Mindlin second-gradient elastic properties from dilute two-phase Cauchy-elastic composites. Part I: Closed form expression for the effective higher-order constitutive tensor

It is shown that second-order homogenization of a Cauchy-elastic dilute suspension of randomly distributed inclusions yields an equivalent second gradient (Mindlin) elastic material. This result is valid for both plane and three-dimensional problems and extends earlier findings by Bigoni and Drugan [Bigoni, D., Drugan, W.J., 2007. Analytical derivation of Cosserat moduli via homogenization of heterogeneous elastic materials. J. Appl. Mech. 74, 741–753] from several points of view: (i) the result holds for anisotropic phases with spherical or circular ellipsoid of inertia; (ii) the displacement boundary conditions considered in the homogenization procedure is independent of the characteristics of the material; (iii) a perfect energy match is found between heterogeneous and equivalent materials (instead of an optimal bound). The constitutive higher-order tensor defining the equivalent Mindlin solid is given in a surprisingly simple formula. Applications, treatment of material symmetries and positive definiteness of the effective higher-order constitutive tensor are deferred to Part II of the present article.     

Effect of low cycle fatigue pre-damage on very high cycle fatigue

Carbon-manganese steel is often applied in components of pipes in nuclear plant. Ultrasonic fatigue tests following low cycle fatigue (LCF) cycles damaged are used to study the strength of very high cycle fatigure (VHCF). The comparison of test results of simple VHCF and cumulative fatigue (LCF plus VHCF) shows that LCF load influences the following VHCF strength. Continuum damage mechanics model is extended to VHCF region. The effect of LCF load on VHCF is studied by an improved cumulative damage model.     

Structural transition in compressed amorphous sulfur

Properties of amorphous sulfur (a-S) were investigated by synchrotron x-ray diffraction up to 100 GPa between 40 and 175 K. Measurements of the structure factor yielded the radial distribution function and the densities of two amorphous forms. a-S undergoes a structural transition above 65 GPa, accompanied by density discontinuity of 7%. These results indicate the amorphous-amorphous transition, from a low-density to a high-density form, and open up the possibility for the direct measurements of density of liquid-amorphous materials at extreme conditions.     

一个IP服务质量控制模型:DiffServ over MPLS

融合了多协议标记交换（Multiprotocol Label Switching,MPLS)和区分服务（Differentiated Services,DiffServ）技术,建立了DiffServ over MPLS模型,研究了在模型上承载区分服务,以实现端到端的服务质量（Quality of Service,QoS) 的技术。详细描述了其中的重要概念、分组的转发处理过程及基于约束路由的标记分发协议（Constraint-based Routing Label Distribution Protocol,CR-LDP)的扩展细节。     

The effects of added foreign ions in Gd2O2S : Tb; crystal field calculations, lifetimes, photo-luminescence and absorption spectra

A spectroscopic study is carried out in which the effects of added Ca²⁺ and Ru⁴⁺ transition metal ions on some characteristics of the emission of Gd₂O₂S : Tb³⁺ phosphors (energy levels, intensities, lifetimes) are examined and compared. In order to distinguish the Tb³⁺ emissions from impurity ones, the electronic energy levels of trivalent terbium are determined and the energy level scheme is completed by a crystal field analysis. The optical spectra reveal no terbium doped impurity phase; however, other rare earth ions present as impurities in the starting materials are detected. They are identified, and the influence of the added Ca²⁺ and Ru⁴⁺ on their emission lines is also examined.     

Application of the palladium-catalyzed borylation/Suzuki coupling (BSC) reaction to the synthesis of biologically active biaryl lactams

The palladium-catalyzed, two-step, one-pot borylation/Suzuki coupling (BSC) reaction was developed to synthesize sterically hindered 2,2'-disubstituted biphenyl and phenyl-indole compounds in a short, simple, and efficient manner from two easily accessible aryl halides. High yields can be obtained by choosing properly both components according to their rough electronic properties. The illustration of the utility of this method was provided by the solution and solid-phase synthesis of seven- or eight-membered biphenyl lactams 5a-e, as well as paullone 3a. These compounds exhibit moderate albeit significant cytotoxicities and may serve as structural models for future medicinal chemistry developments.     

An error estimate for finite volume methods for the Stokes equations on equilateral triangular meshes

We give here an error estimate for a finite volume discretization of the Stokes equations in two space dimensions on equilateral triangular meshes. This work was initiated by an analogous result presented by Alami‐Idrissi and Atounti for general triangular meshes. However, in this latter article, the result is not actually proven. We state here the restricting assumptions (namely equilateral triangles) under which the error estimate holds, using the tools which were introduced by Eymard, Gallouet and Herbin and used by Alami‐Idrissi and Atounti. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004     

On the possibility of enrichment of H2O nuclear spin isomers by adsorption

Experimental data on the enrichment of H₂O nuclear spin isomers by means of adsorption, as suggested in several works by other authors, are reported. We were unable to observe any enrichment of isomers. The conclusion was drawn that the adsorption characteristics of water ortho and para isomers were insignificantly different. An analysis of the relaxation of H₂O spin isomers induced by the intramolecular mixing of the molecular ortho and para spin states and caused by collisions with paramagnetic oxygen molecules was performed.     

Far infrared pure rotational spectrum of methylacetylene

The pure rotational spectrum of methylacetylene has been recorded in the far infrared region between 10 and 60 cm^?1 with a Fourier transform spectrometer whose theoretical resolution was 0.025 cm^?1. From the measured wavenumbers it has been possible to determine the rotational constants in the ground state and in the v₅ = 1, v₈ = 1, v₁₀ = 1, 2, 3, 4 levels.