Mechanical calculation

1. Special types of work are those engaged in underground, high altitude, high temperature, heavy physical work and toxic and harmful work. If the bricklayer is engaged in high-rise construction and works at height, it is a special type of work. If only engaged in ordinary housing construction and low altitude work, it is not a special type of work
clay workers are engaged in the construction engineering instry, building houses and engaging in decoration. They are specialized in pasting ceramic tiles and floor tiles, building seals, plastering walls, and all the buildings in contact with mud and water
special type of work refers to the general term for special post work, which is prone to casualties and has great harm to the safety of operators, others and surrounding facilities. The former Ministry of labor of the people's Republic of China defined the types of work engaged in underground, high altitude, high temperature, heavy manual labor and toxic and harmful work as special types of work, and made it clear that the scope of special types of work should be determined by the competent departments or labor departments of various instries.

2. Hello, I'm an old worker of Cheng 107 mailbox. You should be talking about general workers. General workers (porters, universal workers, etc.) are not special types of work. The common types of special harmful work are welders, painters, special operations (nuclear power, chemistry) and so on. Generally, only outdoor high temperature subsidies are available for mechanical workers. Please accept it. Thank you.

3. Is the vertical work of a pesticide factory a special type of work? Also need the appraisal of labor security department

4. It's transliterated. Ethernet

Ethernet is a low-level network protocol, which usually operates in the physical layer and data link layer of OSI model. It is the most common coaxial cable system with data rate of 10Mbps in bus protocol. The system is relatively cheap and easy to install. By directly using the bnc-t connector on each workstation network card, the cable can be connected from one workstation to another to complete the network transmission control task
History
the initial progress of Ethernet technology comes from one of many pioneer technology projects of Xerox Palo Alto Research Center. Ethernet is generally believed to have been invented in 1973, when Robert Metcalfe wrote a memo to his Parc boss about the potential of Ethernet. But Metcalfe himself believes that Ethernet came into being only a few years later. In 1976, Metcalf and his assistant David Boggs published an article entitled "Ethernet: distributed packet switching technology for local computer networks"
in 1979, Metcalf left Xerox to develop personal computers and local area networks and founded 3Com. 3com lobbied digito, Intel, and Xerox to work with them to standardize Ethernet. This general Ethernet standard was issued on September 30, 1980. At that time, there were two popular non-public network standards, token ring network and ARCNET. Under the impact of the tide of Ethernet, they were quickly shrunk and replaced. In this process, 3Com has become an international company
Metcalf once joked that Jerry saltzer contributed to 3Com's success. Saltzer pointed out in an influential paper that token ring network is superior to Ethernet in theory. Influenced by this conclusion, many computer manufacturers are hesitant or decide not to use Ethernet interface as the standard configuration of the machine, so 3Com will have the opportunity to make a big profit from selling Ethernet network card. This situation also leads to another saying that "Ethernet is not suitable for theoretical research, but only for practical application". Maybe it's just a joke, but it illustrates such a technical viewpoint: generally, the actual data flow characteristics in the network are different from the estimation before the popularity of LAN, and it is the simple structure of Ethernet that makes LAN popular. Metcalfe and saltzer worked on the same floor of the MAC project at MIT when he was working on his Harvard thesis, laying the theoretical foundation for Ethernet technology
Ethernet. It refers to the baseband LAN specification created by Xerox and jointly developed by Xerox, Intel and Dec. Ethernet uses CSMA / CD (carrier sense multiple access and conflict detection) technology, and runs on various types of cables at the rate of 10m / s. Ethernet is similar to IEEE802.3 series standard
it is not a specific network, but a technical specification
Ethernet is the most common communication protocol standard used in LAN nowadays. This standard defines the cable types and signal processing methods used in local area networks (LANs). Ethernet transmits packets at the rate of 10 ~ 100Mbps between interconnected devices. Twisted pair cable 10base t Ethernet has become the most widely used Ethernet technology because of its low cost, high reliability and 10Mbps rate. DSSS wireless Ethernet can reach 11Mbps, and many procts provided by manufacturers can use common software protocol for communication, with the best openness.

5. English: in late 1972, Metcalfe and his Xerox PARC libraries developed the first experimental Ethernet
system to connect the Xerox Alto. The Experimental Ethernet was used to link Altos to one
another, and to servers and laser printers; s system clock, which resulted in a data transmission rate on the
experimental Ethernet of 2.94 Mbps.
Metcalfe' s first experimental network was called the Alto Aloha Network. In 1973, Metcalfe
changed the name to " Ethernet," to make it clear that the system could support any computer—not
just Altos—and to point out that his new network mechanisms had evolved well beyond the Aloha
system. He chose to base the name on the word " ether" as a way of describing an essential feature
of the system: the physical medium (i.e., a cable) carries bits to all stations, much the same way that
the old " luminiferous ether" Was once thought to propagate electromagnetic waves through space. *
thus, Ethernet was born.
Chinese: at the end of 1972, Metcalfe and his colleagues at Xerox park developed the first experimental Ethernet
system interconnection Xerox bass. The Experimental Ethernet was used to connect the ertos one
in addition to the server and the laser printer. The clock signal is the system clock of the Experimental Ethernet interface
from the bass, which results in the data transmission rate
between 2.94 Mbps of the Experimental Ethernet
the first experimental network of invertebrate Metcalfe is called Alto Aloha network. In 1973, the name of Metcalfe
was changed to & quot; Ethernet & quot, To make it clear that the system can support any computer without
galtos -, and point out that his new network mechanism has evolved far beyond the Aloha
system. He chose the name of the base and changed it to & quot; Ether & quot; A way to describe one of my basic characteristics
the system: physical media (such as cable TV) all stations with drill bit, many in the same way
Old & quot; Luminiferous methyl ether, It's a propaganda of ideas. Electromagnetic waves pass through space. *
therefore, Ethernet is born
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6. According to the "classification of physical labor intensity", the average energy consumption of 8-hour workday is 7310.2 kJ / person, and the labor time rate is 73%, that is, the net labor time is 350 minutes, which is equivalent to heavy labor
the arm and trunk work with loads, such as lifting heavy objects, shoveling, hammering, sawing or chiseling hardwood, mowing, digging, etc.

7. According to the "classification of physical labor intensity", the average energy consumption of 8-hour workday is 7310.2 kJ / person, and the labor time rate is 73%, that is, the net labor time is 350 minutes, which is equivalent to heavy labor. Arm and trunk load work, such as lifting heavy objects, shoveling, hammering, sawing or chiseling hardwood, mowing, digging, etc.

8. The origin of Ethernet

Ethernet is a LAN networking specification developed by Xerox, digital equipment and Intel. It was first published in the early 1980s and is called dix1.0. The revised version in 1982 is dix2.0. These three companies submitted this specification to IEEE 802 Committee, which was revised and approved by IEEE members, and became the formal standard of IEEE, and numbered IEEE802.3. Although Ethernet and IEEE802.3 have many different regulations, the term Ethernet is generally considered compatible with 802.3. IEEE submitted 802.3 standard to Joint Technical Committee 1 (JTC1) of international organization for Standardization (ISO)
overview of Ethernet
Ethernet is the most common communication protocol standard used in current LAN, which was established in the early 1970s. Ethernet is a common LAN standard with transmission rate of 10Mbps. In Ethernet, all computers are connected to a coaxial cable. The CSMA / CD method with collision detection is adopted. The competition mechanism and bus topology are adopted. Basically, Ethernet consists of shared transmission media, such as twisted pair cable or coaxial cable, and multiport hubs, bridges, or switches. In a star or bus configuration, a hub / switch / bridge connects computers, printers, and workstations to each other through cables. The general characteristics of Ethernet are summarized as follows:
shared media: all network devices use the same communication media in turn
broadcast domain: the frame to be transmitted is sent to all nodes, but only the addressed node receives the frame
CSMA / CD: Carrier Sense Multiple Access / collision detection is used in Ethernet to prevent twp or more nodes from sending at the same time
MAC address: all Ethernet network interface cards (NICS) in MAC layer adopt 48 bit network address. This kind of address is unique in the world. Ethernet basic network composition:
shared media and cable: 10baset (twisted pair), 10base-2 (thin coaxial cable), 10BASE-5 (thick coaxial cable)
repeater or hub: a hub or hub is a type of device used to receive a large number of Ethernet connections on network devices. The data obtained by the receiving parties through a certain connection is reused and sent to all the connecting devices in the transmitting parties to obtain the transmitting device
bridge: the bridge belongs to the second layer equipment, which is responsible for dividing the network into independent conflict domains and segments, so as to achieve the goal of maintaining broadcasting and sharing in the same domain / segment. The bridge includes a table covering all segments and forwarding frames to ensure normal communication within and around segments
switch: switch, the same as bridge, belongs to the second layer device, and is a multi port device. The function supported by the switch is similar to the bridge, but it has the advantage over the bridge that it can temporarily connect any two ports together. The switch includes a switching matrix through which ports can be quickly connected or disconnected. Unlike a hub, a switch only forwards frames from one port to other connected target nodes and does not contain broadcast ports. Ethernet protocol: Ethernet frame structure is provided in IEEE 802.3 standard. Currently, Ethernet supports four transmission rates supported by optical fiber and twisted pair media:
10 Mbps – 10Base-T Ethernet (802.3)
100 Mbps – Fast Ethernet (802.3u)
1000 Mbps – Gigabit Ethernet (802.3z))
10 Gigabit Ethernet – IEEE 802.3ae

9. Ether in Ethernet can be regarded as that all forces between objects must be transferred through some intermediate medium, and there is no over distance effect. The information is just like this. As for the difference between Ethernet and other LANs, such as token return network, Ethernet uses carrier monitoring, multiple access and conflict detection technology