Photoemission study (XPS,UPS) of PuFe2

XPS and UPS investigations of PuFe₂ add support to the claim that Pu 5f electrons are localized in this compound. The surface composition is similar to that of lanthanide—transition metal compounds. Some capacity for surface healing has been observed after exposure to the atmosphere.     

Cycloaddition reaction of quadricyclane and fluoroolefins

Reaction of quadricyclane (1) with fluoroolefins of different structure results in stereoselective formation of polyfluorinated exo-tricyclo[4.2.1.0^2,5]non-7-enes. The reaction of a mixture of trans/cis CF₃CFCFCF₃ with 1 is stereoselective and the resulting cycloadducts 7a, b preserve the original alkene stereochemistry. The relative rate constants of cycloaddition of a series of fluoroolefins to 1 under pseudo first-order conditions measured by kinetic NMR at 109 °C provide a kinetic scale of reactivities of the fluoroolefins in this reaction.These relative rate constants correlate well with the number of fluoroalkyl groups connected to the double bond, reaching a maximum for the tri-substituted olefin: CF₃CFCF₂:CF₃CFCFCF₃:(CF₃)₂CC(CF₃)₂:(CF₃)₂CCFC₂F₅ = 1:1.2-1.9:4:138.     

Discrete rearranging disordered patterns, part II: 2D plasticity, elasticity and flow of a foam

The plastic flow of a foam results from bubble rearrangements. We study their occurrence in experiments where a foam is forced to flow in 2D: around an obstacle; through a narrow hole; or sheared between rotating disks. We describe their orientation and frequency using a topological matrix defined in the companion paper (F. Graner, B. Dollet, C. Raufaste, and P. Marmottant, this issue, 25 (2008) DOI 10.1140/epje/i2007-10298-8), which links them with continuous plasticity at large scale. We then suggest a phenomenological equation to predict the plastic strain rate: its orientation is determined from the foam's local elastic strain; and its rate is determined from the foam's local elongation rate. We obtain a good agreement with statistical measurements. This enables us to describe the foam as a continuous medium with fluid, elastic and plastic properties. We derive its constitutive equation, then test several of its terms and predictions.     

A projected subgradient method for solving generalized mixed variational inequalities

We consider the projected subgradient method for solving generalized mixed variational inequalities. In each step, we choose an ε_k-subgradient u^k of the function f and w^k in a set-valued mapping T, followed by an orthogonal projection onto the feasible set. We prove that the sequence is weakly convergent.     

Projective functors for algebraic groups

We investigate the regular subquotient category introduced by Soergel in [W. Soergel, On the relation between intersection cohomology and representation theory in positive characteristic, J. Pure Appl. Algebra 152 (1–3) (2000) 311–335]. A detailed study of projective functors enables one to relate those categories for semi-simple algebraic group G and its subgroup schemata G_rT. As an application we derive some information about the characters of tilting modules for G.     

Ultrafast solid–liquid–vapor phase change of a gold film induced by pico- to femtosecond lasers

Melting, vaporization and resolidification processes of thin gold film irradiated by a femtosecond pulse laser are studied numerically. The nonequilibrium heat transfer in electrons and lattice is described using a two-temperature model. The solid–liquid interfacial velocity, as well as elevated melting temperature and depressed solidification temperature, is obtained by considering the interfacial energy balance and nucleation dynamics. An iterative procedure based on energy balance and gas kinetics law to track the location of liquid–vapor interface is utilized to obtain the material removal by vaporization. The effect of surface heat loss by thermal radiation was discussed. The influences of laser fluence and duration on the evaporation process are studied. Results show that higher laser fluence and shorter laser pulse width lead to higher interfacial temperature, deeper melting and ablation depths.     

DAIP改性环氧树脂研究

采用共固化的方法,得到酚醛环氧树脂(F-51)和间苯二甲酸二烯丙基酯(DAIP)的共固化树脂。实验结果表明:DAIP的加入降低了F-51环氧树脂的粘度[体系粘度为150～350mPa·s(25℃)],利于工艺操作;提高了F-51环氧树脂的耐热性,热变形温度达200℃。研究了F-51环氧树脂和DAIP共固化的固化行为、不同配比对共固化物形态结构的影响;并研究了不同配比对固化物耐热性的影响。     

The first chemical synthesis of F-4-GlcAβ(1→3)GlcNAc-UDP with the potential of novel substrate and enzyme inhibitor for hyaluronic acid synthases (HASs)

The first chemical synthesis of F-4-GlcAβ(1→3)GlcNAc-UDP is described here. This compound can serve as a novel substrate to study the catalytic mechanism of hyaluronic acid synthases (HASs) and has potential to be donor for these enzymes that extend HA chain at the reducing end. Moreover, it may also behave as inhibitor for the enzymes that act on non-reducing end in the assembly of HA chain.     

F-127作为模板剂合成微孔-介孔SAPO-11分子筛及其在长链烷烃异构化中的应用

在常规水热法合成SAPO-11的基础上,添加适量F-127作为软模板构造介孔结构,成功合成出了SAPO-11分子筛微介复合体.考察了F-127添加量对分子筛内部的孔道结构的影响,并通过XRD、N2吸附-脱附曲线、SEM和Py-FTIR等途径对催化剂进行表征.以正十二烷为原料,对负载Pt金属的SAPO-11分子筛进行临氢异构化反应性能评价.结果表明:添加F-127的分子筛内部出现了明显的介孔结构,并且随着F-127添加量的增加,分子筛的介孔孔容呈先增大后减小的趋势;异构化反应结果表明催化剂活性位的数量与分子筛介孔孔容有关;随着温度的升高,异构烷烃转化率升高,异构烃收率下降.催化剂的异构化转化率伴随着F-127的添加量的增加而降低,F-127添加量在一定范围内的增加可使异构烃收率得到提高.在F-127添加量为10;时,异构烃收率达到最高为57.62;.