Diverse effects of gaze direction on heading perception in humans.

Gaze change can misalign spatial reference frames encoding visual and vestibular signals in cortex, which may affect the heading discrimination. Here, by systematically manipulating the eye-in-head and head-on-body positions to change the gaze direction of subjects, the performance of heading discrimination was tested with visual, vestibular, and combined stimuli in a reaction-time task in which the reaction time is under the control of subjects. We found the gaze change induced substantial biases in perceived heading, increased the threshold of discrimination and reaction time of subjects in all stimulus conditions. For the visual stimulus, the gaze effects were induced by changing the eye-in-world position, and the perceived heading was biased in the opposite direction of gaze. In contrast, the vestibular gaze effects were induced by changing the eye-in-head position, and the perceived heading was biased in the same direction of gaze. Although the bias was reduced when the visual and vestibular stimuli were combined, integration of the 2 signals substantially deviated from predictions of an extended diffusion model that accumulates evidence optimally over time and across sensory modalities. These findings reveal diverse gaze effects on the heading discrimination and emphasize that the transformation of spatial reference frames may underlie the effects.

Exploring the Coordination Effect of GO@MOF-5 as Catalyst on Thermal Decomposition of Ammonium Perchlorate.

Prepared composite materials based on [Zn4O(benzene-1,4-dicarboxylate)3] (MOF-5) and graphene oxide (GO) via a simple green solvothermal method, at which GO was used as platform to load MOF-5, and applied to the thermal decomposition of AP. The obtained composites were characterized by various techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption, Fourier transform infrared (FT-IR), differential scanning calorimetry and thermalgravimetric (DSC-TG). The analyses confirmed that the composite material (GO@) MOF-5 can not only improve the decomposition peak temperature of AP from the initial 409.7 °C to 321.9 °C, but also can improve the enthalpy (△H) from 576 J g-1 to 1011 J g-1 and reduce the activation energy (Ea), thereby accelerating the decomposition reaction. The high-specific surface area of the MOF material can provide a large number of active sites, so that the transition metal ions supported thereon can participate more effectively in the electron transfer process, and GO plays its role as a bridge by its efficient thermal and electrical conductivity. Together, accelerate the thermal decomposition process of AP.

Inkjet printing of energetic composites with high density.

To explore a new manufacturing method in preparing energetic composites, an inkjet printing device possessing the ability of high precision and flexibility was utilized to deposit six 3,4-dinitrofurazanofuroxan (DNTF) and hexogen (RDX) based explosive inks. The printed quality, inner structure, printed density and crystal morphology of energetic composites were tested, as well as their thermal decomposition properties and detonation properties. The results indicate that inkjet printing provides a good formation uniformity for explosive inks. Interestingly, all energetic composites exhibit excellent printed density with all values higher than 90% theoretical maximum density (TMD). Meanwhile, the composite DNTF/RDX/EC/GAP (54/36/5/5) performs best, reaching 96.88% TMD, which has reached a new height in the three-dimensional printing of energetic composites. Further study manifests that there is no appearance of new material, and the stacking manner of rodlike structures in multilayer manufacturing is the key to achieving such an amazing result. The particles in the energetic composites are spherical with the size ranging from 500 nm to 2 µm and connect with each other closely in the matrix of binders. Moreover, the energetic composites that were directly deposited into wedge channels display a good capability in steadily detonating above the size of 1 × 0.32 mm.