Electrospun PA66/Graphene Fiber Films and Application on Flexible Triboelectric Nanogenerators.

Triboelectric nanogenerators (TENGs) are considered to be the most promising energy supply equipment for wearable devices, due to their excellent portability and good mechanical properties. Nevertheless, low power generation efficiency, high fabrication difficulty, and poor wearability hinder their application in the wearable field. In this work, PA66/graphene fiber films with 0, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt% graphene and PVDF films were prepared by electrospinning. Meanwhile, TENGs were prepared with PA66/graphene fiber films, PVDF films and plain weave conductive cloth, which were used as the positive friction layer, negative friction layer and the flexible substrate, respectively. The results demonstrated that TENGs prepared by PA66/graphene fiber films with 2 wt% grapheme showed the best performance, and that the maximum open circuit voltage and short circuit current of TENGs could reach 180 V and 7.8 µA, respectively, and that the power density was 2.67 W/m2 when the external load was 113 MΩ. This is why the PA66/graphene film produced a more subtle secondary network with the addition of graphene, used as a charge capture site to increase its surface charge. Additionally, all the layered structures of TENGs were composed of breathable electrospun films and plain conductive cloth, with water vapor transmittance (WVT) of 9.6 Kgm-2d-1, reflecting excellent wearing comfort. The study showed that TENGs, based on all electrospinning, have great potential in the field of wearable energy supply devices.

[The textual research on the evolution of the toothbrush shape in ancient China].

Archaeological discovery demonstrates that the ancient plant hair brush first appeared in the Tang dynasty. According to the evolution of the shape of the head and handle of the toothbrush in ancient times, we can divide the evolution of the shapes into three major stages of development: (1) the Tang and the Five dynasties; (2) the Liao, Song, Jin, Yuan dynasties; (3) Ming, Qing and the Republic periods. The toothbrush heads and handles had no significant differences during the Tang and the Five dynasties. However, the shapes of them in the Liao, Song, Jin, Yuan dynasties are somewhat different. In the Ming and Qing and the republic of China periods, the shape of toothbrush head and handle had further refinement. Recently, some scholars raised doubts about the "plant hair toothbrush doctrine". They believe that the archaeological bone graft handle brush was used to wipe hair oil or clean water when washing and dressing. However, according to shape and function and ancient literature records, the archaeological bone graft handle brush should be a plant hair toothbrush used to clean and protect teeth.

[New exploration on the types and forms of stone needle].

The basic use of stone needles in curing disease is cutting the carbuncles and purulences and pricking and draining off the sores. As a result, the forms of stone needle need to have a sharp cutting edge or slender point. Combining with corresponding unearthed material objects of archeology, the microlithic stone needle of mainly consists of a scraper, tip-like device and stone arrowheads. The stone needle of polished stone implements can be divided into three categories according to different forms and functions, that is conical-tip stone needles for pricking, e. g. lithostyle, coup de poing and stone arrowhead etc. ; sickle-shaped needle stone for cutting, e. g. stone knife, stone sickle, stone adze and stone chisel etc; spear-shaped stone needle for both cutting and pricking, e. g. stone spear, stone sword, jade (stone) spear etc. From the usage cases recorded in the ancient literature, the conical-tip stone needle for pricking ought to be the most used of the ancient stone needles. Use of the stone needle for hot stroking, massage and knocking at the body surface, which was raised by some related scholars, does not belong to the domain of ancient stone needles.