Man made glass more than 5000 years ago. Archaeological evidence shows that in Egypt and Mesopotamia in 3000 BC, people have made some small handicrafts such as amulets and beads with glass.

　　By around 1500 BC, people’s skills in making glass were becoming more and more mature, and the first glass container appeared in human history. The ancient Egyptians also mastered the technology of coloring glass. They know that adding copper powder to glass can make red glass, adding cobalt powder can make blue glass, and adding tin powder can make white glass … These colored glasses are used by some unscrupulous businessmen to pretend to be jewelry, deceiving many people.

　　In the 1st century BC, Syrians invented the technology of blowing glass. With this technology, making glass becomes simple, fast and cheap. Since then, the glass industry has flourished in the Roman Empire and quickly spread to other countries under the rule of the Roman Empire.

　　Around the 1st century A.D., the Romans discovered that adding a proper amount of manganese dioxide to glass could make colorless glass, so they began to make windows out of glass and install them on buildings. Although the optical performance of glass at that time was very poor, glass windows were still "standard" for buildings in Rome, Pompeii and other places.

　　In the 8th century, Venice concentrated a large number of glass workers and became the glass manufacturing center at that time. Later, with the progress of science and art, people "played" more tricks, such as dyeing paint on glass and drawing colorful patterns. Many churches we see now have stained glass windows, which is the architectural style left over at that time.

　　In the mid-15th century, a glass worker in Venice invented a new type of super transparent glass. Soon, this new type of glass was used to make telescopes, thermometers, flasks, microscopes and other scientific instruments, which led to many important scientific discoveries.

　　Around the 18th century, the glass manufacturing center in Europe moved from Venice to Britain. At that time, the output of British glass factories was very high. At one time, the British government would levy taxes based on the number of windows in each house, on the grounds that wealthy families would install more windows, and of course they should pay more taxes. However, "there are policies above and countermeasures below", and many families simply blocked the windows in order to avoid paying taxes-this story shows that the use of glass was quite common in Britain at that time.

　　Since the industrial revolution, steel and glass have become important building materials for modern architecture. In 1851, Britain built a "Crystal Palace", which only used steel and glass. This miraculous building was also the exhibition hall of the first World Expo in London. In 1950s, a German architect innovatively covered the facade of the building with a layer of glass, which made the appearance of the building look unprecedented. This innovative design can be successful, on the one hand, because there is a reinforced frame inside the modern building, and the facade does not need to bear the weight of the whole building; On the other hand, because the strength of glass has become higher. So many skyscrapers we see now have glass facades.

　　Nowadays, scientists and engineers have developed a variety of glasses, which have important uses in many fields. For example, there is a kind of glass that can quickly transmit network information, that is, optical cable, which is filled with thousands of glasses as thin as hair, in which communication signals shuttle in the form of light and quickly transmit information to all parts of the world.

　　Sand and glass

　　The main component of glass is silica, that is, Shi Ying, which is one of the most common minerals on the earth. The sand that can be seen everywhere is actually a small particle in Shi Ying. When Shi Ying is heated to 1400℃, it will melt, then become soft and become a transparent, viscous liquid-then it will be cooled and shaped, and then the glass will be finished.

　　How did sand become glass?

　　On the atomic scale, silicon dioxide is composed of silicon atoms and oxygen atoms, and they are arranged in order in Shi Ying. For example, a group of silicon atoms and oxygen atoms are neatly arranged to form a "queue" with specific arrangement rules, and the whole "queue" is Shi Ying particles. A structure like this, which consists of a large number of microscopic substance units (such as atoms and ions) arranged in an orderly manner according to certain rules, is called a crystal.

　　After Shi Ying melted, its internal crystal structure was destroyed, or the original "queue" was disrupted, and silicon atoms and oxygen atoms began to "run" freely, making Shi Ying change from solid to liquid. Of course, if the liquid Shi Ying can be cooled quickly, the crystal structure will be re-formed, just like the silicon atoms and oxygen atoms that "run" at will "stand" in the original position in the queue again.

　　However, if the cooling speed is too fast, so that silicon atoms and oxygen atoms can’t return to their original positions, then they can only be condensed in their current positions. Therefore, the final glass is like a snapshot of liquid Shi Ying. Scientists have a special name for this state of solid, called "amorphous solid", which means that this kind of solid is different from crystal, and there is no orderly arrangement rule in its internal structure.

　　Why is glass transparent?

　　We can’t go straight through the glass, but our eyes can see the objects on the other side through the glass. Why?

　　We can see an object because the light is reflected or scattered after it reaches this object, which makes some light enter our eyes and let us see the shape and color of the object. Only a part of light energy is received by our eyes, and the rest is absorbed or intercepted by objects.

　　How much light an object can intercept depends on the kind of molecules or atoms that make it up.

　　Most of the atoms in the glass don’t intercept light, and almost all the light that reaches the glass can be received by the eyes (glass can intercept ultraviolet light, but our eyes can’t see ultraviolet light). In addition, glass is not crystal, and there is no edge edge edge of crystal structure inside, so it will not scatter light. So, when the light reaches the glass, it will go straight through without changing its direction.

　　However, if a piece of glass is slightly thicker in some places, the propagation path of light will be bent, which is the working principle of a prism.

This article is from Science Illustrated.

[car home Xishuangbanna Preferential Promotion Channel] Recently, a large-scale preferential activity was ushered in in Xishuangbanna, which attracted much attention. At present, the maximum preferential amount reached an astonishing 115,000 yuan, which reduced the minimum starting price of this luxury electric car to 314,900 yuan. Interested friends, please click "Check the car price" in the quotation form, and strive for higher discount.

BMW i4 stands out with its unique front face design and dynamic lines. Its air intake grille adopts a closed design, which shows its pure electric identity without losing the iconic characteristics of the BMW family. On the whole, the exterior style of BMW i4 is both sporty and scientific, which is impressive.

The length, width and height of BMW i4 are 4785mm, 1852mm and 1455mm respectively, and the wheelbase reaches 2856mm. The side lines of the car body are smooth and matched with 18-inch rims, in which the front wheel tyre size is 245/45 R18 and the rear wheel tyre size is 255/45 R18, which further enhances the sense of movement and handling performance of the car.

The interior style of BMW i4 is full of modern technology and luxury atmosphere. The center console is equipped with a 14.9-inch high-definition touch screen, which integrates multimedia system, navigation, telephone and air-conditioning voice recognition control system, making it easy to operate. The steering wheel is made of leather, which feels comfortable and supports manual adjustment up, down and forward to meet the needs of different drivers. There are multiple USB and Type-C interfaces in the car, two in the front row and two in the back row. At the same time, the front row is also equipped with wireless mobile phone charging function, which provides convenience for passengers. In terms of seats, both the driver’s and driver’s seats support multi-directional adjustment, including front and rear, backrest, height, leg rest and lumbar support, and the front seats have heating function. The seat material of BMW i4 is rich, and you can choose imitation leather, genuine leather or fabric/suede materials to meet the individual needs of different consumers. In addition, the driver’s seat also has an electric seat memory function, which improves the driving experience. The rear seats support proportional tilting, which further enhances the practicability of the vehicle.

BMW i4 is equipped with a high-performance motor with a maximum power of 250 kW and a maximum torque of 430 Nm, which provides excellent power performance for drivers.

According to the owner’s evaluation, the design of BMW i4 is really impressive. He said: "The configuration parameters of Series I’s 3, 5 and X3 are almost the same, except that the shell has been changed. I want to buy I4 for more than 100,000 yuan. Of course, it is still imported, and there is no need to do such a thing as buying it home. At first glance, the big nostrils are not mediocre. When I drive out, people are guessing at 600,000. I am sorry. " This design and personalized configuration make the BMW i4 a unique model, which not only satisfies the owner’s pursuit of face value, but also brings full pride.

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The BMW i4 adopts a unique front face design, and the air intake grille adopts a closed design, with sharp LED headlights, which shows a sense of modernity and technology. The body lines are smooth, and the waistline on the side is simple and dynamic, creating a sense of movement. The overall style is both luxurious and futuristic, which leaves a deep impression on people.

Bmw i4 adopts streamlined design, with body size of 4785*1852*1455mm, wheelbase of 2856mm, front tread of 1601mm and rear tread of 1630mm. The side lines of the car body are smooth, with 18-inch rims, which are 245/45 R18 in front of tyre size and 255/45 R18 in rear of tyre size, showing a dynamic style as a whole.

The interior design of BMW i4 is simple and exquisite, which highlights the perfect combination of luxury and technology. The steering wheel is made of genuine leather, which feels comfortable and supports manual adjustment up and down and back and forth to meet the needs of different drivers. The center console is equipped with a 14.9-inch touch screen with smooth operation and clear interface. Support the voice recognition control of multimedia system, navigation, telephone and air conditioner, which makes the driver more convenient during driving. The car is also equipped with multiple USB and Type-C interfaces, which provides convenience for passengers to charge. The front seats are made of imitation leather, genuine leather or leather /Alcantara mixed material, which provides a variety of choices. The front seats also have heating function, which brings passengers a comfortable driving experience. In addition, both the main seat and the auxiliary seat support a variety of adjustment methods, including front and rear adjustment, backrest adjustment, height adjustment, leg rest adjustment and lumbar support, to meet different driving needs. The front row is also equipped with wireless charging function, so that drivers do not have to worry about charging problems. The rear seats can be laid down in proportion, which increases the flexibility of storage space.

The BMW i4 is equipped with a powerful motor, with a maximum power of 210 kW and a peak torque of 400 Nm, providing excellent power output and driving experience for drivers.

The owner of car home spoke highly of the BMW i4, and he specifically mentioned that the vehicle has excellent sound insulation effect, strong power performance, and the appearance is even more king-class. Especially the volcanic red interior, he feels that the design is unique and not inferior to Mercedes-Benz.

　　In recent years, "big data" has gradually moved from academic concept to industrial application, and has become the "window" for the Internet industry to compete for each other. However, although there are endless ideas, research and plans about big data in the industry, most companies have not actually enjoyed the change dividend brought by big data.

　　Nowadays, with the maturity of face recognition, artificial intelligence, cloud computing and other technologies, big data applications have also landed and begun to reshape existing business models.

　　Fashion can also be customized.

　　The favorite color of young people born after 1995 in China is "unsaturated black" with RGB value of 22/20/24. When buying clothes, the colors they most often match with black are "red, yellow and blue". The favorite clothing materials are cotton, wool and leather, and the favorite colors are printing, graffiti and letters … …

　　The above conclusions come from the "China Post-90s Fashion Color Report" jointly released by Tencent and e-commerce platform Vipshop. Relying on Tencent’s AI (artificial intelligence) face recognition and image processing technology, based on Tencent’s QQ space 2 trillion social media photos and Vipshop’s 100 million e-commerce users’ sales data, the two companies jointly "calculated" China’s "post-1995" dressing preferences.

　　It is not easy to extract the "fashion factor" from 2 trillion photos and 100 million e-commerce user data. According to Liang Zhu, vice president of Tencent Group and head of Youtu Lab, finding these popular colors needs to overcome many technical difficulties. For example, the photos uploaded by users in QQ space are mainly life photos, and the background and colors are very complicated. In order to achieve accurate color acquisition, its technical team uses many artificial intelligence algorithms, including human body detection and clothes segmentation, to separate the human body and clothes in the photos from the background, and its pixel segmentation accuracy reaches 95%.

　　It is understood that the two companies jointly invited designers to design fashion clothes based on the calculation results, and plan to sell them online on the Vipshop e-commerce platform this fall.

　　"Face recognition and image processing technology based on machine learning has always been a hot technology in the future, and its application range is very wide. At present, Tencent Youtu’s AI image recognition technology is very mature and can be applied in different scenarios. " Beam-column representation.

　　No longer "looking at the number and sighing"

　　In the past, big data applications were mostly confined to the marketing level. Its essence was to use the advantages of "big data" to analyze market factors such as user behavior by traditional computing methods, which was not a real big data application. In the face of massive and precious data, it is often impossible to really use it, and it can only be "sighing and sighing".

　　Nowadays, the application of big data has broken through the limitations of data capture and statistical methods in the past, and has begun to penetrate into all aspects of the industrial chain, becoming a "closed-loop ecology" that runs through big data.

　　In the retail field, following the concept of "new retail" put forward by Alibaba last year, at the beginning of the new year, Alibaba Group signed a comprehensive strategic cooperation agreement with Bailian Group, announcing the joint efforts to explore and develop a new retail model. According to Ali, based on big data and Internet technology, the two sides will cooperate in six areas: all-format integration and innovation, new retail technology research and development, supply chain integration, member system interoperability, payment financial interconnection and logistics system coordination.

　　"The new retail is to use the Internet and big data to ‘ People, goods and fields ’ And other traditional business elements, including the reconstruction of production processes, the reconstruction of the relationship between merchants and consumers, and the reconstruction of consumer experience. In the future, business will no longer be divided into online and offline, and there will be no difference between virtual entities. " Zhang Yong, CEO of Alibaba Group said.

　　In the field of household appliances, according to the newly released White Paper on Smart Air Conditioning Market in China in 2016, the domestic smart air conditioning industry has been improved in manufacturing, channels, services, resources and application level of new technologies in 2016, especially the introduction and resource sharing of cloud and big data technology, which has laid a solid foundation for resource sharing and service innovation in related industries.

　　Take Haier, a home appliance company, as an example. Relying on big data, the air conditioners produced by Haier not only built an intelligent energy-saving system, but also applied big data to the fields of heating and power supply. In Jiangsu, Haier’s air-conditioning cloud data has been effectively connected with the State Grid, so as to adjust the peak power load of residents, reduce the peak-valley difference of the grid by 18.47%, and greatly ease the operating pressure of the grid.

　　Realize "personalized mass production"

　　In fact, the continuous application of big data is solving the contradiction between "personalization" and "mass production" in the past, which has brought about changes in business models.

　　In the past, mass-produced products could hardly meet the individual needs of customers. Even with massive data as the marketing basis, we could only subdivide the needs of users as much as possible, and then mass-produce in each subdivision. With the penetration of Internet, big data, cloud planning and other technologies, it is possible to meet personalized and customized needs, and personalized mass production is being tried and explored. According to Chen Feifei, senior director of Vipshop, it is a bold cross-border innovation to apply big data to the fashion industry and conduct e-commerce operation. "Let photo big data, sales big data, artificial intelligence collide with fashion trends, connect data with art, and provide more inspiration and possibilities for creation in the fashion field." Chen Feifei said.

　　This attempt has brought obvious changes to the production mode of fashion industry, that is, from the former designer-led mode to the user-centered personalized mass production mode. Consumption data will become the most valuable resource in the fashion industry ecological chain. Whoever has more accurate user data will have more market opportunities.

　　Similarly, in the field of household appliances, Haier air conditioning can simulate 30 body parts, 20 metabolic modes, 162 neuron sensors and 17 warm and cold environments through joint research and development of intelligent bionic human technology. At the same time, relying on bionic people, we have developed original technologies and products such as natural wind, self-cleaning and ion air supply to realize personalized energy saving for thousands of people and make every air conditioner produced in batches "different".

　　In the field of medical and health care, because of the different disease history and genetic composition of each person, the standardized treatment scheme for diseases in the past is more like a "stopgap measure" under technical restrictions. Nowadays, with the breakthrough of medical sensors, monitors and diagnostic technologies, patient data has become complete and detailed. On this basis, the artificial intelligence system can comb the medical records, genome sequences and other health behavior data of millions of patients, so as to match the personalized treatment plan.

　　Various trends show that this change in business model is rapidly infiltrating into various industries. The universal landing of "personalized mass production" will also be possible with the support of big data.

　　Xinhua News Agency, Washington, January 20th　(International observation) Biden’s "political achievements" in power for one year are hard to be recognized by the people.

　　Xinhua News Agency reporter Deng Xianlai

　　US President Biden celebrated the first anniversary of his administration on the 20th. Over the past year, the Biden administration’s achievements in preventing and controlling the epidemic, reviving the economy, easing social contradictions and diplomatic fields have been lackluster. The series of problems he promised to solve have not only improved little, but even got worse.

　　On January 19th, US President Biden held a press conference at the White House in Washington (video screenshot). (Xinhua News Agency)

　　Policy obstruction

　　When Biden came to power, he made scientific prevention and control of COVID-19 epidemic and returning to normal life as soon as possible as a policy priority. He invited Anthony Fauci, an infectious disease expert, to be the president’s chief medical adviser, and prompted Congress to pass a $1.9 trillion economic aid plan to rapidly promote vaccination. These measures were recognized by many voters. However, since then, in order to curb the epidemic rebound caused by COVID-19 mutant strains such as Delta and Omicron, the White House issued a compulsory vaccine order for employees of large private enterprises, which was strongly resisted by the Republican ruling state and some business groups. The US Supreme Court recently ruled that the injunction could not be implemented, which frustrated Biden’s government policy.

　　On January 13th, medical staff took samples from the examiners at a Covid-19 test site in Washington, DC. (Xinhua News Agency, photo by Shen Ting)

　　On the economic front, although Biden pushed Congress to pass a large-scale infrastructure construction bill, problems such as high inflation, supply chain bottlenecks and labor shortage continue to be difficult to solve, and the road to economic recovery in the United States is full of thorns. According to data from the US Department of Labor, the US consumer price index rose by 7% year-on-year in December last year, the largest year-on-year increase in nearly 40 years. In the same month, the number of new jobs in the non-agricultural sector was only 199,000, and the number of unemployed people due to the epidemic was still as high as 3.1 million. The employment situation is still grim.

　　Politically, the struggle between the two parties in the United States and social tears have not eased, which has led Biden to fail to achieve policy goals such as easing racial conflicts, controlling the proliferation of guns, controlling border immigrants, and stopping violent law enforcement through congressional legislation. Recently, the two parties in Congress launched a fierce attack on two electoral reform bills proposed by Democrats to protect voters’ voting rights. The controversy over election reform may further deepen some conservative Republican voters’ doubts about Biden’s administration’s "ruling legitimacy."

　　On the diplomatic front, Biden promised to abolish a series of unilateralist policies during the Trump administration and prove to allies that "the United States is back." However, in diplomacy, he "broke more and established less" and lacked constructive policies. Some analysts believe that although Biden fulfilled his promise to withdraw troops from Afghanistan, the withdrawal plan was sloppy, the process was chaotic and the consequences were serious, which was widely criticized; He emphasized stability and predictability in relations with Russia, but ignored Russia’s security concerns on issues related to Russia’s core interests such as the Ukrainian crisis, which led to the continuous deterioration of US-Russia relations. He promised to let the United States return to the Iranian nuclear deal, but he did not show enough flexibility in the negotiations with Iran, so the prospect of reaching an agreement between the two sides is still unclear.

　　Difficult to be recognized

　　When Biden took office, he made many promises: to cure American "democracy", to defeat the COVID-19 epidemic, to solve deep-rooted racial and economic problems, and to restore America’s position in the world. However, one year later, his performance in preventing and controlling epidemic situation, curbing inflation, and policy legislation has not been recognized by the American people.

　　According to a poll released by Quinnipiac University recently, voters’ satisfaction with Biden’s administration has dropped to 33%. The American media pointed out that Biden broke the record of popular votes in the 2020 US presidential election, but now he has become one of the most unpopular US presidents.

　　Bill galston, a researcher at the Brookings Institution in the United States, said that Biden failed to meet the expectations of voters, and his anti-epidemic performance was particularly disappointing. At the same time, the chaos of Afghanistan’s withdrawal has also seriously damaged the image of Biden’s government.

　　This is a photo of local residents and Taliban in Kandahar, Afghanistan on August 31, 2021. Kenneth Mackenzie, commander of the US Central Command, announced on August 30, 2021 that the US military has completed the task of withdrawing from Afghanistan, and the US military operations in Afghanistan for nearly 20 years have officially ended. (Xinhua News Agency, photo by Sanaula)

　　Sarah Langweil, a Republican strategist in the United States, found through a one-year interview that Biden’s rating by voters continued to decline, and even "failed", and there were many democratic voters who were dissatisfied with Biden. Langweil believes that the survey results reflect people’s general dissatisfaction with the long-term persistence of the epidemic and rising inflation.

　　The Atlantic Monthly recently pointed out that compared with the consistent strong dissatisfaction of Republican voters with Biden, the rapid decline of Biden’s support rate among Democrats and independent voters deserves more attention. The internal differences and conflicts among the Democratic voters are becoming more and more obvious. Some voters think that the Democratic Party is not pushing the New Deal fast enough, while others disapprove of the ideas that the Democratic Party is pursuing at present.

　　Division remains the same

　　In recent years, the partisan struggle in the United States has become increasingly acute, and the opposition among the people has become increasingly fierce. The riots on Capitol Hill at the beginning of last year marked a new high in the top-down division of American society. One year after Biden took office, this polarization and tearing has not only not eased, but has further intensified.

　　Republicans totally deny Biden’s policy, American media are keen to play up opposing feelings, and former President Trump still has influence in the Republican Party, all of which are the reasons why the United States is deeply mired in opposition and tearing.

　　On January 6, US President Biden delivered a speech at the Capitol in Washington to commemorate the first anniversary of the riots on Capitol Hill. (Xinhua News Agency, Pool photo, photo by Michael Reynolds)

　　Rick Taylor, a Republican strategist, believes that Biden’s Democratic Party’s dominant position in Congress is extremely weak, and it is usually difficult to realize its policy proposition through legislation, and the presidential executive order he signed lacks overwhelming persuasion. This means that it is difficult for Biden to have the ability to unite the United States.

　　Analysts pointed out that over the past year, the division of the United States has been intensifying, Biden’s patience with Republicans has almost run out, and the two parties have been arguing over the reasons for the division. Some people even question whether it is necessary for the two parties to have a consensus. In this case, it seems destined to be an unreachable dream to bridge differences and unite the United States.