![Several problems should be considered in soot purification technology]() |
The following factors should be considered in the research of soot purification technology:
1. The novelty, advancement and applicability of technology. The novelty of technology includes not only the breakthrough of its purification principle, but also the advanced and reasonable structure, including the composite composition between technologies, so as to achieve advanced, improve purification efficiency, ensure stable operation and easy installation and maintenance. At the same time, we must consider the applicability between the product and the market, that is, the variety of specifications and varieties, suitable for the displacement of different kitchen stoves and the size of the floor to meet different requirements.
2. The contradiction between technology and policy laws. The contradiction between technology and policy law is related to the resistance of product sales. The high-altitude emission policy of the environmental protection department and the policy of the urban construction department that does not allow the pipeline to climb the external wall to affect the city's aesthetics have an impact on the application of technology. However, the law of high-altitude emission and the law of private property rights also conflict, and the pipeline is not easy to pass through the outer wall of the private house. Can not be ignored.
3. Economical product technology. Economics include the price of the product, engineering cost, operating costs, maintenance costs, etc. When researching, consider the purchasing power of the application object, both high-end and medium-low. It is suitable for the needs of different consumption levels to achieve the ultimate goal of pollution control. In particular, there are many people who are laid off and reemployed at this stage. Many laid-off workers rely on the company's tens of thousands of yuan to pay for small restaurants, and they must consider the economics of the products.
4, the fume purification technology should be a hundred flowers. The current fume purification technologies have their own characteristics. As long as they meet the relevant national product standards and obtain the qualified inspection and certification of the designated inspection department of the country, they should be recommended. Any technology needs to be continuously improved and improved with the support of certain markets. This is the need for the survival of enterprises and the necessary condition for technological improvement. Only when a hundred flowers bloom, can we maximize technological competition and technological revolution, and thus continuously promote the healthy development of soot purification technology.
5. Technology and economic development should be compatible. The economic development of various provinces and cities in China is unbalanced, and the economic benefits of each catering industry unit are also different. If the price of the products provided is relatively high, the regions with poor economic development and the units with poor economic returns cannot bear it. Therefore, the problem of pollution of the exhaust fumes can only be partially solved and cannot be controlled by a large area, which is not conducive to the ultimate goal of controlling pollution. Therefore, the blooming of the purification technology has made the price of the product high, medium and low, which makes the areas with poor economic development and the units with poor economic benefits have a choice, so that the oil can be polluted at the same time as the economic development. Effectively controlled, both economic and social benefits can be achieved.
In general, to engage in environmental protection work, we must consider both the economic benefits of the enterprise and the economic benefits of the society; we must consider environmental policies and regulations as well as relevant national policies and laws and regulations. The contradictions that arise between them are often solved through appropriate techniques. Applicable fume purification technology is beneficial to technical competition and technological revolution, which is conducive to the formation of high, medium and low grades of product prices, which is conducive to the selection of pollutant discharge units, and ultimately conducive to the realization of pollution control objectives and the steady development of social economy.
Bone Screw
Bone screws, also known as fracture fixation screws, are commonly used in clinical practice to fix orthopedic implants.
Bone screws are usually used to fix internal fractures or dislocations by directly screing into two different bone blocks or fixing an internal implant such as a bone plate to achieve fracture fixation, position the bone and promote its healing. Bone screws are used in a wide range of areas, including the shoulder, elbow, hip, knee, spine, etc. For example, pedicle screw systems are used for spinal fusion, and compression bone screws are commonly used for foot and ankle surgery or fixation of other fractures under pressure. Similar to traditional mechanical screws, the main structures of bone screws also include nail cap, nail body, and nail tip. Screws can be used to fix bone plates or bone fragments. When used for the former, they are called plate screws, and when used for the latter (to prevent the collapse of bone fragments), they are called positional screws. The latter can be inserted into the plate holes, and can be placed on the bone alone (also known as compression screws). Compression screws can be used to increase interfragment pressure.
(1) The screw cap
The screw cap has three main functions: the first is to optimize the force. The protruding cap makes the contact area between the screw and bone larger, increases the load area, optimizes the local force at the screw insertion site, and reduces the risk of bone rupture caused by excessive stress. The second is the positioning effect. The prominent cap makes the bone nail can only be screwed into a certain depth to prevent the whole bone nail from being screwed into the bone completely. The third function is to provide the position of force application by rotating the force groove at the cap to move the bone nail forward and drive it into the bone. Now, the force groove is mostly inner hexagonal, which does not require axial force to maintain the actuator in the center position and is suitable for a wider range of fractures.
(2) Screw the body
The size of the nail body determines the strength and fatigue resistance of the bone nail. The larger the diameter of the nail body, the stronger the strength will be, and the corresponding fatigue resistance will be better. In addition to the diameter of the nail body, the pitch and tooth depth of the screw body thread are also the key parameters of the nail body design. Different thread design has an important effect on the pressure and occlusal performance of the screw.
(3) Screw tip
Tapping is the process of phalangeal nail cutting thread in the bone. According to the shape of the nail tip, the bone nail can be divided into self-tapping nail and non-self-tapping nail. The nail tip of the self-tapping nail is sharper and can be directly screwed into the bone without pre-drilling. Usually, self-tapping screws are used for Cancellous bone, and the bone is compressed when the screw is inserted, so as to increase the bone density of the occlusal part locally and enhance the occlusal effect. However, when inserting screws in Cortical bone, the screw channel is generally pre-punched, and then the bone screw is screwed. Usually, the self-tapping screw is not directly used to prevent the bone screw from being stuck or damaged because the cortical bone is too hard.
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