沼泽地段输气管道应力校核及安全性分析

输气管道穿越沼泽地低洼地带,在自然下沉或浮力的作用下,易发生变形破坏。因此,需要在设计阶段对沼泽地段的管道进行应力和位移分析。本文根据某区管道的设计资料,建立了相应的应力分析模型,首次采用CAESAR II软件对沼泽地段输气管道进行了数值模拟。结果表明:对于下沉的管道,沉降量在5cm~10cm范围内时,沉降量对管道应力的影响较大(沉降量每增加1cm,应力值增大约30MPa),最高及次高应力均产生在过渡段与沼泽地段的交界处;对于上浮的管道,管道最大应力产生在管道过渡段,而不是沼泽地段。说明对于上浮管道,水浮力的作用可以降低过渡段与沼泽地段交界处的集中应力,且偶然载荷工况下的应力值最高,所以工程中建议:若管道处于上浮状态应重点对偶然上浮载荷工况进行分析。     

Highly Enantioselective [3+2] Annulation of Indoles with Quinones to Access Structurally Diverse Benzofuroindolines

A facile and efficient method to produce optically pure benzofuroindolines, especially those without 3‐substituents that are susceptible to rearomatization, through [3+2] annulation of indoles with quinones is described. The suitable combination of a BOX ligand Cu^II hydrate complex and freshly activated molecular sieves functions to give controllably dynamic release of water, which enables the success of this reaction. This reaction can be performed on a gram scale with only 0.5 mol % catalyst loading.     

Quantum Dot Sensitized Solar Cell: Photoanodes,Counter Electrodes,and Electrolytes

In this study, we provide the reader with an overview of quantum dot application in solar cells to replace dye molecules, where the quantum dots play a key role in photon absorption and excited charge generation in the device. The brief shows the types of quantum dot sensitized solar cells and presents the obtained results of them for each type of cell, and provides the advantages and disadvantages. Lastly, methods are proposed to improve the efficiency performance in the next researching.     

Preparation of a porous aromatic framework via the Chan-Lam reaction: a coating for solid-phase microextraction of antioxidants and preservatives

Microchimica Acta - The Chan-Lam reaction was applied to the preparation of a porous aromatic framework (PAF) at room temperature in air without employing expensive noble metal catalysts. The PAF...     

两种典型的含硫磷添加剂之复配体系在润滑油中的协同作用机理

润滑油品的质量是决定现代科学技术和工业生产发展的重要因素之一，而改进润滑油添加剂的性能并开发其复配技术则是提高油品质量的关键，硫化烯烃和二正丁基亚磷酸酯化为极压抗磨减摩添加剂已经广泛地应用于Ｓ－Ｐ型齿轮油中，两者者复配使用可以产生协同效应也有一些研究报道，但还未见有关其协同作用机理方面深入系统的研究成果发表，因此，利用ＨＱ－１型摩擦磨损试验机考察了这两常用的典型添加剂复配体系的润滑性能，并用微观分     

SPACE-TIME FINITE ELEMENT METHOD FOR SCHRODINGER EQUATION AND ITS CONSERVATION

Energy conservation of nonlinear Schrodinger ordinary differential equation was proved through using continuous finite element methods of ordinary differential equation; Energy integration conservation was proved through using space-time continuous fully discrete finite element methods and the electron nearly conservation with higher order error was obtained through using time discontinuous only space continuous finite element methods of nonlinear Schrodinger partial equation. The numerical results are in accordance with the theory.     

Systematic analysis of the structural,elastic, and electronic properties of Ti–Cu–Me (Me=Al,Ga and In) ternary intermetallics

The structural, elastic, and electronic properties of eight intermetallics in Ti–Cu–Me (Me=Al, Ga and In) systems were investigated with the first-principles method. The calculations were performed within the generalized gradient approximation (GGA) with the density functional theory (DFT) using the supercell (SC) method. Calculation results show that the SC approximation is accurate at zero pressure. These intermetallics are classified as stable and metastable in our investigation. The stable phases are those presented in the equilibrium phase diagram at room temperature. The metastable phases are those that usually appear in the equilibrium phase diagram at higher temperatures. The values of calculations show that the TiCuAl, Ti₂CuAl₅, and TiCu₂In compounds are brittle, and the Ti_0.5CuAl_0.5, TiCu₂Al, TiCuGa, Ti₂CuGa₅, and Ti_0.5CuIn_0.5 compounds are ductile at zero pressure.