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AMC business blockchain
Publish: 2021-04-17 16:37:43
1. When you open an online bank, you have the option to export the private key.
by default, you can't
now you have to go to the bank to reopen it
by default, you can't
now you have to go to the bank to reopen it
2. Technology 1: blockchain
about how to build a rigorous database, the blockchain method is to innovate the structure of the database, divide the data into different blocks, link each block to the back of the previous block through specific information, and present a complete set of data in sequence, which is also the source of the three words "blockchain"
block: in blockchain technology, data is stored permanently in the form of electronic records, and the files in which these electronic records are stored are called "blocks". Blocks are generated one by one in chronological order. Each block records all the value exchange activities ring its creation, and all blocks are combined to form a record set
block structure: the transaction data in the block generation period will be recorded in the block, and the block body is actually a collection of transaction information. The structure design of each blockchain may not be exactly the same, but the large structure is divided into two parts: header and body. The block head is used to link to the previous block and guarantee the integrity of the blockchain database. The block body contains all the verified records of value exchange ring the block creation process
Bubi blockchain: it uses cryptography provable algorithm to build multi center network trust, which is open, transparent, tamper proof and revocable; Multi party participation in information transparent sharing, the establishment of authentic traceability chain path, direct to consumers
the block structure has two very important characteristics: first, the transactions recorded on each block are all the value exchange activities after the formation of the previous block and before the creation of the block, which ensures the integrity of the database. Second, in most cases, once a new block is added to the end of the blockchain, the data record of the block can no longer be changed or deleted. This feature ensures the rigor of the database, that is, it cannot be tampered with
as the name suggests, blockchain is the combination of blockchains. The database formed in this way is called blockchain database. Blockchain is a transaction database shared by all nodes in the system. These nodes participate in the network of blockchain based on value exchange protocol
how does blockchain work? Because the block head of each block contains the transaction information compression value of the previous block, it makes the connection from the genesis block (the first block) to the current block form a long chain. Since there is no way to generate the current block if the "transaction miniature" value of the previous block is not known, each block must follow the previous block in chronological order. The structure that all blocks contain the previous block reference makes the existing block set form a long data chain
summarizes the basic structure of blockchain: "people pack the information (including data or code) generated in a period of time into a block, stamp it with a time stamp, and connect it with the previous block. The page capital of each next block contains the index data of the previous block, and then write new information in this page, so as to form a new block, end to end, Finally, a blockchain was formed. " The magic of this structure: block (Complete History) + Chain (complete verification) = timestamp
"block + Chain" structure provides us with a complete history of the database. From the first block to the latest block, all the historical data of the system are stored in the blockchain
blockchain provides us with the function of searching every data in the database. Every transaction data on the blockchain can be traced back to its origin and verified one by one through the structure of the "blockchain"
blockchain = timestamp, which is the biggest innovation of blockchain database. The blockchain database allows the network wide recorders to stamp a time stamp in each block for accounting, indicating that the information is written at this time, forming a database that cannot be tampered with or forged. We believe that timestamp is a great technological innovation in blockchain. What can it prove<
Technology 2: distributed structure - open source, decentralized protocol
after we have the data of block + chain, we need to consider the problem of record and storage. Who should we let to participate in the data recording, and where should we store the time stamped data? In today's centralized system, data are centrally recorded and stored on the central computer. However, the ingenious design of the blockchain structure is here. It does not agree to record and store data on one or several centralized computers. Instead, it allows every node participating in data transaction to record and store all data
1. As for how to make all nodes participate in the recording, the method of blockchain is to build a complete set of protocol mechanism, so that each node in the whole network can participate in the recording and verify the correctness of the recording results of other nodes at the same time. Only when most nodes (or even all nodes) in the whole network think that the record is correct at the same time, or all nodes participating in the record are consistent with the comparison results, the authenticity of the record can be recognized by the whole network, and the record data can be written into the block
2. As for how to store the rigorous database of "blockchain", the method of blockchain is to build a distributed network system, so that all the data in the database can be updated in real time and stored in all the network nodes participating in the records. In this way, even if some nodes are damaged or attacked by hackers, the data record and information update of the whole database will not be affected
according to the open source and decentralized protocol determined by the system, the blockchain constructs a distributed architecture, which enables the information of value exchange to be transmitted to the whole network through distributed propagation, determines the content of information and data through distributed accounting, generates block data after stamping it with time stamp, and then sends it to each node through distributed propagation to realize distributed storage<
Distributed Accounting - distributed accountability
from the perspective of hardware, behind the blockchain is a network composed of a large number of information recording stores (such as computers, etc.). How does this network record all the value exchange activities in the network? Instead of reserving a specific place for professional accounting recorders, blockchain designers hope to establish a distributed accounting system in which everyone can participate in recording information through the voluntary principle, so as to decentralize the accounting responsibility and let all participants in the whole network record together
every new transaction in the blockchain spreads in a distributed structure. According to the P2P network layer protocol, messages are sent directly from a single node to all other nodes in the whole network
blockchain technology enables all data in the database to be stored in all computer nodes of the system and updated in real time. The completely decentralized structure enables the data to be recorded in real time and updated in each network node participating in data storage, which greatly improves the security of the database
through the three "distributions" of Distributed Accounting, distributed communication and distributed storage, we can find that no one, no organization or even no country can control the system, and the data storage, transaction verification and information transmission process in the system are all decentralized. In the absence of a center, large-scale participants reached a consensus and jointly built a blockchain database. It can be said that this is the first time in human history to build a truly decentralized system. It can even be said that the blockchain technology has built an immortal system - as long as not all the participating nodes in the network collectively collapse at the same time, the database system can continue to run
now that we have a rigorous database and a protocol available for recording and storing this database, when we apply this database to the actual society, we have to solve the core problem (problem 3): how to make this rigorous and completely stored database reliable, So that we can successfully prevent fraud in the context of Internet without real name
technology 3: asymmetric encryption algorithm
what is asymmetric encryption? In short, it allows us to use two passwords in the process of "encryption" and "decryption". The two passwords have asymmetric characteristics: (1) the encryption password (known as the "public key" in the blockchain) is public and visible throughout the network, and everyone can use their own public key to encrypt a piece of information (the authenticity of information) 2) The password (called "private key" in the blockchain) ring decryption is only known by the information owner, and the encrypted information can only be decrypted by the person who has the corresponding private key (Information Security)
simple summary: in the blockchain system, the basis of ownership verification mechanism is asymmetric encryption algorithm. Common asymmetric encryption algorithms include RSA, ElGamal, D-H, ECC (elliptic curve encryption algorithm), etc. In asymmetric encryption algorithm, if two keys in a "key pair" satisfy the following two conditions: 1; 2. When one of the keys is public, no one can calculate the other according to the public key, then we call this key pair asymmetric key pair, the public key is called public key, and the secret key is called private key. In the transaction of blockchain system, there are two basic usage scenarios of asymmetric key: 1. The public key encrypts the transaction information, and the private key decrypts the transaction information. After decryption, the private key holder can use the value received. 2. The private key signs the information and the public key verifies the signature. The information verified by the public key signature is sent to the private key holder
we can see that from the perspective of trust, blockchain is actually the proct of mathematical methods to solve trust problems. In the past, people relied on the "villagers" in acquaintance society, the "comrades" in the party society, and the "Alipay" in the traditional Internet trading platform. In blockchain technology, all rules are expressed in the form of algorithm program in advance. People don't need to know whether the opposite party of the transaction is a "gentleman" or a "villain", and they don't need to turn to a centralized third-party organization for transaction endorsement. They just need to trust the mathematical algorithm to establish mutual trust. Behind the blockchain technology, in essence, algorithms are creating credit for people and reaching consensus endorsement
technology 4: script
script can be understood as a programmable smart contract. If the blockchain technology is only to adapt to a specific transaction, the script embedding is unnecessary. The system can directly define the conditions that need to be met to complete the value exchange activities. However, in a decentralized environment, all agreements need to be agreed in advance,
about how to build a rigorous database, the blockchain method is to innovate the structure of the database, divide the data into different blocks, link each block to the back of the previous block through specific information, and present a complete set of data in sequence, which is also the source of the three words "blockchain"
block: in blockchain technology, data is stored permanently in the form of electronic records, and the files in which these electronic records are stored are called "blocks". Blocks are generated one by one in chronological order. Each block records all the value exchange activities ring its creation, and all blocks are combined to form a record set
block structure: the transaction data in the block generation period will be recorded in the block, and the block body is actually a collection of transaction information. The structure design of each blockchain may not be exactly the same, but the large structure is divided into two parts: header and body. The block head is used to link to the previous block and guarantee the integrity of the blockchain database. The block body contains all the verified records of value exchange ring the block creation process
Bubi blockchain: it uses cryptography provable algorithm to build multi center network trust, which is open, transparent, tamper proof and revocable; Multi party participation in information transparent sharing, the establishment of authentic traceability chain path, direct to consumers
the block structure has two very important characteristics: first, the transactions recorded on each block are all the value exchange activities after the formation of the previous block and before the creation of the block, which ensures the integrity of the database. Second, in most cases, once a new block is added to the end of the blockchain, the data record of the block can no longer be changed or deleted. This feature ensures the rigor of the database, that is, it cannot be tampered with
as the name suggests, blockchain is the combination of blockchains. The database formed in this way is called blockchain database. Blockchain is a transaction database shared by all nodes in the system. These nodes participate in the network of blockchain based on value exchange protocol
how does blockchain work? Because the block head of each block contains the transaction information compression value of the previous block, it makes the connection from the genesis block (the first block) to the current block form a long chain. Since there is no way to generate the current block if the "transaction miniature" value of the previous block is not known, each block must follow the previous block in chronological order. The structure that all blocks contain the previous block reference makes the existing block set form a long data chain
summarizes the basic structure of blockchain: "people pack the information (including data or code) generated in a period of time into a block, stamp it with a time stamp, and connect it with the previous block. The page capital of each next block contains the index data of the previous block, and then write new information in this page, so as to form a new block, end to end, Finally, a blockchain was formed. " The magic of this structure: block (Complete History) + Chain (complete verification) = timestamp
"block + Chain" structure provides us with a complete history of the database. From the first block to the latest block, all the historical data of the system are stored in the blockchain
blockchain provides us with the function of searching every data in the database. Every transaction data on the blockchain can be traced back to its origin and verified one by one through the structure of the "blockchain"
blockchain = timestamp, which is the biggest innovation of blockchain database. The blockchain database allows the network wide recorders to stamp a time stamp in each block for accounting, indicating that the information is written at this time, forming a database that cannot be tampered with or forged. We believe that timestamp is a great technological innovation in blockchain. What can it prove<
Technology 2: distributed structure - open source, decentralized protocol
after we have the data of block + chain, we need to consider the problem of record and storage. Who should we let to participate in the data recording, and where should we store the time stamped data? In today's centralized system, data are centrally recorded and stored on the central computer. However, the ingenious design of the blockchain structure is here. It does not agree to record and store data on one or several centralized computers. Instead, it allows every node participating in data transaction to record and store all data
1. As for how to make all nodes participate in the recording, the method of blockchain is to build a complete set of protocol mechanism, so that each node in the whole network can participate in the recording and verify the correctness of the recording results of other nodes at the same time. Only when most nodes (or even all nodes) in the whole network think that the record is correct at the same time, or all nodes participating in the record are consistent with the comparison results, the authenticity of the record can be recognized by the whole network, and the record data can be written into the block
2. As for how to store the rigorous database of "blockchain", the method of blockchain is to build a distributed network system, so that all the data in the database can be updated in real time and stored in all the network nodes participating in the records. In this way, even if some nodes are damaged or attacked by hackers, the data record and information update of the whole database will not be affected
according to the open source and decentralized protocol determined by the system, the blockchain constructs a distributed architecture, which enables the information of value exchange to be transmitted to the whole network through distributed propagation, determines the content of information and data through distributed accounting, generates block data after stamping it with time stamp, and then sends it to each node through distributed propagation to realize distributed storage<
Distributed Accounting - distributed accountability
from the perspective of hardware, behind the blockchain is a network composed of a large number of information recording stores (such as computers, etc.). How does this network record all the value exchange activities in the network? Instead of reserving a specific place for professional accounting recorders, blockchain designers hope to establish a distributed accounting system in which everyone can participate in recording information through the voluntary principle, so as to decentralize the accounting responsibility and let all participants in the whole network record together
every new transaction in the blockchain spreads in a distributed structure. According to the P2P network layer protocol, messages are sent directly from a single node to all other nodes in the whole network
blockchain technology enables all data in the database to be stored in all computer nodes of the system and updated in real time. The completely decentralized structure enables the data to be recorded in real time and updated in each network node participating in data storage, which greatly improves the security of the database
through the three "distributions" of Distributed Accounting, distributed communication and distributed storage, we can find that no one, no organization or even no country can control the system, and the data storage, transaction verification and information transmission process in the system are all decentralized. In the absence of a center, large-scale participants reached a consensus and jointly built a blockchain database. It can be said that this is the first time in human history to build a truly decentralized system. It can even be said that the blockchain technology has built an immortal system - as long as not all the participating nodes in the network collectively collapse at the same time, the database system can continue to run
now that we have a rigorous database and a protocol available for recording and storing this database, when we apply this database to the actual society, we have to solve the core problem (problem 3): how to make this rigorous and completely stored database reliable, So that we can successfully prevent fraud in the context of Internet without real name
technology 3: asymmetric encryption algorithm
what is asymmetric encryption? In short, it allows us to use two passwords in the process of "encryption" and "decryption". The two passwords have asymmetric characteristics: (1) the encryption password (known as the "public key" in the blockchain) is public and visible throughout the network, and everyone can use their own public key to encrypt a piece of information (the authenticity of information) 2) The password (called "private key" in the blockchain) ring decryption is only known by the information owner, and the encrypted information can only be decrypted by the person who has the corresponding private key (Information Security)
simple summary: in the blockchain system, the basis of ownership verification mechanism is asymmetric encryption algorithm. Common asymmetric encryption algorithms include RSA, ElGamal, D-H, ECC (elliptic curve encryption algorithm), etc. In asymmetric encryption algorithm, if two keys in a "key pair" satisfy the following two conditions: 1; 2. When one of the keys is public, no one can calculate the other according to the public key, then we call this key pair asymmetric key pair, the public key is called public key, and the secret key is called private key. In the transaction of blockchain system, there are two basic usage scenarios of asymmetric key: 1. The public key encrypts the transaction information, and the private key decrypts the transaction information. After decryption, the private key holder can use the value received. 2. The private key signs the information and the public key verifies the signature. The information verified by the public key signature is sent to the private key holder
we can see that from the perspective of trust, blockchain is actually the proct of mathematical methods to solve trust problems. In the past, people relied on the "villagers" in acquaintance society, the "comrades" in the party society, and the "Alipay" in the traditional Internet trading platform. In blockchain technology, all rules are expressed in the form of algorithm program in advance. People don't need to know whether the opposite party of the transaction is a "gentleman" or a "villain", and they don't need to turn to a centralized third-party organization for transaction endorsement. They just need to trust the mathematical algorithm to establish mutual trust. Behind the blockchain technology, in essence, algorithms are creating credit for people and reaching consensus endorsement
technology 4: script
script can be understood as a programmable smart contract. If the blockchain technology is only to adapt to a specific transaction, the script embedding is unnecessary. The system can directly define the conditions that need to be met to complete the value exchange activities. However, in a decentralized environment, all agreements need to be agreed in advance,
3. Millions of fans have no official account in China. It's already very good. You can make money by advertising, or you can join Tencent's traffic owners and put wechat ads to make money
4. How is that possible? You'd better not believe this kind of false information. If you can't get it right, you'll have to pay for it yourself
5. The shearer of Shandong Zhongmei company is suitable for mining height of 1.4-2.4m and inclination angle of less than 30 °， Longwall coal mining face with medium hard or less hard coal seam and a small amount of stone inclusion. The electrical equipment of the shearer meets the requirements of mine explosion-proof regulations, and can be used in mines where the methane, coal st, hydrogen sulfide and carbon dioxide in the surrounding air do not exceed the safety content specified in "coal mine safety regulations". The shearer can be matched with hydraulic support and scraper conveyor, which can realize comprehensive mechanized coal mining in the working face. In addition, because the shearer body is short and narrow, it can also be matched with single hydraulic prop, metal hinged top beam and working face conveyor, which can realize high-grade mechanized coal mining in the working face.
6.
Meitu company has bought a large number of virtual currencies before, but now the price of virtual currencies has skyrocketed, so the value of this reserve currency has also risen a lot according to media statistics, since last year, Meitu has started to invest in cryptocurrency with its reserve currency. Although it has invested in more than one cryptocurrency, Meitu has accumulated more than US $100 million in cryptocurrency. Coincidentally, ring this period, the price of cryptocurrency has been rising again and again, so Meitu has made a lot of profits by investing in cryptocurrency. The chairman of the board of directors even said with great pride that Meitu should be the first company in Hong Kong to use cryptocurrency as its reserve currency
7. 1. The longest fully mechanized working face in China is reported to be the longest 360 meter extended working face in China, which was built in Yujialiang coal mine of Shenhua Shendong mining area in September 2005. The strike length of 44206 fully mechanized working face in 4-2 coal seam of Yujialiang coal mine is 1762m, the average mining height is 3.3m, the recoverable reserves is 2.69 million tons, and the strike of coal seam is gentle
2. Generally speaking, the length of fully mechanized working face in China is 150m or 240m
if the cut length of the fully mechanized working face you designed is too long, is there any problem in the matching of the three machines, and is the mine pressure law appropriate? Is there a complete set of equipment such as shearer options, support selection, scraper conveyor and transfer capacity? In addition, you may be engaged in mine design or mining area design, your geological conditions permit
in addition, the most important thing is that you are in a high gas mine. On the premise that the three machines you use are matched, have you calculated the haulage speed of the shearer, the exposure of the coal wall, and the gas emission? Whether the ventilation is reasonable, whether the gas can be diluted normally and kept in a reasonable range? Ventilation capacity must be checked. According to my experience, I estimate that under the condition of super long working face and high gas, the ventilation capacity is a problem, which is impossible at all
these are all problems that need to be solved
I suspect that you are in the great leap forward and launching satellites. If you hand in your design, you may be questioned by the teacher. For reference only.
2. Generally speaking, the length of fully mechanized working face in China is 150m or 240m
if the cut length of the fully mechanized working face you designed is too long, is there any problem in the matching of the three machines, and is the mine pressure law appropriate? Is there a complete set of equipment such as shearer options, support selection, scraper conveyor and transfer capacity? In addition, you may be engaged in mine design or mining area design, your geological conditions permit
in addition, the most important thing is that you are in a high gas mine. On the premise that the three machines you use are matched, have you calculated the haulage speed of the shearer, the exposure of the coal wall, and the gas emission? Whether the ventilation is reasonable, whether the gas can be diluted normally and kept in a reasonable range? Ventilation capacity must be checked. According to my experience, I estimate that under the condition of super long working face and high gas, the ventilation capacity is a problem, which is impossible at all
these are all problems that need to be solved
I suspect that you are in the great leap forward and launching satellites. If you hand in your design, you may be questioned by the teacher. For reference only.
8. Coal mine safety regulation sixty-ninth provision:
shearer must install internal and external spray device. When the coal is cut off, spray must be used to rece st. The spray pressure should not be less than 2MPa, and the spray pressure should not be less than 1.5MPa. The spray flow should match the model. If the internal spray device is not properly sprayed, the external spray pressure should not be less than 4MPa. When the water or spray device is damaged, it must be shut down.
shearer must install internal and external spray device. When the coal is cut off, spray must be used to rece st. The spray pressure should not be less than 2MPa, and the spray pressure should not be less than 1.5MPa. The spray flow should match the model. If the internal spray device is not properly sprayed, the external spray pressure should not be less than 4MPa. When the water or spray device is damaged, it must be shut down.
9. 300 refers to the cutting power of a single rocker arm. The total power of two rocker arms is 300 * 2 = 600. The others should be 40 * 2 traction power, and 20 is the power of raising. The total power is 700, that is 300 / 700. WD refers to chainless electric traction
10. I'll give you the web address, and I'll do it myself. If you can't, give me the mailbox< br /> http://wenku..com/view/d14821dec1c708a1284a4432.html
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