The screw system contains cortical screw, cancellous screw and Cannulated Screw. Torx and Hex pattern are available. The material is Alloy Titanium or Stainless Steel. The screw use asymmery thread to increase the holding force. Locking screw use four-thread design for quick screw fixing. The screw has self-taping and self-drilling features.
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Bone Screw Bone Screw,Orthopedic Bone Screws,Cortical Screws,Cannulated Screw Shandong Hangwei Orthopedics Medcial Instrument Co., Ltd. , https://www.hangweimedical.com
The eco-agricultural technology model can be developed and popularized in waste lands such as coastal and inland waste lands and abandonment lands, which can not only improve the land development and utilization, but also improve the ecological and economic benefits, and the social benefits are also very significant. The technical highlights of its model construction are as follows.
I. Construction and preparation of greenhouses
1. The area of ​​pool pools for scaffolding construction is generally 0.5--1.0 mu (667 square meters), the pool depth is 0.8--1.2 meters, the water depth is 0.3--0.8 meters, and the east-west direction is Suitably, the bottom of the pool is flat, and the slope ratio of the pool is 1:1.5; the steel frame or bamboo frame of the plastic greenhouse is opened at both ends, and the big film mesh is used to fasten it around the membrane and is buried in the soil. A bamboo row bridge is set in the middle of the shed, which is 30 cm above the water surface and is easy to use for management, observation and feeding. 20 centimeters from the bottom of the pool, two gas pipelines are installed, three air holes are drilled every 25 centimeters or so, and a heating boiler is installed in winter.
2. Desilting the wild and desolated fields should clear the thick silt and turn over the sun. About 10 days prior to planting, 667 square meters shall be cleared with 250 kg of quick lime.
3. Transplanting aquatic grass ponds to transplant water peanuts, bitter grasses, or disinfected willow roots, brown skins, etc., to set up attachments, which will help young crabs to clam shells and habitat, and aquatic grasses cover 40% to 60% of the water surface.
4. The one week before the fertilizer bait is released, the 60-80 mesh sieve is screened, the inlet water is 30 cm, the chicken manure 50 kg is applied on 667 square meters, and the urea 5 kg is used to cultivate the basic biological feed.
5, adjust the water temperature within the greenhouse temperature is generally 22--28 °C, crabs into the shed when the water temperature and nursery crab pool temperature difference is not more than 3 °C is appropriate.
Second, crab seedlings
Generally 667 square meters of crab seedlings 5 ​​- 10 kg, requiring the size of crabs tidy, robust, physically intact. Before putting the seedlings into the water, sprinkle with water for 3 - 4 times or soak in the bath for 2 - 3 times, 1 - 2 minutes each time, and put them into the pool after acclimation.
Third, production management
1. Adjust the water level within 15 days of the seedlings, keep the water level within 36 centimeters, and then gradually increase it to 80 centimeters; increase the amount of water in the middle and late period of culture, and change the water daily by 50% - 80%.
2, water quality control to fertilizer, live, tender, cool as the principle, according to the water, timely change of water, maintain a transparency of 40 - 50 cm.
3. Feeding crab seedlings into the pond for 1 week, stir-fry with egg, milk powder and fish worms (copepods), feeding rate 150% - 100%, directly after the phase III feeding fish or fish Hey. The feeding rate of II--III young crabs was 80%--50%, the feeding rate of IV----V was 30%-15%, and the number of daily feedings I----II period 5-- 7 times, II----III stage 3--4 times, IV--V stage once or twice.
4. Disease prevention and treatment Each month, 667 square meters of lime will be produced with 5-10 kilograms of lime. Mix 1% furazolidone or oxytetracycline and bait for 2 to 3 days. Reduce the number of water changes in the shell stage.
5, daily management often into the shed inspection, high temperature season, open the door from 9 am to 3 pm ventilation, oxygen, timely change of water.
Fourth, the young crab out of the pool
Juvenile crabs are cultured for about 30 days, and the scale reaches 2000--5,000/kg. According to customer requirements, they can go out of the pool and adopt methods such as drainage collection, digging nets, and picking water and using nets.
V. Benefit Analysis
General growth rate of 20% - 40%, 667 square meters of young crab production 80--120 kilograms, 667 square meters of output value of 2.5--4 million, 667 square meters of profit of 0.8 - 15,000 yuan .
Sixth, problems and suggestions
1. Place the seedlings in shallow water and plants where they are more important;
2, buy crabs to learn more about the quality of seedlings, so as not to survive the rate is high;
3, aquatic plants to keep fresh, the area can not be less than 30% of the water surface.
We strive to provide superior benefits to professionals and patients through the development of reliable products.
The cultivation of juvenile crabs in plastic greenhouses is the technical basis for the development of various models of crabs and is an important part of raising the size of commodity crabs and increasing the survival rate of seedlings. The principle is based on the biological characteristics of juvenile crabs, providing a good ecological environment (water grass, water temperature, bait, etc.) needed for its growth and oyster shells, and achieving simultaneous improvement of ecological benefits and economic benefits.