China is the first country in the world to master the use of paint. According to archaeological evidence, as early as 8000 years ago, the ancestors of the Crossing Lake Bridge had already understood the properties of lacquer and started to use it. The “lacquer bow” unearthed at the site was called the “source of lacquer” in China by experts. In the Neolithic Age, the ancestors of our country have realized the importance of lacquer and used it to make utensils. The lacquer may originally be produced by people’s painting, marking symbols and the pursuit of the beauty of practical utensils. In the Xia, Shang and Zhou periods, lacquer handicrafts emerged due to the development of bronze tools. During this period, lacquer was also used as a tribute. In the Shang Dynasty, the lacquer manufacturing industry began to take shape and formed a unique system, manifested in the continuous increase in the number and types of lacquerware, and the richer colors and patterns. In the Spring and Autumn Period and the Warring States Period, the lacquer culture developed by leaps and bounds. The Han Dynasty was the first peak of the lacquer culture. Since then, the development of the Jinyinping lacquerware in the Tang Dynasty, the plain lacquerware in the Song Dynasty and the carving lacquer in the Yuan, Ming and Qing Dynasties all have their own characteristics and shows in different ways.
Why is the thumb so short?
The most special of the five fingers of a person is the thumb, which is the shortest and most powerful. Why is it so special? Japanese scholar Sakai Keno explained the special feature of the thumb: “Can you button up a suit and turn a book without your thumb? Although it is not impossible, it takes a lot of time.” In fact, the thumb is responsible for more important tasks. The thumb and the palm of the hand are opposed to each other, and the force is generated by opposing movement to grasp the object. This structure is only available in human hands. Through the evolution of the thumb, human beings can operate the tool steadily. The palm of a chimpanzee is very long, which allows its 4 fingers to easily grasp a branch like a hook. But the slender palms also make it difficult for chimpanzees to make a tight fist like humans, because their thumbs are far away from the other 4 fingers. Our palms are short, and our thumbs can hold the index and middle fingers tightly. The ring and little fingers are curled up again. The palms are constrained by muscles to form a compact fist. Such a fist means concentration of strength. In the evolutionary history, individuals with too long palms were at a disadvantage in fighting because they could not clenched their fists tightly, while humans who “clenched their fists” have come to this day.
Why use the red carpet to welcome guests?
Laying the red carpet is a high-level courtesy commonly seen in formal occasions to welcome the heads of state and government and other VIP guests. The description of the welcome on the red carpet first appeared in the famous play “Agamemnon” by the ancient Greek tragedy poet Aeschylus in the 5th century BC: the hero Agamemnon returned triumphantly from Troy, and his wife welcomed him And laid the red carpet. In Renaissance art works, gods, saints, and members of the royal family usually appear on the red carpet.
In 1821, the then-U.S. President Monroe visited Georgetown and the city laid a red carpet to greet him. In 1922, the Hollywood play “Robin Hood, the Hero of the Green Forest” premiered at the time. In order to welcome guests to the premiere, the scene was paved The red carpet is said to be the source of the red carpet show and the entertainment circle. Today, the use of the red carpet as a symbol of high-level concierge is no longer confined to the political and entertainment circles.
How many underage Internet users in my country?
According to the National Research Report on Internet Usage by Minors in 2018, as of July 31, 2018, the number of minor Internet users in China reached 169 million, and the Internet penetration rate of minors reached 93.7%, which was significantly higher than the national population in the same period. Internet penetration rate (57.7%). Mobile phones are the primary Internet access device for minors, with 92% of them using it. From the perspective of online time, 76.4% of minors spend less than 2 hours on the Internet per day, but 13.2% of minors also spend more than 3 hours online. Among minors’ online activities, the top ones are studying (87.4%), listening to music (68.1%), playing games (64.2%), and chatting (58.9%). As a new entertainment application, short videos made by users are favored by minors, with a usage rate of 40.5%.
What do you say in your dreams?
Scientists analyzed the sleep talk and found that more than half of the sleep talk was incomprehensible or non-verbal, such as whispering and laughing. Among the remaining comprehensible words, a considerable part of the dream talk is negative or aggressive: 24% express negative connotations, and 22% contain swear words. When talking in sleep, “no” appears 4 times more frequently than when you are awake, and swear words are 800 times than when you are awake. Researchers believe this reflects the threat simulation theory of dreams. Dreams simulate threats, such as dreaming of being chased or attacked, which can make people recognize threats and improve their ability to respond to threats when they wake up. When people in their sleep face threats, they are more likely to say “no” and swear words.
The lawn was the first sign of nobility?
The idea of setting up a lawn in front of private houses and public buildings was born in the castles of the nobles of Britain and France in the late Middle Ages. By the early modern period, this habit had become deeply rooted and became a symbol of nobility. To have a beautiful lawn, in addition to land, you have to pay labor, especially in the past when there were no automatic sprinklers and lawn mowers. The lawn does not produce any value, poor farmers cannot afford it, and it is absolutely impossible to waste precious land or time on the lawn.
By the 19th century, the emerging middle class also loved lawns. In the beginning, only bankers, lawyers, and entrepreneurs had the money to furnish such luxuries in their private residences. The Industrial Revolution expanded the middle class and invented lawn mowers and automatic sprinklers, so millions of families could suddenly plant a lawn in front of their homes. Therefore, in the suburbs of the United States, the smooth and beautiful lawns have also changed from the luxury of the rich to the necessities of the middle class.
Why don’t fish in the Antarctic and Arctic freeze to death?
There is thick ice and snow everywhere in the Antarctic and Arctic. Why can’t fish be frozen to death in such a cold place? It turns out that fish is a kind of temperature-changing animal, and its body temperature will change with water temperature. Compared with fish in other places, Antarctic fish has more protein in body fluid, and protein is the guarantee of heat energy and is “non-freezing liquid”. It is precisely by virtue of this that Antarctic fish can grow healthily in the ice and snow. Of course, don’t try to put Antarctic fish in the tropical ocean. Every kind of creature has a limit to its adaptability. If it exceeds the limit, it will die.
Electricity of the head can help people restore short-term memory?
A study in the United States found that the reason why the working memory of the elderly is not as good as that of the young is that certain areas of the brain are “disconnected”. Using short-term brain stimulation may reverse part of the effects of aging in the brain of the elderly. People generally divide memory into three parts: sensory memory, working memory (also called short-term memory) and long-term memory. Working memory is one of the key parts of intelligence and one of the most sensitive cognitive functions to aging. The researchers conducted a series of working memory tests on 42 young people aged 20 to 27 and 42 elderly people aged 60 to 76, while monitoring their brain activity with EEG. Whether it is the speed of answering or the accuracy of the results, the elderly are far inferior to the young. The difference is that there is a special interaction between neurons in the left temporal lobe and prefrontal lobe in young people, but not in the brain of old people. Through transcranial sympathetic stimulation (a non-invasive electrical stimulation method), neuronal activity can be resynchronized. As long as 25 minutes of stimulation, the working memory of elderly subjects can be equivalent to that of younger control subjects, and the effect can last at least 50 minutes. This method is also effective for young people with poor memory.