Wubantu configuration Ethereum installation Web3
just like bitcoin, Ethereum is neither controlled nor owned by anyone - it is an open source project created by many people around the world. Different from bitcoin protocol, Ethereum's design is very flexible and adaptable. It is very easy to create new applications on the Ethereum platform. With the release of homestead, anyone can use the applications on this platform safely
Ethereum is a programmable blockchain. It does not give users a series of preset operations, but allows users to create complex operations according to their own wishes. In this way, it can be used as a platform for many types of decentralized blockchain applications
in a narrow sense, Ethereum refers to a series of protocols that define a decentralized application platform. The core of Ethereum is Ethereum virtual machine (EVM), which can encode any complex algorithm. In computer science terminology, Ethereum is "Turing complete.". Developers can use the existing JavaScript and python as the model of other friendly programming languages to create applications running on the Ethereum simulator.
Ethereum is a new and open blockchain platform, which allows anyone to build and use decentralized applications running through blockchain technology in the platform. Like bitcoin, Ethereum is neither controlled nor owned by anyone - it's an open source project created by many people around the world
Different from bitcoin protocol, Ethereum is very flexible and adaptable. It's very easy to create new applications on the Ethereum platform. Anyone can use the applications on the platform safely 
Ethereum is a programmable blockchain. It does not give users a series of preset operations (such as bitcoin trading), but allows users to create complex operations according to their own wishes. In this way, it can be used as a platform for many types of decentralized blockchain applications, including but not limited to cryptocurrency
in a narrow sense, Ethereum refers to a series of protocols that define a decentralized application platform. The core of Ethereum is Ethereum virtual machine (EVM), which can encode any complex algorithm. In computer science terminology, Ethereum is "Turing complete.". Developers can use the existing JavaScript and python as the model of other friendly programming languages to create applications running on the Ethereum simulator
like other blockchains, Ethereum also has a peer-to-peer network protocol. Ethereum blockchain database is maintained and updated by many nodes connected to the network. Each network node runs the Ethereum simulator and executes the same instructions. Therefore, people sometimes call Ethereum "world computer"
this massive parallel operation throughout the Ethernet network is not to make the operation more efficient. In fact, this process makes computing on Ethereum slower and more expensive than on traditional computers. However, each Ethereum node runs Ethereum virtual machine in order to maintain the consistency of the whole blockchain. The consistency of decentralization makes Ethereum have high fault tolerance, zero downtime, and can keep the data stored on the blockchain unchanged and anti censorship
Ethereum platform has no characteristics and value. Like programming languages, it's up to entrepreneurs and developers to decide what to use. However, it is clear that some application types benefit more from the functions of Ethereum than others. Ethereum is especially suitable for those applications that automatically interact directly between points or promote group coordination activities across networks
for example, coordinate the application of point-to-point market, or the automation of complex financial contracts. Bitcoin enables indivials to exchange money without the help of financial institutions, banks or governments. The impact of Ethereum may be more profound
in theory, any complex financial activities or transactions can be automatically and reliably carried out on Ethereum with coding. In addition to financial applications, any application scenario with high requirements for trust, security and persistence, such as asset registration, voting, management and Internet of things, will be affected by Ethereum platform on a large scale
Ethereum Community Foundation (ECF) is a non-profit organization. Its original idea was to give community projects a bonus to support incubation of early projects and research. Then in 2018, omisego, Golem, status, maker, Web3 (Polkadot), cosmos and ef (Ethereum Fund) were set up in Tokyo as consultants
ECF 2.0 is the upgrade of ECF, which has two core goals:
< UL >
coordinate community relations through various harmonious ways, such as bonus, strategic and business support, and community activities
in order to become an open capital network, ECF emphasizes its initial vision, which is to form a network with various funds to realize the support and contribution to the community
In addition, ECF 2.0 upgrade will not only support non-profit infrastructure projects, ecation programs, instrial community activities, but also support application and tool development, and even commercial projectsIf you want to query the transaction records on the main network, you can use Etherscan. However, if you build your own private chain, how should you query the transaction records
the answer is that you need to listen to the logs on the chain, save them in the database, and then query them in the database. For example:
< pre t = "code" L = "Java" > varaddr = & quot& quot;< br />varfilter=web3.eth.filter({fromB lock:0 ,toBlock:' latest', address:addr });< br />filter.get(function(err,transactions){transactions.forEach(function(tx){
vartxInfo=web3.eth.getTransaction(tx.transactionHash);
/ / at this time, the transaction information txinfo can be stored in the database
})< br />});
Web3. Eth. Filter() is used to monitor the log on the chain, and Web3. Eth. Gettransaction() is used to extract the information of the specified transaction. Once the transaction information is obtained, it can be stored in the database for query
recommend a practical introction, you can see: Ethereum tutorial
Percy Jackson is an ordinary 12-year-old boy who was diagnosed with dyslexia and hyperactivity disorder. During a field trip organized by the school, he was interviewed by his algebra teacher; Specific function & quot; Scared me. After that, Percy Jackson found that he was not an ordinary person, but a mythical figure and a descendant of human beings< After discovering the mystery of his life, Percy Jackson was sent to a special school. The children studying in this school are the offspring of many mythical characters. When Percy Jackson came to school, Poseidon immediately declared Jackson his own child. In this school, Percy Jackson met two good friends. One is the beautiful Annabeth chase, the descendant of Athena, the goddess of wisdom and skill; The other is Grover Underwood, a descendant of orcs. Not long in the school, Percy Jackson was accused by the gods of stealing the thunder rod of Zeus. Percy Jackson is required to hand over his thunder wand within 10 days, otherwise, his mother will be killed by these gods, and the war between the gods is inevitable...
there is still one minute left: three discriminated high school students have invented a time machine that allows them to go back in time and change their social status, And help other unfairly treated children to avoid the humiliation of discrimination in high school
twilight 2, new moon and 1 are about vampires. Bella (Kristen Stewart) is 18 years old and her father gives her a gift. Edward (Robert Pattinson) shows her love generously and tells her the legend of the Italian vampire king. Edward's red haired sister Alice (Ashley Greene, Ashley Greene) holds a birthday party specially for Bella. During the party, Bella accidentally cuts her arm and is attacked by Gaspar. Only with Edward's protection can she escape. However, since then, Edward graally alienated Bella and proposed to break up. This makes Bella cold, but Edward also has difficulties, still secretly protect Bella. Bella is in the empty window period, and her old friend Jacob (Taylor Lautner) makes a warm call, which makes their relationship warm up. Since then, Bella because of the cliff rescue, just know that Jacob is a werewolf, specialized in dealing with vampires. At the same time, Edward, who didn't know about it, thought Bella had committed suicide and was disheartened. He came to Italy to ask the royal family to end his life...
bloodthirsty daybreak, I think the ending is a little ironic
2012 is also very good, and the fantasy show of Arthur and his mini kingdom is also very good
As we all know, expectant mothers with medical insurance can claim their own proction expenses
however, there is no social medical insurance for the newborn, so the high hospitalization expenses ring this period can only be paid by themselves
after the birth certificate of the newborns is processed, the BB medical insurance card can be handled at the household registration office.
it is worth noting that, Taking Yuexiu District as an example, it takes about a month from the application to the issuance of BB medical insurance card. The hospitalization expenses of newborns need to be reimbursed within three months, otherwise it will be difficult to recover after expiration
therefore, after the birth of BB, parents should set their names as soon as possible, go through household registration, apply for medical insurance card and other proceres to enjoy medical insurance
here, based on my own experience, I would like to share how to claim the hospitalization expenses of newborns< Proction hospital: Guangzhou Women's and children's Medical Center (Zhujiang New Town women and children)
hospitalization date of neonatal jaundice: March 12 to March 14, 2012, a total of two and a half days
birth cost: 1100 yuan + (living in incubator for one day + nursing cost, etc.)
actual medical insurance return: more than 300 yuan
hospitalization cost of neonatal jaundice: two and a half days, a total of about 2500 yuan + (including, Excluding pathological jaundice, physical examination expenses - B-ultrasound blood test, nursing expenses ring hospitalization, milk powder expenses, etc.) Zhujiang New City women, children and newborns in hospital are not allowed to visit in person, can only watch video at a specified time. Not to send breast milk, the hospital said is to avoid breast milk jaundice
actual medical insurance reimbursement: more than 1500 yuan
note: the proction and hospitalization expenses of the newborn need to be reimbursed to the inpatient department within three months with the newborn's medical insurance card and hospitalization documents (red charge sheet and list of hospitalization expenses). So you'd better think of a good name and go through the entry proceres as soon as possible
reimbursement process of neonatal medical insurance:
the first step is to apply for birth certificate - the mother needs to go to the hospital in person to apply for it, and if she can't come, she needs to write a letter of authorization
required information: bring the original and of both parents' ID cards and household register when handling
processing time: issued on the same day
the second step is to enter the household - the Guangzhou account needs to be handled by the head of household
information: husband and wife account book, household identity card, husband and wife ID card, quasi birth certificate, couple's marriage certificate, BB birth certificate, BB's only child certificate (sole certificate voluntary processing) - the original certificate + two copies, to the administrative center of registered residence.
processing time: issued on the same day
third steps, BB medical insurance
information: BB birth certificate, registered residence book - above certificate original + photo, to the household registration street.
for medical insurance, 80 yuan per year can be paid in cash. For automatic bank transfer, a of the bank card of ICBC or ABC and a of the cardholder's ID card should be submitted< The fourth step is to go to the inpatient department or outpatient department of the hospital for reimbursement.
1. Information required for reimbursement of hospitalization expenses: it can be handled by either parent, with the ID card of the handler, BB birth certificate - two copies of the above documents, BB medical insurance card and original diagnosis and treatment card. List of hospitalization expenses, red charge sheet. Take all the above information to the inpatient department to find the resident at that time to prove that the expenses incurred in hospitalization are true, and then go to the charge Office of the inpatient department for reimbursement. Return the reimbursement cash directly
processing time: return cash on the same day
2. Information required for reimbursement of outpatient expenses: BB diagnosis and treatment card, outpatient red charge sheet. Go to the first floor of Zhujiang New Town to make a list, and then go to the eastern refund window on the second floor. Note: Outpatient can only claim part of the cost of medicine, inspection fee can not be reimbursed
processing time: return cash on the same day