Precautions:
Pregnant women eat seafood is a taboo, mothers must pay attention to the following points:
First, in early pregnancy, crabs must not eat. Special emphasis is placed on the meat of crab's big forceps, which can cause early fetal miscarriage and is extremely dangerous.
Second, seafood must be cooked. Don't eat raw seafood. If pregnant women eat raw seafood, some parasites or germs are easily absorbed by the baby in your stomach. The consequences are unthinkable.
Third, pregnant women should not eat contaminated seafood regularly, and they can choose to eat fish that have not been contaminated by mercury. For pregnant women, if a large number of marine fishes with high mercury content are frequently consumed, the harmful mercury substances ingested by the mother will enter the fetus through the placenta and cause damage to various organs and systems of the fetus such as brain nerves, liver and kidneys. .
Fourth, shrimp contains high levels of calcium. If pregnant women do not have adverse reactions after eating shrimp, such as allergies and abdominal pain, there is no problem. Appropriate amount of shrimp or shrimp during pregnancy can be added calcium, zinc and other trace elements, especially calcium can promote the growth of young children. Eating shrimp can also promote the development of young children's brains. Therefore, as long as you have no adverse reactions to shrimp, you can eat, but it is appropriate.
Fifth, pregnant women should eat less fish
The news that the seafood contains mercury in excess of standards has often been reported recently, which has caused many people to criticize directly: Can we still eat seafood? Research from nutrition experts in the United States believes that seafood, including fish, shrimp, crab and shellfish, should still be an indispensable part of people’s daily diet.
Nutritionist Dr. Rick Schroeder published an article in the latest issue of the Journal of the American Medical Association. He said that middle-aged and older people, especially women, should eat more seafood, and it is best to ensure that they use 2-3 times a week, 100 grams each time. Unsaturated fatty acids in marine fish can reduce low-density cholesterol in the blood while also resisting blood clotting, thereby reducing the risk of coronary heart disease, hypertension, and stroke in the elderly.
However, some people really should eat less seafood. The amount of mercury in seafood is getting higher and higher. If pregnant women and lactating women often eat seafood (more than 100 grams per week, more than 100 grams each time), it will affect the development of the nervous system of the fetus and the newborn, and some symptoms should be It does not appear until the child is 7 years old or even 14 years old. Experts believe that pregnant women and nursing women should eat less seafood, 1-2 times a week, each 100 grams or less, and do not eat tuna, swordfish and other high mercury-containing fish.
We may have ever heard of the Bullet Fixed Focus Camera/ Fixed Focus Bullet Camera HD/ Bullet Fixed Focus Journal Camera/ Fixed Focus Bullet Camera IR/ Fixed Focus Bullet Surveillance Cameras/ Fixed Focus Analog Bullet Cameras, so what is the Bullet Fixed Focus Camera? We know that the Bullet refers to the camera shape, so what about the Fixed Focus? Actually, the Fixed Focus refers to a type of the camera lens. Today let me introduce the camera lens for you.
The camera lens is the key equipment of the video system. The lens' quality (index) directly affects the overall index of the camera. The lens is equivalent to the lens of the human eye. As you know, if there is no lens, the human eye cannot see anything. That is to say, if there is no lens, then the output image of the camera will just be white without any clear image output; which is consistent with the principle of our home cameras.
Actually, there are many classifications for the camera lens. Today please let me introduce one classification for you---the classification according to the structure.
1. The fixed focus lens with the fixed aperture
The lens has only one focus adjustment ring that can be manually adjusted. Rotating the ring left and right can make the image on the CCD target surface clearest. There is no aperture adjustment ring, so the aperture cannot be adjusted, and the luminous flux entering the lens cannot be changed by changing the lens factors, but can only be adjusted by changing the illuminance of the shooting site. The structure is simple and the price is cheap.
2. The fixed focus lens with the manual iris
Compared with fixed focus lens with the fixed aperture, the fixed focus lens with the manual iris has an extra aperture adjustment ring. The aperture range is generally from F1.2 or F1.4 to fully closed, which can easily adapt to the illuminance of the shooting site, and the aperture adjustment is done manually. The illuminance is uniform and the price is cheap.
3. The fixed focus lens with the automatic iris
Compared with the fixed focus lens with the manual iris, the fixed focus lens with the automatic iris has an extra gear-driven micro motor on the iris adjustment ring, and a 3 or 4-core shielded wire is drawn from the drive circuit, then connected to the camera's automatic iris interface seat. When the luminous flux entering the lens changes, the charge generated by the CCD target surface of the camera changes accordingly, thenthe video signal level changes, and a control signal will be generated and transmitted to the automatic iris lens, so that the motor in the lens can perform the corresponding rotation to complete the task of resizing.
4.The electric zoom lens with the automatic iris
Compared with the fixed focus lens with the automatic iris, the electric zoom lens with the automatic iris two extra micro motors. One motor is connected with the zoom ring of the lens, and can control the focal length of the lens when it rotates; the other motor is connected with the focus ring of the lens, and it can complete the focus of the lens When it rotates with control from the former motor. However, due to the addition of two motors and an increase in the number of lens groups, the size of the lens has also increased accordingly.
All in all, it would be helpful to know about the camera lens if you want to know more about the Bullet Fixed Focus Camera and the whole video monitoring field.
Bullet Fixed Focus Camera, Fixed Focus Bullet Camera HD, Bullet Fixed Focus Journal Camera, Fixed Focus Bullet Camera IR, Fixed Focus Bullet Surveillance Cameras, Fixed Focus Analog Bullet Cameras
SHENZHEN SANAN TECHNOLOGY CO.,LTD , https://www.sanan-cctv.com