If the topic is too big, use your imagination and enlarge it casually.
Personal opinion: The key to the development of bridge technology lies in the development of material engineering.
The development direction and potential of papermaking technology in 2 1 century. At the 35th pulp seminar held by Tokyo University, the pulp research committee of Japan Fiber Society discussed the development direction and potential possibility of papermaking technology in the 2/kloc-0 century, covering media, raw materials, pulp, bleaching, surrounding environment and market. The main points are as follows:
People, Society and Paper in 2 1 Century
At present, various electronic media are active in society, and whether they can finally replace the traditional "paper" media depends on its affinity with people. According to its use, electronic media can be divided into two categories: information retrieval and reading. The electronic display screen provided for reading is not as simple as reading. The key is to see whether visual information such as words or images can leave memories in the human brain. In the future, as a means of digital information, the development of digital paper will advance with each passing day, and how to give people a proper amount of * * * and help them form memories is the content that must be paid attention to in design and development.
Raw material problem
For the pulp production industry, resources are the most critical issue. Wood grown in Japan is generally cut for 50-60 years (such as fir, juniper and larch), with a minimum of 30 years. In view of the current situation of wood shortage, Japanese industry mostly adopts the way of producing wood (planting trees) in foreign countries with good meteorological conditions, especially by planting short-term trees such as eucalyptus and acacia, and introducing short-term production methods, which successfully shortens the above-mentioned time to 5 ~ 12 years.
In addition, in order to improve production efficiency, we must also pay attention to the material problem of pulp raw materials. Now, experts are studying molecular breeding through gene transformation. In the future, the application of this technology will reduce the cost of cooking and drying, reduce the amount of chemical liquid, thus reducing the discharge of sewage and making contributions to environmental protection. In addition, it can also improve the influence of cellulose on pulp.
Pulping and bleaching technology
In 1980s, Japan's pulp industry made great progress. At the same time, a medium concentration deaerated wood treatment system is introduced to treat wastewater discharge.
In the early 1990s, fiber production in Northern Europe turned to chlorine-free ECF bleaching and chlorine-free TCF bleaching of series chemicals. Later, ozone bleaching appeared and an efficient ozone AMZ agitator was developed. Compared with ECF bleaching, ozone bleaching is more effective in reducing cost, improving pulp quality and improving environment. At present, many TCF bleaching devices have been used as "ozone -ECF" devices.
Challenges faced by paper machines
Up to now, although the consumption of printing paper, wrapping paper and paper towels is increasing, with the emergence of electronic media and packaging materials, the market space is facing some changes. In order to ensure market share, the paper industry must make more efforts to reduce costs and improve quality, and at the same time, it must introduce new technologies to reduce the use of various raw materials, such as fibers, microfibers, fillers and chemicals.
In the past few decades, the progress of paper machine speed has made great contributions to improving work efficiency. Now we must pay attention to the balanced development of paper and papermaking technology, and save energy and water.
Globalized market
The annual growth rate of paper and paperboard consumption reached 3. 1%, especially in Asia and South America. On the one hand, the demand for pulp is sluggish; On the other hand, recycled paper is widely used in the world. In terms of varieties, printing paper, wrapping paper and paperboard account for a relatively high proportion in paper consumption.
The pulp trade is mainly carried out between regions with superior geographical position and close economic ties. In recent years, countries with increased pulp exports include South Korea and Indonesia.
Many enterprises in the industry are carrying out mergers and acquisitions. In order to improve their market competitiveness, enterprises must strengthen their supply capacity through expansion or merger. In contrast, the latter has less investment than the former, and increasing market share through mergers and acquisitions will not cause the expansion of the production scale of the whole industry, thus avoiding vicious price competition. The influence of IT revolution and pulp industry and market on paper demand is directly reflected in pulp. At present, with the rapid popularization of computers and mobile phones, the extensive use of related advertisements and instructions has greatly promoted the growth of paper consumption in the information industry. But at the same time, it has also brought some adverse effects to newspapers, DM and commodity catalogues.
What is the development direction of 2 1 century submarines? According to the current research situation of new submarines in major military powers and the rapid development of high technology in 2 1 century, it can be seen that 2 1 new submarines will have the following development trends: First, the hull structure with large diving depth and high noise reduction. The diving depth of traditional submarines is generally 250-400 meters. At present, the maximum diving depth of Russian "North Wind" class and "Typhoon" class submarines using high-strength new materials has reached 900 meters. In the future, the new submarine diving to 1000 meters is only a passing line. In the future, the noise of new submarines will be greatly reduced. Double-hull structure, shell anechoic tile, smart skin and effective noise reduction propulsion technology will make 2 1 century submarines become real "underwater ghosts" and greatly enhance their battlefield survivability. The second is a high-power closed power plant that does not rely on nuclear energy and air. In recent years, Russia, Germany and many other countries have made great progress in this regard. In 2 1 century, new power devices such as Stirling engine, fuel cell, closed-loop engine and pump jet propeller will provide powerful and lasting power for submarines. In addition, the power of nuclear power will be greatly improved, which will greatly improve the maneuverability of submarines. The third is the long-range multifunctional weapon system. With the further development of large-scale guided torpedoes and new submarine-launched missiles, especially submarine-launched cruise missiles, the weapon and equipment system of the new generation of attack submarines will further develop in the direction of multi-variety, large quantity, full function and long distance. 2 1 century new submarine will realize long-range anti-submarine, anti-ship and land attack, and can complete some strategic attack tasks. Fourth, a navigation communication device with high precision and high penetration. At present, the Roland C/ satellite navigation system on the improved nuclear submarine in the United States can make the instantaneous navigation accuracy of the submarine reach 100 meter. The positioning accuracy of the electrostatic gyro navigator successfully developed in the United States can reach about 50 meters, and the average time between failures exceeds 4000 hours. In addition, the United States has also successfully developed an extremely low frequency submarine communication receiver, underwater 1000 meters to 16 knots.
When sailing at high speed, communication can be carried out smoothly, thus changing the situation that submarine communication mainly depends on high-frequency radio. With the development of laser communication, the underwater laser communication device with high data rate and strong anti-interference ability will make the underwater communication depth of the new generation submarine in 2 1 century reach 300 ~ 400 meters. In addition, 2 1 century submarines will also have the characteristics of carrying weapons and diversification of tasks. Compared with other services, the navy will give priority to development.
The army, navy, air force and missile force have their own advantages and uniqueness. However, after entering 2 1 century, the advantages of the navy are obviously more prominent. Today, all modern countries pay more attention to the development of the navy. On the one hand, they actively develop new warships and improve their overall operational potential. On the other hand, constantly improve the naval establishment system. It is no accident that all countries are trying to exclude their navies from this process in disarmament negotiations. The most obvious thing is that the naval expenditure of developed countries generally accounts for 30% ~ 40% of the military budget. For example, the naval expenditure of the United States accounts for more than 1/3 of its total military expenditure. The most obvious improvement in the role of the navy is manifested in the continuous expansion of the activities of developed countries in realizing their military and political strategic policies, and Germany and Japan are very representative in this regard.
In 2 1 century, the navy received more attention and gave priority to development. The main reasons are as follows: First, Zaoyang, a place where the navy is active, has many resources. When there is friction or armed conflict due to marine resources, the navy is the most important force to protect maritime rights and interests. Second, the navy itself is very mobile. The activities of naval vessels are not limited by time and place, and the forces can be concentrated in the required sea area in a short time, and nuclear submarines can launch large-scale raids anytime and anywhere. One of the most important trends in the future development of the armed forces is to strengthen their mobility. This is also the result of the new military and political situation in the world, that is, new dangers are constantly emerging, with various forms and unpredictable characteristics. This situation requires the armed forces to improve their mobility accordingly, and the navy is the most suitable one among the armed forces. Third, it depends on the development trend of future conflicts and regional wars. In the conflicts and wars in the 2 1 century, one aspect that attracts more and more attention from all countries is the factor of "naval victory", that is, "attacking from the sea" determines the outcome of wars and conflicts or plays a key role in their procedures. The navy is increasingly affecting the deep battlefield of land and air. This trend was manifested in the wars between Britain and Oman, the Gulf War and the Kosovo War. In the 2 1 century, the navy will play an irreplaceable role. If the 20th century is a war style period dominated by land-sea engagement, then the 20th century is an era of rapid development of the sea-air combat style attacking from the sea.
Therefore, the navy in 2 1 century will be a strategic force to contain the world, and it will also be the backbone of the competition in the "Ocean Century".
What do you think is the development direction of track and field in 2 1 century? You have a wide range. You should define a small scope, such as track and field sports and middle-aged and elderly people in the 2 1 century, the development of track and field sports in the national fitness in the 2 1 century, or be more professional. The development direction of short-distance projects between Liu Xiang and China should be determined as folk, amateur or professional. I suggest you consider the development of folk track and field sports, so that it is easier to collect the information and evidence needed for the paper. Ask the tutor more questions, listen to his suggestions and ask him for advice. The most important thing is to have a good attitude and ask more questions, hehe, I see.
265438+ I think the development direction of novels in the 20th century. Nowadays, novels tend to be light novels related to life. Maybe many people say that there is no spiritual connotation, but I think that kind of novel has many voices of life and is closer to life. Personally, I prefer it
Briefly describe the development direction of bridge technology. In the examination, fast 1 and long-span bridges develop in a more K, larger and more flexible direction.
This paper studies the application of long-span bridges in aerodynamics, earthquakes and earthquakes. Vehicle dynamic function-the safety and stability of the structure, making the cross section into various streamlined stiffening beams to meet aerodynamic requirements and increase the stiffness of super-long-span bridges; The spatial network bearing system with stay cables as the main part is adopted; Using suspension cable and cable-stayed mixed system; Lightweight and high-rigidity composite materials are used as stiffening beams, and lightweight and high-strength carbon fiber materials are used as main cables.
2. Development and application of new materials
The new material should have the characteristics of high strength, high elastic modulus and light weight. A series of materials, such as ultra-high strength silicon powder and polymer concrete, high strength dual-phase steel wire and steel fiber concrete, fiber plastic and so on, are studied to replace the steel and concrete used in bridges at present.
3. Adopt highly developed computer-aided means in the design stage.
Carry out effective rapid optimization and simulation analysis, use intelligent manufacturing system to produce parts in factories, and use GPS and remote control technology to control bridge construction.
4. Large-scale deep-water foundation projects
At present, the bridge foundation in the world has not exceeded1300m deep-sea foundation engineering, and the practice of 100 ~ 300 m deep-sea foundation will be carried out in the next step.
5, the safety of the bridge
After the bridge is completed and put into use, the automatic monitoring and management system will ensure the safety and normal operation of the bridge. In case of failure or damage, the damaged parts and maintenance countermeasures will be automatically reported.
6. Attach importance to bridge aesthetics and environmental protection.
Bridge is one of the most outstanding buildings of mankind. The famous Golden Gate Bridge in San Francisco, Australia's Sydney Harbour Bridge, London Bridge in England, Akashi Strait Bridge in Japan, Yangpu Bridge in China, Second Yangtze River Bridge in Nanjing and Tsing Ma Bridge in Hong Kong are all precious space works of art, which have become landscapes of land, rivers, oceans and the sky and become urban landmark buildings. The spectacular Sydney Harbour Bridge in Australia is integrated with the unique modern Sydney Opera House, becoming the symbol of Sydney today. Therefore, the bridge structure in 2 1 century will pay more attention to architectural art modeling, bridge aesthetics and landscape design, and environmental protection, so as to achieve the perfect combination of human landscape and environmental landscape.
Based on the great development of bridge engineering in the 20th century and the great blueprint of 2 1 century, the bridge construction technology will have greater updated development.
What is the development direction of table tennis technology in the world? In the past, speed was the main thing, but in that case, every round was scored too fast (especially in men's competitions), which was ok for experts, but it was incomprehensible to laymen, and there was nothing to see.
The purpose of changing table tennis from 38mm to 40mm is to reduce the speed of the ball, increase the number of balls in the game and improve the appreciation. The reduction of speed makes the players work hard on the rotation. Many players in China team emphasize ball control and feel with pure wooden boards.
Table tennis is an irregular and irregular sport, which determines the high complexity and particularity of this sport. On the technical level, there are many ways to hit the ball, many kinds of techniques, fast conversion and close connection between technical actions, high randomness and rapid change in technical application, and uncertainty is widespread. It embodies the true charm of table tennis.
In the game, the technical confrontation between players is mainly manifested in how the two sides restrain each other's strength through speed, strength, rotation, placement and rhythm, so as to find opportunities and create conditions for their own attack.
The development trend of table tennis technology is as follows:
The use and rationality of new technologies such as 1 and torsional tension in the table.
2. The application and effectiveness of new tactics, including: serving and attacking, receiving and attacking, combination of rubbing and attacking, methods and means to deal with short balls and long balls on the baseline in Taiwan, and the timing of attack and defense conversion.
3. Use new equipment (soleplate, rubber, etc.). )
4. The use of new balls and the influence of table tennis rules on table tennis.
What is the development direction of Gaowei Technology? Gaowei technology has changed from traditional production and processing to intelligent manufacturing, and the production mode has been upgraded to automation, reducing costs and improving efficiency, which has brought a qualitative leap to the development of Gaowei technology and Gaowei products.