Thermoelastoplastic deformation of a thick-walled cylinder with a radial crack

The thermoelastoplastic fracture mechanics problem of a thick-walled cylinder subjected to internal pressure and a nonuniform temperature field is solved by the method of elastic solutions combined with the finite-element method. The correctness of the solution is provided by using the Barenblatt crack model, in which the stress and strain fields are regular. The elastoplastic problem of a cracked cylinder subjected to internal pressure and a nonuniform temperature field are solved. The calculation results are compared with available data. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 173–183, May–June, 2008.     

DUAL RECIPROCITY HYBRID BOUNDARY NODE METHOD FOR THREE-DIMENSIONAL ELASTICITY WITH BODY FORCE

Combining Dual Reciprocity Method （DRM） with Hybrid Boundary Node Method （HBNM）, the Dual Reciprocity Hybrid Boundary Node Method （DRHBNM） is developed for three-dimensional linear elasticity problems with body force. This method can be used to solve the elasticity problems with body force without domain integral, which is inevitable by HBNM. To demonstrate the versatility and the fast convergence of this method, some numerical examples of 3-D elasticity problems with body forces are examined. The computational results show that the present method is effective and can be widely applied in solving practical engineering problems.     

关于一个数论函数的导数及应用

Kanemitsu教授给出了欧拉求和函数的推广公式Lu(x,a)=0n相似文献   

Solid state NMR characterization of formation of poly(ϵ‐caprolactone)/maghnite nanocomposites by in situ polymerization

Results of multinuclear MAS NMR spectroscopy are reported for poly (ε‐caprolactone)/maghnite nanocomposite formation, with ε‐caprolactone in situ polymerized in the presence of maghnite, a proton exchanged montmorillonite clay. Exfoliated and intercalated materials with different maghnite loading in the range 3–15 wt % were investigated. ¹H NMR evidences Brønsted acid hydroxyl groups in the silicate layers and shows that their broad signal at 7.6 ppm present in the parent clay disappears in the nanocomposite material. ²⁷Al MAS NMR results show that beside the hexacoordinated aluminum signal, two additional peaks corresponding to two different tetrahedral Al sites are present in the clay framework. The NMR signal intensity of only one of them was found to be affected in the nanocomposites compared with the parent maghnite, suggesting that these specific aluminum sites are the reactive ones at the initial stages of the polymerization. However almost no changes occurred in the ²⁹Si NMR spectra, confirming that the polymer grafting, as indicated earlier by atomic force microscopy, took place on the aluminum tetracoordinated sites rather than on the silicon sites. A mechanism of maghnite surface catalyzed polymerization of ε‐caprolactone was proposed, involving Brønsted and Lewis acid sites. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3060–3068, 2007     

扫描力显微术在高聚物薄膜玻璃化转变研究中的应用

简述了高聚物薄膜玻璃化转变的复杂性，并结合文章作者的的一些研究结果介绍了扫描力显微术(SFM)在研究高聚物玻璃化转变中的一些方法，包括观察高聚物薄膜形貌的变化，测量其摩擦力、粘附力和弹性模量等物理量的变化，最后指出SFM是研究高聚物薄膜玻璃化转变的有力工具。     

Surface roughness investigation of semi-conductor wafers

Conventionally, surface roughness is predominantly determined through the use of stylus instruments. However, there are certain limitations involved in the method, particularly when a test specimen, such as a silicon wafer, has a smooth mirror-like surface. Hence, it is necessary to explore alternative non-contact techniques. Light scattering has recently been gaining popularity as an optical technique to provide prompt and precise inspection of surface roughness. In this paper, the total integrated scattering (TIS) model is modified to retrieve parameters on surface micro-topography through light scattering. The applicability of the proposed modified TIS model is studied and compared with an atomic force microscope. Experimental results obtained show that the proposed technique is highly accurate for measuring surface roughness in the nanometer range.     

提高YBCO块材在外磁场中悬浮力

本给出了三种提高YBCO块材在外磁场中悬浮力的方法．第一种方法是增强外磁场，对于此方法，本研究了一块直径为30mm的圆柱状YBCO块材分别在圆柱状NdFeB永磁体和NdFeB永磁导轨上的悬浮力．测量结果表明在77K温度下YBCO块在圆柱状NdFeB永磁体上的最大悬浮力为50N，在NdFeB永磁导轨上的最大悬浮力为103．ON．第二种方法是提高YBCO块材自身的性能，包括临界电流密度、俘获磁通和块材尺寸，对于此方法，本仅研究了块材尺寸对悬浮力的影响．三块直径分别为30mm、35mm、40mm的圆柱状YBC0块材在NdFeB永磁导轨上的悬浮力被测量，77K温度下5mm悬浮间距时的悬浮力分别为103．ON、134．5N、175．ON．第三方法是将YBCO块材变成准永久磁体，此种情况下，直径为40mm的圆柱状YBCO块材在77K温度下5mm悬浮间距时的悬浮力高达218．3N．     

非保守力和非完整约束对Hamilton系统Lie对称性的影响

研究非保守力和非完整约束对Hamilton系统的Lie对称性和守恒量的影响.分别研究了Hamilt on系统受到非保守力和非完整约束作用时，系统的Lie对称性保持不变的条件，同时给出了 系统的结构方程和守恒量保持不变的条件.以著名的Emden方程和Appell-Hamel模型为例进行 了分析讨论. 关键词： 分析力学 Hamilton系统 非保守力 非完整约束 对称性 守恒量     

非对称核物质中同位旋对称势的动量和密度依赖性

在Brueckner-Hartree-Fock理论框架内, 研究了同位旋非对称核物质中质子和中子单粒子势的动量相关性及其随同位旋非对称度的变化, 在此基础上计算了同位旋对称势, 并讨论了三体核力的影响. 结果表明同位旋对称势对于同位旋非对称度的依赖性很弱, 但对于动量和密度均有较强的依赖性. 当密度固定时, 同位旋对称势随动量增加而减小. 尽管三体核力对于质子和中子单粒子势的动量相关性有较大影响, 但对同位旋对称势的影响很小. 还与目前重离子碰撞输运理论模型中所使用的各种参数化的唯象对称势进行了比较.     

Structural characterization of nanopatterned surfaces

In this work, chemically and topographically nanopatterned surfaces were produced by a top-down processing approach for biosensing devices. The nanopatterning was the result of the combination of plasma polymerisation (pp) of biofunctional materials and colloidal lithography techniques. The morphological and chemical properties induced by the plasma deposition-etching treatment were characterised by optical method combining ellipsometry and Fourier Transform Infrared spectroscopy studies. This method supported by atomic force microscopy measurements, allowed the full optical characterization of each step of the top-down process. The optical characterization of the end-up nanopatterned samples demonstrated that the chosen process is able to produce well-defined nanostructured surfaces with controlled chemical and morphological properties.