The choice of intrinsic axis under multi-cue conditions.

In the course of spatial representation, the choice of intrinsic axis depends on various spatial and non-spatial properties. The main purpose of the current study is to investigate how people choose the intrinsic axis in a virtual reality environment with spatial cues from different categories. Sixty-four participants (32 males and 32 females) each took part in one of two experiments. In each experiment, participants learned a layout comprising seven objects and viewed the scene through a head-mounted display from two perspectives. They then completed partial-scene-recognition tasks. Experiment 1 used objects lacking intrinsic orientations, and the directions of the symmetric axis (45°-315°) and the vertical side (0°-180°) of the mat were incongruent. Experiment 2 used avatars whose orientations were all aligned with the vertical mat side. Response patterns showed that the axis which was consistent with the initial learning perspective was chosen as the intrinsic axis in Experiment 1, while in Experiment 2, the 0°-180° axis was chosen. The results indicated that people would choose the intrinsic axis according to their original egocentric experience when there were two conflicting geometric cues of different categories, but if there were three geometric cues, the axis that was consistent with more cues was more likely to be chosen as intrinsic axis.

Maltitol-Derived Sacrificial Agent for Enhancing the Compatibility between PCE and Cement Paste.

At present, it is known that when there is clay in concrete, polycarboxylates (PCE) will preferably adsorb in the clay, so that PCE cannot be fully combined with cement particles, which reduces the workability of the cement slurry. In this paper, a new type of maltitol-ammonium salt cationic (KN-lm) sacrificial agent (SA) has been successfully developed via a simple method, which makes PCE easier to bond with cement particles in the cement slurry containing clay. The effect of KN-lm on the fluidity of clay-containing cement paste is studied, and the experimental results show that KN-lm, as an efficient SA of cement slurry, makes PCE more compatible with clay-containing cement slurry, and increases the initial fluidity of cement slurry by about 19%. Further investigations of TOC, XRD, and zeta potential measurements reveal that a KN-lm ion is only preferably adsorbed into clay compared to PCE through electrostatic adsorption but without having any crystal structure change, thus resulting in good dispersion of cement particles. The addition of KN-lm plays an important role in hindering the hydration expansion of the clay by preferential electrostatic adsorption, which means PCE cannot easily insert into the interlayer of the clay.