Investigation of selective molecular interactions using two-dimensional Fourier transform IR spectroscopy

A novel method of studying molecular interactions is introduced. It is a method based on the framework of a two-dimensional (2D) infrared (IR) correlation spectroscopy technique with a new data pretreatment strategy. In this method, an additional external perturbation stimulates the system to cause some selective changes in the state, order, and surroundings of system constituents. The overall response of the stimulated system to the applied external perturbation leads to distinctive changes in the measured spectrum, and a series of perturbation-induced dynamic spectra are collected in a systematic manner. Such a set of dynamic spectra are then transformed into a set of 2D correlation spectra by cross-correlation analysis. Temperature was chosen as an external perturbation, and the molecular interaction between 4-aminopyridine (Apy) and methacrylic acid (MAA) was investigated by 2D IR correlation spectroscopy. Synchronous cross peaks exist between the stretching vibration of the C–O group of MAA at 1,298 and 1,202 cm⁻¹ and the C=N group of Apy at 1,531 cm⁻¹, and between the carbonyl group of MAA at 1,705 cm⁻¹ and the amino group of Apy at 3,382 and 3,212 cm⁻¹. The synchronous cross peaks are from orientation of MAA and Apy vibrations generated at the same time; the synchronization of microstructure movements in the molecules indicates that there exists strong interactions between MAA and Apy. According to 2D correlation rules, static electricity and hydrogen-bonding interactions exist between Apy and MAA. Such results were further verified by ¹H-NMR spectroscopy. The successful application demonstrates that 2D IR correlation spectroscopy may be a convenient and effective method in the study of molecular interactions.     

金属多级类蜂窝的压溃行为研究

通过实验和数值模拟方法系统研究了单胞壁开孔金属多级类蜂窝与双胞壁开孔金属多级类蜂窝的压溃行为. 重点分析了试件尺寸、开孔位置、孔偏距和孔梯度等因素对多级类蜂窝力学性能的影响. 结果表明,多级类蜂窝的压溃过程可分为3个阶段:弹性变形、屈曲变形以及密实;单胞壁开孔多级类蜂窝的压溃过程趋向于渐近内凹压溃,而双胞壁开孔多级类蜂窝趋向于轴向压溃;试件尺寸对多级类蜂窝的力学行为有明显的影响,当胞元数达到一定数目时,其力学性能几乎与蜂窝胞元数无关. 单胞壁开孔多级类蜂窝的峰值应力大于双胞壁开孔多级类蜂窝的峰值应力,但其平均压溃应力小于双胞壁开孔多级类蜂窝的平均压溃应力;与传统蜂窝相比,蜂窝胞壁开孔设计降低了蜂窝材料的比吸能;孔偏距的存在导致单胞壁开孔多级类蜂窝的峰值应力降低,但随着孔偏距的增加其平均压溃应力呈先减低后增加趋势;多梯度孔设计对多级类蜂窝材料的力学性能有重要影响,与均匀孔多级类蜂窝相比,正梯度孔分布设计降低了多级类蜂窝峰值应力,但提高了其平均压溃应力;多梯度孔分布设计对多级类蜂窝的峰值应力和平均压溃应力影响不大.      

苯氧基修饰的ZPS-PVPA轴向配位固载手性Salen Mn(Ⅲ)催化剂的合成及催化非功能化烯烃的不对称环氧化反应研究

制备了两种经不同链长苯氧基修饰的有机聚合物一无机杂化载体ZPS-PVPA轴向同载手性Salen Mn(Ⅲ)催化剂(1a,1b),将其应用于非官能烯烃的多相不对称环氧化反应.详细比较了1a,1b在不同氧源下对非功能化烯烃的不对称环氧化反应结果,研究发现:在以间氯过氧苯甲酸为氧源体系中,非均相催化剂1a,1b在轴向添加剂的...     

High density peptide microarrays. In situ synthesis and applications

The technologies enabling the creation of large scale, miniaturized peptide or protein microarrays are emerging. The focuses of this review are the synthesis and applications of peptide and peptidomimetic microarrays, especially the light directed parallel synthesis of individually addressable high density peptide microarrays using a novel photogenerated reagent chemistry and digital photolithography (Gao et al., 1998, J. Am. Chem. Soc. 120, 12698; Pellois et al. 2002, Nat. Biotechnol. 20, 922). Concepts related to the synthesis are discussed, such as the reactions of photogenerated acids in the deprotection step of peptide synthesis or oligonucleotide synthesis, and the applications of high density peptide chips in antibody binding assays are discussed. Peptide chips provide versatile tools for probing antigen-antibody, protein-protein, peptide-ligand interactions and are basic components for miniaturization, automation, and system integration in research and clinical diagnosis applications.     

气相色谱和气相色谱/质谱法分析高级脂肪伯醇混合物的化学组分

多廿醇是从制糖滤泥中分离得到的一种高级脂肪伯醇天然混合物,其化学组成分析未见报道。本文采用气相色谱法（GC）和气相色谱／质谱法（GC／MS）,对其组分和结构进行了分析和鉴定。     

考虑运动硬化的DD3镍基合金力学行为研究

详细介绍了镍基合金的晶体塑性本构模型,在Asaro大变形晶体塑性框架下,详细介绍了镍基合金的晶体塑性本构模型,在Asaro大变形晶体塑性框架下,引入了运动硬化规律,考虑了温度和应变率对晶体塑性变形的影响,通过针对每个滑移系考虑屈服准则和流动规律建立了晶体塑性模型. 对积分过程进行了推导,通过编写ABAQUS材料用户子程序(UMAT), 实现本构模型的有限元积分算法. 在此基础上模拟了DD3镍基单晶合金在单轴拉伸和循环载荷下的响应,并与实验数据进行了对比. 利用该模型可以很好地模拟镍基单晶所具有的各向异性特性,体现了镍基单晶在循环载荷作用下的拉-压不对称性.      

Natural boundary of the random power series

We investigate convergence properties of random Taylor series whose coefficients are ψ-mixing random variables. In particular, we give sufficient conditions such that the circle of the convergence of the series forms almost surely a natural boundary.

     

A concise synthesis of (+)-botryolide-E and its C-7 epimer

The first synthesis of (+)-botryolide-E and its C-7 epimer has been achieved in 8 steps from d-Glucono-δ-lactone, and their antibiotic activities were also investigated preliminarily.     

高韧性管道动态断裂的气体减压模式和材料韧性研究

天然气管道上动态裂纹扩展包含气体、结构和断裂的相互作用．因此，分析射流场分布特性及其与管壁开裂变形的相互作用是数值模拟过程的关键问题．随着钢管韧性等级的迅速提升和气体压力的不断提高，原有的经验公式乃至算法多数不再适用，亟需通过理论、试验和数值模拟给出新的扩展与止裂判据，以控制裂纹在管道上扩展的速度和距离．本文通过一系列的韧性试验校正了现行的管材韧性判定办法，并对不同工况下的裂纹动态扩展以及超声速射流场进行了数值仿真，以建立一套工程适用的评价体系。     

A Highly Selective Rhodamine Based Colorimetric Sensor Toward Cu2+

A probe for recognition of Cu²⁺ was developed based on rhodamine B. The probe was synthesized by condensation between rhodamine B and quinoline-2-carbaldehyde. The probe exhibits highly selectivity toward Cu²⁺ detection. It binds Cu²⁺ in a 1:1 stoichiometry in acetonitrile solution. Distinct color change can be observed upon the addition of Cu²⁺ and little interference with other biologically relevant metal ions. Only Fe³⁺ addition shows a little disturbance in absorption enhancement. In addition, the limit of detection toward Cu²⁺ is about 235 times lower than the World Health Organization (WHO) recommended level in drinking water.