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The concept of clock server in blockchain
Publish: 2021-05-25 04:06:55
1. The definition of Chongqing jinwowo analysis blockchain technology is as follows:
1. Blockchain is a distributed database (system) placed in a non secure environment
2. The blockchain uses cryptography to ensure that the existing data cannot be tampered with
3, the blockchain uses consensus algorithm to reach consensus on new data
the system with the above three properties is blockchain.
1. Blockchain is a distributed database (system) placed in a non secure environment
2. The blockchain uses cryptography to ensure that the existing data cannot be tampered with
3, the blockchain uses consensus algorithm to reach consensus on new data
the system with the above three properties is blockchain.
2. digital currency will not be stolen in general. If you use a regular wallet and invest in a regular digital currency, there will be no problem!
3. In order to prevent the double spending problem, the system will automatically time stamp the transaction information of each block and mark it with time brand. How much money you spend at this time is spent. It has been recorded and can't be used to buy other things
how to record it? In fact, the time stamp and other transaction information on the block are calculated to obtain an encrypted value, which is called "hash value". Each new block contains the hash value of the previous block, thus forming a blockchain
so we say: bitcoin system is actually a layer by layer nested, never-ending, very powerful timestamp system, which uses timestamps to ensure that each block is linked into a "chain" (that is, block chain) in chronological order
from this point of view, time stamp literally means to time stamp a block. Its practical function is to provide an important parameter for later hash value calculation, which is an essential and very important information in the process of calculation and verification
finally, we summarize the content of this section. This section mainly introces two terms: utxo and timestamp. These two concepts are important means to solve the "double flower problem", which can ensure that bitcoin can not be used many times without a third party organization.
how to record it? In fact, the time stamp and other transaction information on the block are calculated to obtain an encrypted value, which is called "hash value". Each new block contains the hash value of the previous block, thus forming a blockchain
so we say: bitcoin system is actually a layer by layer nested, never-ending, very powerful timestamp system, which uses timestamps to ensure that each block is linked into a "chain" (that is, block chain) in chronological order
from this point of view, time stamp literally means to time stamp a block. Its practical function is to provide an important parameter for later hash value calculation, which is an essential and very important information in the process of calculation and verification
finally, we summarize the content of this section. This section mainly introces two terms: utxo and timestamp. These two concepts are important means to solve the "double flower problem", which can ensure that bitcoin can not be used many times without a third party organization.
4. Bitcoin market suddenly soared, and now you can buy it. But you have to buy by yourself. Think about it, because bitcoin is a virtual currency. Market uncertainty, buy carefully.
5. In Figure 1, 1 is the cylinder and 2 is the two position four-way solenoid valve
(2) when the solenoid valve is energized, the spool of the directional valve moves to the right, and the piston of cylinder 1 moves to the right. When the piston rod runs to the end point, press down the stroke valve 4, and the piston rod of cylinder 2 moves to the right. When the end point is reached, press down the stroke switch, and the solenoid valve is powered off
(3) when the solenoid valve is powered off, the piston rod of cylinder 1 moves to the left. When the piston rod runs to the end, the valve 4 resets and the piston rod of cylinder 2 moves to the left. When the piston rod runs to the end, the whole working cycle is completed.
(2) when the solenoid valve is energized, the spool of the directional valve moves to the right, and the piston of cylinder 1 moves to the right. When the piston rod runs to the end point, press down the stroke valve 4, and the piston rod of cylinder 2 moves to the right. When the end point is reached, press down the stroke switch, and the solenoid valve is powered off
(3) when the solenoid valve is powered off, the piston rod of cylinder 1 moves to the left. When the piston rod runs to the end, the valve 4 resets and the piston rod of cylinder 2 moves to the left. When the piston rod runs to the end, the whole working cycle is completed.
6. The shearer itself has many kinds of classification methods. I don't know what kind of shearer the owner wants to know.
at present, the mainstream fully mechanized working faces in China basically use electric traction (hydraulic traction is rare), double drum shearer, which is commonly known as longwall shearer. However, some coal mines of Shenhua Group and most coal mines in the United States also use continuous shearer, It belongs to short wall shearer. The shearer mechanism itself is more, I hope the problem is more detailed
let's first introce the current mainstream Shearer in China electric traction double drum shearer
in short, shearers are mainly divided into cutting part and walking part, and other parts can be said to be auxiliary parts. The cutting section is commonly known as the rocker arm plus roller. In fact, it is an independent recer, which outputs power through the motor on the rocker arm. Finally, the roller (that is, the cutter) completes coal cutting, coal loading and coal dropping through deceleration The coal falls on the scraper and is transported away)
the traction part is actually the same process, but the final output part is the pin rail wheel, which completes the walking action by meshing with the pin row on the scraper conveyor
as for other electric control boxes, as the name suggests, they are used to control the action of the shearer and the completion of some other auxiliary actions
the height adjustment system is to complete the swing up and down of the rocker arm to achieve the goal of mining height. The high-pressure oil is generated by the height adjustment pump in the auxiliary system to push the cylinder piston rod and realize the lifting of the rocker arm
shearer also has some spray cooling system, high pressure box part, some shearers and stall device and crushing device.
if necessary, you can continue to leave a message, specific problems, specific solutions...
here are some information from the network, hoping to help the landlord<
drum shearer
a kind of milling type shallow cutting depth shearer, which is composed of cutting part, traction part and power part. The cutting part includes working mechanism and recer, the traction part includes traveling mechanism (sprocket, traction chain and its tension device) and hydraulic transmission device, and the power part includes motor and electric control box. In addition, there are auxiliary devices, including bottom bracket, cable rack, spray device and signal lighting equipment. The drum shearer is suitable for coal seam with small thickness change, no stone inclusion, simple geological structure and coal seam dip angle of 15 ° It can be used under the condition that the roof is easy to manage. When the inclination angle is large, the anti-skid device should be installed. The drum shearer works on the bendable scraper conveyor and runs back and forth along the working face. The spiral drum is equipped with picks arranged according to certain rules. When the drum rotates, the pick cuts many grooves on the coal body in a certain order, so that the coal body between the grooves is broken, and the coal body is loaded into the conveyor through the rotary blade of the drum and the arc-shaped coal baffle. The diameter of the drum is the cutting diameter measured to the pick tip. Different manufacturers have different series, which are selected according to the mining height. The width of the roller is equivalent to the cutting depth, and there are several specifications such as 0.6, 0.8, 1.0 and 1.2m. Drum shearer is divided into single drum and double drum:
Single Drum Shearer
there are three ways of feed: first, the advanced cutter moves back the head, generally using oblique cutting feed, which is simple and easy, but the feed time is long; ② It can make full use of the working time by moving the head before cutting, but the workload of cutting is heavy; ③ Feed at the same time move the head, feed simple, short time, but need to push the conveyor equipment. There are two ways to cut coal: ① one-way coal mining, the shearer moves upward to cut coal, and the coal is loaded downward. The advantage is that it can make full use of the machine to load coal with high efficiency, but it takes a long time to cut a knife in the working face and the roof hanging time is long. It is generally applicable to the coal seam with stable roof, large mining height and large amount of resial coal. ② Two way coal mining, back and forth each into a knife. The advantages are that the utilization rate of working hours can be improved, the proction capacity of the working face is large, the roof is supported in time, and the working procere is compact, but the workload of cleaning floating coal is large when the mining height is large
double drum shearer
mining full thickness at one time, there is a drum at both ends of the shearer. The front drum cuts the top coal on the top and the rear drum cuts the bottom coal on the bottom. The two rollers generally rotate in opposite directions. The roller on the driver's left side uses the left screw, and the roller on the driver's right side uses the right screw. It can also rotate in opposite directions. The roller on the driver's left side uses the right screw, and the roller on the driver's right side uses the left screw. Generally, it adopts the way of two-way coal mining and the advanced cutter moves the machine head backward; It can also adopt the tangent feed mode of moving the machine head at the same time.
at present, the mainstream fully mechanized working faces in China basically use electric traction (hydraulic traction is rare), double drum shearer, which is commonly known as longwall shearer. However, some coal mines of Shenhua Group and most coal mines in the United States also use continuous shearer, It belongs to short wall shearer. The shearer mechanism itself is more, I hope the problem is more detailed
let's first introce the current mainstream Shearer in China electric traction double drum shearer
in short, shearers are mainly divided into cutting part and walking part, and other parts can be said to be auxiliary parts. The cutting section is commonly known as the rocker arm plus roller. In fact, it is an independent recer, which outputs power through the motor on the rocker arm. Finally, the roller (that is, the cutter) completes coal cutting, coal loading and coal dropping through deceleration The coal falls on the scraper and is transported away)
the traction part is actually the same process, but the final output part is the pin rail wheel, which completes the walking action by meshing with the pin row on the scraper conveyor
as for other electric control boxes, as the name suggests, they are used to control the action of the shearer and the completion of some other auxiliary actions
the height adjustment system is to complete the swing up and down of the rocker arm to achieve the goal of mining height. The high-pressure oil is generated by the height adjustment pump in the auxiliary system to push the cylinder piston rod and realize the lifting of the rocker arm
shearer also has some spray cooling system, high pressure box part, some shearers and stall device and crushing device.
if necessary, you can continue to leave a message, specific problems, specific solutions...
here are some information from the network, hoping to help the landlord<
drum shearer
a kind of milling type shallow cutting depth shearer, which is composed of cutting part, traction part and power part. The cutting part includes working mechanism and recer, the traction part includes traveling mechanism (sprocket, traction chain and its tension device) and hydraulic transmission device, and the power part includes motor and electric control box. In addition, there are auxiliary devices, including bottom bracket, cable rack, spray device and signal lighting equipment. The drum shearer is suitable for coal seam with small thickness change, no stone inclusion, simple geological structure and coal seam dip angle of 15 ° It can be used under the condition that the roof is easy to manage. When the inclination angle is large, the anti-skid device should be installed. The drum shearer works on the bendable scraper conveyor and runs back and forth along the working face. The spiral drum is equipped with picks arranged according to certain rules. When the drum rotates, the pick cuts many grooves on the coal body in a certain order, so that the coal body between the grooves is broken, and the coal body is loaded into the conveyor through the rotary blade of the drum and the arc-shaped coal baffle. The diameter of the drum is the cutting diameter measured to the pick tip. Different manufacturers have different series, which are selected according to the mining height. The width of the roller is equivalent to the cutting depth, and there are several specifications such as 0.6, 0.8, 1.0 and 1.2m. Drum shearer is divided into single drum and double drum:
Single Drum Shearer
there are three ways of feed: first, the advanced cutter moves back the head, generally using oblique cutting feed, which is simple and easy, but the feed time is long; ② It can make full use of the working time by moving the head before cutting, but the workload of cutting is heavy; ③ Feed at the same time move the head, feed simple, short time, but need to push the conveyor equipment. There are two ways to cut coal: ① one-way coal mining, the shearer moves upward to cut coal, and the coal is loaded downward. The advantage is that it can make full use of the machine to load coal with high efficiency, but it takes a long time to cut a knife in the working face and the roof hanging time is long. It is generally applicable to the coal seam with stable roof, large mining height and large amount of resial coal. ② Two way coal mining, back and forth each into a knife. The advantages are that the utilization rate of working hours can be improved, the proction capacity of the working face is large, the roof is supported in time, and the working procere is compact, but the workload of cleaning floating coal is large when the mining height is large
double drum shearer
mining full thickness at one time, there is a drum at both ends of the shearer. The front drum cuts the top coal on the top and the rear drum cuts the bottom coal on the bottom. The two rollers generally rotate in opposite directions. The roller on the driver's left side uses the left screw, and the roller on the driver's right side uses the right screw. It can also rotate in opposite directions. The roller on the driver's left side uses the right screw, and the roller on the driver's right side uses the left screw. Generally, it adopts the way of two-way coal mining and the advanced cutter moves the machine head backward; It can also adopt the tangent feed mode of moving the machine head at the same time.
7. This one or two sentences are really unclear. I suggest you look for some books on hydraulic pressure. There are hydraulic symbols on the books. If you compare them one by one, maybe you will understand a lot!
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