Research on object placement method based on trajectory recognition in Metaverse

Many studies focus on only one aspect while placing objects in virtual reality environment, such as efficiency, accuracy or interactivity. However, striking a balance between these aspects and taking into account multiple indicators is important as it is the key to improving user experience. Therefore, this paper proposes an efficient and interactive object placement method for recognizing controller trajectory in virtual reality environment. For creating user-friendly feedback, we visualize the intersection of the ray and the scene by linking the controller motion information and the ray. The trajectory is abstracted as point-clouds for matching, and the corresponding object is instantiated at the center of the trajectory. To verify the interactive performance and user satisfaction with this method, we carry out a study on user experience. The results show that both the efficiency and interaction interest are improved by applying our new method, which provides a good idea for the interactive design of virtual reality layout applications

Surface-charged polyacrylonitrile/poly(vinyl alcohol) (PAN/PVA) colloids used to prepare proton conducting materials

Proton exchange membranes exhibiting a well-organized structure were successfully prepared by a novel self-assembling technique using surface-charged latex nanoparticles as building blocks. The nanoparticles were synthesized in water by free-radical copolymerization. Free-standing membranes were obtained by casting the polymer emulsions followed by a cross-linking reaction. The acquired membrane exhibited a high proton conductivity of 0.04 S cm-1 with an ion exchange capacity (IEC) as low as 0.48 mmol g-1. The enhanced proton conductivity is thought to be derived from the formation of a co-continuous ionic network for ion channels by the closely packed surface-charged latex nanoparticles, facilitating proton transportation in the membranes

Application-Oriented Characterization and Analysis of Core Materials Under Medium-Frequency Condition

In medium-frequency applications, magnetic components generally operate in high-temperature conditions caused by higher power loss and more difficult heat dissipation, which results in changes in their electromagnetic characteristics. In this article, the application-oriented characterization of the typical core materials, Mn-Zn ferrite and Fe-based nanocrystalline alloy, is comprehensively studied. The magnetic parameters under sinusoidal (5-50 kHz) and square (10 kHz) excitation from 20 °C to 125 °C are analyzed detailedly. Combined with the micromagnetic theory, the influence factors of electromagnetic parameters such as permeability and power factor angle are investigated. The loss variation of ferrite with temperature, flux density, and frequency is explained by using the energy loss ratio. The proportion of Ph and Pdy in total loss with temperature and frequency is compared, and the loss fluctuation of nanocrystalline alloys and ferrite is analyzed. Moreover, the reasonable range of frequency that needs to consider temperature effect in practical applications is suggested. The difference between the B-H loop bias under asymmetrical square excitation and dc bias conditions is compared and illuminated. The effectiveness and limitation of typical Steinmetz equations considering the temperature and duty cycle effect are analyzed, and the suggestion of loss calculation is given combined with the material characteristics.</p

Characterization of a Catalytic Ligand Bridging Metal Ions in Phosphodiesterases 4 and 5 by Molecular Dynamics Simulations and Hybrid Quantum Mechanical/Molecular Mechanical Calculations

Cyclic nucleotide phosphodiesterases (PDEs) constitute a large superfamily of enzymes regulating concentrations of intracellular second messengers cAMP and cGMP through PDE-catalyzed hydrolysis. Although three-dimensional x-ray crystal structures of PDE4 and PDE5 have been reported, it is uncertain whether a critical, second bridging ligand (BL2) in the active site is H(2)O or HO(−) because hydrogen atoms cannot be determined by x-ray diffraction. The identity of BL2 is theoretically determined by performing molecular dynamics simulations and hybrid quantum mechanical/molecular mechanical (QM/MM) calculations, for the first time, on the protein structures resolved by x-ray diffraction. The computational results confirm our previous suggestion, which was based on QM calculations on a simplified active site model, that BL2 in PDE4 should be HO(−), rather than H(2)O, serving as the nucleophile to initialize the catalytic hydrolysis of cAMP. The molecular dynamics simulations and QM/MM calculations on PDE5 demonstrate for the first time that the BL2 in PDE5 should also be HO(−) rather than H(2)O as proposed in recently published reports on the x-ray crystal structures, which serves as the nucleophile to initialize the PDE5-catalyzed hydrolysis of cGMP. These fundamental structural insights provide a rational basis for future structure-based drug design targeting PDEs