Scaled in Cartesian Coordinates Ab Initio Molecular Force Fields of DNA Bases: Application to Canonical Pairs

The model of Regularized Quantum Mechanical Force Field (RQMFF) was applied to the joint treatment of ab initio and experimental vibrational data of the four primary nucleobases using a new algorithm based on the scaling procedure in Cartesian coordinates. The matrix of scaling factors in Cartesian coordinates for the considered molecules includes diagonal elements for all atoms of the molecule and off-diagonal elements for bonded atoms and for some non-bonded atoms (1–3 and some 1–4 interactions). The choice of the model is based on the results of the second-order perturbation analysis of the Fock matrix for uncoupled interactions using the Natural Bond Orbital (NBO) analysis. The scaling factors obtained within this model as a result of solving the inverse problem (regularized Cartesian scale factors) of adenine, cytosine, guanine, and thymine molecules were used to correct the Hessians of the canonical base pairs: adenine–thymine and cytosine–guanine. The proposed procedure is based on the block structure of the scaling matrix for molecular entities with non-covalent interactions, as in the case of DNA base pairs. It allows avoiding introducing internal coordinates (or coordinates of symmetry, local symmetry, etc.) when scaling the force field of a compound of a complex structure with non-covalent H-bonds.

Observation of temperature-dependent Dzyaloshinskii–Moriya interaction within the 50–300 K range

The Dzyaloshinskii–Moriya interaction (DMI) is essential for the formation of chiral objects in magnetic heterostructures. Herein, the temperature (T)-dependence of the DMI in Pt/Co/MgO is investigated over a wide range below 300 K. The T-dependent behavior of the DMI is stronger than that of the Heisenberg exchange interaction; thus, the anisotropic exchange is more T-sensitive than the isotropic exchange. Additionally, D∝M4.79 and A∝M2 for Pt/Co/MgO, and different ferromagnet (FM) layers can originate from different scaling factors between D and M. Therefore, the DMI T-dependence in a Pt-based multilayer system depends on the FM type, which implies that orbital hybridization at an interface may elucidate the relation between D and M.

Influence of pallet pattern on top-to-bottom compression performance of unitized loads

Environmental scaling factors estimate a corrugated container’s ability to withstand various conditions it will encounter during the storage and distribution process. In this project, we examined the compressive resistance of unitized loads using differing pallet stacking patterns. To simulate real-world failure scenarios in our laboratory tests, we used two different nominal board grades of single-wall C-flute regular slotted containers loaded with a plywood panel and bagged salt to direct the failure location to the bottom of the stack. Our results showed that the columnar aligned pattern provided the greatest compressive resistance and the interlocked stacking arrangement yielded the lowest of the patterns evaluated. Based on the study results, we calculated box compression retention multipliers for each pattern and compared them to scaling factors published by the Fibre Box Association.

Mathematical Modeling and Dynamic Analysis of a Compact Vectored Thruster

In this paper, a compact vectored thruster based on a composite gear train is proposed. First, the space transformation between different coordinate systems is carried out, and the mathematical model of the vectored thruster is established, according to classical navigation mechanics theory. Then, the swing and roll motion analysis of the composite gear train is implemented, and the motion relationship of the whole thruster structure is analyzed systematically. Moreover, SolidWorks and MATLAB software are used for simulation to verify the accuracy of the mathematical model. In addition, the trajectories of the propeller shaft under different motion modes are analyzed and compared. Finally, the dynamic analysis of the vectored thruster is carried out, and the change trend of the scaling factors of the vector thrust components with the swing angle δ and the roll angle χ is studied, and comparison with the scaling factors of the vectored water jet propeller presented in other literature is taken into account. To endow the thruster with superior maneuverability, the fairwater structure of the vectored thruster is optimized, and the lateral vector component of the optimized vectored thruster is greatly increased.