China is also one of the first countries in the world to discover and utilize oil. In the "Han Shu" written by Ban Gu (32-92 AD) of the Eastern Han Dynasty, it is recorded that "Gao Nu has water that can be ignited". Gaonu is near Yanchang, Shaanxi, and Weishui is a tributary of the
As early as the 10th century BC, ancient civilizations such as ancient Egypt, Babylon and India had collected natural asphalt for construction, anti-corrosion, bonding, decoration, and pharmaceuticals. The ancient Egyptians could even estimate the amount of oil seeping out of oil seedlings . There are also records in cuneiform writing about the extraction of natural
Elemental composition The fundamental reason why petroleum oils vary in appearance and physical properties is that their chemical composition is not identical. Petroleum is neither a simple substance composed of a single element nor a compound composed of two or more elements, but a mixture of various compounds composed of various elements. Therefore, its properties
The representative Daqing Petroleum belongs to low-sulfur paraffin-based petroleum, and most of the exploited oil is low-sulfur paraffin-based. This kind of petroleum has low sulfur content, high wax content, and high freezing point. It can produce high-quality kerosene, diesel oil, solvent oil, lubricating oil and commercial paraffin. Straight-run gasoline has good lead sensitivity. Some petroleum
Petroleum is an industrial term, relative to mineral resources, the commonly referred to as the petroleum industry, is a mineral resource industry. In the process of oil exploration, the oil reserves are calculated and determined according to the degree of exploration and proven conditions. Petroleum reserves are the results of geological exploration and a kind
Petroleum refers to a mixture of gaseous, liquid and solid hydrocarbons in natural occurrence. Petroleum is divided into crude oil, natural gas, natural gas liquid and natural tar, etc., but it is customary to use "oil" as the definition of "crude oil". Petroleum is a viscous, dark brown liquid known as the "blood of industry".
The main functions of the switch include physical addressing, network topology, error checking, frame sequence, and flow control. The switch also has some new functions, such as support for VLAN (virtual local area network), support for link aggregation, and some even have the function of firewall. study: The Ethernet switch understands the MAC address of
Switches work on the second layer of the OSI reference model, the data link layer. The CPU inside the switch will form a MAC table by matching the MAC address with the port when each port is successfully connected. In the future communication, the data packet sent to this MAC address will only be sent