哈达山水利枢纽坝基砂层震动液化研究

砂层震动液化问题是哈达山水利枢纽工程首要的工程地质问题。根据工程勘察取得的大量试验资料,通过标贯、GJS原状取砂、OYO— 3000系列密度测井及瑞利波测试等综合方法,对砂层震动液化问题进行了深入的研究,为坝基加固处理提供了重要依据。其中瑞利波测试技术用于砂土震动液化是一个新的尝试。     

DNA Switches: From Principles to Applications

The base sequence of nucleic acid encodes structural and functional properties into the biopolymer. Structural information includes the formation of duplexes, G‐quadruplexes, i‐motif, and cooperatively stabilized assemblies. Functional information encoded in the base sequence involves the strand‐displacement process, the recognition properties by aptamers, and the catalytic functions of DNAzymes. This Review addresses the implementation of the information encoded in nucleic acids to develop DNA switches. A DNA switch is a supramolecular nucleic acid assembly that undergoes cyclic, switchable, transitions between two distinct states in the presence of appropriate triggers and counter triggers, such as pH value, metal ions/ligands, photonic and electrical stimuli. Applications of switchable DNA systems to tailor switchable DNA hydrogels, for the controlled drug‐release and for the activation of switchable enzyme cascades, are described, and future perspectives of the systems are addressed.     

乙二胺双缩5-氯水杨醛Schiff碱铜配合物的合成及晶体结构

合成了N,N′-二(5-氯水杨醛)缩乙二胺合铜配合物([Cu(5-ClSalen)]),用单晶X射线衍射法测定了晶体结构.其晶体属三斜晶系,空间群P-1,晶胞参数a=0.83285(1)nm,b=0.95170(4)nm,c=1.09304(4)nm,α=115.130(2)°,β=94.694(2)°,γ=101.127(2)°,V=0.75642(4)nm3,分子式C16H12Cl2CuN2O2,Mr=398.72,Z=2,Dc=1.751g/cm3.在配合物中,Cu处于两个氮原子和两个酚氧原子形成的平面四方场中.     

Fourier transform infrared photoacoustic spectroscopy of dental calculus

The mid and far FTIR spectra of supragingival and subgingival calculus were measured, respectively. From the subtraction spectra of the two types of calculus, the protein components of calculus have been obtained. The results of photoacoustic spectroscopy indicated the presence of protein layer on the surface of early calculus.     

Electrochemical surface plasmon resonance detection of enzymatic reaction in bilayer lipid membranes

In this paper, electrochemical surface plasmon resonance (SPR) method was first used to detect enzymatic reaction in bilayer lipid membrane (BLM) based on immobilizing horseradish peroxidase (HRP) in the BLMs supported by the redox polyaniline (PAn) film. By SPR kinetic curve in situ monitoring the redox transformation of PAn film resulted from the reaction between HRP and PAn, the enzymatic reaction of HRP with H(2)O(2) was successfully analyzed by electrochemical SPR spectroscopy. The results show that this BLM supported on PAn film cannot only preserve the bioactivity of HRP immobilized in the membrane, but also provide a channel for the transfer of electrons between HRP and PAn on electrode surface. These characteristics enabled the development of SPR biosensor for sensitively detecting H(2)O(2). H(2)O(2) has been detected by electrochemical SPR spectroscopy in the concentration range of 5 x 10(-5)M to 2 x 10(-3)M. After each of detections, the SPR sensor surface was completely regenerated by electrochemically reducing the oxidized PAn to its reduced state. This method provides a novel route for enhancing the detection of small ligand of enzymatic reaction in BLM by electrochemical SPR spectroscopy.     

振动系统动力学设计迭代算法及解的存在性讨论

振动系统动力学设计被抽象为高维广义非线性特征值反问题。若系统构成以可变参数表示，则可构造一个非线性多元函数。基于多元函数极小原理，提出了一套求解这一特征值反问题的迭代算法。该算法不受系统给定阶数和给定方向的限制，也适用于具有重特征值的退化情况，系统或结构的构成材料可以是任意的。文中同时讨论了解的存在条件，且以显式表达，可方便地应用于工程实际。结合某直升机旋翼桨叶的动力学设计，给出了应用的数值算例。大量数值仿真结果及应用实践表明，本文算法具很好的收敛性，并有较高的计算精度。     

Single‐Molecule Visualization of the Activity of a Zn2+‐Dependent DNAzyme

We demonstrate the single‐molecule imaging of the catalytic reaction of a Zn²⁺‐dependent DNAzyme in a DNA origami nanostructure. The single‐molecule catalytic activity of the DNAzyme was examined in the designed nanostructure, a DNA frame. The DNAzyme and a substrate strand attached to two supported dsDNA molecules were assembled in the DNA frame in two different configurations. The reaction was monitored by observing the configurational changes of the incorporated DNA strands in the DNA frame. This configurational changes were clearly observed in accordance with the progress of the reaction. The separation processes of the dsDNA molecules, as induced by the cleavage by the DNAzyme, were directly visualized by high‐speed atomic force microscopy (AFM). This nanostructure‐based AFM imaging technique is suitable for the monitoring of various chemical and biochemical catalytic reactions at the single‐molecule level.