According to our previous works on cellulose Iβ and Iα, the weak interactions, though easily ignored, play certain role in the stability mechanism of nature cellulose. These weak interactions should never be ignored or underestimated. In this work, a molecular dynamics study of cellulose Iα was reported to evaluate the weak interactions under various temperatures. The polar and non-polar solvation interactions and hydrogen bonding were taken into account. The Van der Waals, electrostatic, polar solvation and non-polar solvation energy per chain were estimated up to −131.68, −56.38, 29.16 and −41.76 Kcal/mol at room temperature. The weak interactions behaviors of cellulose Iα, including that of the cellulose Iβ and Iα reported previously, were compared. The results indicate that hydrogen bonding contribute obviously for the intrachain stability. The interchain electrostatic interaction maintain a reasonable level under 300 K but decreases rapidly with the ascending of temperature. The polar and non-polar solvation interaction plays an important role not only to interchain under high temperature but also to the intersheet stability. In addition, the hydrogen bonding in intersheet is weaker than that of intrachain and interchain. The result is same as cellulose Iβ that relatively weak hydrogen bonding and strong nonbonded interactions keep the intersheet stability collaboratively.

Research of flexible sensors for human wearable health monitoring are of paramount importance. In view of the problems of traditional sensors, such as complexity, low sensitivity, insufficient strain, short service life and incompatibility with human body, the research progress of Graphene-based flexible sensors in wearable health monitoring is systematically introduced. Benefitting from the commendable flexible mechanical properties and high durability, flexible Graphene-based sensors promote its applications in motion detection, body temperature monitoring, sweat ion real-time monitoring, voice recognition, pulsebeating, and respiration detection. The challenges and prospects of the application of Graphene-based flexible sensors in wearable health monitoring are pointed out. It is expected that most current research, which is still experimental, will need several more years of study before it becomes widely used. In the future, more attention should be paid to the lack of flexibility and high sensitivity of Graphene, the preparation of high purity Graphene, the application of composite materials and the development of advanced technology.

The drape performance of the fabric is an important part of the fabric style, as well as a special expression of the structural parameters and mechanical properties. The comprehensive drape performance of fabric can support fabric matching. This study was conducted to match fabric based on 3D triangular meshes of draped fabrics. Firstly, the three-dimensional (3D) point cloud of draped fabric was scanned with a self-built 3D scanning device followed with triangulation. Secondly, three drape indicators, i.e., drape coefficient, the number of fabric drape nodes, and the solid rate of a draped fabric was extracted, as well as the wavelet kernel signatures (WKS) of triangular meshes. The WKS of vertices on the 3D boundary was selected and clustered into different classes with K-Means. With the cluster centers, the WKS of vertices on the boundary was encoded into a vector with a fixed length. Finally, two methods for matching fabrics were proposed based on WKS+DR and a vector consisting of three drape indicators separately. The results show that WKS+DR outperforms the vector consisting of drape indicators in characterizing the drape configuration details of a draped fabric. The accuracy of the method based on WKS+DR could reach 89.6%. The fabrics obtained with this method are close to the matching fabrics in both drape-ability and details of a triangle surface.

Backpacks have been widely used to increase load carriage capacity, but the pressure at the body surface may cause discomfort or pains. Previous studies revealed that chest straps and hip belts of backpack helped to relieve the discomfort feeling, but how the pressure changes are still unclear. In this study, the influence of strap tying and the posture change on the pressure distribution were investigated. A daily backpack with 5kg load was used in the experiment. Five young females carried the backpack to stand, walk and jog. The pressures were measured at the shoulder, waist and hip, which are the primary load bearing regions. The trunk forward lean angle (TFL) was captured by using the Vicon motion capture system. Results showed that tying both the chest strap and hip belt reduced the shoulder pressure and increased the pressure at the hip and waist. From standing, walking to running, TFL increased gradually and the pressure transferred from shoulder to back and hip. These findings help us to better understand and quantify the load carrying performance of a backpack.

With the rapid development of photonic crystals (PCs), PC structural colouration has gained great attention from many more researchers. Dyeing methods can benefit a lot from PC structural colours and become more environmentally friendly. This modified colouration is superior to the traditional ordinary and chemical dyes and pigments, because of the special characteristics of PC structural colours, such as high brightness, high saturation, never fading, iridescent effect, polarization phenomenon, and so on. In this work, the concept and clarification of PCs, the PC structural colour, the mechanism of structural colouration and various methods of preparing artificial PC are reviewed. Generally, PC can be divided into different types because of diverse spatial distribution characteristics of the photonic band gap. The basic principle of the structural colouration is explained in detail. In the process of producing structural colour, it is of great importance to synthesize silica nanoparticles by solvent change technique (SVT) and self-assembly gravity sedimentation method is described minutely in this paper. Meanwhile, the strengths and weakness of these methods are compared to select the best method for manufacturing structural colours. The applications of PC structural colour are summarized, and some problems are proposed which need to be solved in PC development in the future.