Member of enterprise Ethereum Alliance
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about the variability of blockchain
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eth, if most people agree to modify the chain, that is, variability, then they can modify the blockchain records and contracts
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etc, blockchain records and contracts can't be modified, that is, they can't be tampered with
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here are the advantages and disadvantages of the two methods
The advantage of -
variability is that people can make timely changes to make the right decisions. Therefore, modifying the specification is more practical than finding loopholes
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non modifiability means that no matter how smart people are at that time, it is impossible not to make mistakes. Therefore, when problems arise in this scheme, it is best to find and solve the loopholes through the existing legal framework
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differences in development
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eth, whether it is intentionally arranged or since its birth, the core decisions of blockchain are made by Ethereum foundation with the participation of the community and most of them are developed by it
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etc, the decision-making of blockchain is mainly decided by the feedback of three loose, collaborative teams with community participation
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in any case, anyone can put forward improvement suggestions for the two kinds of blockchains. This is the benefit of open source, and it is also very common. You will find that developers of the two chains communicate with each other through GitHub and reddit. I hope to improve the frequency of communication in order to achieve the common goal
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about compatibility
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at present, the two kinds of blockchains are compatible with each other. Contracts or applications written by eth can be applied on etc, and vice versa
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eth, focusing on ewasm, is committed to providing a platform for more and more developers, while the issue of contract security is secondary, such as viper
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etc focuses on making developers create more secure contracts, such as viper, iohk research, at the cost of consuming the number of potential developers
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it's obvious that both chains can accept each other, regardless of whether their wishes are the same or not. My view is that the number of developers is not necessarily related to the quality of the proct
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about the transaction speed
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eth, the average is 25 seconds, which will be shortened after upgrading
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etc, with an average time of 14 seconds, maintained at 10-14 seconds after upgrade, according to ecip-1010 and ecip-1036 protocols
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about the block capacity
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eth, with the daily trading volume of eth graally reaching 5 million, the block capacity is graally saturated. This situation is similar to the recent transaction cost of bitcoin. This problem can be solved by expanding the block capacity by increasing the default fuel limit
ETC， At present, there is still a lot of room for block capacity. As more and more people accept etc, the block capacity will also increase, just like eth
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about community
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eth, mainly discuss on reddit
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etc, mainly discuss on slack
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about monetary policy
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eth, the planned supply is growing steadily, resulting in an average inflation of 3% in eth blockchain in its life cycle
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etc, before 2025, inflation will reach 3%, and then the total supply will reach 200 million etc, and then there will be deflation
As for the regional distribution of trading volume, China accounts for 20%, South Korea 25% and the United States 25% In etc, China accounts for 50%, South Korea 25% and the United States 10% About securities, at present, investors do not have the option to trade securities. Recently, one of eth's ETFs, trading open-end index funds, was denied by the regulators -
etc owns etc trading trust, which allows investors to own etc instead of the asset itself
money circle, one day, ten years on earth
the high housing prices destroyed the post-80s and post-90s
and then the world came back. Today's virtual currency
the post-80s also pulled back a round. Whether it is worth buying is not to see whether its current price is high or low
but to see whether it has value in the future and whether it will be useful for everyone's life There must be only a few bitcoins in total.
bitcoin has become a kind of value preservation proct corresponding to gold
decentralized anonymity advantage
bitcoin comparable to gold
moreover, more and more businesses have accepted bitcoin transactions
some institutions have also accepted bitcoin donations, and bitcoin ATM has become a hot topic Put into use
the second is
Ethereum (ETH)
it can be said that it is an evolutionary version of bitcoin
bitcoin is gold, Ethereum is silver
Ethereum's technology can be applied to real world applications
JPMorgan Chase, Microsoft, etc. are all optimistic about Ethereum technology
In my opinion, the most stable return is the twoand the other multifarious currencies have gone up and down sharply. Ordinary people's hearts can't stand
at present, domestic users can buy through this website
transactions
it's not the price rise of the currency but the price rise of the currency through the bar The number of coins is rising
the first stage: the basic theory of blockchain technology is suitable for students who have various needs for blockchain technology. It is the most comprehensive and up-to-date curriculum system at present. With the rapid appreciation of bitcoin, blockchain technology has become more and more sought after and studied by people from all walks of life, Or from the perspective of technology research and development, this set of courses are very suitable for you to download and learn. Schele: Lesson 1 ICO & amp; EOS understands the risks of ICO and ICO projects, How to judge whether an ICO is reliable lesson 2 the past and present of bitcoin blockchain understand the origin and related background knowledge of bitcoin and blockchain lesson 3 cryptography master the necessary knowledge of blockchain related cryptography lesson 4 bitcoin transaction in-depth discussion of what happened behind bitcoin transaction lesson 5 block generation and link in-depth discussion of how blockchain is generated Lesson 6 bifurcation principle of blockchain and how to operate the coins in hand before and after the bifurcation Lesson 7 how does the wallet know how much money I have and how to hold the coins in hand more safely Lesson 8 mining understanding the history and principle of mining, Experience mining in bitcoin regression test environment Lesson 9 blockchain security, understand the security problems of blockchain, how to "steal" other people's money Lesson 10 smart contract learn the principle of blockchain 2.0 smart contract, understand how the smart contract is written and run
2
stage 2: introction to blockchain technology research and development, Blockchain technology is a very popular new technology at present, which is highly praised by large IT companies and experts all over the world. Not long ago, the blockchain technology platform enterprise Ethereum Alliance (EEA) announced its formal establishment, and nearly 30 giants including JPMorgan Chase, Microsoft and Intel joined in. Extremely optimistic about the future of Ethereum. At present, the term blockchain is very popular, but few people really understand blockchain technology. If you no longer want to be a onlooker, you are welcome to learn this course. After learning this course, you can master the following contents: deeply master the blockchain technology, understand what mining is, learn how to build your own blockchain network, how to publish your own applications on your own blockchain network or enterprise Ethernet network, and how to write smart contracts, Blockchain technology applications. This course is based on practical teaching, mainly teaching front-line practical skills, to ensure that students can quickly learn to apply! Timetable: 1. Introction to blockchain 1.1 introction to blockchain technology 1.2 blockchain platform, Ethereum, an open source blockchain technology platform 1.3 Ethereum working principle, Ethereum virtual machine, account 1.4 what can Ethereum do, Blockchain technology application appreciation 1.5 Ethereum white paper 2. Client installation and operation 2.1 client installation 2.2 Ethereum account creation and management 2.3 multi signature account 2.4 Ethereum 3. Ethereum network 3.1 Ethernet network type 3.2 building local private network, User defined Genesis block 3.3 mining on local private network 4. Introction to smart contract programming 4.1 Ethereum multiple private nodes networking 4.2 multiple nodes, Introction to writing, deploying and using smart contracts 4.3 introction to development language solidy 4.4 introction to building development environment 4.5 basic variable types 5.solidy complex variable types 5.1 enumeration 5.2 structure 5.3 mapping 5.4 delete 5.5 common attributes and methods of block and transaction 6.solidy method 6.1 anonymous method 6.2 modifier 7.solidy inheritance and event 8.solidid Y programming practice 8.1 smart contract -- "vote" 9.solidy programming practice 9.1 smart contract -- "create your own token" 9.2 smart contract -- "public auction" 10.decentralized application DAPP project practice 10.1 Ethereum Web3 interface 10.2 building Ethereum online wallet 10.3 building the development framework of truss on Windows
3
Level 3 In addition to video tutorials, we have also collected a number of classic e-books for students to learn and understand the knowledge of blockchain technology. These e-books are expensive, and published relatively new, reading format is very rich, not just PDF kind, suitable for mobile phone installation of common reading software. Lesson schele: 1. How blockchain will redefine the world; 2. Blockchain Society: decoding global application and investment cases of blockchain; 3. Blockchain Revolution: how bitcoin underlying technology changes currency, technology and technology Business and the world 4. Blockchain: from digital currency to credit society 5. Blockchain: technology driven finance 6. Blockchain: Reshaping economy and the world 7. Illustrated blockchain 8. The age of artificial intelligence, A book reads block chain finance "(Internet plus era enterprise management real battle Series) 9." block chain technology guide "10." block chain: define the new pattern of future finance and economy "11." business block chain: open a new era of encryption economy "12." Accenture ":" block chain + "13." bitcoin "
(1) jaw crusher (tiger mouth): the crushing action is to periodically press the movable jaw plate to the fixed jaw plate to crush the ore block in it
(2)
cone crusher: the ore block is between the inner and outer cones, the outer cone is fixed, and the inner cone swings eccentrically to crush or break the ore block
(3)
roller crusher: in the gap between two opposite rotating round rollers, the ore block is mainly subject to continuous crushing, but it also has the function of grinding and stripping, and the toothed roller surface also has the function of splitting
(4)
impact crusher: the ore block is broken by the impact of fast rotating moving parts. Belong to this category can be divided into: hammer crusher; Cage crusher; Impact crusher<
(5)
grinding machine: the ore is crushed by the impact and grinding of grinding medium (steel ball, steel bar, gravel or ore block) in the rotating cylinder
(6)
other types of crushing mills: A. roller mill: crushing materials by rotating rollers< B. disc mill: the disc rotation of vertical axis or horizontal axis is used as crushing part
C. centrifugal mill. High speed rotating parts and medium are used to proce centrifugal force to complete crushing
D. vibration mill. High frequency vibration is proced by the rotating shaft, which makes the medium and material collide with each other to complete the crushing effect. All kinds of crushers have different specifications, different scope of use. At present, jaw crusher or rotary cone crusher are mostly used for coarse crushing in concentrator; The standard cone crusher is used for intermediate crushing; Short head cone crusher is used for fine crushing.
there are 10 grades of steel procts: H40, J55, K55, N80, C75, L80, C90, C95, P110 and q125
proction range: oil casing
4-1 / 2 & quot
to
20 & quot
(usually seamless pipe)
button type: BTC, LTC, STC
for N80 casing, the manufacturer's proction length is R-1 (4.88-7.62m), R-2 (7.62-10.36m) and R-3 (10.36m-longer)
the surface defects of unqualified N80 casing include fish scale fold, slag inclusion fold and slag pit. When choosing the cooperative manufacturer, we should pay more attention to the time and place of the manufacturer
through negotiation between the manufacturer and the demander, submerged arc welded straight seam pipe can be used for large diameter casing (diameter greater than 508mm) used to transport natural gas, gas, oil, water and other liquids and gases
in order to rece the cost, improve the safety and prolong the service life of the casing of the demander, the type of pipe end buckle can be selected as long round thread, partial trapezoidal thread, short round thread and special buckle. The Demander shall specify the type of pipe end buckle in the contract when selecting< The mechanical properties control requirements of N80 raw materials selected by the manufacturer:
in order to make the mechanical properties of N80
grade (36Mn2V)
hot rolled seamless tube meet the API requirements, it is stipulated that the continuous casting slab is heated evenly, the starting rolling temperature is controlled at 1150 ~ 1220
℃, the rolling rhythm is well controlled, and the finishing rolling temperature is 920 ~ 950
℃< N80 oil casing pipe is a kind of seamless steel pipe with high strength and toughness.
the commonly used methods in the world are as follows:
quenching and tempering (including direct quenching and tempering after rolling), normalizing, normalizing +
tempering and tempering after rolling
36Mn2V
is a special steel for N80
grade oil casing, which belongs to microalloyed non quenched and tempered steel. The steel is suitable for processing by temperature control, cooling control and deformation control. The steel pipe can achieve the required performance without quenching and tempering, thus simplifying the proction process and recing the manufacturing cost of steel pipe
the demander's conversion of common units in the inquiry sheet of casing manufacturer: outer diameter 25.4mm = 1in, weight 1.49kg/m
= 1lb / ft, length 1m = 3.28ft.