How big is the smallest single block chain
(1) distributed ledger, that is, transaction bookkeeping is completed by multiple nodes distributed in different places, and each node records complete accounts, so they can participate in monitoring the legitimacy of transactions, At the same time, they can testify together
different from traditional distributed storage, the uniqueness of distributed storage of blockchain is mainly reflected in two aspects: one is that each node of blockchain stores complete data according to block chain structure, while traditional distributed storage generally stores data in multiple copies according to certain rules. Second, the storage of each node in the blockchain is independent and has the same status, which relies on the consensus mechanism to ensure the consistency of storage, while the traditional distributed storage generally synchronizes data from the central node to other backup nodes[ 8]
no single node can record the account data separately, so as to avoid the possibility that a single bookkeeper is controlled or bribed to record false accounts. In theory, unless all the nodes are destroyed, the accounts will not be lost, so as to ensure the security of the account data
(2) asymmetric encryption and authorization technology, the transaction information stored on the blockchain is public, but the account identity information is highly encrypted, which can only be accessed under the authorization of the data owner, thus ensuring the data security and personal privacy
(3) consensus mechanism is how to reach a consensus among all accounting nodes to determine the validity of a record, which is not only a means of identification, but also a means of preventing tampering. Blockchain proposes four different consensus mechanisms, which are suitable for different application scenarios and achieve a balance between efficiency and security
the consensus mechanism of blockchain has the characteristics of "the minority is subordinate to the majority" and "everyone is equal", in which "the minority is subordinate to the majority" does not completely refer to the number of nodes, but also can be the computing power, the number of shares or other characteristics that can be compared by computers“ "Everyone is equal" means that when the nodes meet the conditions, all nodes have the right to put forward the consensus results first, and then directly recognized by other nodes, and finally may become the final consensus results. Taking bitcoin as an example, the workload proof is adopted. Only when more than 51% of the accounting nodes in the whole network are controlled can a nonexistent record be forged. When there are enough nodes in the blockchain, this is basically impossible, thus eliminating the possibility of fraud.
(4) smart contract, which is based on these trusted and tamperable data, can automatically execute some pre-defined rules and terms. Take insurance as an example. If everyone's information (including medical information and risk occurrence information) is true and reliable, it is easy to carry out automatic claim settlement in some standardized insurance procts
From the current technology, the next bitcoin in the bitcoin data structure can be divided into 8 decimal places, so the minimum unit of bitcoin is 0.00000001btc, but the transaction can not be so small
according to the statistics of bitbao, at present, the common minimum trading unit of bitcoin trading platform in China is 0.01btc, so the 0.0001 proposed by the owner is not available for sale< br />
Deflection refers to the linear displacement of the axis of the member perpendicular to the axis or the central plane of the shell perpendicular to the central plane when the force or non-uniform temperature changes
the deflection of slender body (such as beam or column) refers to the displacement of each point on its axis in the normal plane of the axis at that point. The deflection of thin plate or shell refers to the displacement of each point on the middle plane normal at this point. The rule that the deflection of each point on the object changes with position and time is called deflection function or displacement function
the deflection observation of building includes the deflection observation of building foundation, building main body and independent structure (such as independent wall and column). For high-rise buildings, when there is a large concentrated load on a small area, it may lead to the settlement of the foundation and buildings. The uneven settlement will lead to the inclination of the building, the bending of local components and the generation of cracks
extended data
1. Deflection calculation formula: ymax = 5ql ^ 4 / (384ei) (EI is the bending stiffness of beam under uniform load q)
deflection is related to load size, member section size and material physical properties of member
Deflection the linear displacement of the centroid of the cross section along the direction perpendicular to the axis ring bending deformation is called deflection γ Expressionrotation angle the angle at which the cross section turns relative to its original position ring bending deformation is called rotation angle θ Expression
The traditional bridge deflection measurement mostly uses dial indicator or displacement meter to measure directly, which is still widely used in bridge maintenance, old bridge safety assessment or new bridge acceptanceit's convenient to buy and sell on the phone and online
a blockchain is a distributed database maintained by the collective formed by cryptography.