable against the pH changes in the range of pH 4.5–9.5. These features enable [Ru(MAA-phen)₃]²⁺ to be used as a probe for the highly selective and sensitive luminescence detection of NO in weakly acidic, neutral, and weakly basic media.     

Spherical hollow mesoporous silica supported phosphotungstic acid as a promising catalyst for α-arylstyrenes synthesis via Friedel-Crafts alkenylation

This work presents a scalable approach for preparing spherical hollow mesoporous silica with high surface area/pore volume, serving as outstanding support for supported phosphotungstic acid catalyst with much superior catalytic performance to the one on previously reported spherical mesoporous silica toward diverse transformations, ascribed to the strengthened mass transfer and the enlarged exposure degree of acidic sites to reactants those resulting from unique hollow and mesoporous morphology.     

高温和高压对乙烷在氧气中爆炸极限影响的实验研究

获得高温、高压下可燃介质爆炸极限数值，对完善复杂工况下可燃介质燃爆安全理论、构建可燃介质爆炸防护技术提供支持。搭建了适用于开展高温、高压工况的20 L球形爆炸实验装置，测量了初始温度为20～270 ℃，初始压力为0.5～2.6 MPa下乙烷在氧气中的爆炸极限，分析温度、压力单因素对乙烷在氧气中的爆炸极限的影响以及温度和压力双因素的耦合影响。结果表明，随着初始压力和初始温度的提高，乙烷在氧气中的爆炸极限逐渐扩大。在温度小于140 ℃时，在高压和低压两种情况下，压力对乙烷爆炸上限的影响基本一致。在温度高于140 ℃时，压力的升高使乙烷爆炸上限升高，但其影响的效果逐渐减小。在初始压力小于1.6 MPa时，温度的升高使乙烷的爆炸上限升高，但其影响的效果变化很小。在压力大于1.6 MPa，温度高于140 ℃时，温度的升高使乙烷的爆炸上限升高，且其影响的效果逐渐增大。温度和压力的升高均使乙烷的爆炸下限降低，但其影响较小。初始温度和初始压力对乙烷在氧气中爆炸极限的耦合作用略小于两个因素作用的和，但大于单个因素的作用。通过拟合得到了C₂H₆/O₂爆炸极限随初始压力、初始温度变化的定量规律。     

薄板弯曲分析的节点积分高阶无网格法

采用高阶无网格法求解薄板弯曲问题，在已发展的线性曲率光顺方案的基础上，通过引入泰勒展开技术，建立了能够精确再现纯弯曲和线性弯曲模式的节点积分方法。与之相比，目前无网格薄板分析主要采用的节点积分方法仅能精确再现纯弯曲模式。数值结果表明，本文方法可精确通过纯弯曲和线性弯曲试验，且能得到光滑、无振荡的弯矩场。与标准的高斯积分方法和目前已存在的节点积分方法相比，本文方法在计算精度、效率以及弯矩分布等方面均展现出显著优势。     

板结构计算模型的新发展

现代复合材料层合板具有高强和轻型的突出优点，从而在军工和民用等诸多领域发挥着重要作用。这种板结构的特点是随着纤维走向的不同，层间材料的物理-力学特性发生剧烈变化。沿板厚方向变形的梯度比较陡峭，并在层间结合面处发生强不连续，呈现zig-zag （锯齿状）现象。这导致横向剪应变在板的静态和动态响应中发生重要作用，不计横向变形的经典组合板计算模型CLPT难以适应现代多层板计算分析的需要。考虑横向剪切变形影响的板的计算模型得到重视和发展。需要指出，现有各种考虑剪切变形影响的计算模型虽然有了很大的发展，但在全面和准确性上仍然存在一定的不足，难以适应现代多层组合板横向力和物理性能多变的情况。模型预测的沿板厚方向位移和应力的变化规律难以通过严格的检验。本文提出的以比例边界有限元为基础的正交各向异性板的数值计算模型，同时可适用于各种薄板与厚板的分析，对现代复合材料层合板的分析具有特殊的优越性。所得到的板的位移、正应力和剪应力沿板厚方向的变化，与三维弹性理论的标准解高度吻合。数值算例进一步表明，随着层间纤维走向的变化，板内位移场和应力场沿板厚方向剧烈变化所呈现的锯齿现象均可以精准地进行模拟。据此，本文建议方法对现代板分析的广泛适应性和高度准确性得到了充分论证。     

基于Voronoi切割算法的碎冰区构造及离散元分析

离散元方法广泛应用于海冰，特别是碎冰区的动力过程及其对海洋结构作用过程的数值模拟。为构造碎冰区中的冰块几何特性，基于二维Voronoi图方法对计算域进行随机切割以生成碎冰区中冰块的几何形态，并采用球体单元对每个碎冰块单元进行填充，从而确定碎冰区的初始分布场。在采用Voronoi图进行碎冰区构造时，可对冰块尺寸、几何形态和密集度等海冰参数进行设定。为确定冰块的不同几何规则度，综合采用排斥法和扰动法以定量地控制碎冰块几何形态从完全随机分布到规则分布的连续变换。为分析不同几何规则度下碎冰块的几何特性概率分布规律，对计算域内冰块的面积和边数等参数进行统计分析，从而可更合理地参数化控制初始冰场中碎冰块的几何特性。在此基础上，本文基于粘接-破碎的球体离散元方法对不同冰况下锥体结构的冰荷载进行了数值计算，讨论分析了碎冰区的海冰密集度、冰块面积和几何规则度对冰载荷的影响。     

High-efficiency α-benzoyloxylation and hydroxylation of β-keto amides by phase transfer catalysis

A facile and efficient protocol for α-benzoyloxylation and α-hydroxylation of β-keto amides by phase-transfer catalysis is presented. This methodology provides mild and practical access to a variety ofα-oxygenated β-keto amides. Furthermore, α-benzoyloxylation products can be easily converted into α-hydroxylation compounds, which are useful synthetic precursors of biological targets.     

An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid

An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid was discovered in a diazo-coupling process.The reaction occurred under mild reaction conditions (pH 8.0-9.0.0-5 C,solvent:water) within a short reaction time(1h).A plausible substitution reaction mechanism by phenol-ketone resonance was proposed.     

Strain-dependent internal parameters in hyperelastic biological materials

The behavior of hyperelastic energies depending on an internal parameter, which is a function of the deformation gradient, is discussed. As an example, the analysis of two models where the parameter describes the activation of a tetanized skeletal muscle tissue is presented. In those models, the activation parameter depends on the strain and it is shown the importance of considering the derivative of the parameter with respect to the strain in order to capture the proper stress–strain relations.     

A mass‐fraction‐based interface‐capturing method for multi‐component flow

An interface‐capturing method based on mass fraction is developed to solve the Riemann problem in multi‐component compressible flow. Equations of mass fraction with modified form, which is derived from conservative equations of mass, are employed here to capture the interface. By introducing mass fraction into Euler equations system, as well as other conservative coefficients, a quasi‐conservative numerical model is created. Numerical examples show that the mass fraction model performs well not only in multi‐component fluids modeled by simple stiffened gas equation of state (EOS) but also in that modeled by complex Mie–Grüneisen EOS. Moreover, the mass fraction model is applied to Riemann problem with piecewise EOS; the expression of which depends on density. It is found that the mass fraction model can well adapt to the analytic change in piecewise EOS and produce accuracy solutions with fewer unknown quantities, and the model can be easily extended to m‐component fluid mixture by using only m + 4 equations with no additional conditions. Copyright © 2013 John Wiley & Sons, Ltd.