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The purpose of this paper is to explore a novel measurement approach for wheel-terrain contact angle using laser scanning sensors based on near-terrain perception. Laser scanning sensors have rarely been applied to the measurement of wheel-terrain contact angle for wheeled mobile robots (WMRs) in previous studies; however, it is an effective way to measure wheel-terrain contact angle directly with the advantages of simple, fast and high accuracy.

First, kinematics model for a WMR moving on rough terrain was developed, taking into consideration wheel slip and wheel-terrain contact angle. Second, the measurement principles of wheel-terrain contact angle using laser scanning sensors was presented, including “rigid wheel - rigid terrain” model and “rigid wheel - deformable terrain” model.

In the proposed approach, the measurement of wheel-terrain contact angle using laser scanning sensors was successfully demonstrated. The rationality of the approach was verified by experiments on rigid and sandy terrains with satisfactory results.

This paper proposes a novel, fast and effective wheel-terrain contact angle measurement approach for WMRs moving on both rigid and deformable terrains, using laser scanning sensors.

The purpose of this paper is to investigate the effect of urea–formaldehyde (UF) nanoparticles on the barrier property and delamination resistance for epoxy coating in a 3.5% NaCl aqueous solution.

The UF resin was synthesized via sol–gel method, and UF/epoxy composite coating was prepared through ball-milling process; the microstructure and chemical composition of UF resin were observed using the Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy; the bonding strength of coating/metal interface was investigated through adhesion test; the mechanical properties of the coatings were studied by tensile tests; and the barrier and corrosion resistance properties were verified using salt spray test, cathodic delamination test and electrochemical impedance spectroscopy measurements.

The experimental results indicated that the UF resin presented uniformly dispersed nanoparticles in the epoxy matrix and enhanced the bonding strength of coating/metal interface and then improved the delamination resistance for composite coating, which resulted in the enhancement of the barrier property and corrosion resistance for UF/epoxy composite coating.

In this paper, an easily prepared blending compounding coating with excellent corrosion resistance property was synthesized via sol–gel method and ball-milling process. The effects of UF nanoparticles on the barrier property and delamination resistance were investigated in detail.

The purpose of this paper is to evaluate the actual status of roles and responsibilities of boards in nonprofit organizations in China by comparative analysis and through setting the USA as a frame of reference.

Five roles and responsibilities are compared between Chinese and American nonprofits. Among Chinese nonprofits, foundations and associations are compared. Both primary and secondary data are used.

On the roles and responsibilities of nonprofit boards, developed countries such as the USA are more active than China. Within China, boards of foundations are more active than the boards of associations.

Small sampling limits universality and applicability of this paper's conclusions. Every sort of role and responsibility are not further divided.

This paper examines the extent to which boards fulfill roles and responsibilities, and provides reference effects for further researches and for improvement of board governance of nonprofits in China.