In recent years, as the rural population shifts to urban areas and secondary and tertiary industries, the agricultural labor force in some tea areas is becoming more and more tense. Therefore, it is urgent to promote the mechanized pruning technology of tea gardens. According to some precautions in the management of tea gardens, combined with the actual operation, the tea processing technicians at Jintiange Tea Factory simply summarized the technical details as follows:
1. The advantages of mechanized pruning in tea gardens Compared with manual pruning, the main advantages of machine shearing are as follows: First, improve the efficiency and not forget the time of farming. Manually trimming 1 hectare of adult tea garden requires 30 labors, and 1 mechanical two-person daily trimming amount is 2/3~1 hectare, which can improve the effect by more than 10 times. This will help to complete this work during the best pruning period of the tea garden throughout the year, without delaying the farming time. Second, the garden phase can be significantly changed. The machine shears can make the mining surface smooth, which is convenient for tea garden management and picking. Therefore, the mechanical picking tea garden must be cut first. The third is to save the cost of trimming. The direct cost of machine shear (labor wage, maintenance cost, fuel consumption, etc.) is about 150 yuan/ha, which is 30% of manual trimming. The fourth is to reduce labor intensity. Tea farmers can be freed from heavy physical labor.
2, mechanized pruning should be selected light and deep pruning can choose the double lift trimmer produced by Nanchang Aircraft Manufacturing Company or the Japanese imported Kawasaki double lift trimmer. The price of domestically produced machines is moderate, easy to use, but the durability is poor; the imported machine is expensive, durable, and the accessories are slightly difficult. The effects of the two models are basically the same. Taichung and half-powder pruning should be selected for tea garden and Taiwan.
3. Tea garden type suitable for machine cutting The existing tea garden trimming machine is suitable for the annual light pruning of tea gardens and deep pruning once every 3~5 years. Light pruning is a mild pruning method that picks up the face of the tea tree every year, promotes the formation and growth of axillary buds, and facilitates the picking and reduction of flowers and fruits. It is required to be lightly trimmed, only to cut off the protruding branches of the awning, and to cut the flatness, and the cutting mouth needs to be increased by 2~3 cm per year in order to maintain a certain thickness of the green leaf layer. After several years of picking and light pruning, the tea tree forms a lot of dense and small decay branches (commonly known as chicken claw branches), which affects the yield and quality. Deep pruning is a layer of "chicken claws" that is cut 10-15 cm deep on the awning every 4-5 years. It is required to have a large amount of trimming, leaving no or little green leaf layer, and the imported pump Castel red wine is smooth and neat, in order to restore the tree potential and improve the germination ability.
4, tea garden machine cutting time The best time for light pruning is from the end of September to mid-October after the closure of the park, generally after the cut wound can heal, axillary bud can form but not germination is the most appropriate, premature axillary bud germination, If the wound is not healed too late, it will delay the germination time of spring tea; the second is from late April to May after the end of spring tea. The best time for deep pruning is the high and medium-grade spring tea after the harvest of the valley rain to Xiaoman, can also be trimmed during the spring before the spring tea to the horror. The best time for Taichung and Bantai is carried out from mid-February to early March before the spring tea germination, and can be carried out in time after the spring tea is harvested.
5, tea garden machine shear method Tea leaves and dried piles with a diameter of 1 cm or more should be removed from the tea garden that must be cut by machine to prevent damage to the trimming machine. The machine shear operator should fully understand the mechanical properties and be proficient in the use method; the deputy requires the body to be strong and skilled. The used steam and engine oil must not contain harmful substances such as lead. The depth should be appropriate when trimming, the operation should be smooth, and the speed should be balanced.
6. The supporting management after the tea garden machine is to increase the application of fertilizer and promote new shoots. For deep-cut or Taitung tea gardens, fertilizers must be quickly added. Generally, 667 square meters of urea, 20-30 kg of organic fertilizer, or 30-40 kg of organic biological fertilizers are combined with shallow tillage and weeding soil. Second, the pruned shoots can be covered on the spot or used as stalks to cover the tea gardens, water and fertilizer, and promote the growth of new shoots. The third is to pay attention to the prevention of pests and diseases. After pruning, spray a higher concentration of insecticides in time to avoid pests damaging new shoots. Fourth, the deep-pruned tea garden should be left 3-5 cm after germination, and then lightly trimmed before picking.
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.
Bone Screw,Cancellous Screw,screws in bone,Cortical Screw
Jiangsu Aomed Ortho Medical Technology Co.,Ltd , https://www.aomedortho.com