利用近场MVDR双聚焦波束成形方法实现被动测距

本文分析了近场环境下基于双聚焦波束成形的水下被动测距方法。通过修正MVDR方向矢量,得到了适用于近场环境的MVDR。仿真实验证明近场MVDR双聚焦波束成形测距方法优于普通波束成形和远场MVDR双聚焦波束成形,能明显减小目标距离估计的模糊区域。在相邻两个日标的定位性能上,MVDR双聚焦波束成形技术也比MVDR单聚焦系统体现出更大的优势,能较好地分辨目标。     

格蕴涵代数的素对偶理想

在格蕴涵代数中定义了一类特殊的素对偶理想,讨论了它们的结构和性质,证明了该格蕴涵代数中的蕴涵运算可以由这些特殊的素对偶理想所确定,并且这些特殊的素对偶理想全体自然地构成一个格蕴涵代数,它和原格蕴涵代数具有格蕴涵代数同构关系。     

Design of stapled oxyntomodulin analogs containing functionalized biphenyl cross-linkers

A panel of three lipid-modified, functionalized biphenyl cross-linkers (fBph) were synthesized and subsequently employed in the preparation of the stapled oxyntomodulin (OXM) analogs. In a luciferase-based reporter assay, these stapled OXM analogs showed varying degree of potency in activating GLP-1R and GCGR, presumably due to the disparate effect of the lipid chains on the local environment close to the ligand-receptor binding interface. In particular, the fBph-1 cross-linked peptide with the lipid chain attached to position-3 of the biphenyl cross-linker exhibited the highest dual agonist activity.     

TEM study of the deformation structures around nano-scratches

An in-plane transmission electron microscopy (TEM) investigation carried out on nano-scratches made in a Ni₃Al foil revealed a high dislocation density within the scratch core, resulting in severe crystal rotations. The amount and sense of rotation were found to be asymmetrical about the longitudinal centre line of the scratch. Cross-sectional TEM analysis revealed that almost all the dislocations were confined within a semicircular zone having a radius similar to the calculated tip-sample contact size during scratching, in agreement with the in-plane TEM observations.     

Characterization of the fracture toughness of micro-sized tungsten single crystal notched specimens

Fracture experiments using micrometer-sized notched cantilevers were conducted to investigate the possibility of determining fracture mechanical parameters for the semi-brittle material tungsten. The experiments were also used to improve the understanding of semi-brittle fracture processes for which single crystalline tungsten serves as a model material. Due to the large plastic zone in relation to the micrometer sample size, linear elastic fracture mechanics is inapplicable and elastic-plastic fracture mechanics has to be applied. Conditional fracture toughness values J _Q were calculated from corrected force vs. displacement diagrams. Crack growth was accessible by direct observation of in-situ experiments as well as with the help of unloading compliances. As a further tool, fracture toughness can be determined via crack tip opening displacement. The micro samples behave more ductile and exhibit higher fracture toughness values compared to macro-sized single crystals and fail by stable crack propagation.     

Perfect Pairs of Ideals and Duals in Numerical Semigroups

This article considers numerical semigroups S that have a nonprincipal relative ideal I such that μ _S (I)μ _S (S ? I) = μ _S (I + (S ? I)). We show the existence of an infinite family of such pairs (S, I) in which I + (S ? I) = S\{0}. We also show examples of such pairs that are not members of this family. We discuss the computational process used to find these examples and present some open questions pertaining to them.