镜煤吡啶不溶物及其热解加氢产物的NMR研究

本文对镜煤吡啶不溶物、热解加氢后吡啶及四氢呋喃不溶物进行了固体NMR研究,获得了12种结构参数,并对热解加氢产物中的苯可溶各馏份进行了一维、二维液体NMR研究,归属了其¹³C和¹H谱,计算了各馏份的平均分子结构.     

模压全息衍射效率的分析

本文指出光刻胶所记录到的是浮雕型相位光栅,经历了电铸、模压转移到PET薄膜上,在此过程中光栅刻蚀深度的转移是非线性的,即深度浅的地方,其最后结果将更浅,甚至丢失。由于散射物体散斑的光强分布是严重不均匀的,故光刻胶上记录下各散斑的光栅刻蚀深度也严重不均匀,经过电铸、模压后,进一步加重了这种不均匀性,使得模压片的衍射效率降低,解决的办法是尽可能地使各个散斑上的光栅刻蚀深度趋于均匀化。     

山莨菪碱和樟柳碱的NMR研究

本文用二维NMR和双共振技术确定了山莨菪碱和樟柳碱的¹H和¹³CNMR谱线归属,并对其结果进行了讨论,推断出山莨菪碱的NCH₃主要取平展构型,樟柳碱的NCH₃取直立构型。     

Synthesis of cost-effective porous polyimides and their gas storage properties

Porous polyimide (PI) networks with surface area up to 660 m(2) g(-1) were synthesized by planar structure monomers without detrimental catalysts.     

Domino N-H/C-H bond activation: copper-catalyzed synthesis of nitrogen-bridgehead heterocycles using azoles and 1,4-dihalo-1,3-dienes

Copper-catalyzed tandem coupling of 1,4-dihalo-1,3-dienes with azoles via an N-H bond and its adjacent C-H bond activation has been described. The reaction exhibits good regioselectivity when unsymmetrical 1,4-dihalo-1,3-diene is employed. This method provided a novel route to the synthesis of nitrogen-bridgehead azolopyridine derivatives.     

A novel matrix method for coupled vibration and damping effect analyses of liquid-filled circular cylindrical shells with partially constrained layer damping under harmonic excitation

A novel matrix method is further developed for a liquid-filled circular cylindrical shell with partially constrained layer damping (CLD), which consists of treating liquid domain with Bessel function approach, and shell domain with transfer matrix equation based on a new set of first order matrix differential equation. In order to indicate its advantage to the finite element method (FEM), free vibration analysis on such an empty shell under clamped–clamped boundary are carried out by using the present method together with FEM. Meanwhile, coincident result is yielded for the liquid-filled shell by adopting the present method with by other transfer matrix method. Finally, a series of valuable numerical results are obtained by this method.     

丁苯接枝的高乙烯基聚丁二烯橡胶合成及其与丁苯橡胶的相容性研究

以n-BuLi为引发剂,THF为结构调节剂合成一定分子量和苯乙烯结构单元含量的丁苯大分子(SB).在SB的加氢汽油溶液中用Mo-Al(正辛醇取代的MoCl5和Al(OPhCH3)(i-Bu)2)催化丁二烯配位聚合制备丁苯接枝的高乙烯基聚丁二烯橡胶(SB-grafted HVPBR).接枝结构是通过聚丁二烯活性链与SB分...     

Representation of the coherent state for a beam splitter operator and its applications

A beam splitter operator is a very important linear device in the field of quantum optics and quantum information. It can not only be used to prepare complete representations of quantum mechanics, entangled state representation, but it can also be used to simulate the dissipative environment of quantum systems. In this paper, by combining the transform relation of the beam splitter operator and the technique of integration within the product of the operator, we present the coherent state representation of the operator and the corresponding normal ordering form. Based on this, we consider the applications of the coherent state representation of the beam splitter operator, such as deriving some operator identities and entangled state representation preparation with continuous-discrete variables. Furthermore, we extend our investigation to two single and two-mode cascaded beam splitter operators, giving the corresponding coherent state representation and its normal ordering form. In addition, the application of a beam splitter to prepare entangled states in quantum teleportation is further investigated, and the fidelity is discussed. The above results provide good theoretical value in the fields of quantum optics and quantum information.     

Finely Controlled Platinum Nanoparticles over ZnO Nanorods for Selective Hydrogenation of 3-Nitrostyrene to 3-Vinylaniline

Metallic platinum nanocatalysts play a key role in the liquid-phase selective hydrogenation of substrates with more than one unsaturated bond. However, the commonly applied explanation for the effects of different electronic and geometric properties of catalysts on reactions remains of a heuristic nature due to the difficulties involved in preparing catalysts with precise structure. In this work, we have directly loaded pre-synthesized metallic platinum nanoparticles onto well-structured ZnO nanorods and then subjected them to thermal treatment in a reductive atmosphere for different temperatures. The effects of the different electronic and geometric properties of the catalysts on the selective reduction of 3-nitrostyrene to 3-vinylaniline as a model reaction have been rigorously explored through an analysis of the catalyst structures and the activity and selectivity profiles. Both the electron transfer from zinc to platinum and the decreased platinum surface density as a result of the formation of PtZn intermetallic compounds are key factors for improving the selectivity for the desired 3-vinylaniline. Azobenzene was detected in the reaction with all the Pt/ZnO catalysts after 10–90 min, which indicates that the reaction follows a condensation mechanism.     

Pharmacokinetic Characterization of (Poly)phenolic Metabolites in Human Plasma and Urine after Acute and Short-Term Daily Consumption of Mango Pulp

Pharmacokinetic (PK) evaluation of polyphenolic metabolites over 24 h was conducted in human subjects (n = 13, BMI = 22.7 ± 0.4 kg/m²) after acute mango pulp (MP), vitamin C (VC) or MP + VC test beverage intake and after 14 days of MP beverage intake. Plasma and urine samples were collected at different time intervals and analyzed using targeted and non-targeted mass spectrometry. The maximum concentrations (C_max) of gallotannin metabolites were significantly increased (p < 0.05) after acute MP beverage intake compared to VC beverage alone. MP + VC beverage non-significantly enhanced the C_max of gallic acid metabolites compared to MP beverage alone. Pyrogallol (microbial-derived metabolite) derivatives increased (3.6%) after the 14 days of MP beverage intake compared to 24 h acute MP beverage intake (p < 0.05). These results indicate extensive absorption and breakdown of gallotannins to galloyl and other (poly)phenolic metabolites after MP consumption, suggesting modulation and/or acclimation of gut microbiota to daily MP intake.