Whiteness arises from the random scattering of incident light from disordered structures. [1] Opaque white materials have to contain a sufficiently large number of scatterers and therefore usually require thicker, material-rich nanostructures than structural color arising from the coherent interference of light. [2,3] In nature, bright white appearance arises from the dense arrays of pterin pigments in pierid butterflies, [4] guanine crystals in spiders, [5] or leucophore cells in the flexible skin of cuttlefish. [6] A striking example of such whiteness is found in the chitinous networks of white beetles, e.g., Lepidiota stigma and Cyphochilus sp. [7][8][9] Previous research investigating these beetle structures has shown that the chitinous network is one of the most strongly scattering materials in nature, and therefore the question arises whether this structure is evolutionary optimized for strong scattering while minimizing the Most studies of structural color in nature concern periodic arrays, which through the interference of light create color. The "color" white however relies on the multiple scattering of light within a randomly structured medium, which randomizes the direction and phase of incident light. Opaque white materials therefore must be much thicker than periodic structures. It is known that flying insects create "white" in extremely thin layers. This raises the question, whether evolution has optimized the wing scale morphology for white reflection at a minimum material use. This hypothesis is difficult to prove, since this requires the detailed knowledge of the scattering morphology combined with a suitable theoretical model. Here, a cryoptychographic X-ray tomography method is employed to obtain a full 3D structural dataset of the network morphology within a white beetle wing scale. By digitally manipulating this 3D representation, this study demonstrates that this morphology indeed provides the highest white retroreflection at the minimum use of material, and hence weight for the organism. Changing any of the network parameters (within the parameter space accessible by biological materials) either increases the weight, increases the thickness, or reduces reflectivity, providing clear evidence for the evolutionary optimization of this morphology. amount of employed material, thus reducing the weight of the organism. The brilliant white reflection from Cyphochilus beetles is assumed to be important for camouflage among white fungi and in a shady environment.In contrast to periodic photonic materials, for which the optical response is straightforward to calculate, the reflection of light from such disordered network morphologies requires a detailed knowledge of local geometry. [2,3,9,10] For these complex cases, the validity of the diffusion approximation is limited, since single scattering elements are difficult to be identified. [7] To fully understand the correlation between the structure and (optical) properties of complex materials, the detailed real-space structure in combination with a s...

The original algorithm holds that the weight and impact force of rockfall are large different. For easy calculation, the rockfall own weight can be almost neglected. But the impact force of rockfall has a slow increase of the process by the resisting effect of the soil during landfall and rockfall impacting soil over the pipe, which the rockfall own weight to the contribution of the impact force is great. Therefore, it is necessary to study on impact force of landfall and rockfall. We establish the mathematical model of impact force of landfall and rockfall by mathematics and mechanics knowledge, and put forward the wallop amplification coefficient method by the count, which results more close to the actual situation, comparing with the original algorithm. It shows that result, which is better than the original algorithm results, by the wallop amplification coefficient method can be widely used in practical projects.

The phenomenon of railway and road tunnel passing through the debris flow gully is more and more prevalent, for the rapid development of the construction of railways and highways. At present, the construction experience of tunnels passing through the debris flow gully is not rich enough, so the study on this part is necessary. The engineering geological conditions of Cangyuan Tunnel are complex and the construction of which is difficult. The three-step seven-step method, tunnel surface grouting and tunnel root piles reinforcement basis are used to ensure the stability of the tunnel surrounding rock, based on the characteristics of Cangyuan Tunnel which passes through the debris flow gully. The deformation is controlled within the specification range, which indicates that the construction effect of Cangyuan Tunnel is good. These construction measures solve the construction problems of tunnels which pass through the debris flow gully and ensure project quality and duration, therefore, these construction measures can be used in similar projects.

At present, system research on performance of the physics, deformation, strength and other properties of light mixed soil already exists in China, but the study on permeability is just in the initial stage and the system study on permeability of EPS beads-mixed lightweight soil is lack of, therefore, it is necessary to study the permeability of EPS beads-mixed lightweight soil. This article draw some reliable conclusions which include the permeability of EPS beads-mixed lightweight soil decreases with the increasing of curing age and cement ratio, and decreasing of EPS beads ratio and particle size and the cement ratio has quadratic polynomial function relationship when EPS beads ratio has linear relationship, by analyzing the effects of curing age, cement ratio, EPS beads ratio and particle size. The paper proposes multiple linear regression equation, considering the relationship of lightweight soil permeability between EPS particles and cement ratio. These will do good to the application of the practice engineering.

Because the joists in the wall-beams are in eccentric tension during work and the concrete tensile strength is low, the bending capacity of normal section of wall-beams is not too large. Steel fibers mixed into the concrete, playing enhancement and crack-resistance roles would lead to changes in the nature of concrete materials so that it is impossible to fully use the existing research results of ordinary concrete wall-beams simply supported when studying bending behavior of normal section of steel fiber reinforced concrete wall-beams simply supported. Therefore, it is necessary to do pilot studies on bending behavior of normal section of steel fiber reinforced concrete wall-beams simply supported. Based on the vertical static load test of 12 steel fiber reinforced concrete wall-beams simply supported specimens under different fiber volume ratio conditions, the strains of steel and concrete, cracking load, failure load and development situation in the cracks were tested while working characteristics of steel fiber reinforced concrete wall-beams simply supported were studied. This paper discussed the effect of fiber volume ratio on cracking moment and ultimate moment of steel fiber reinforced concrete wall-beams simply supported, which shows that the optimum mixing amount of steel fiber is 1.2%. The conclusion is of great significance in both theory and engineering practice, and it helps to guide the application of practical engineering.