Sweaters are knitted by machine or by hand. The history of Sweater knitting is very long. Human beings used leaves and animal skins to cover their bodies in primitive life, and later learned to use knitting techniques, so sweaters were produced. With the evolution of civilization and the invention of technology, there are more and more types of sweaters, with better and better quality. The function of sweaters is generally to keep warm, but with the progress of mankind, people began to pursue the beauty of sweaters.
Yacheng Knitting Co., Ltd. can mass produce customized high-quality knitted garments, including sweaters, Custom Knit Sweaters, Knitted Pants, Knitted Skirt, Knitted Shoes, Knitted Scarves and Knitting Blanket. If you need to order knitted products, please contact us.
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The International Energy Agency estimates that oil, natural gas, and coal will peak after 30, 60, and 120 years, respectively, after which production will gradually decline. Although it is not ruled out that with the advancement of technology, new oil fields, gas fields, and coal fields will be pushed back to the peak, the situation based on fossil energy is unsustainable from the perspective of human long-term development and ultimately solves the energy problem. Still need to rely on new energy.
Hydro-nuclear energy is the main force for military endeavors, and China has made great efforts in the field of new energy. Data released at the New Energy Finance Summit held in London in March this year shows that China’s investment in new energy has increased by more than 40% annually during the past three years. In 2009, China’s investment in new energy sources ranked first in the world.
China has already proposed a new energy development plan. By 2020, the ratio of non-fossil energy to primary energy consumption will increase to 15%. Among them, water energy will increase from the current 190 million kilowatts to 300 million kilowatts, nuclear energy from 10 million kilowatts to 70 million kilowatts, wind energy installed capacity from 20 million kilowatts to 100 million to 120 million kilowatts, and solar energy from 3 million kilowatts. To 20 million kilowatts or more.
Cheng Siwei believes that in the new energy technologies, the hydro and nuclear energy technologies are mature, and increasing the proportion of non-fossil energy to 15% depends mainly on water and nuclear energy. While some key technologies for other new energy sources have not yet been mastered in China, technically controlled people have affected the development of new energy in China. In the future, China's chemical industry has a lot of work to do in solar film technology, biofuel technology, and so on.
Wind energy must be turned "three mountains"
Cheng Siwei believes that there are three major problems in the development of wind power in China, namely that the power generation capacity is limited by the wind speed, the equipment is not large enough, and wind power is difficult to access.
Cheng Siwei said that due to material restrictions, most of the devices in China cannot generate electricity at wind speeds of less than 3 m/s. The base material of wind turbine blades is mostly glass-reinforced epoxy resin. If the blade is not removed when the typhoon strikes, it will be damaged. The installed capacity of domestic wind power is very large, but it is only 2,300 hours that the power generation capacity is converted to full capacity, and the utilization rate is less than 1/3.
Wind power is divided into offshore wind power and land-based wind power. The cost of offshore wind power construction is high, requiring at least 5 MW of equipment, preferably 10 MW. Most of the wind turbines manufactured in China have just rolled off the 1.5 MW, 3 MW and 3.5 MW equipment. The technological gaps in large-scale equipment such as automatic control technology, shaft and blade technology have restricted wind power, especially the development of offshore wind power.
Then there is the difficulty of entering the network. China now stipulates that the proportion of wind energy can not exceed 10%, and one of the important factors is that it is restricted by the power grid technology. China is developing smart grid technology. As the technology continues to mature, the proportion of wind power connected to the Internet may increase.
According to Cheng Siwei, China is studying more power generation technologies, such as magnetic levitation wind power generation. With this technology, wind speeds of 1 to 1.5 m/s can generate electricity. Because the blade structure is not adopted, the typhoon can still generate electricity when it strikes. However, at present, maglev wind power generation is still in the initial stage of development, with a power generation capacity of only 1 kilowatt, which is complementary to solar power generation sound and light, and provides power for urban street lights.
Solar energy is affected by the cost and conversion rate Cheng Siwei said that the first-generation solar energy technology is a solar cell, which consumes a large amount of energy in the refining and conversion process and there is pollution; the theoretical limit value of photoelectric conversion efficiency is about 23%, but usually only 12% to 15% . Baoding Yingli Company improved the photoelectric conversion efficiency to 18.5% after adopting the silane method to improve the silicon production technology.
The second generation is silicon thin film technology, and two technological routes have been developed: plasma enhanced chemical vapor deposition (PECVD) and physical vapor deposition (PVD). The advantage of this technology is that it can save raw materials, but the photoelectric conversion efficiency is only 8% to 10%, which is lower than the first-generation technology. DuPont and others have made great efforts in this area.
The third generation is based on gallium arsenide as a representative of multi-junction three-five compound film technology. According to reports, the theoretical photoelectric conversion efficiency of this technology is as high as 50%, and it is practically around 25%, which is significantly higher than the previous two generations of technology. At present, China has not conducted any research in this area and is a direction that can be considered in the future.
Cheng Siwei said that these three technologies have their own advantages and disadvantages and will coexist for a long time. The ultimate competitiveness will depend on the cost of silicon and the level of photoelectric conversion efficiency.
Our company can produce various styles of sweaters. You are welcome to provide drawings and we will customize them for you.
"One of the biggest problems in the development of new energy is that the cost is too high. To develop new energy, we must work hard at the political, economic, and technological levels. The most critical thing is to achieve more breakthroughs at the technological level. Only by breaking through can we talk about economy.†Cheng Siwei, former vice chairman of the Standing Committee of the National People's Congress and Honorary Director of the Process Systems Engineering Committee, proposed the current development of new energy at the 2010 China Process Systems Engineering Conference held last week. The crux lies. He pointed out that China is vigorously developing low-carbon economy, circular economy and ecological economy, and its intersection is energy, especially new energy.
May 19, 2021