Aqua­(benzamidato-κN)bis­[3,5-difluoro-2-(pyridin-2-yl)phenyl-κC 1]iridium(III) methanol monosolvate

In the title compound, [Ir(C11H6F2N)2(C7H6NO)(H2O)]·CH3OH, the IrIII ion adopts an octa­hedral geometry, and is coordinated by two 3,5-difluoro-2-(pyridin-2-yl)phenyl ligands, one mol­ecule of water and one benzamidate anion. The two 2-(4,6-difluoro­phen­yl)pyridyl ligands are arranged in a cis-C,C′ and trans-N,N′ fashion. Additionally, there is a bystanding methanol mol­ecule outside the coordination sphere of the IrIII ion. In the crystal, mol­ecules of the title compound are linked by O—H⋯O and O—H⋯N hydrogen bonds. One F atom of each ligand is equally disordered over two sites. The C atom of the solvent molecule is likewise disordered over two sites in a 0.589 (11):0.411 (11) ratio

Meso-scale Modeling of the Drilling of Carbon Fibre Reinforced Plastic: Geometry and Numerical Analysis

This paper discussed the 3D finite element modeling (FEM) of the drilling of uni-directional Carbon Fibre Reinforced Plastic (CFRP). Most of the real life parts of CFRP are modeled with single layer shell element and can be modeled as composite by assigning a composite property to it. A Meso-Scale (Laminate Level) approach has been developed to extract displacements, overall stiffness behavior, and detailed stresses and strains. The objective of this study is to implement a ply-based modeling technology to model the laminates and to analyze the interaction mechanisms between the drilling tool and material to validate if the meso-scale approach would be the ideal solution to characterize the drilling induced damage. Results show the model has proved its ability to correctly estimate the thrust force and torque

The manufacturing and the application of polycrystalline diamond tools – A comprehensive review

Advanced materials such as titanium alloys and metal matrix composites are extensively used in the aerospace industry and biomedical engineering. They are difficult to machine because of the severe abrasion and high temperature at the tool/chip and tool/workpiece interfaces which cause severe tool wear and premature tool rejection. Compared with conventional cutting tools, polycrystalline diamond (PCD) tools are promising in machining refractory metals and hard-to-machine materials because of the outstanding mechanical properties of PCD. This paper reviewed the manufacturing and application of PCD cutting tools. The researches on manufacturing process of PCD tools and the application in cutting hard-to-machine materials were analysed, and the results and findings were comprehensively discussed. Two most widely used refining methods including abrasive grinding and electrical discharge grinding (EDG) as well as the defects caused by the processes were presented. The wear process of PCD tools in different industrial cutting methods and the wear mechanism of different PCD materials were explained in both micro-scale and macro-scale. Research directions and the trend of the application of PCD cutting tools were introduced

Deflection Prediction on Machining Thin- Walled Monolithic Aerospace Component

Structural titanium alloys are coming in for increased use because they are light, ductile and have good fatigue and corrosion-resistance properties As a result; more manufacturing engineers are learning that machining these alloys can be a tricky job due to their unique physical and chemical properties. The problems are worsened when machining with the lowrigidity part which makes the precision difficult to master. This paper consist of two parts, a new CAD/CAE/CAM integrated methodology for predicting the surface errors when machining a thin-wall low rigidity component and secondly, the statistical analysis to determine the correlation between a criterion variable (form errors) and a combination of a predictor (cutting parameters and component attributes). The proposed modelwould be an efficient means for analysing the root cause of errors induced during machining of thin-wall parts and provide an input for downstream decision making on error compensation. A set of machining tests have been done in order to validate the accuracy of the model and the results between simulation and experiment were found in a good agreemen

InfoEntropy Loss to Mitigate Bias of Learning Difficulties for Generative Language Models

Generative language models are usually pretrained on large text corpus via predicting the next token (i.e., sub-word/word/phrase) given the previous ones. Recent works have demonstrated the impressive performance of large generative language models on downstream tasks. However, existing generative language models generally neglect an inherent challenge in text corpus during training, i.e., the imbalance between frequent tokens and infrequent ones. It can lead a language model to be dominated by common and easy-to-learn tokens, thereby overlooking the infrequent and difficult-to-learn ones. To alleviate that, we propose an Information Entropy Loss (InfoEntropy Loss) function. During training, it can dynamically assess the learning difficulty of a to-be-learned token, according to the information entropy of the corresponding predicted probability distribution over the vocabulary. Then it scales the training loss adaptively, trying to lead the model to focus more on the difficult-to-learn tokens. On the Pile dataset, we train generative language models at different scales of 468M, 1.2B, and 6.7B parameters. Experiments reveal that models incorporating the proposed InfoEntropy Loss can gain consistent performance improvement on downstream benchmarks

Nonparaxiality-triggered Landau-Zener transition in topological photonic waveguides

Photonic lattices have been widely used for simulating quantum physics, owing to the similar evolutions of paraxial waves and quantum particles. However, nonparaxial wave propagations in photonic lattices break the paradigm of the quantum-optical analogy. Here, we reveal that nonparaxiality exerts stretched and compressed forces on the energy spectrum in the celebrated Aubry-Andre-Harper model. By exploring the mini-gaps induced by the finite size of the different effects of nonparaxiality, we experimentally present that the expansion of one band gap supports the adiabatic transfer of boundary states while Landau-Zener transition occurs at the narrowing of the other gap, whereas identical transport behaviors are expected for the two gaps under paraxial approximation. Our results not only serve as a foundation of future studies of dynamic state transfer but also inspire applications leveraging nonparaxial transitions as a new degree of freedom.Comment: 17 pages, 4 figure