Étude théorique d'une électrode tournante à double annfau: Partie III. Simulation d'un courant constant sur l'anneau interne

Digital simulation treatments supposing constant current flowing suddenly imposed across the internal electrode for two rotating systems, the ring-disk and the double ring, are compared. Results are given for a double ring system.     

Structure-Guided Design of a Group B Streptococcus Type III Synthetic Glycan–Conjugate Vaccine

Identification of glycan functional epitopes is of paramount importance for rational design of glycoconjugate vaccines. We recently mapped the structural epitope of the capsular polysaccharide from type III Group B Streptococcus (GBSIII), a major cause of invasive disease in newborns, by using a dimer fragment (composed of two pentasaccharide repeating units) obtained by depolymerization complexed with a protective mAb. Although reported data had suggested a highly complex epitope contained in a helical structure composed of more than four repeating units, we showed that such dimer conjugated to a carrier protein with a proper glycosylation degree elicited functional antibodies comparably to the full-length conjugated polysaccharide. Here, starting from the X-ray crystallographic structure of the polysaccharide fragment–mAb complex, we synthesized a hexasaccharide comprising exclusively the relevant positions involved in binding. Combining competitive surface plasmon resonance and saturation transfer difference NMR spectroscopy as well as in-silico modeling, we demonstrated that this synthetic glycan was recognized by the mAb similarly to the dimer. The hexasaccharide conjugated to CRM₁₉₇, a mutant of diphtheria toxin, elicited a robust functional immune response that was not inferior to the polysaccharide conjugate, indicating that it may suffice as a vaccine antigen. This is the first evidence of an X-ray crystallography-guided design of a synthetic carbohydrate-based conjugate vaccine.     

Fragments of Arithmetic and true sentences

By a theorem of R. Kaye, J. Paris and C. Dimitracopoulos, the class of the Π_n+1‐sentences true in the standard model is the only (up to deductive equivalence) consistent Π_n+1‐theory which extends the scheme of induction for parameter free Π_n+1‐formulas. Motivated by this result, we present a systematic study of extensions of bounded quantifier complexity of fragments of first‐order Peano Arithmetic. Here, we improve that result and show that this property describes a general phenomenon valid for parameter free schemes. As a consequence, we obtain results on the quantifier complexity, (non)finite axiomatizability and relative strength of schemes for Δ_n+1‐formulas. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

面向并行设计的局部特征识别技术研究

为支持在并行设计过程中设计特征模型到加工特征模型的逐步转换，提出了局部特征识别的方法．在并行设计中，设计特征模型和加工特征模型通过面名历史图共享零件的实体模型，设计特征的变动通过局部特征识别自动地转换为相应的加工特征．局部特征识别是由基于最小条件子图特征识别方法改进来的，它以零件的局部区域为识别对象，通过搜索匹配局部区域构成的边界模式，识别出该局部区域中所包含的加工特征．局部特征识别方法的特点是只对设计中发生变动的区域进行识别．     

Direct Synthesis of Nano‐Ferrierite along the 10‐Ring‐Channel Direction Boosts Their Catalytic Behavior

Ferrierite zeolites with nanosized crystals and external surface areas higher than 250 m² g^?1 have been prepared at relatively low synthesis temperature (120 °C) by means of the collaborative effect of two organic structure directing agents (OSDA). In this way, hierarchical porosity is achieved without the use of post‐synthesis treatments that usually involve leaching of T atoms and solid loss. Adjusting the synthesis conditions it is possible to decrease the crystallite size in the directions of the 8‐ and 10‐ring channels, [010] and [001] respectively, reducing their average pore length to 10–30 nm and increasing the number of pores accessible. The small crystal size of the nano‐ferrierites results in an improved accessibility of reactants to the catalytic active centers and enhanced product diffusion, leading to higher conversion and selectivity with lower deactivation rates for the oligomerization of 1‐pentene into longer‐chain olefins.