Chunyue is a new cultivar resistant to breeding selected by Nanjing Vegetable Seed Station. It is suitable for overwintering or spring cultivation. It will be supplied to the market in the absence of spring from mid-February to early May.
The sowing period in the middle and lower reaches of the Yangtze River is from February 10 to 25, and the autumn sowing is from September 20 to October 5. Small arch sheds are required for spring sowing and seedlings, and the supply period is from early April to early May. Seedlings are sown in autumn, and the supply period is from mid-February to late March.
Cultivate strong seedlings, plow the sunburn, apply 2000 kg per acre of cooked manure, and prepare a 1.5-meter-wide seedbed. Use 700 grams of seed per acre of seedbed, the ratio of seedbed to field is 1:10. After emergence, dilute manure water is applied 2 to 3 times to promote seedling growth.
Site preparation and early plowing and plowing hoeing, 50 kg of compound fertilizer per acre of base fertilizer, and ridge preparation with a width of 2 meters. Vegetable seedlings were planted at 4-5 leaf stage and 30 days of seedling age. Spring planting row spacing is 22 cm, plant spacing is 18 cm, autumn planting row spacing is 25 cm, plant spacing is 20 cm. It should be planted shallowly in spring so as to slow down seedlings and plants; it should be planted deep in autumn to reduce freezing damage.
After field planting, the spring planting of field-planted live trees was topdressed 2 or 3 times, applying 5 kg of urea per acre each time, and spreading while raining. Watering in dry weather, clearing ditch when raining. The rearing of autumn sowing depends on the weather conditions and the management of vegetable seedling growth. If the temperature is high and the vegetable seedlings are large, the amount of watering should be controlled to slow down the growth rate; if the temperature is low and the vegetable seedlings are small, it should be covered with straw to prevent cold and keep warm. In winter, it is appropriate to maintain the condition to reduce frost damage. After planting live trees, fertilize once, apply 5 kg of urea per acre, and spread it in the rain; after the spring, the plants are planted and weeded once before the line is sealed, and at the same time, 10 kg of urea are applied per ditch.
Prevention and control of pests and diseases In early spring, attention should be paid to the control of diamondback moth, and in late autumn, attention should be paid to the control of aphids and pupae. Use 5% card dead grams of 2000-3000 times solution or 5% acetaminophen 2000-3000 times solution spray to control vegetable maggots, use 311 diamond moth enemy 600-1000 times solution or 5% wicked 2000 times solution spray to control vegetable worms and vegetables Moths were sprayed with 3000% solution of 10% imidacloprid to control aphids. Diseases are mainly soft rot and downy mildew. Prevention of downy mildew by spraying 72% DuPont Kerou 600-800 times liquid or 55% cream to 800-1000 times liquid spray; use 72% agricultural streptomycin 4000 times liquid or 50% sterilin 1000 times liquid spray to prevent soft rot disease.
Harvested in time for autumn sowing in mid-February to late March, spring sowing in early April to early May, yield per mu of 2500 ~ 3000 kg.
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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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