Guang'an to central town

1. Most of them can work, but they don't support 3G networks in China. Wi-Fi network or edge should be available for Internet access.

2. 1L solution
to Taobao to buy, I am, although it can't upgrade, but even if you keep under it is enough
10 yuan RMB can buy 100-200 yuan program is enough for you

3. It can be used.
but the biggest problem now is that if you are not proficient in computers, or don't pay attention to upgrading frequently,
the iPhone will lose its meaning

4.

The iPhone 12 in China supports 5g, and the Bank of China version also supports 5g. 5g network is not only a major upgrade point of the new iPhone 12, but also a highlight of the iPhone 12 series

however, Apple's support for frequency bands is quite perfect, and the iPhone 12 and iPhone 12 Mini support up to 17 5g bands. In order to balance the power consumption, Apple has added a smart data mode, which can intelligently switch between 4G and 5g according to the bandwidth required by the current application

extended data:

material technology of Apple 12

1. Antenna system

adopts new antenna system to improve 5g performance. Apple said it optimized the IOS system to take advantage of 5g speed while maintaining power efficiency

2, intelligent data

iPhone 12 has intelligent data mode, which can intelligently switch between 4G and 5g data speed

3. Front screen glass

Apple used a new cover plate surface treatment named "super porcelain crystal panel" on the front screen glass, which improved the rability of the equipment and improved the anti falling performance by four times

4, camera

Apple has updated the camera system of iPhone 12, adopting a new 12 megapixel wide-angle camera with wider aperture

5, wireless charging

iPhone 12 has MagSafe function, which is used to enhance wireless charging with magnetic absorption

5. Generally, the calculation steps of rolling bearing life are as follows:
1. According to the technical parameters of the main engine and the structure of the supporting parts, the type and size of the bearing are preliminarily selected, and the load acting on the bearing is calculated
2. Calculate the equivalent dynamic load
3. Calculate the bearing life according to the bearing rated life formula
4. Check the rated static load and limit speed
the rated life of rolling bearings refers to the number of running hours (106 revolutions) that 90% of bearings in a batch can reach or exceed before fatigue spalling, or the number of working hours at a certain speed
for the basic rated life of ball bearing:
L10 = (CR / PR) 3 (million revolutions)
in actual calculation, the working hours are generally used to express the bearing life (hours), which is:
LH = (CR / PR) 3 / (60N) * 106 (hours)
where Cr: is the radial basic rated dynamic load (KN), which refers to the constant radial load that a set of rolling bearings can bear, The basic rated life under this load is one million revolutions
PR: refers to the radial equivalent dynamic load (KN), which refers to the radial equivalent variable load of various external loads actually received by the bearing
for the basic rated life of roller bearing:
L10 = (CR / PR) 10 / 3 (million revolutions)
the working hours are used to express the bearing life (hours):
LH = (CR / PR) 10 / 3 / (60N) * 106 (hours)
the calculation method of rated life is determined according to ordinary bearing steel and general working conditions, and the life reliability is 90%. Considering the influence of materials and service conditions as well as the requirement of high reliability, ISO revised the formula of rated life by adding reliability coefficient, material coefficient and service condition coefficient
at present, the actual service life of foreign advanced ball bearings is more than ten times of the calculated life, and the reliability is more than 95%. The service life level of ball bearings proced by our factory can reach the domestic advanced level.

6. It is possible to calculate the bearing life, both of which should be less than 0.8