7 . When you go running in the woods in your running tights, elastane (氨纶) is the reason why they fit you so comfortably. Elastane is an elastic material that allows the fabric to stretch and adapt to your body.

But when elastane fibres are mixed with cotton, wool, nylon or other fibres, as is the case in many clothes today, the clothes become almost impossible to recycle. It is extremely difficult to separate out the different fibres, and therefore the materials in the clothes cannot be recycled.

But this may change, says Assistant Professor Steffan Kvist Kristensen from the Interdisciplinary Nanoscience Center at Aarhus University. Together with a number of colleagues, he is behind a new technology that can separate out fibres in mixed fabrics.

“We’ve developed a method to remove elastane completely from nylon. We’re not quite there yet with cotton, because some of the cotton fibres are broken down in the process. But we believe that, with some minor adjustments, we can solve this problem,” he says.

It is not easy to separate elastane and other fibres once they have been woven(编织) together. Clothes are made by winding the main fibres, such as nylon or cotton, around the elastane fibres, which consist of long chains of molecules (分子). The fibres only break apart if we break the long chains of molecules, explains Steffan Kvist Kristensen.

By heating the clothes to 225 degrees Celsius and adding a specific alcohol, the researchers have found a method to break down the bonds in elastane chain. When this happens, the chains fall apart and the materials separate. “The whole process takes place in what is in effect a large pressure cooker that we feed the clothes into. We then add a little alcohol and a potassium hydroxide(氢氧化钾) base and heat it up. Then we let it cook for just over four hours, and when we open the lid again, the different fibres will have been separated.” says Steffan Kvist Kristensen.

So far, Steffan Kvist Kristensen and his colleagues have only experimented with two nylon stockings at a time. The technology is therefore not yet ready for application at industrial scale.

Within the Qing (1644-1911) imperial court, a unique collection of paintings can be identified, which were created by European missionaries (传教士) working at the imperial court.

One outstanding example is Pine, Hawk, and Lingzhi Fungus   (《嵩献英芝图》),     1     (complete) in 1724 during the Yongzheng period, and crafted by Italian court painter Giuseppe Castiglione (1688-1766), known by his Chinese name, Lang Shining. This artwork    2     (present) as a birthday gift to Emperor Yongzheng.

    3     are described in the painting-pine trees, a white hawk, and lingzhi fungus-is to symbolize longevity in traditional Chinese culture. Lang Shining perfectly combined Chinese themes of auspicious (吉祥的)     4    (bless), through tangible objects with Western painting techniques, such as point perspective. This combination brought    5    fresh perspective to traditional Chinese bird-and-flower paintings.

Perspective, the Western painting technique introduced by Lang Shining, also found its     6     (influential) in Principles of Visual Perspective (Shixue《视学》), authored by knowledgeable Nian Xiyao (1671-1738),     7     learned from Lang Shining about Western perspectives and drawing techniques. He also played a significant role in the history of Chinese painting,     8     (serve) as a pioneer in cultural exchanges between China and the West. By absorbing Western painting skills    9    traditional Chinese bird-and-flower paintings, he breathed new life into the Chinese painting field,     10     (particular) during the Qing Dynasty.

10 . The Ministry of Education and three other ministries have jointly issued a notice about launching a national campaign on short-sightedness prevention and control to protect children’s eyesight.

A paragraph in the notice says that primary and secondary school students should engage in appropriate outdoor activities during class breaks. Additionally, 30 minutes of physical activity during the daily midmorning break will be organized to give students more time to engage in outdoor activities and long-distance viewing, enabling their eyes to rest fully from visual fatigue.

Midmorning breaks can address more than just vision problems. Physical activity during breaks helps children to not only exercise but also reduce stress, making subsequent classroom learning more focused and effective. At the same time, midmorning physical activities provide children a platform to engage in social activities, strengthening their social adaptation abilities.

Sometime toward the end of 2023 there was a huge demand after some schools did away with even 10-minute breaks for primary and secondary school students. The Ministry of Education responded by saying that it would further regulate activities in schools. Before the latest notice was introduced, several related policies had been guaranteeing midmorning physical activity for primary and secondary school students, which have now been implemented in many cities, showing good results.

To effectively utilize (利用) the 30-minute midmorning break, teachers play an essential role because they can enrich the activities to the maximum extent by combining the interests and hobbies of children of different age groups and adding various sports activities that will benefit children the most. At the same time, it should be clear that the midmorning break is not only the responsibility of physical education teachers. It requires joint efforts from physical education teachers, class teachers and other staff members to ensure the breaks are used effectively.

To make the most of the 30-minute midmorning break, it is also crucial to stimulate the enthusiasm of children. Innovating the form and content of the midmorning break and mobilizing children’s enthusiasm and initiative to participate in midmorning activities are urgent priorities.