Unusually stable helical coil allotrope of phosphorus

We have identified an unusually stable helical coil allotrope of phosphorus. Our ab initio Density Functional Theory calculations indicate that the uncoiled, isolated straight 1D chain is equally stable as a monolayer of black phosphorus dubbed phosphorene. The coiling tendency and the attraction between adjacent coil segments add an extra stabilization energy of about 12 meV/atom to the coil allotrope, similar in value to the approximately 16 meV/atom inter-layer attraction in bulk black phosphorus. Thus, the helical coil structure is essentially as stable as black phosphorus, the most stable phosphorus allotrope known to date. With an optimum radius of 2.4 nm, the helical coil of phosphorus may fit well and even form inside wide carbon nanotubes.Comment: The paper has been accepted by Nano. Lett. (2016

Analysis of contact mechanics in micro flexible rolling

Micro flexible rolling is a new microforming method by online controlling and adjusting the roll gap to make various strip thickness in the submillimeter range. The micro flexibly rolled strips can be divided into three zones of the thicker zone, the thinner zone and the transition zone after experiencing the upward and downward rolling processes. However, it is tough to achieve the final target thickness especially in the transition zone due to a number of issues relating to the contact mechanics such as the change in the central neutral point/zone, the touch at the edges of the work rolls, the elastic deformation of the work rolls, the roll bite arc modifications in real time and the tribological conditions. All of these factors have significant influences on flatness, profile and surface finish of the rolled products, as well as the rolling forces. In the current work, a new model has been developed in order to clarify the micro flexible rolling process. This model considers a non-circular contact arc which includes an elastic loading region at the start of the roll gap, a plastic reduction region with backward slip, a central flattened region without slip, the plastic reduction region with forward slip, and an elastic unloading region at the end of the roll gap. In this study, the effect of speed ratio (the ratio of the lifting speed and the rolling speed) on the dimensions and the rolling forces along the transition zones is investigated. The contact mechanics in the micro flexible rolling are systematically analysed. The simulation results are found to be in line with the experimental ones, which means that the developed model with high precision is suitable for the analysis of the micro flexible rolling process

Polyffusion: A Diffusion Model for Polyphonic Score Generation with Internal and External Controls

We propose Polyffusion, a diffusion model that generates polyphonic music scores by regarding music as image-like piano roll representations. The model is capable of controllable music generation with two paradigms: internal control and external control. Internal control refers to the process in which users pre-define a part of the music and then let the model infill the rest, similar to the task of masked music generation (or music inpainting). External control conditions the model with external yet related information, such as chord, texture, or other features, via the cross-attention mechanism. We show that by using internal and external controls, Polyffusion unifies a wide range of music creation tasks, including melody generation given accompaniment, accompaniment generation given melody, arbitrary music segment inpainting, and music arrangement given chords or textures. Experimental results show that our model significantly outperforms existing Transformer and sampling-based baselines, and using pre-trained disentangled representations as external conditions yields more effective controls.Comment: In Proceedings of the 24th Conference of the International Society for Music Information Retrieval (ISMIR 2023), Milan, Ital

Complete genome assembly and characterization of an outbreak strain of the causative agent of swine erysipelas – Erysipelothrix rhusiopathiae SY1027

BACKGROUND: Erysipelothrix rhusiopathiae is the causative agent of animal erysipelas and, to a fewer occurrences, human erysipeloid. It is ubiquitous in nature and commensal in diverse species of animals, wild or domestic, from mammals and birds to reptiles and fish. Mechanisms of its virulence and pathogenicity are poorly understood. RESULTS: Making use of the complete genome sequencing of E. rhusiopathiae strain SY1027 and comparative genome analysis between the three highly pathogenic strains (SY1027, Fujisawa and ATCC19414), the genomic structure and putative functional elements, such as pathogenicity island (PAI)-like regions, potential virulence factors and horizontal transferring genes of the bacteria are identified. Strain SY1027 genome is 1,752,910 base pairs long, just 30 kilobases smaller than strain Fujisawa, with the same GC level of 36.36%. It contains 1,845 open reading frames (ORF) predicted by GLIMMER 3.02, of which 1,775 were annotated by PGAAP, 1,757 (~95.23%) were annotated by NCBI nr blast, 1,209 by COG database and 1,076 by KEGG database. 37 potential virulence factors were annotated in strain SY1027 by VFDB, while 19 (~51.35%) of them are common in the 2 strains, 7 of which are potentially related to antibiotic resistance and highly conserved (~98-100% match identity (ID)) amongst the three strains of E. rhusiopathiae and modestly homologous to other gastrointestinal tract-inhabiting Firmicutes (~40% match ID), e.g. Clostridium spp., Enterococcus spp. Genomic island- and pathogenicity island-like regions were also predicted, in which some showed association with tRNA and potential virulence factors. CONCLUSION: Complete genome sequencing of Erysipelothrix rhusiopathiae, the causative agent of animal erysipelas, was performed. Molecular identification of various genomic elements pave the way to the better understanding of mechanisms underlying metabolic capabilities, pathogenicity of swine erysipelas and prospective vaccine targets besides the widely used SpaA antigens

Study on micro hydro-mechanical deep drawing using finite element method

A numerical model was established to investigate the micro hydro-mechanical deep drawing process of austenitic stainless steel 304 foil (0.05 mm thickness). Due to the miniaturisation of the specimen size, the effect of grain size, gap distance and radial pressure during drawing process could be prominent. The results indicate that the appropriate radial pressure and gap distance could improve the limit drawing ratio (LDR) of manufactured cylindrical cups by reducing the friction resistance. The maximum LDR obtained in the present work reaches 3.2, which is much higher than that obtained by conventional deep drawing process